Objects/bytearrayobject.c

/* PyByteArray (bytearray) implementation */

#define PY_SSIZE_T_CLEAN
#include "Python.h"
#include "structmember.h"
#include "bytes_methods.h"
#include "bytesobject.h"
#include "pystrhex.h"

/*[clinic input]
class bytearray "PyByteArrayObject *" "&PyByteArray_Type"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=5535b77c37a119e0]*/

char _PyByteArray_empty_string[] = "";

void
PyByteArray_Fini(void)
{
}

int
PyByteArray_Init(void)
{
    return 1;
}

/* end nullbytes support */

/* Helpers */

static int
_getbytevalue(PyObject* arg, int *value)
{
    long face_value;

    if (PyLong_Check(arg)) {
        face_value = PyLong_AsLong(arg);
    } else {
        PyObject *index = PyNumber_Index(arg);
        if (index == NULL) {
            PyErr_Format(PyExc_TypeError, "an integer is required");
            *value = -1;
            return 0;
        }
        face_value = PyLong_AsLong(index);
        Py_DECREF(index);
    }

    if (face_value < 0 || face_value >= 256) {
        /* this includes the OverflowError in case the long is too large */
        PyErr_SetString(PyExc_ValueError, "byte must be in range(0, 256)");
        *value = -1;
        return 0;
    }

    *value = face_value;
    return 1;
}

static int
bytearray_getbuffer(PyByteArrayObject *obj, Py_buffer *view, int flags)
{
    void *ptr;
    if (view == NULL) {
        PyErr_SetString(PyExc_BufferError,
            "bytearray_getbuffer: view==NULL argument is obsolete");
        return -1;
    }
    ptr = (void *) PyByteArray_AS_STRING(obj);
    /* cannot fail if view != NULL and readonly == 0 */
    (void)PyBuffer_FillInfo(view, (PyObject*)obj, ptr, Py_SIZE(obj), 0, flags);
    obj->ob_exports++;
    return 0;
}

static void
bytearray_releasebuffer(PyByteArrayObject *obj, Py_buffer *view)
{
    obj->ob_exports--;
}

static int
_canresize(PyByteArrayObject *self)
{
    if (self->ob_exports > 0) {
        PyErr_SetString(PyExc_BufferError,
                "Existing exports of data: object cannot be re-sized");
        return 0;
    }
    return 1;
}

#include "clinic/bytearrayobject.c.h"

/* Direct API functions */

PyObject *
PyByteArray_FromObject(PyObject *input)
{
    return PyObject_CallFunctionObjArgs((PyObject *)&PyByteArray_Type,
                                        input, NULL);
}

PyObject *
PyByteArray_FromStringAndSize(const char *bytes, Py_ssize_t size)
{
    PyByteArrayObject *new;
    Py_ssize_t alloc;

    if (size < 0) {
        PyErr_SetString(PyExc_SystemError,
            "Negative size passed to PyByteArray_FromStringAndSize");
        return NULL;
    }

    /* Prevent buffer overflow when setting alloc to size+1. */
    if (size == PY_SSIZE_T_MAX) {
        return PyErr_NoMemory();
    }

    new = PyObject_New(PyByteArrayObject, &PyByteArray_Type);
    if (new == NULL)
        return NULL;

    if (size == 0) {
        new->ob_bytes = NULL;
        alloc = 0;
    }
    else {
        alloc = size + 1;
        new->ob_bytes = PyObject_Malloc(alloc);
        if (new->ob_bytes == NULL) {
            Py_DECREF(new);
            return PyErr_NoMemory();
        }
        if (bytes != NULL && size > 0)
            memcpy(new->ob_bytes, bytes, size);
        new->ob_bytes[size] = '\0';  /* Trailing null byte */
    }
    Py_SIZE(new) = size;
    new->ob_alloc = alloc;
    new->ob_start = new->ob_bytes;
    new->ob_exports = 0;

    return (PyObject *)new;
}

Py_ssize_t
PyByteArray_Size(PyObject *self)
{
    assert(self != NULL);
    assert(PyByteArray_Check(self));

    return PyByteArray_GET_SIZE(self);
}

char  *
PyByteArray_AsString(PyObject *self)
{
    assert(self != NULL);
    assert(PyByteArray_Check(self));

    return PyByteArray_AS_STRING(self);
}

int
PyByteArray_Resize(PyObject *self, Py_ssize_t requested_size)
{
    void *sval;
    PyByteArrayObject *obj = ((PyByteArrayObject *)self);
    /* All computations are done unsigned to avoid integer overflows
       (see issue #22335). */
    size_t alloc = (size_t) obj->ob_alloc;
    size_t logical_offset = (size_t) (obj->ob_start - obj->ob_bytes);
    size_t size = (size_t) requested_size;

    assert(self != NULL);
    assert(PyByteArray_Check(self));
    assert(logical_offset <= alloc);
    assert(requested_size >= 0);

    if (requested_size == Py_SIZE(self)) {
        return 0;
    }
    if (!_canresize(obj)) {
        return -1;
    }

    if (size + logical_offset + 1 <= alloc) {
        /* Current buffer is large enough to host the requested size,
           decide on a strategy. */
        if (size < alloc / 2) {
            /* Major downsize; resize down to exact size */
            alloc = size + 1;
        }
        else {
            /* Minor downsize; quick exit */
            Py_SIZE(self) = size;
            PyByteArray_AS_STRING(self)[size] = '\0'; /* Trailing null */
            return 0;
        }
    }
    else {
        /* Need growing, decide on a strategy */
        if (size <= alloc * 1.125) {
            /* Moderate upsize; overallocate similar to list_resize() */
            alloc = size + (size >> 3) + (size < 9 ? 3 : 6);
        }
        else {
            /* Major upsize; resize up to exact size */
            alloc = size + 1;
        }
    }
    if (alloc > PY_SSIZE_T_MAX) {
        PyErr_NoMemory();
        return -1;
    }

    if (logical_offset > 0) {
        sval = PyObject_Malloc(alloc);
        if (sval == NULL) {
            PyErr_NoMemory();
            return -1;
        }
        memcpy(sval, PyByteArray_AS_STRING(self),
               Py_MIN(requested_size, Py_SIZE(self)));
        PyObject_Free(obj->ob_bytes);
    }
    else {
        sval = PyObject_Realloc(obj->ob_bytes, alloc);
        if (sval == NULL) {
            PyErr_NoMemory();
            return -1;
        }
    }

    obj->ob_bytes = obj->ob_start = sval;
    Py_SIZE(self) = size;
    obj->ob_alloc = alloc;
    obj->ob_bytes[size] = '\0'; /* Trailing null byte */

    return 0;
}

PyObject *
PyByteArray_Concat(PyObject *a, PyObject *b)
{
    Py_ssize_t size;
    Py_buffer va, vb;
    PyByteArrayObject *result = NULL;

    va.len = -1;
    vb.len = -1;
    if (PyObject_GetBuffer(a, &va, PyBUF_SIMPLE) != 0 ||
        PyObject_GetBuffer(b, &vb, PyBUF_SIMPLE) != 0) {
            PyErr_Format(PyExc_TypeError, "can't concat %.100s to %.100s",
                         Py_TYPE(a)->tp_name, Py_TYPE(b)->tp_name);
            goto done;
    }

    size = va.len + vb.len;
    if (size < 0) {
            PyErr_NoMemory();
            goto done;
    }

    result = (PyByteArrayObject *) PyByteArray_FromStringAndSize(NULL, size);
    if (result != NULL) {
        memcpy(result->ob_bytes, va.buf, va.len);
        memcpy(result->ob_bytes + va.len, vb.buf, vb.len);
    }

  done:
    if (va.len != -1)
        PyBuffer_Release(&va);
    if (vb.len != -1)
        PyBuffer_Release(&vb);
    return (PyObject *)result;
}

static PyObject *
bytearray_format(PyByteArrayObject *self, PyObject *args)
{
    if (self == NULL || !PyByteArray_Check(self)) {
        PyErr_BadInternalCall();
        return NULL;
    }

    return _PyBytes_FormatEx(PyByteArray_AS_STRING(self),
                             PyByteArray_GET_SIZE(self),
                             args, 1);
}

/* Functions stuffed into the type object */

static Py_ssize_t
bytearray_length(PyByteArrayObject *self)
{
    return Py_SIZE(self);
}

static PyObject *
bytearray_iconcat(PyByteArrayObject *self, PyObject *other)
{
    Py_ssize_t mysize;
    Py_ssize_t size;
    Py_buffer vo;

    if (PyObject_GetBuffer(other, &vo, PyBUF_SIMPLE) != 0) {
        PyErr_Format(PyExc_TypeError, "can't concat %.100s to %.100s",
                     Py_TYPE(other)->tp_name, Py_TYPE(self)->tp_name);
        return NULL;
    }

    mysize = Py_SIZE(self);
    size = mysize + vo.len;
    if (size < 0) {
        PyBuffer_Release(&vo);
        return PyErr_NoMemory();
    }
    if (PyByteArray_Resize((PyObject *)self, size) < 0) {
        PyBuffer_Release(&vo);
        return NULL;
    }
    memcpy(PyByteArray_AS_STRING(self) + mysize, vo.buf, vo.len);
    PyBuffer_Release(&vo);
    Py_INCREF(self);
    return (PyObject *)self;
}

static PyObject *
bytearray_repeat(PyByteArrayObject *self, Py_ssize_t count)
{
    PyByteArrayObject *result;
    Py_ssize_t mysize;
    Py_ssize_t size;

    if (count < 0)
        count = 0;
    mysize = Py_SIZE(self);
    if (count > 0 && mysize > PY_SSIZE_T_MAX / count)
        return PyErr_NoMemory();
    size = mysize * count;
    result = (PyByteArrayObject *)PyByteArray_FromStringAndSize(NULL, size);
    if (result != NULL && size != 0) {
        if (mysize == 1)
            memset(result->ob_bytes, self->ob_bytes[0], size);
        else {
            Py_ssize_t i;
            for (i = 0; i < count; i++)
                memcpy(result->ob_bytes + i*mysize, self->ob_bytes, mysize);
        }
    }
    return (PyObject *)result;
}

static PyObject *
bytearray_irepeat(PyByteArrayObject *self, Py_ssize_t count)
{
    Py_ssize_t mysize;
    Py_ssize_t size;
    char *buf;

    if (count < 0)
        count = 0;
    mysize = Py_SIZE(self);
    if (count > 0 && mysize > PY_SSIZE_T_MAX / count)
        return PyErr_NoMemory();
    size = mysize * count;
    if (PyByteArray_Resize((PyObject *)self, size) < 0)
        return NULL;

    buf = PyByteArray_AS_STRING(self);
    if (mysize == 1)
        memset(buf, buf[0], size);
    else {
        Py_ssize_t i;
        for (i = 1; i < count; i++)
            memcpy(buf + i*mysize, buf, mysize);
    }

    Py_INCREF(self);
    return (PyObject *)self;
}

static PyObject *
bytearray_getitem(PyByteArrayObject *self, Py_ssize_t i)
{
    if (i < 0)
        i += Py_SIZE(self);
    if (i < 0 || i >= Py_SIZE(self)) {
        PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
        return NULL;
    }
    return PyLong_FromLong((unsigned char)(PyByteArray_AS_STRING(self)[i]));
}

static PyObject *
bytearray_subscript(PyByteArrayObject *self, PyObject *index)
{
    if (PyIndex_Check(index)) {
        Py_ssize_t i = PyNumber_AsSsize_t(index, PyExc_IndexError);

        if (i == -1 && PyErr_Occurred())
            return NULL;

        if (i < 0)
            i += PyByteArray_GET_SIZE(self);

        if (i < 0 || i >= Py_SIZE(self)) {
            PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
            return NULL;
        }
        return PyLong_FromLong((unsigned char)(PyByteArray_AS_STRING(self)[i]));
    }
    else if (PySlice_Check(index)) {
        Py_ssize_t start, stop, step, slicelength, cur, i;
        if (PySlice_GetIndicesEx(index,
                                 PyByteArray_GET_SIZE(self),
                                 &start, &stop, &step, &slicelength) < 0) {
            return NULL;
        }

        if (slicelength <= 0)
            return PyByteArray_FromStringAndSize("", 0);
        else if (step == 1) {
            return PyByteArray_FromStringAndSize(
                PyByteArray_AS_STRING(self) + start, slicelength);
        }
        else {
            char *source_buf = PyByteArray_AS_STRING(self);
            char *result_buf;
            PyObject *result;

            result = PyByteArray_FromStringAndSize(NULL, slicelength);
            if (result == NULL)
                return NULL;

            result_buf = PyByteArray_AS_STRING(result);
            for (cur = start, i = 0; i < slicelength;
                 cur += step, i++) {
                     result_buf[i] = source_buf[cur];
            }
            return result;
        }
    }
    else {
        PyErr_Format(PyExc_TypeError,
                     "bytearray indices must be integers or slices, not %.200s",
                     Py_TYPE(index)->tp_name);
        return NULL;
    }
}

static int
bytearray_setslice_linear(PyByteArrayObject *self,
                          Py_ssize_t lo, Py_ssize_t hi,
                          char *bytes, Py_ssize_t bytes_len)
{
    Py_ssize_t avail = hi - lo;
    char *buf = PyByteArray_AS_STRING(self);
    Py_ssize_t growth = bytes_len - avail;
    int res = 0;
    assert(avail >= 0);

    if (growth < 0) {
        if (!_canresize(self))
            return -1;

        if (lo == 0) {
            /* Shrink the buffer by advancing its logical start */
            self->ob_start -= growth;
            /*
              0   lo               hi             old_size
              |   |<----avail----->|<-----tail------>|
              |      |<-bytes_len->|<-----tail------>|
              0    new_lo         new_hi          new_size
            */
        }
        else {
            /*
              0   lo               hi               old_size
              |   |<----avail----->|<-----tomove------>|
              |   |<-bytes_len->|<-----tomove------>|
              0   lo         new_hi              new_size
            */
            memmove(buf + lo + bytes_len, buf + hi,
                    Py_SIZE(self) - hi);
        }
        if (PyByteArray_Resize((PyObject *)self,
                               Py_SIZE(self) + growth) < 0) {
            /* Issue #19578: Handling the memory allocation failure here is
               tricky here because the bytearray object has already been
               modified. Depending on growth and lo, the behaviour is
               different.

               If growth < 0 and lo != 0, the operation is completed, but a
               MemoryError is still raised and the memory block is not
               shrinked. Otherwise, the bytearray is restored in its previous
               state and a MemoryError is raised. */
            if (lo == 0) {
                self->ob_start += growth;
                return -1;
            }
            /* memmove() removed bytes, the bytearray object cannot be
               restored in its previous state. */
            Py_SIZE(self) += growth;
            res = -1;
        }
        buf = PyByteArray_AS_STRING(self);
    }
    else if (growth > 0) {
        if (Py_SIZE(self) > (Py_ssize_t)PY_SSIZE_T_MAX - growth) {
            PyErr_NoMemory();
            return -1;
        }

        if (PyByteArray_Resize((PyObject *)self,
                               Py_SIZE(self) + growth) < 0) {
            return -1;
        }
        buf = PyByteArray_AS_STRING(self);
        /* Make the place for the additional bytes */
        /*
          0   lo        hi               old_size
          |   |<-avail->|<-----tomove------>|
          |   |<---bytes_len-->|<-----tomove------>|
          0   lo            new_hi              new_size
         */
        memmove(buf + lo + bytes_len, buf + hi,
                Py_SIZE(self) - lo - bytes_len);
    }

    if (bytes_len > 0)
        memcpy(buf + lo, bytes, bytes_len);
    return res;
}

static int
bytearray_setslice(PyByteArrayObject *self, Py_ssize_t lo, Py_ssize_t hi,
               PyObject *values)
{
    Py_ssize_t needed;
    void *bytes;
    Py_buffer vbytes;
    int res = 0;

    vbytes.len = -1;
    if (values == (PyObject *)self) {
        /* Make a copy and call this function recursively */
        int err;
        values = PyByteArray_FromObject(values);
        if (values == NULL)
            return -1;
        err = bytearray_setslice(self, lo, hi, values);
        Py_DECREF(values);
        return err;
    }
    if (values == NULL) {
        /* del b[lo:hi] */
        bytes = NULL;
        needed = 0;
    }
    else {
        if (PyObject_GetBuffer(values, &vbytes, PyBUF_SIMPLE) != 0) {
            PyErr_Format(PyExc_TypeError,
                         "can't set bytearray slice from %.100s",
                         Py_TYPE(values)->tp_name);
            return -1;
        }
        needed = vbytes.len;
        bytes = vbytes.buf;
    }

    if (lo < 0)
        lo = 0;
    if (hi < lo)
        hi = lo;
    if (hi > Py_SIZE(self))
        hi = Py_SIZE(self);

    res = bytearray_setslice_linear(self, lo, hi, bytes, needed);
    if (vbytes.len != -1)
        PyBuffer_Release(&vbytes);
    return res;
}

static int
bytearray_setitem(PyByteArrayObject *self, Py_ssize_t i, PyObject *value)
{
    int ival;

    if (i < 0)
        i += Py_SIZE(self);

    if (i < 0 || i >= Py_SIZE(self)) {
        PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
        return -1;
    }

    if (value == NULL)
        return bytearray_setslice(self, i, i+1, NULL);

    if (!_getbytevalue(value, &ival))
        return -1;

    PyByteArray_AS_STRING(self)[i] = ival;
    return 0;
}

static int
bytearray_ass_subscript(PyByteArrayObject *self, PyObject *index, PyObject *values)
{
    Py_ssize_t start, stop, step, slicelen, needed;
    char *buf, *bytes;
    buf = PyByteArray_AS_STRING(self);

    if (PyIndex_Check(index)) {
        Py_ssize_t i = PyNumber_AsSsize_t(index, PyExc_IndexError);

        if (i == -1 && PyErr_Occurred())
            return -1;

        if (i < 0)
            i += PyByteArray_GET_SIZE(self);

        if (i < 0 || i >= Py_SIZE(self)) {
            PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
            return -1;
        }

        if (values == NULL) {
            /* Fall through to slice assignment */
            start = i;
            stop = i + 1;
            step = 1;
            slicelen = 1;
        }
        else {
            int ival;
            if (!_getbytevalue(values, &ival))
                return -1;
            buf[i] = (char)ival;
            return 0;
        }
    }
    else if (PySlice_Check(index)) {
        if (PySlice_GetIndicesEx(index,
                                 PyByteArray_GET_SIZE(self),
                                 &start, &stop, &step, &slicelen) < 0) {
            return -1;
        }
    }
    else {
        PyErr_Format(PyExc_TypeError,
                     "bytearray indices must be integers or slices, not %.200s",
                      Py_TYPE(index)->tp_name);
        return -1;
    }

    if (values == NULL) {
        bytes = NULL;
        needed = 0;
    }
    else if (values == (PyObject *)self || !PyByteArray_Check(values)) {
        int err;
        if (PyNumber_Check(values) || PyUnicode_Check(values)) {
            PyErr_SetString(PyExc_TypeError,
                            "can assign only bytes, buffers, or iterables "
                            "of ints in range(0, 256)");
            return -1;
        }
        /* Make a copy and call this function recursively */
        values = PyByteArray_FromObject(values);
        if (values == NULL)
            return -1;
        err = bytearray_ass_subscript(self, index, values);
        Py_DECREF(values);
        return err;
    }
    else {
        assert(PyByteArray_Check(values));
        bytes = PyByteArray_AS_STRING(values);
        needed = Py_SIZE(values);
    }
    /* Make sure b[5:2] = ... inserts before 5, not before 2. */
    if ((step < 0 && start < stop) ||
        (step > 0 && start > stop))
        stop = start;
    if (step == 1) {
        return bytearray_setslice_linear(self, start, stop, bytes, needed);
    }
    else {
        if (needed == 0) {
            /* Delete slice */
            size_t cur;
            Py_ssize_t i;

            if (!_canresize(self))
                return -1;

            if (slicelen == 0)
                /* Nothing to do here. */
                return 0;

            if (step < 0) {
                stop = start + 1;
                start = stop + step * (slicelen - 1) - 1;
                step = -step;
            }
            for (cur = start, i = 0;
                 i < slicelen; cur += step, i++) {
                Py_ssize_t lim = step - 1;

                if (cur + step >= (size_t)PyByteArray_GET_SIZE(self))
                    lim = PyByteArray_GET_SIZE(self) - cur - 1;

                memmove(buf + cur - i,
                        buf + cur + 1, lim);
            }
            /* Move the tail of the bytes, in one chunk */
            cur = start + (size_t)slicelen*step;
            if (cur < (size_t)PyByteArray_GET_SIZE(self)) {
                memmove(buf + cur - slicelen,
                        buf + cur,
                        PyByteArray_GET_SIZE(self) - cur);
            }
            if (PyByteArray_Resize((PyObject *)self,
                               PyByteArray_GET_SIZE(self) - slicelen) < 0)
                return -1;

            return 0;
        }
        else {
            /* Assign slice */
            Py_ssize_t i;
            size_t cur;

            if (needed != slicelen) {
                PyErr_Format(PyExc_ValueError,
                             "attempt to assign bytes of size %zd "
                             "to extended slice of size %zd",
                             needed, slicelen);
                return -1;
            }
            for (cur = start, i = 0; i < slicelen; cur += step, i++)
                buf[cur] = bytes[i];
            return 0;
        }
    }
}

static int
bytearray_init(PyByteArrayObject *self, PyObject *args, PyObject *kwds)
{
    static char *kwlist[] = {"source", "encoding", "errors", 0};
    PyObject *arg = NULL;
    const char *encoding = NULL;
    const char *errors = NULL;
    Py_ssize_t count;
    PyObject *it;
    PyObject *(*iternext)(PyObject *);

    if (Py_SIZE(self) != 0) {
        /* Empty previous contents (yes, do this first of all!) */
        if (PyByteArray_Resize((PyObject *)self, 0) < 0)
            return -1;
    }

    /* Parse arguments */
    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|Oss:bytearray", kwlist,
                                     &arg, &encoding, &errors))
        return -1;

    /* Make a quick exit if no first argument */
    if (arg == NULL) {
        if (encoding != NULL || errors != NULL) {
            PyErr_SetString(PyExc_TypeError,
                            "encoding or errors without sequence argument");
            return -1;
        }
        return 0;
    }

    if (PyUnicode_Check(arg)) {
        /* Encode via the codec registry */
        PyObject *encoded, *new;
        if (encoding == NULL) {
            PyErr_SetString(PyExc_TypeError,
                            "string argument without an encoding");
            return -1;
        }
        encoded = PyUnicode_AsEncodedString(arg, encoding, errors);
        if (encoded == NULL)
            return -1;
        assert(PyBytes_Check(encoded));
        new = bytearray_iconcat(self, encoded);
        Py_DECREF(encoded);
        if (new == NULL)
            return -1;
        Py_DECREF(new);
        return 0;
    }

    /* If it's not unicode, there can't be encoding or errors */
    if (encoding != NULL || errors != NULL) {
        PyErr_SetString(PyExc_TypeError,
                        "encoding or errors without a string argument");
        return -1;
    }

    /* Is it an int? */
    count = PyNumber_AsSsize_t(arg, PyExc_OverflowError);
    if (count == -1 && PyErr_Occurred()) {
        if (PyErr_ExceptionMatches(PyExc_OverflowError))
            return -1;
        PyErr_Clear();
    }
    else if (count < 0) {
        PyErr_SetString(PyExc_ValueError, "negative count");
        return -1;
    }
    else {
        if (count > 0) {
            if (PyByteArray_Resize((PyObject *)self, count))
                return -1;
            memset(PyByteArray_AS_STRING(self), 0, count);
        }
        return 0;
    }

    /* Use the buffer API */
    if (PyObject_CheckBuffer(arg)) {
        Py_ssize_t size;
        Py_buffer view;
        if (PyObject_GetBuffer(arg, &view, PyBUF_FULL_RO) < 0)
            return -1;
        size = view.len;
        if (PyByteArray_Resize((PyObject *)self, size) < 0) goto fail;
        if (PyBuffer_ToContiguous(PyByteArray_AS_STRING(self),
            &view, size, 'C') < 0)
            goto fail;
        PyBuffer_Release(&view);
        return 0;
    fail:
        PyBuffer_Release(&view);
        return -1;
    }

    /* XXX Optimize this if the arguments is a list, tuple */

    /* Get the iterator */
    it = PyObject_GetIter(arg);
    if (it == NULL)
        return -1;
    iternext = *Py_TYPE(it)->tp_iternext;

    /* Run the iterator to exhaustion */
    for (;;) {
        PyObject *item;
        int rc, value;

        /* Get the next item */
        item = iternext(it);
        if (item == NULL) {
            if (PyErr_Occurred()) {
                if (!PyErr_ExceptionMatches(PyExc_StopIteration))
                    goto error;
                PyErr_Clear();
            }
            break;
        }

        /* Interpret it as an int (__index__) */
        rc = _getbytevalue(item, &value);
        Py_DECREF(item);
        if (!rc)
            goto error;

        /* Append the byte */
        if (Py_SIZE(self) + 1 < self->ob_alloc) {
            Py_SIZE(self)++;
            PyByteArray_AS_STRING(self)[Py_SIZE(self)] = '\0';
        }
        else if (PyByteArray_Resize((PyObject *)self, Py_SIZE(self)+1) < 0)
            goto error;
        PyByteArray_AS_STRING(self)[Py_SIZE(self)-1] = value;
    }

    /* Clean up and return success */
    Py_DECREF(it);
    return 0;

 error:
    /* Error handling when it != NULL */
    Py_DECREF(it);
    return -1;
}

/* Mostly copied from string_repr, but without the
   "smart quote" functionality. */
static PyObject *
bytearray_repr(PyByteArrayObject *self)
{
    const char *quote_prefix = "bytearray(b";
    const char *quote_postfix = ")";
    Py_ssize_t length = Py_SIZE(self);
    /* 15 == strlen(quote_prefix) + 2 + strlen(quote_postfix) + 1 */
    size_t newsize;
    PyObject *v;
    Py_ssize_t i;
    char *bytes;
    char c;
    char *p;
    int quote;
    char *test, *start;
    char *buffer;

    if (length > (PY_SSIZE_T_MAX - 15) / 4) {
        PyErr_SetString(PyExc_OverflowError,
            "bytearray object is too large to make repr");
        return NULL;
    }

    newsize = 15 + length * 4;
    buffer = PyObject_Malloc(newsize);
    if (buffer == NULL) {
        PyErr_NoMemory();
        return NULL;
    }

    /* Figure out which quote to use; single is preferred */
    quote = '\'';
    start = PyByteArray_AS_STRING(self);
    for (test = start; test < start+length; ++test) {
        if (*test == '"') {
            quote = '\''; /* back to single */
            break;
        }
        else if (*test == '\'')
            quote = '"';
    }

    p = buffer;
    while (*quote_prefix)
        *p++ = *quote_prefix++;
    *p++ = quote;

    bytes = PyByteArray_AS_STRING(self);
    for (i = 0; i < length; i++) {
        /* There's at least enough room for a hex escape
           and a closing quote. */
        assert(newsize - (p - buffer) >= 5);
        c = bytes[i];
        if (c == '\'' || c == '\\')
            *p++ = '\\', *p++ = c;
        else if (c == '\t')
            *p++ = '\\', *p++ = 't';
        else if (c == '\n')
            *p++ = '\\', *p++ = 'n';
        else if (c == '\r')
            *p++ = '\\', *p++ = 'r';
        else if (c == 0)
            *p++ = '\\', *p++ = 'x', *p++ = '0', *p++ = '0';
        else if (c < ' ' || c >= 0x7f) {
            *p++ = '\\';
            *p++ = 'x';
            *p++ = Py_hexdigits[(c & 0xf0) >> 4];
            *p++ = Py_hexdigits[c & 0xf];
        }
        else
            *p++ = c;
    }
    assert(newsize - (p - buffer) >= 1);
    *p++ = quote;
    while (*quote_postfix) {
       *p++ = *quote_postfix++;
    }

    v = PyUnicode_DecodeASCII(buffer, p - buffer, NULL);
    PyObject_Free(buffer);
    return v;
}

static PyObject *
bytearray_str(PyObject *op)
{
        if (Py_BytesWarningFlag) {
                if (PyErr_WarnEx(PyExc_BytesWarning,
                                 "str() on a bytearray instance", 1))
                        return NULL;
        }
        return bytearray_repr((PyByteArrayObject*)op);
}

static PyObject *
bytearray_richcompare(PyObject *self, PyObject *other, int op)
{
    Py_ssize_t self_size, other_size;
    Py_buffer self_bytes, other_bytes;
    PyObject *res;
    Py_ssize_t minsize;
    int cmp, rc;

    /* Bytes can be compared to anything that supports the (binary)
       buffer API.  Except that a comparison with Unicode is always an
       error, even if the comparison is for equality. */
    rc = PyObject_IsInstance(self, (PyObject*)&PyUnicode_Type);
    if (!rc)
        rc = PyObject_IsInstance(other, (PyObject*)&PyUnicode_Type);
    if (rc < 0)
        return NULL;
    if (rc) {
        if (Py_BytesWarningFlag && (op == Py_EQ || op == Py_NE)) {
            if (PyErr_WarnEx(PyExc_BytesWarning,
                            "Comparison between bytearray and string", 1))
                return NULL;
        }

        Py_RETURN_NOTIMPLEMENTED;
    }

    if (PyObject_GetBuffer(self, &self_bytes, PyBUF_SIMPLE) != 0) {
        PyErr_Clear();
        Py_RETURN_NOTIMPLEMENTED;
    }
    self_size = self_bytes.len;

    if (PyObject_GetBuffer(other, &other_bytes, PyBUF_SIMPLE) != 0) {
        PyErr_Clear();
        PyBuffer_Release(&self_bytes);
        Py_RETURN_NOTIMPLEMENTED;
    }
    other_size = other_bytes.len;

    if (self_size != other_size && (op == Py_EQ || op == Py_NE)) {
        /* Shortcut: if the lengths differ, the objects differ */
        cmp = (op == Py_NE);
    }
    else {
        minsize = self_size;
        if (other_size < minsize)
            minsize = other_size;

        cmp = memcmp(self_bytes.buf, other_bytes.buf, minsize);
        /* In ISO C, memcmp() guarantees to use unsigned bytes! */

        if (cmp == 0) {
            if (self_size < other_size)
                cmp = -1;
            else if (self_size > other_size)
                cmp = 1;
        }

        switch (op) {
        case Py_LT: cmp = cmp <  0; break;
        case Py_LE: cmp = cmp <= 0; break;
        case Py_EQ: cmp = cmp == 0; break;
        case Py_NE: cmp = cmp != 0; break;
        case Py_GT: cmp = cmp >  0; break;
        case Py_GE: cmp = cmp >= 0; break;
        }
    }

    res = cmp ? Py_True : Py_False;
    PyBuffer_Release(&self_bytes);
    PyBuffer_Release(&other_bytes);
    Py_INCREF(res);
    return res;
}

static void
bytearray_dealloc(PyByteArrayObject *self)
{
    if (self->ob_exports > 0) {
        PyErr_SetString(PyExc_SystemError,
                        "deallocated bytearray object has exported buffers");
        PyErr_Print();
    }
    if (self->ob_bytes != 0) {
        PyObject_Free(self->ob_bytes);
    }
    Py_TYPE(self)->tp_free((PyObject *)self);
}


/* -------------------------------------------------------------------- */
/* Methods */

#define FASTSEARCH fastsearch
#define STRINGLIB(F) stringlib_##F
#define STRINGLIB_CHAR char
#define STRINGLIB_SIZEOF_CHAR 1
#define STRINGLIB_LEN PyByteArray_GET_SIZE
#define STRINGLIB_STR PyByteArray_AS_STRING
#define STRINGLIB_NEW PyByteArray_FromStringAndSize
#define STRINGLIB_ISSPACE Py_ISSPACE
#define STRINGLIB_ISLINEBREAK(x) ((x == '\n') || (x == '\r'))
#define STRINGLIB_CHECK_EXACT PyByteArray_CheckExact
#define STRINGLIB_MUTABLE 1

#include "stringlib/fastsearch.h"
#include "stringlib/count.h"
#include "stringlib/find.h"
#include "stringlib/join.h"
#include "stringlib/partition.h"
#include "stringlib/split.h"
#include "stringlib/ctype.h"
#include "stringlib/transmogrify.h"


/* The following Py_LOCAL_INLINE and Py_LOCAL functions
were copied from the old char* style string object. */

/* helper macro to fixup start/end slice values */
#define ADJUST_INDICES(start, end, len)         \
    if (end > len)                              \
        end = len;                              \
    else if (end < 0) {                         \
        end += len;                             \
        if (end < 0)                            \
            end = 0;                            \
    }                                           \
    if (start < 0) {                            \
        start += len;                           \
        if (start < 0)                          \
            start = 0;                          \
    }

Py_LOCAL_INLINE(Py_ssize_t)
bytearray_find_internal(PyByteArrayObject *self, PyObject *args, int dir)
{
    PyObject *subobj;
    char byte;
    Py_buffer subbuf;
    const char *sub;
    Py_ssize_t len, sub_len;
    Py_ssize_t start=0, end=PY_SSIZE_T_MAX;
    Py_ssize_t res;

    if (!stringlib_parse_args_finds_byte("find/rfind/index/rindex",
                                         args, &subobj, &byte, &start, &end))
        return -2;

    if (subobj) {
        if (PyObject_GetBuffer(subobj, &subbuf, PyBUF_SIMPLE) != 0)
            return -2;

        sub = subbuf.buf;
        sub_len = subbuf.len;
    }
    else {
        sub = &byte;
        sub_len = 1;
    }
    len = PyByteArray_GET_SIZE(self);

    ADJUST_INDICES(start, end, len);
    if (end - start < sub_len)
        res = -1;
    else if (sub_len == 1
#ifndef HAVE_MEMRCHR
            && dir > 0
#endif
    ) {
        unsigned char needle = *sub;
        int mode = (dir > 0) ? FAST_SEARCH : FAST_RSEARCH;
        res = stringlib_fastsearch_memchr_1char(
            PyByteArray_AS_STRING(self) + start, end - start,
            needle, needle, mode);
        if (res >= 0)
            res += start;
    }
    else {
        if (dir > 0)
            res = stringlib_find_slice(
                PyByteArray_AS_STRING(self), len,
                sub, sub_len, start, end);
        else
            res = stringlib_rfind_slice(
                PyByteArray_AS_STRING(self), len,
                sub, sub_len, start, end);
    }

    if (subobj)
        PyBuffer_Release(&subbuf);

    return res;
}

PyDoc_STRVAR(find__doc__,
"B.find(sub[, start[, end]]) -> int\n\
\n\
Return the lowest index in B where subsection sub is found,\n\
such that sub is contained within B[start,end].  Optional\n\
arguments start and end are interpreted as in slice notation.\n\
\n\
Return -1 on failure.");

static PyObject *
bytearray_find(PyByteArrayObject *self, PyObject *args)
{
    Py_ssize_t result = bytearray_find_internal(self, args, +1);
    if (result == -2)
        return NULL;
    return PyLong_FromSsize_t(result);
}

PyDoc_STRVAR(count__doc__,
"B.count(sub[, start[, end]]) -> int\n\
\n\
Return the number of non-overlapping occurrences of subsection sub in\n\
bytes B[start:end].  Optional arguments start and end are interpreted\n\
as in slice notation.");

static PyObject *
bytearray_count(PyByteArrayObject *self, PyObject *args)
{
    PyObject *sub_obj;
    const char *str = PyByteArray_AS_STRING(self), *sub;
    Py_ssize_t sub_len;
    char byte;
    Py_ssize_t start = 0, end = PY_SSIZE_T_MAX;

    Py_buffer vsub;
    PyObject *count_obj;

    if (!stringlib_parse_args_finds_byte("count", args, &sub_obj, &byte,
                                         &start, &end))
        return NULL;

    if (sub_obj) {
        if (PyObject_GetBuffer(sub_obj, &vsub, PyBUF_SIMPLE) != 0)
            return NULL;

        sub = vsub.buf;
        sub_len = vsub.len;
    }
    else {
        sub = &byte;
        sub_len = 1;
    }

    ADJUST_INDICES(start, end, PyByteArray_GET_SIZE(self));

    count_obj = PyLong_FromSsize_t(
        stringlib_count(str + start, end - start, sub, sub_len, PY_SSIZE_T_MAX)
        );

    if (sub_obj)
        PyBuffer_Release(&vsub);

    return count_obj;
}

/*[clinic input]
bytearray.clear

    self: self(type="PyByteArrayObject *")

Remove all items from the bytearray.
[clinic start generated code]*/

static PyObject *
bytearray_clear_impl(PyByteArrayObject *self)
/*[clinic end generated code: output=85c2fe6aede0956c input=e524fd330abcdc18]*/
{
    if (PyByteArray_Resize((PyObject *)self, 0) < 0)
        return NULL;
    Py_RETURN_NONE;
}

/*[clinic input]
bytearray.copy

    self: self(type="PyByteArrayObject *")

Return a copy of B.
[clinic start generated code]*/

static PyObject *
bytearray_copy_impl(PyByteArrayObject *self)
/*[clinic end generated code: output=68cfbcfed484c132 input=6d5d2975aa0f33f3]*/
{
    return PyByteArray_FromStringAndSize(PyByteArray_AS_STRING((PyObject *)self),
                                         PyByteArray_GET_SIZE(self));
}

PyDoc_STRVAR(index__doc__,
"B.index(sub[, start[, end]]) -> int\n\
\n\
Like B.find() but raise ValueError when the subsection is not found.");

static PyObject *
bytearray_index(PyByteArrayObject *self, PyObject *args)
{
    Py_ssize_t result = bytearray_find_internal(self, args, +1);
    if (result == -2)
        return NULL;
    if (result == -1) {
        PyErr_SetString(PyExc_ValueError,
                        "subsection not found");
        return NULL;
    }
    return PyLong_FromSsize_t(result);
}


PyDoc_STRVAR(rfind__doc__,
"B.rfind(sub[, start[, end]]) -> int\n\
\n\
Return the highest index in B where subsection sub is found,\n\
such that sub is contained within B[start,end].  Optional\n\
arguments start and end are interpreted as in slice notation.\n\
\n\
Return -1 on failure.");

static PyObject *
bytearray_rfind(PyByteArrayObject *self, PyObject *args)
{
    Py_ssize_t result = bytearray_find_internal(self, args, -1);
    if (result == -2)
        return NULL;
    return PyLong_FromSsize_t(result);
}


PyDoc_STRVAR(rindex__doc__,
"B.rindex(sub[, start[, end]]) -> int\n\
\n\
Like B.rfind() but raise ValueError when the subsection is not found.");

static PyObject *
bytearray_rindex(PyByteArrayObject *self, PyObject *args)
{
    Py_ssize_t result = bytearray_find_internal(self, args, -1);
    if (result == -2)
        return NULL;
    if (result == -1) {
        PyErr_SetString(PyExc_ValueError,
                        "subsection not found");
        return NULL;
    }
    return PyLong_FromSsize_t(result);
}


static int
bytearray_contains(PyObject *self, PyObject *arg)
{
    Py_ssize_t ival = PyNumber_AsSsize_t(arg, PyExc_ValueError);
    if (ival == -1 && PyErr_Occurred()) {
        Py_buffer varg;
        Py_ssize_t pos;
        PyErr_Clear();
        if (PyObject_GetBuffer(arg, &varg, PyBUF_SIMPLE) != 0)
            return -1;
        pos = stringlib_find(PyByteArray_AS_STRING(self), Py_SIZE(self),
                             varg.buf, varg.len, 0);
        PyBuffer_Release(&varg);
        return pos >= 0;
    }
    if (ival < 0 || ival >= 256) {
        PyErr_SetString(PyExc_ValueError, "byte must be in range(0, 256)");
        return -1;
    }

    return memchr(PyByteArray_AS_STRING(self), (int) ival, Py_SIZE(self)) != NULL;
}


/* Matches the end (direction >= 0) or start (direction < 0) of self
 * against substr, using the start and end arguments. Returns
 * -1 on error, 0 if not found and 1 if found.
 */
Py_LOCAL(int)
_bytearray_tailmatch(PyByteArrayObject *self, PyObject *substr, Py_ssize_t start,
                 Py_ssize_t end, int direction)
{
    Py_ssize_t len = PyByteArray_GET_SIZE(self);
    const char* str;
    Py_buffer vsubstr;
    int rv = 0;

    str = PyByteArray_AS_STRING(self);

    if (PyObject_GetBuffer(substr, &vsubstr, PyBUF_SIMPLE) != 0)
        return -1;

    ADJUST_INDICES(start, end, len);

    if (direction < 0) {
        /* startswith */
        if (start+vsubstr.len > len) {
            goto done;
        }
    } else {
        /* endswith */
        if (end-start < vsubstr.len || start > len) {
            goto done;
        }

        if (end-vsubstr.len > start)
            start = end - vsubstr.len;
    }
    if (end-start >= vsubstr.len)
        rv = ! memcmp(str+start, vsubstr.buf, vsubstr.len);

done:
    PyBuffer_Release(&vsubstr);
    return rv;
}


PyDoc_STRVAR(startswith__doc__,
"B.startswith(prefix[, start[, end]]) -> bool\n\
\n\
Return True if B starts with the specified prefix, False otherwise.\n\
With optional start, test B beginning at that position.\n\
With optional end, stop comparing B at that position.\n\
prefix can also be a tuple of bytes to try.");

static PyObject *
bytearray_startswith(PyByteArrayObject *self, PyObject *args)
{
    Py_ssize_t start = 0;
    Py_ssize_t end = PY_SSIZE_T_MAX;
    PyObject *subobj;
    int result;

    if (!stringlib_parse_args_finds("startswith", args, &subobj, &start, &end))
        return NULL;
    if (PyTuple_Check(subobj)) {
        Py_ssize_t i;
        for (i = 0; i < PyTuple_GET_SIZE(subobj); i++) {
            result = _bytearray_tailmatch(self,
                                      PyTuple_GET_ITEM(subobj, i),
                                      start, end, -1);
            if (result == -1)
                return NULL;
            else if (result) {
                Py_RETURN_TRUE;
            }
        }
        Py_RETURN_FALSE;
    }
    result = _bytearray_tailmatch(self, subobj, start, end, -1);
    if (result == -1) {
        if (PyErr_ExceptionMatches(PyExc_TypeError))
            PyErr_Format(PyExc_TypeError, "startswith first arg must be bytes "
                         "or a tuple of bytes, not %s", Py_TYPE(subobj)->tp_name);
        return NULL;
    }
    else
        return PyBool_FromLong(result);
}

PyDoc_STRVAR(endswith__doc__,
"B.endswith(suffix[, start[, end]]) -> bool\n\
\n\
Return True if B ends with the specified suffix, False otherwise.\n\
With optional start, test B beginning at that position.\n\
With optional end, stop comparing B at that position.\n\
suffix can also be a tuple of bytes to try.");

static PyObject *
bytearray_endswith(PyByteArrayObject *self, PyObject *args)
{
    Py_ssize_t start = 0;
    Py_ssize_t end = PY_SSIZE_T_MAX;
    PyObject *subobj;
    int result;

    if (!stringlib_parse_args_finds("endswith", args, &subobj, &start, &end))
        return NULL;
    if (PyTuple_Check(subobj)) {
        Py_ssize_t i;
        for (i = 0; i < PyTuple_GET_SIZE(subobj); i++) {
            result = _bytearray_tailmatch(self,
                                      PyTuple_GET_ITEM(subobj, i),
                                      start, end, +1);
            if (result == -1)
                return NULL;
            else if (result) {
                Py_RETURN_TRUE;
            }
        }
        Py_RETURN_FALSE;
    }
    result = _bytearray_tailmatch(self, subobj, start, end, +1);
    if (result == -1) {
        if (PyErr_ExceptionMatches(PyExc_TypeError))
            PyErr_Format(PyExc_TypeError, "endswith first arg must be bytes or "
                         "a tuple of bytes, not %s", Py_TYPE(subobj)->tp_name);
        return NULL;
    }
    else
        return PyBool_FromLong(result);
}


/*[clinic input]
bytearray.translate

    self: self(type="PyByteArrayObject *")
    table: object
        Translation table, which must be a bytes object of length 256.
    [
    deletechars: object
    ]
    /

Return a copy with each character mapped by the given translation table.

All characters occurring in the optional argument deletechars are removed.
The remaining characters are mapped through the given translation table.
[clinic start generated code]*/

static PyObject *
bytearray_translate_impl(PyByteArrayObject *self, PyObject *table,
                         int group_right_1, PyObject *deletechars)
/*[clinic end generated code: output=2bebc86a9a1ff083 input=b749ad85f4860824]*/
{
    char *input, *output;
    const char *table_chars;
    Py_ssize_t i, c;
    PyObject *input_obj = (PyObject*)self;
    const char *output_start;
    Py_ssize_t inlen;
    PyObject *result = NULL;
    int trans_table[256];
    Py_buffer vtable, vdel;

    if (table == Py_None) {
        table_chars = NULL;
        table = NULL;
    } else if (PyObject_GetBuffer(table, &vtable, PyBUF_SIMPLE) != 0) {
        return NULL;
    } else {
        if (vtable.len != 256) {
            PyErr_SetString(PyExc_ValueError,
                            "translation table must be 256 characters long");
            PyBuffer_Release(&vtable);
            return NULL;
        }
        table_chars = (const char*)vtable.buf;
    }

    if (deletechars != NULL) {
        if (PyObject_GetBuffer(deletechars, &vdel, PyBUF_SIMPLE) != 0) {
            if (table != NULL)
                PyBuffer_Release(&vtable);
            return NULL;
        }
    }
    else {
        vdel.buf = NULL;
        vdel.len = 0;
    }

    inlen = PyByteArray_GET_SIZE(input_obj);
    result = PyByteArray_FromStringAndSize((char *)NULL, inlen);
    if (result == NULL)
        goto done;
    output_start = output = PyByteArray_AsString(result);
    input = PyByteArray_AS_STRING(input_obj);

    if (vdel.len == 0 && table_chars != NULL) {
        /* If no deletions are required, use faster code */
        for (i = inlen; --i >= 0; ) {
            c = Py_CHARMASK(*input++);
            *output++ = table_chars[c];
        }
        goto done;
    }

    if (table_chars == NULL) {
        for (i = 0; i < 256; i++)
            trans_table[i] = Py_CHARMASK(i);
    } else {
        for (i = 0; i < 256; i++)
            trans_table[i] = Py_CHARMASK(table_chars[i]);
    }

    for (i = 0; i < vdel.len; i++)
        trans_table[(int) Py_CHARMASK( ((unsigned char*)vdel.buf)[i] )] = -1;

    for (i = inlen; --i >= 0; ) {
        c = Py_CHARMASK(*input++);
        if (trans_table[c] != -1)
            if (Py_CHARMASK(*output++ = (char)trans_table[c]) == c)
                    continue;
    }
    /* Fix the size of the resulting string */
    if (inlen > 0)
        if (PyByteArray_Resize(result, output - output_start) < 0) {
            Py_CLEAR(result);
            goto done;
        }

done:
    if (table != NULL)
        PyBuffer_Release(&vtable);
    if (deletechars != NULL)
        PyBuffer_Release(&vdel);
    return result;
}


/*[clinic input]

@staticmethod
bytearray.maketrans

    frm: Py_buffer
    to: Py_buffer
    /

Return a translation table useable for the bytes or bytearray translate method.

The returned table will be one where each byte in frm is mapped to the byte at
the same position in to.

The bytes objects frm and to must be of the same length.
[clinic start generated code]*/

static PyObject *
bytearray_maketrans_impl(Py_buffer *frm, Py_buffer *to)
/*[clinic end generated code: output=1df267d99f56b15e input=5925a81d2fbbf151]*/
{
    return _Py_bytes_maketrans(frm, to);
}


/* find and count characters and substrings */

#define findchar(target, target_len, c)                         \
  ((char *)memchr((const void *)(target), c, target_len))


/* Bytes ops must return a string, create a copy */
Py_LOCAL(PyByteArrayObject *)
return_self(PyByteArrayObject *self)
{
    /* always return a new bytearray */
    return (PyByteArrayObject *)PyByteArray_FromStringAndSize(
            PyByteArray_AS_STRING(self),
            PyByteArray_GET_SIZE(self));
}

Py_LOCAL_INLINE(Py_ssize_t)
countchar(const char *target, Py_ssize_t target_len, char c, Py_ssize_t maxcount)
{
    Py_ssize_t count=0;
    const char *start=target;
    const char *end=target+target_len;

    while ( (start=findchar(start, end-start, c)) != NULL ) {
        count++;
        if (count >= maxcount)
            break;
        start += 1;
    }
    return count;
}


/* Algorithms for different cases of string replacement */

/* len(self)>=1, from="", len(to)>=1, maxcount>=1 */
Py_LOCAL(PyByteArrayObject *)
replace_interleave(PyByteArrayObject *self,
                   const char *to_s, Py_ssize_t to_len,
                   Py_ssize_t maxcount)
{
    char *self_s, *result_s;
    Py_ssize_t self_len, result_len;
    Py_ssize_t count, i;
    PyByteArrayObject *result;

    self_len = PyByteArray_GET_SIZE(self);

    /* 1 at the end plus 1 after every character;
       count = min(maxcount, self_len + 1) */
    if (maxcount <= self_len)
        count = maxcount;
    else
        /* Can't overflow: self_len + 1 <= maxcount <= PY_SSIZE_T_MAX. */
        count = self_len + 1;

    /* Check for overflow */
    /*   result_len = count * to_len + self_len; */
    assert(count > 0);
    if (to_len > (PY_SSIZE_T_MAX - self_len) / count) {
        PyErr_SetString(PyExc_OverflowError,
                        "replace string is too long");
        return NULL;
    }
    result_len = count * to_len + self_len;

    if (! (result = (PyByteArrayObject *)
                     PyByteArray_FromStringAndSize(NULL, result_len)) )
        return NULL;

    self_s = PyByteArray_AS_STRING(self);
    result_s = PyByteArray_AS_STRING(result);

    /* TODO: special case single character, which doesn't need memcpy */

    /* Lay the first one down (guaranteed this will occur) */
    Py_MEMCPY(result_s, to_s, to_len);
    result_s += to_len;
    count -= 1;

    for (i=0; i<count; i++) {
        *result_s++ = *self_s++;
        Py_MEMCPY(result_s, to_s, to_len);
        result_s += to_len;
    }

    /* Copy the rest of the original string */
    Py_MEMCPY(result_s, self_s, self_len-i);

    return result;
}

/* Special case for deleting a single character */
/* len(self)>=1, len(from)==1, to="", maxcount>=1 */
Py_LOCAL(PyByteArrayObject *)
replace_delete_single_character(PyByteArrayObject *self,
                                char from_c, Py_ssize_t maxcount)
{
    char *self_s, *result_s;
    char *start, *next, *end;
    Py_ssize_t self_len, result_len;
    Py_ssize_t count;
    PyByteArrayObject *result;

    self_len = PyByteArray_GET_SIZE(self);
    self_s = PyByteArray_AS_STRING(self);

    count = countchar(self_s, self_len, from_c, maxcount);
    if (count == 0) {
        return return_self(self);
    }

    result_len = self_len - count;  /* from_len == 1 */
    assert(result_len>=0);

    if ( (result = (PyByteArrayObject *)
                    PyByteArray_FromStringAndSize(NULL, result_len)) == NULL)
        return NULL;
    result_s = PyByteArray_AS_STRING(result);

    start = self_s;
    end = self_s + self_len;
    while (count-- > 0) {
        next = findchar(start, end-start, from_c);
        if (next == NULL)
            break;
        Py_MEMCPY(result_s, start, next-start);
        result_s += (next-start);
        start = next+1;
    }
    Py_MEMCPY(result_s, start, end-start);

    return result;
}

/* len(self)>=1, len(from)>=2, to="", maxcount>=1 */

Py_LOCAL(PyByteArrayObject *)
replace_delete_substring(PyByteArrayObject *self,
                         const char *from_s, Py_ssize_t from_len,
                         Py_ssize_t maxcount)
{
    char *self_s, *result_s;
    char *start, *next, *end;
    Py_ssize_t self_len, result_len;
    Py_ssize_t count, offset;
    PyByteArrayObject *result;

    self_len = PyByteArray_GET_SIZE(self);
    self_s = PyByteArray_AS_STRING(self);

    count = stringlib_count(self_s, self_len,
                            from_s, from_len,
                            maxcount);

    if (count == 0) {
        /* no matches */
        return return_self(self);
    }

    result_len = self_len - (count * from_len);
    assert (result_len>=0);

    if ( (result = (PyByteArrayObject *)
        PyByteArray_FromStringAndSize(NULL, result_len)) == NULL )
            return NULL;

    result_s = PyByteArray_AS_STRING(result);

    start = self_s;
    end = self_s + self_len;
    while (count-- > 0) {
        offset = stringlib_find(start, end-start,
                                from_s, from_len,
                                0);
        if (offset == -1)
            break;
        next = start + offset;

        Py_MEMCPY(result_s, start, next-start);

        result_s += (next-start);
        start = next+from_len;
    }
    Py_MEMCPY(result_s, start, end-start);
    return result;
}

/* len(self)>=1, len(from)==len(to)==1, maxcount>=1 */
Py_LOCAL(PyByteArrayObject *)
replace_single_character_in_place(PyByteArrayObject *self,
                                  char from_c, char to_c,
                                  Py_ssize_t maxcount)
{
    char *self_s, *result_s, *start, *end, *next;
    Py_ssize_t self_len;
    PyByteArrayObject *result;

    /* The result string will be the same size */
    self_s = PyByteArray_AS_STRING(self);
    self_len = PyByteArray_GET_SIZE(self);

    next = findchar(self_s, self_len, from_c);

    if (next == NULL) {
        /* No matches; return the original bytes */
        return return_self(self);
    }

    /* Need to make a new bytes */
    result = (PyByteArrayObject *) PyByteArray_FromStringAndSize(NULL, self_len);
    if (result == NULL)
        return NULL;
    result_s = PyByteArray_AS_STRING(result);
    Py_MEMCPY(result_s, self_s, self_len);

    /* change everything in-place, starting with this one */
    start =  result_s + (next-self_s);
    *start = to_c;
    start++;
    end = result_s + self_len;

    while (--maxcount > 0) {
        next = findchar(start, end-start, from_c);
        if (next == NULL)
            break;
        *next = to_c;
        start = next+1;
    }

    return result;
}

/* len(self)>=1, len(from)==len(to)>=2, maxcount>=1 */
Py_LOCAL(PyByteArrayObject *)
replace_substring_in_place(PyByteArrayObject *self,
                           const char *from_s, Py_ssize_t from_len,
                           const char *to_s, Py_ssize_t to_len,
                           Py_ssize_t maxcount)
{
    char *result_s, *start, *end;
    char *self_s;
    Py_ssize_t self_len, offset;
    PyByteArrayObject *result;

    /* The result bytes will be the same size */

    self_s = PyByteArray_AS_STRING(self);
    self_len = PyByteArray_GET_SIZE(self);

    offset = stringlib_find(self_s, self_len,
                            from_s, from_len,
                            0);
    if (offset == -1) {
        /* No matches; return the original bytes */
        return return_self(self);
    }

    /* Need to make a new bytes */
    result = (PyByteArrayObject *) PyByteArray_FromStringAndSize(NULL, self_len);
    if (result == NULL)
        return NULL;
    result_s = PyByteArray_AS_STRING(result);
    Py_MEMCPY(result_s, self_s, self_len);

    /* change everything in-place, starting with this one */
    start =  result_s + offset;
    Py_MEMCPY(start, to_s, from_len);
    start += from_len;
    end = result_s + self_len;

    while ( --maxcount > 0) {
        offset = stringlib_find(start, end-start,
                                from_s, from_len,
                                0);
        if (offset==-1)
            break;
        Py_MEMCPY(start+offset, to_s, from_len);
        start += offset+from_len;
    }

    return result;
}

/* len(self)>=1, len(from)==1, len(to)>=2, maxcount>=1 */
Py_LOCAL(PyByteArrayObject *)
replace_single_character(PyByteArrayObject *self,
                         char from_c,
                         const char *to_s, Py_ssize_t to_len,
                         Py_ssize_t maxcount)
{
    char *self_s, *result_s;
    char *start, *next, *end;
    Py_ssize_t self_len, result_len;
    Py_ssize_t count;
    PyByteArrayObject *result;

    self_s = PyByteArray_AS_STRING(self);
    self_len = PyByteArray_GET_SIZE(self);

    count = countchar(self_s, self_len, from_c, maxcount);
    if (count == 0) {
        /* no matches, return unchanged */
        return return_self(self);
    }

    /* use the difference between current and new, hence the "-1" */
    /*   result_len = self_len + count * (to_len-1)  */
    assert(count > 0);
    if (to_len - 1 > (PY_SSIZE_T_MAX - self_len) / count) {
        PyErr_SetString(PyExc_OverflowError, "replace bytes is too long");
        return NULL;
    }
    result_len = self_len + count * (to_len - 1);

    if ( (result = (PyByteArrayObject *)
          PyByteArray_FromStringAndSize(NULL, result_len)) == NULL)
            return NULL;
    result_s = PyByteArray_AS_STRING(result);

    start = self_s;
    end = self_s + self_len;
    while (count-- > 0) {
        next = findchar(start, end-start, from_c);
        if (next == NULL)
            break;

        if (next == start) {
            /* replace with the 'to' */
            Py_MEMCPY(result_s, to_s, to_len);
            result_s += to_len;
            start += 1;
        } else {
            /* copy the unchanged old then the 'to' */
            Py_MEMCPY(result_s, start, next-start);
            result_s += (next-start);
            Py_MEMCPY(result_s, to_s, to_len);
            result_s += to_len;
            start = next+1;
        }
    }
    /* Copy the remainder of the remaining bytes */
    Py_MEMCPY(result_s, start, end-start);

    return result;
}

/* len(self)>=1, len(from)>=2, len(to)>=2, maxcount>=1 */
Py_LOCAL(PyByteArrayObject *)
replace_substring(PyByteArrayObject *self,
                  const char *from_s, Py_ssize_t from_len,
                  const char *to_s, Py_ssize_t to_len,
                  Py_ssize_t maxcount)
{
    char *self_s, *result_s;
    char *start, *next, *end;
    Py_ssize_t self_len, result_len;
    Py_ssize_t count, offset;
    PyByteArrayObject *result;

    self_s = PyByteArray_AS_STRING(self);
    self_len = PyByteArray_GET_SIZE(self);

    count = stringlib_count(self_s, self_len,
                            from_s, from_len,
                            maxcount);

    if (count == 0) {
        /* no matches, return unchanged */
        return return_self(self);
    }

    /* Check for overflow */
    /*    result_len = self_len + count * (to_len-from_len) */
    assert(count > 0);
    if (to_len - from_len > (PY_SSIZE_T_MAX - self_len) / count) {
        PyErr_SetString(PyExc_OverflowError, "replace bytes is too long");
        return NULL;
    }
    result_len = self_len + count * (to_len - from_len);

    if ( (result = (PyByteArrayObject *)
          PyByteArray_FromStringAndSize(NULL, result_len)) == NULL)
        return NULL;
    result_s = PyByteArray_AS_STRING(result);

    start = self_s;
    end = self_s + self_len;
    while (count-- > 0) {
        offset = stringlib_find(start, end-start,
                                from_s, from_len,
                                0);
        if (offset == -1)
            break;
        next = start+offset;
        if (next == start) {
            /* replace with the 'to' */
            Py_MEMCPY(result_s, to_s, to_len);
            result_s += to_len;
            start += from_len;
        } else {
            /* copy the unchanged old then the 'to' */
            Py_MEMCPY(result_s, start, next-start);
            result_s += (next-start);
            Py_MEMCPY(result_s, to_s, to_len);
            result_s += to_len;
            start = next+from_len;
        }
    }
    /* Copy the remainder of the remaining bytes */
    Py_MEMCPY(result_s, start, end-start);

    return result;
}


Py_LOCAL(PyByteArrayObject *)
replace(PyByteArrayObject *self,
        const char *from_s, Py_ssize_t from_len,
        const char *to_s, Py_ssize_t to_len,
        Py_ssize_t maxcount)
{
    if (maxcount < 0) {
        maxcount = PY_SSIZE_T_MAX;
    } else if (maxcount == 0 || PyByteArray_GET_SIZE(self) == 0) {
        /* nothing to do; return the original bytes */
        return return_self(self);
    }

    if (maxcount == 0 ||
        (from_len == 0 && to_len == 0)) {
        /* nothing to do; return the original bytes */
        return return_self(self);
    }

    /* Handle zero-length special cases */

    if (from_len == 0) {
        /* insert the 'to' bytes everywhere.   */
        /*    >>> "Python".replace("", ".")     */
        /*    '.P.y.t.h.o.n.'                   */
        return replace_interleave(self, to_s, to_len, maxcount);
    }

    /* Except for "".replace("", "A") == "A" there is no way beyond this */
    /* point for an empty self bytes to generate a non-empty bytes */
    /* Special case so the remaining code always gets a non-empty bytes */
    if (PyByteArray_GET_SIZE(self) == 0) {
        return return_self(self);
    }

    if (to_len == 0) {
        /* delete all occurrences of 'from' bytes */
        if (from_len == 1) {
            return replace_delete_single_character(
                    self, from_s[0], maxcount);
        } else {
            return replace_delete_substring(self, from_s, from_len, maxcount);
        }
    }

    /* Handle special case where both bytes have the same length */

    if (from_len == to_len) {
        if (from_len == 1) {
            return replace_single_character_in_place(
                    self,
                    from_s[0],
                    to_s[0],
                    maxcount);
        } else {
            return replace_substring_in_place(
                self, from_s, from_len, to_s, to_len, maxcount);
        }
    }

    /* Otherwise use the more generic algorithms */
    if (from_len == 1) {
        return replace_single_character(self, from_s[0],
                                        to_s, to_len, maxcount);
    } else {
        /* len('from')>=2, len('to')>=1 */
        return replace_substring(self, from_s, from_len, to_s, to_len, maxcount);
    }
}


/*[clinic input]
bytearray.replace

    old: Py_buffer
    new: Py_buffer
    count: Py_ssize_t = -1
        Maximum number of occurrences to replace.
        -1 (the default value) means replace all occurrences.
    /

Return a copy with all occurrences of substring old replaced by new.

If the optional argument count is given, only the first count occurrences are
replaced.
[clinic start generated code]*/

static PyObject *
bytearray_replace_impl(PyByteArrayObject *self, Py_buffer *old,
                       Py_buffer *new, Py_ssize_t count)
/*[clinic end generated code: output=d39884c4dc59412a input=aa379d988637c7fb]*/
{
    return (PyObject *)replace((PyByteArrayObject *) self,
                               old->buf, old->len,
                               new->buf, new->len, count);
}

/*[clinic input]
bytearray.split

    sep: object = None
        The delimiter according which to split the bytearray.
        None (the default value) means split on ASCII whitespace characters
        (space, tab, return, newline, formfeed, vertical tab).
    maxsplit: Py_ssize_t = -1
        Maximum number of splits to do.
        -1 (the default value) means no limit.

Return a list of the sections in the bytearray, using sep as the delimiter.
[clinic start generated code]*/

static PyObject *
bytearray_split_impl(PyByteArrayObject *self, PyObject *sep,
                     Py_ssize_t maxsplit)
/*[clinic end generated code: output=833e2cf385d9a04d input=24f82669f41bf523]*/
{
    Py_ssize_t len = PyByteArray_GET_SIZE(self), n;
    const char *s = PyByteArray_AS_STRING(self), *sub;
    PyObject *list;
    Py_buffer vsub;

    if (maxsplit < 0)
        maxsplit = PY_SSIZE_T_MAX;

    if (sep == Py_None)
        return stringlib_split_whitespace((PyObject*) self, s, len, maxsplit);

    if (PyObject_GetBuffer(sep, &vsub, PyBUF_SIMPLE) != 0)
        return NULL;
    sub = vsub.buf;
    n = vsub.len;

    list = stringlib_split(
        (PyObject*) self, s, len, sub, n, maxsplit
        );
    PyBuffer_Release(&vsub);
    return list;
}

/*[clinic input]
bytearray.partition

    self: self(type="PyByteArrayObject *")
    sep: object
    /

Partition the bytearray into three parts using the given separator.

This will search for the separator sep in the bytearray. If the separator is
found, returns a 3-tuple containing the part before the separator, the
separator itself, and the part after it.

If the separator is not found, returns a 3-tuple containing the original
bytearray object and two empty bytearray objects.
[clinic start generated code]*/

static PyObject *
bytearray_partition(PyByteArrayObject *self, PyObject *sep)
/*[clinic end generated code: output=45d2525ddd35f957 input=7d7fe37b1696d506]*/
{
    PyObject *bytesep, *result;

    bytesep = PyByteArray_FromObject(sep);
    if (! bytesep)
        return NULL;

    result = stringlib_partition(
            (PyObject*) self,
            PyByteArray_AS_STRING(self), PyByteArray_GET_SIZE(self),
            bytesep,
            PyByteArray_AS_STRING(bytesep), PyByteArray_GET_SIZE(bytesep)
            );

    Py_DECREF(bytesep);
    return result;
}

/*[clinic input]
bytearray.rpartition

    self: self(type="PyByteArrayObject *")
    sep: object
    /

Partition the bytes into three parts using the given separator.

This will search for the separator sep in the bytearray, starting and the end.
If the separator is found, returns a 3-tuple containing the part before the
separator, the separator itself, and the part after it.

If the separator is not found, returns a 3-tuple containing two empty bytearray
objects and the original bytearray object.
[clinic start generated code]*/

static PyObject *
bytearray_rpartition(PyByteArrayObject *self, PyObject *sep)
/*[clinic end generated code: output=440de3c9426115e8 input=9b8cd540c1b75853]*/
{
    PyObject *bytesep, *result;

    bytesep = PyByteArray_FromObject(sep);
    if (! bytesep)
        return NULL;

    result = stringlib_rpartition(
            (PyObject*) self,
            PyByteArray_AS_STRING(self), PyByteArray_GET_SIZE(self),
            bytesep,
            PyByteArray_AS_STRING(bytesep), PyByteArray_GET_SIZE(bytesep)
            );

    Py_DECREF(bytesep);
    return result;
}

/*[clinic input]
bytearray.rsplit = bytearray.split

Return a list of the sections in the bytearray, using sep as the delimiter.

Splitting is done starting at the end of the bytearray and working to the front.
[clinic start generated code]*/

static PyObject *
bytearray_rsplit_impl(PyByteArrayObject *self, PyObject *sep,
                      Py_ssize_t maxsplit)
/*[clinic end generated code: output=a55e0b5a03cb6190 input=a68286e4dd692ffe]*/
{
    Py_ssize_t len = PyByteArray_GET_SIZE(self), n;
    const char *s = PyByteArray_AS_STRING(self), *sub;
    PyObject *list;
    Py_buffer vsub;

    if (maxsplit < 0)
        maxsplit = PY_SSIZE_T_MAX;

    if (sep == Py_None)
        return stringlib_rsplit_whitespace((PyObject*) self, s, len, maxsplit);

    if (PyObject_GetBuffer(sep, &vsub, PyBUF_SIMPLE) != 0)
        return NULL;
    sub = vsub.buf;
    n = vsub.len;

    list = stringlib_rsplit(
        (PyObject*) self, s, len, sub, n, maxsplit
        );
    PyBuffer_Release(&vsub);
    return list;
}

/*[clinic input]
bytearray.reverse

    self: self(type="PyByteArrayObject *")

Reverse the order of the values in B in place.
[clinic start generated code]*/

static PyObject *
bytearray_reverse_impl(PyByteArrayObject *self)
/*[clinic end generated code: output=9f7616f29ab309d3 input=7933a499b8597bd1]*/
{
    char swap, *head, *tail;
    Py_ssize_t i, j, n = Py_SIZE(self);

    j = n / 2;
    head = PyByteArray_AS_STRING(self);
    tail = head + n - 1;
    for (i = 0; i < j; i++) {
        swap = *head;
        *head++ = *tail;
        *tail-- = swap;
    }

    Py_RETURN_NONE;
}


/*[python input]
class bytesvalue_converter(CConverter):
    type = 'int'
    converter = '_getbytevalue'
[python start generated code]*/
/*[python end generated code: output=da39a3ee5e6b4b0d input=29c2e7c26c212812]*/


/*[clinic input]
bytearray.insert

    self: self(type="PyByteArrayObject *")
    index: Py_ssize_t
        The index where the value is to be inserted.
    item: bytesvalue
        The item to be inserted.
    /

Insert a single item into the bytearray before the given index.
[clinic start generated code]*/

static PyObject *
bytearray_insert_impl(PyByteArrayObject *self, Py_ssize_t index, int item)
/*[clinic end generated code: output=76c775a70e7b07b7 input=833766836ba30e1e]*/
{
    Py_ssize_t n = Py_SIZE(self);
    char *buf;

    if (n == PY_SSIZE_T_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "cannot add more objects to bytearray");
        return NULL;
    }
    if (PyByteArray_Resize((PyObject *)self, n + 1) < 0)
        return NULL;
    buf = PyByteArray_AS_STRING(self);

    if (index < 0) {
        index += n;
        if (index < 0)
            index = 0;
    }
    if (index > n)
        index = n;
    memmove(buf + index + 1, buf + index, n - index);
    buf[index] = item;

    Py_RETURN_NONE;
}

/*[clinic input]
bytearray.append

    self: self(type="PyByteArrayObject *")
    item: bytesvalue
        The item to be appended.
    /

Append a single item to the end of the bytearray.
[clinic start generated code]*/

static PyObject *
bytearray_append_impl(PyByteArrayObject *self, int item)
/*[clinic end generated code: output=a154e19ed1886cb6 input=ae56ea87380407cc]*/
{
    Py_ssize_t n = Py_SIZE(self);

    if (n == PY_SSIZE_T_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "cannot add more objects to bytearray");
        return NULL;
    }
    if (PyByteArray_Resize((PyObject *)self, n + 1) < 0)
        return NULL;

    PyByteArray_AS_STRING(self)[n] = item;

    Py_RETURN_NONE;
}

/*[clinic input]
bytearray.extend

    self: self(type="PyByteArrayObject *")
    iterable_of_ints: object
        The iterable of items to append.
    /

Append all the items from the iterator or sequence to the end of the bytearray.
[clinic start generated code]*/

static PyObject *
bytearray_extend(PyByteArrayObject *self, PyObject *iterable_of_ints)
/*[clinic end generated code: output=98155dbe249170b1 input=ce83a5d75b70d850]*/
{
    PyObject *it, *item, *bytearray_obj;
    Py_ssize_t buf_size = 0, len = 0;
    int value;
    char *buf;

    /* bytearray_setslice code only accepts something supporting PEP 3118. */
    if (PyObject_CheckBuffer(iterable_of_ints)) {
        if (bytearray_setslice(self, Py_SIZE(self), Py_SIZE(self), iterable_of_ints) == -1)
            return NULL;

        Py_RETURN_NONE;
    }

    it = PyObject_GetIter(iterable_of_ints);
    if (it == NULL)
        return NULL;

    /* Try to determine the length of the argument. 32 is arbitrary. */
    buf_size = PyObject_LengthHint(iterable_of_ints, 32);
    if (buf_size == -1) {
        Py_DECREF(it);
        return NULL;
    }

    bytearray_obj = PyByteArray_FromStringAndSize(NULL, buf_size);
    if (bytearray_obj == NULL) {
        Py_DECREF(it);
        return NULL;
    }
    buf = PyByteArray_AS_STRING(bytearray_obj);

    while ((item = PyIter_Next(it)) != NULL) {
        if (! _getbytevalue(item, &value)) {
            Py_DECREF(item);
            Py_DECREF(it);
            Py_DECREF(bytearray_obj);
            return NULL;
        }
        buf[len++] = value;
        Py_DECREF(item);

        if (len >= buf_size) {
            buf_size = len + (len >> 1) + 1;
            if (PyByteArray_Resize((PyObject *)bytearray_obj, buf_size) < 0) {
                Py_DECREF(it);
                Py_DECREF(bytearray_obj);
                return NULL;
            }
            /* Recompute the `buf' pointer, since the resizing operation may
               have invalidated it. */
            buf = PyByteArray_AS_STRING(bytearray_obj);
        }
    }
    Py_DECREF(it);

    /* Resize down to exact size. */
    if (PyByteArray_Resize((PyObject *)bytearray_obj, len) < 0) {
        Py_DECREF(bytearray_obj);
        return NULL;
    }

    if (bytearray_setslice(self, Py_SIZE(self), Py_SIZE(self), bytearray_obj) == -1) {
        Py_DECREF(bytearray_obj);
        return NULL;
    }
    Py_DECREF(bytearray_obj);

    Py_RETURN_NONE;
}

/*[clinic input]
bytearray.pop

    self: self(type="PyByteArrayObject *")
    index: Py_ssize_t = -1
        The index from where to remove the item.
        -1 (the default value) means remove the last item.
    /

Remove and return a single item from B.

If no index argument is given, will pop the last item.
[clinic start generated code]*/

static PyObject *
bytearray_pop_impl(PyByteArrayObject *self, Py_ssize_t index)
/*[clinic end generated code: output=e0ccd401f8021da8 input=0797e6c0ca9d5a85]*/
{
    int value;
    Py_ssize_t n = Py_SIZE(self);
    char *buf;

    if (n == 0) {
        PyErr_SetString(PyExc_IndexError,
                        "pop from empty bytearray");
        return NULL;
    }
    if (index < 0)
        index += Py_SIZE(self);
    if (index < 0 || index >= Py_SIZE(self)) {
        PyErr_SetString(PyExc_IndexError, "pop index out of range");
        return NULL;
    }
    if (!_canresize(self))
        return NULL;

    buf = PyByteArray_AS_STRING(self);
    value = buf[index];
    memmove(buf + index, buf + index + 1, n - index);
    if (PyByteArray_Resize((PyObject *)self, n - 1) < 0)
        return NULL;

    return PyLong_FromLong((unsigned char)value);
}

/*[clinic input]
bytearray.remove

    self: self(type="PyByteArrayObject *")
    value: bytesvalue
        The value to remove.
    /

Remove the first occurrence of a value in the bytearray.
[clinic start generated code]*/

static PyObject *
bytearray_remove_impl(PyByteArrayObject *self, int value)
/*[clinic end generated code: output=d659e37866709c13 input=47560b11fd856c24]*/
{
    Py_ssize_t where, n = Py_SIZE(self);
    char *buf = PyByteArray_AS_STRING(self);

    for (where = 0; where < n; where++) {
        if (buf[where] == value)
            break;
    }
    if (where == n) {
        PyErr_SetString(PyExc_ValueError, "value not found in bytearray");
        return NULL;
    }
    if (!_canresize(self))
        return NULL;

    memmove(buf + where, buf + where + 1, n - where);
    if (PyByteArray_Resize((PyObject *)self, n - 1) < 0)
        return NULL;

    Py_RETURN_NONE;
}

/* XXX These two helpers could be optimized if argsize == 1 */

static Py_ssize_t
lstrip_helper(char *myptr, Py_ssize_t mysize,
              void *argptr, Py_ssize_t argsize)
{
    Py_ssize_t i = 0;
    while (i < mysize && memchr(argptr, (unsigned char) myptr[i], argsize))
        i++;
    return i;
}

static Py_ssize_t
rstrip_helper(char *myptr, Py_ssize_t mysize,
              void *argptr, Py_ssize_t argsize)
{
    Py_ssize_t i = mysize - 1;
    while (i >= 0 && memchr(argptr, (unsigned char) myptr[i], argsize))
        i--;
    return i + 1;
}

/*[clinic input]
bytearray.strip

    bytes: object = None
    /

Strip leading and trailing bytes contained in the argument.

If the argument is omitted or None, strip leading and trailing ASCII whitespace.
[clinic start generated code]*/

static PyObject *
bytearray_strip_impl(PyByteArrayObject *self, PyObject *bytes)
/*[clinic end generated code: output=760412661a34ad5a input=ef7bb59b09c21d62]*/
{
    Py_ssize_t left, right, mysize, byteslen;
    char *myptr, *bytesptr;
    Py_buffer vbytes;

    if (bytes == Py_None) {
        bytesptr = "\t\n\r\f\v ";
        byteslen = 6;
    }
    else {
        if (PyObject_GetBuffer(bytes, &vbytes, PyBUF_SIMPLE) != 0)
            return NULL;
        bytesptr = (char *) vbytes.buf;
        byteslen = vbytes.len;
    }
    myptr = PyByteArray_AS_STRING(self);
    mysize = Py_SIZE(self);
    left = lstrip_helper(myptr, mysize, bytesptr, byteslen);
    if (left == mysize)
        right = left;
    else
        right = rstrip_helper(myptr, mysize, bytesptr, byteslen);
    if (bytes != Py_None)
        PyBuffer_Release(&vbytes);
    return PyByteArray_FromStringAndSize(myptr + left, right - left);
}

/*[clinic input]
bytearray.lstrip

    bytes: object = None
    /

Strip leading bytes contained in the argument.

If the argument is omitted or None, strip leading ASCII whitespace.
[clinic start generated code]*/

static PyObject *
bytearray_lstrip_impl(PyByteArrayObject *self, PyObject *bytes)
/*[clinic end generated code: output=d005c9d0ab909e66 input=80843f975dd7c480]*/
{
    Py_ssize_t left, right, mysize, byteslen;
    char *myptr, *bytesptr;
    Py_buffer vbytes;

    if (bytes == Py_None) {
        bytesptr = "\t\n\r\f\v ";
        byteslen = 6;
    }
    else {
        if (PyObject_GetBuffer(bytes, &vbytes, PyBUF_SIMPLE) != 0)
            return NULL;
        bytesptr = (char *) vbytes.buf;
        byteslen = vbytes.len;
    }
    myptr = PyByteArray_AS_STRING(self);
    mysize = Py_SIZE(self);
    left = lstrip_helper(myptr, mysize, bytesptr, byteslen);
    right = mysize;
    if (bytes != Py_None)
        PyBuffer_Release(&vbytes);
    return PyByteArray_FromStringAndSize(myptr + left, right - left);
}

/*[clinic input]
bytearray.rstrip

    bytes: object = None
    /

Strip trailing bytes contained in the argument.

If the argument is omitted or None, strip trailing ASCII whitespace.
[clinic start generated code]*/

static PyObject *
bytearray_rstrip_impl(PyByteArrayObject *self, PyObject *bytes)
/*[clinic end generated code: output=030e2fbd2f7276bd input=e728b994954cfd91]*/
{
    Py_ssize_t right, mysize, byteslen;
    char *myptr, *bytesptr;
    Py_buffer vbytes;

    if (bytes == Py_None) {
        bytesptr = "\t\n\r\f\v ";
        byteslen = 6;
    }
    else {
        if (PyObject_GetBuffer(bytes, &vbytes, PyBUF_SIMPLE) != 0)
            return NULL;
        bytesptr = (char *) vbytes.buf;
        byteslen = vbytes.len;
    }
    myptr = PyByteArray_AS_STRING(self);
    mysize = Py_SIZE(self);
    right = rstrip_helper(myptr, mysize, bytesptr, byteslen);
    if (bytes != Py_None)
        PyBuffer_Release(&vbytes);
    return PyByteArray_FromStringAndSize(myptr, right);
}

/*[clinic input]
bytearray.decode

    encoding: str(c_default="NULL") = 'utf-8'
        The encoding with which to decode the bytearray.
    errors: str(c_default="NULL") = 'strict'
        The error handling scheme to use for the handling of decoding errors.
        The default is 'strict' meaning that decoding errors raise a
        UnicodeDecodeError. Other possible values are 'ignore' and 'replace'
        as well as any other name registered with codecs.register_error that
        can handle UnicodeDecodeErrors.

Decode the bytearray using the codec registered for encoding.
[clinic start generated code]*/

static PyObject *
bytearray_decode_impl(PyByteArrayObject *self, const char *encoding,
                      const char *errors)
/*[clinic end generated code: output=f57d43f4a00b42c5 input=f28d8f903020257b]*/
{
    if (encoding == NULL)
        encoding = PyUnicode_GetDefaultEncoding();
    return PyUnicode_FromEncodedObject((PyObject*)self, encoding, errors);
}

PyDoc_STRVAR(alloc_doc,
"B.__alloc__() -> int\n\
\n\
Return the number of bytes actually allocated.");

static PyObject *
bytearray_alloc(PyByteArrayObject *self)
{
    return PyLong_FromSsize_t(self->ob_alloc);
}

/*[clinic input]
bytearray.join

    iterable_of_bytes: object
    /

Concatenate any number of bytes/bytearray objects.

The bytearray whose method is called is inserted in between each pair.

The result is returned as a new bytearray object.
[clinic start generated code]*/

static PyObject *
bytearray_join(PyByteArrayObject *self, PyObject *iterable_of_bytes)
/*[clinic end generated code: output=a8516370bf68ae08 input=aba6b1f9b30fcb8e]*/
{
    return stringlib_bytes_join((PyObject*)self, iterable_of_bytes);
}

/*[clinic input]
bytearray.splitlines

    keepends: int(c_default="0") = False

Return a list of the lines in the bytearray, breaking at line boundaries.

Line breaks are not included in the resulting list unless keepends is given and
true.
[clinic start generated code]*/

static PyObject *
bytearray_splitlines_impl(PyByteArrayObject *self, int keepends)
/*[clinic end generated code: output=4223c94b895f6ad9 input=8ccade941e5ea0bd]*/
{
    return stringlib_splitlines(
        (PyObject*) self, PyByteArray_AS_STRING(self),
        PyByteArray_GET_SIZE(self), keepends
        );
}

/*[clinic input]
@classmethod
bytearray.fromhex

    cls: self(type="PyObject*")
    string: unicode
    /

Create a bytearray object from a string of hexadecimal numbers.

Spaces between two numbers are accepted.
Example: bytearray.fromhex('B9 01EF') -> bytearray(b'\\xb9\\x01\\xef')
[clinic start generated code]*/

static PyObject *
bytearray_fromhex_impl(PyObject*cls, PyObject *string)
/*[clinic end generated code: output=df3da60129b3700c input=907bbd2d34d9367a]*/
{
    return _PyBytes_FromHex(string, 1);
}

PyDoc_STRVAR(hex__doc__,
"B.hex() -> string\n\
\n\
Create a string of hexadecimal numbers from a bytearray object.\n\
Example: bytearray([0xb9, 0x01, 0xef]).hex() -> 'b901ef'.");

static PyObject *
bytearray_hex(PyBytesObject *self)
{
    char* argbuf = PyByteArray_AS_STRING(self);
    Py_ssize_t arglen = PyByteArray_GET_SIZE(self);
    return _Py_strhex(argbuf, arglen);
}

static PyObject *
_common_reduce(PyByteArrayObject *self, int proto)
{
    PyObject *dict;
    _Py_IDENTIFIER(__dict__);
    char *buf;

    dict = _PyObject_GetAttrId((PyObject *)self, &PyId___dict__);
    if (dict == NULL) {
        PyErr_Clear();
        dict = Py_None;
        Py_INCREF(dict);
    }

    buf = PyByteArray_AS_STRING(self);
    if (proto < 3) {
        /* use str based reduction for backwards compatibility with Python 2.x */
        PyObject *latin1;
        if (Py_SIZE(self))
            latin1 = PyUnicode_DecodeLatin1(buf, Py_SIZE(self), NULL);
        else
            latin1 = PyUnicode_FromString("");
        return Py_BuildValue("(O(Ns)N)", Py_TYPE(self), latin1, "latin-1", dict);
    }
    else {
        /* use more efficient byte based reduction */
        if (Py_SIZE(self)) {
            return Py_BuildValue("(O(y#)N)", Py_TYPE(self), buf, Py_SIZE(self), dict);
        }
        else {
            return Py_BuildValue("(O()N)", Py_TYPE(self), dict);
        }
    }
}

/*[clinic input]
bytearray.__reduce__ as bytearray_reduce

    self: self(type="PyByteArrayObject *")

Return state information for pickling.
[clinic start generated code]*/

static PyObject *
bytearray_reduce_impl(PyByteArrayObject *self)
/*[clinic end generated code: output=52bf304086464cab input=fbb07de4d102a03a]*/
{
    return _common_reduce(self, 2);
}

/*[clinic input]
bytearray.__reduce_ex__ as bytearray_reduce_ex

    self: self(type="PyByteArrayObject *")
    proto: int = 0
    /

Return state information for pickling.
[clinic start generated code]*/

static PyObject *
bytearray_reduce_ex_impl(PyByteArrayObject *self, int proto)
/*[clinic end generated code: output=52eac33377197520 input=0e091a42ca6dbd91]*/
{
    return _common_reduce(self, proto);
}

/*[clinic input]
bytearray.__sizeof__ as bytearray_sizeof

    self: self(type="PyByteArrayObject *")

Returns the size of the bytearray object in memory, in bytes.
[clinic start generated code]*/

static PyObject *
bytearray_sizeof_impl(PyByteArrayObject *self)
/*[clinic end generated code: output=738abdd17951c427 input=6b23d305362b462b]*/
{
    Py_ssize_t res;

    res = sizeof(PyByteArrayObject) + self->ob_alloc * sizeof(char);
    return PyLong_FromSsize_t(res);
}

static PySequenceMethods bytearray_as_sequence = {
    (lenfunc)bytearray_length,              /* sq_length */
    (binaryfunc)PyByteArray_Concat,         /* sq_concat */
    (ssizeargfunc)bytearray_repeat,         /* sq_repeat */
    (ssizeargfunc)bytearray_getitem,        /* sq_item */
    0,                                      /* sq_slice */
    (ssizeobjargproc)bytearray_setitem,     /* sq_ass_item */
    0,                                      /* sq_ass_slice */
    (objobjproc)bytearray_contains,         /* sq_contains */
    (binaryfunc)bytearray_iconcat,          /* sq_inplace_concat */
    (ssizeargfunc)bytearray_irepeat,        /* sq_inplace_repeat */
};

static PyMappingMethods bytearray_as_mapping = {
    (lenfunc)bytearray_length,
    (binaryfunc)bytearray_subscript,
    (objobjargproc)bytearray_ass_subscript,
};

static PyBufferProcs bytearray_as_buffer = {
    (getbufferproc)bytearray_getbuffer,
    (releasebufferproc)bytearray_releasebuffer,
};

static PyMethodDef
bytearray_methods[] = {
    {"__alloc__", (PyCFunction)bytearray_alloc, METH_NOARGS, alloc_doc},
    BYTEARRAY_REDUCE_METHODDEF
    BYTEARRAY_REDUCE_EX_METHODDEF
    BYTEARRAY_SIZEOF_METHODDEF
    BYTEARRAY_APPEND_METHODDEF
    {"capitalize", (PyCFunction)stringlib_capitalize, METH_NOARGS,
     _Py_capitalize__doc__},
    {"center", (PyCFunction)stringlib_center, METH_VARARGS, center__doc__},
    BYTEARRAY_CLEAR_METHODDEF
    BYTEARRAY_COPY_METHODDEF
    {"count", (PyCFunction)bytearray_count, METH_VARARGS, count__doc__},
    BYTEARRAY_DECODE_METHODDEF
    {"endswith", (PyCFunction)bytearray_endswith, METH_VARARGS, endswith__doc__},
    {"expandtabs", (PyCFunction)stringlib_expandtabs, METH_VARARGS | METH_KEYWORDS,
     expandtabs__doc__},
    BYTEARRAY_EXTEND_METHODDEF
    {"find", (PyCFunction)bytearray_find, METH_VARARGS, find__doc__},
    BYTEARRAY_FROMHEX_METHODDEF
    {"hex", (PyCFunction)bytearray_hex, METH_NOARGS, hex__doc__},
    {"index", (PyCFunction)bytearray_index, METH_VARARGS, index__doc__},
    BYTEARRAY_INSERT_METHODDEF
    {"isalnum", (PyCFunction)stringlib_isalnum, METH_NOARGS,
     _Py_isalnum__doc__},
    {"isalpha", (PyCFunction)stringlib_isalpha, METH_NOARGS,
     _Py_isalpha__doc__},
    {"isdigit", (PyCFunction)stringlib_isdigit, METH_NOARGS,
     _Py_isdigit__doc__},
    {"islower", (PyCFunction)stringlib_islower, METH_NOARGS,
     _Py_islower__doc__},
    {"isspace", (PyCFunction)stringlib_isspace, METH_NOARGS,
     _Py_isspace__doc__},
    {"istitle", (PyCFunction)stringlib_istitle, METH_NOARGS,
     _Py_istitle__doc__},
    {"isupper", (PyCFunction)stringlib_isupper, METH_NOARGS,
     _Py_isupper__doc__},
    BYTEARRAY_JOIN_METHODDEF
    {"ljust", (PyCFunction)stringlib_ljust, METH_VARARGS, ljust__doc__},
    {"lower", (PyCFunction)stringlib_lower, METH_NOARGS, _Py_lower__doc__},
    BYTEARRAY_LSTRIP_METHODDEF
    BYTEARRAY_MAKETRANS_METHODDEF
    BYTEARRAY_PARTITION_METHODDEF
    BYTEARRAY_POP_METHODDEF
    BYTEARRAY_REMOVE_METHODDEF
    BYTEARRAY_REPLACE_METHODDEF
    BYTEARRAY_REVERSE_METHODDEF
    {"rfind", (PyCFunction)bytearray_rfind, METH_VARARGS, rfind__doc__},
    {"rindex", (PyCFunction)bytearray_rindex, METH_VARARGS, rindex__doc__},
    {"rjust", (PyCFunction)stringlib_rjust, METH_VARARGS, rjust__doc__},
    BYTEARRAY_RPARTITION_METHODDEF
    BYTEARRAY_RSPLIT_METHODDEF
    BYTEARRAY_RSTRIP_METHODDEF
    BYTEARRAY_SPLIT_METHODDEF
    BYTEARRAY_SPLITLINES_METHODDEF
    {"startswith", (PyCFunction)bytearray_startswith, METH_VARARGS ,
     startswith__doc__},
    BYTEARRAY_STRIP_METHODDEF
    {"swapcase", (PyCFunction)stringlib_swapcase, METH_NOARGS,
     _Py_swapcase__doc__},
    {"title", (PyCFunction)stringlib_title, METH_NOARGS, _Py_title__doc__},
    BYTEARRAY_TRANSLATE_METHODDEF
    {"upper", (PyCFunction)stringlib_upper, METH_NOARGS, _Py_upper__doc__},
    {"zfill", (PyCFunction)stringlib_zfill, METH_VARARGS, zfill__doc__},
    {NULL}
};

static PyObject *
bytearray_mod(PyObject *v, PyObject *w)
{
    if (!PyByteArray_Check(v))
        Py_RETURN_NOTIMPLEMENTED;
    return bytearray_format((PyByteArrayObject *)v, w);
}

static PyNumberMethods bytearray_as_number = {
    0,              /*nb_add*/
    0,              /*nb_subtract*/
    0,              /*nb_multiply*/
    bytearray_mod,  /*nb_remainder*/
};

PyDoc_STRVAR(bytearray_doc,
"bytearray(iterable_of_ints) -> bytearray\n\
bytearray(string, encoding[, errors]) -> bytearray\n\
bytearray(bytes_or_buffer) -> mutable copy of bytes_or_buffer\n\
bytearray(int) -> bytes array of size given by the parameter initialized with null bytes\n\
bytearray() -> empty bytes array\n\
\n\
Construct an mutable bytearray object from:\n\
  - an iterable yielding integers in range(256)\n\
  - a text string encoded using the specified encoding\n\
  - a bytes or a buffer object\n\
  - any object implementing the buffer API.\n\
  - an integer");


static PyObject *bytearray_iter(PyObject *seq);

PyTypeObject PyByteArray_Type = {
    PyVarObject_HEAD_INIT(&PyType_Type, 0)
    "bytearray",
    sizeof(PyByteArrayObject),
    0,
    (destructor)bytearray_dealloc,       /* tp_dealloc */
    0,                                  /* tp_print */
    0,                                  /* tp_getattr */
    0,                                  /* tp_setattr */
    0,                                  /* tp_reserved */
    (reprfunc)bytearray_repr,           /* tp_repr */
    &bytearray_as_number,               /* tp_as_number */
    &bytearray_as_sequence,             /* tp_as_sequence */
    &bytearray_as_mapping,              /* tp_as_mapping */
    0,                                  /* tp_hash */
    0,                                  /* tp_call */
    bytearray_str,                      /* tp_str */
    PyObject_GenericGetAttr,            /* tp_getattro */
    0,                                  /* tp_setattro */
    &bytearray_as_buffer,               /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
    bytearray_doc,                      /* tp_doc */
    0,                                  /* tp_traverse */
    0,                                  /* tp_clear */
    (richcmpfunc)bytearray_richcompare, /* tp_richcompare */
    0,                                  /* tp_weaklistoffset */
    bytearray_iter,                     /* tp_iter */
    0,                                  /* tp_iternext */
    bytearray_methods,                  /* tp_methods */
    0,                                  /* tp_members */
    0,                                  /* tp_getset */
    0,                                  /* tp_base */
    0,                                  /* tp_dict */
    0,                                  /* tp_descr_get */
    0,                                  /* tp_descr_set */
    0,                                  /* tp_dictoffset */
    (initproc)bytearray_init,           /* tp_init */
    PyType_GenericAlloc,                /* tp_alloc */
    PyType_GenericNew,                  /* tp_new */
    PyObject_Del,                       /* tp_free */
};

/*********************** Bytes Iterator ****************************/

typedef struct {
    PyObject_HEAD
    Py_ssize_t it_index;
    PyByteArrayObject *it_seq; /* Set to NULL when iterator is exhausted */
} bytesiterobject;

static void
bytearrayiter_dealloc(bytesiterobject *it)
{
    _PyObject_GC_UNTRACK(it);
    Py_XDECREF(it->it_seq);
    PyObject_GC_Del(it);
}

static int
bytearrayiter_traverse(bytesiterobject *it, visitproc visit, void *arg)
{
    Py_VISIT(it->it_seq);
    return 0;
}

static PyObject *
bytearrayiter_next(bytesiterobject *it)
{
    PyByteArrayObject *seq;
    PyObject *item;

    assert(it != NULL);
    seq = it->it_seq;
    if (seq == NULL)
        return NULL;
    assert(PyByteArray_Check(seq));

    if (it->it_index < PyByteArray_GET_SIZE(seq)) {
        item = PyLong_FromLong(
            (unsigned char)PyByteArray_AS_STRING(seq)[it->it_index]);
        if (item != NULL)
            ++it->it_index;
        return item;
    }

    Py_DECREF(seq);
    it->it_seq = NULL;
    return NULL;
}

static PyObject *
bytearrayiter_length_hint(bytesiterobject *it)
{
    Py_ssize_t len = 0;
    if (it->it_seq)
        len = PyByteArray_GET_SIZE(it->it_seq) - it->it_index;
    return PyLong_FromSsize_t(len);
}

PyDoc_STRVAR(length_hint_doc,
    "Private method returning an estimate of len(list(it)).");

static PyObject *
bytearrayiter_reduce(bytesiterobject *it)
{
    if (it->it_seq != NULL) {
        return Py_BuildValue("N(O)n", _PyObject_GetBuiltin("iter"),
                             it->it_seq, it->it_index);
    } else {
        PyObject *u = PyUnicode_FromUnicode(NULL, 0);
        if (u == NULL)
            return NULL;
        return Py_BuildValue("N(N)", _PyObject_GetBuiltin("iter"), u);
    }
}

static PyObject *
bytearrayiter_setstate(bytesiterobject *it, PyObject *state)
{
    Py_ssize_t index = PyLong_AsSsize_t(state);
    if (index == -1 && PyErr_Occurred())
        return NULL;
    if (it->it_seq != NULL) {
        if (index < 0)
            index = 0;
        else if (index > PyByteArray_GET_SIZE(it->it_seq))
            index = PyByteArray_GET_SIZE(it->it_seq); /* iterator exhausted */
        it->it_index = index;
    }
    Py_RETURN_NONE;
}

PyDoc_STRVAR(setstate_doc, "Set state information for unpickling.");

static PyMethodDef bytearrayiter_methods[] = {
    {"__length_hint__", (PyCFunction)bytearrayiter_length_hint, METH_NOARGS,
     length_hint_doc},
     {"__reduce__",      (PyCFunction)bytearrayiter_reduce, METH_NOARGS,
     bytearray_reduce__doc__},
    {"__setstate__",    (PyCFunction)bytearrayiter_setstate, METH_O,
     setstate_doc},
    {NULL, NULL} /* sentinel */
};

PyTypeObject PyByteArrayIter_Type = {
    PyVarObject_HEAD_INIT(&PyType_Type, 0)
    "bytearray_iterator",              /* tp_name */
    sizeof(bytesiterobject),           /* tp_basicsize */
    0,                                 /* tp_itemsize */
    /* methods */
    (destructor)bytearrayiter_dealloc, /* tp_dealloc */
    0,                                 /* tp_print */
    0,                                 /* tp_getattr */
    0,                                 /* tp_setattr */
    0,                                 /* tp_reserved */
    0,                                 /* tp_repr */
    0,                                 /* tp_as_number */
    0,                                 /* tp_as_sequence */
    0,                                 /* tp_as_mapping */
    0,                                 /* tp_hash */
    0,                                 /* tp_call */
    0,                                 /* tp_str */
    PyObject_GenericGetAttr,           /* tp_getattro */
    0,                                 /* tp_setattro */
    0,                                 /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
    0,                                 /* tp_doc */
    (traverseproc)bytearrayiter_traverse,  /* tp_traverse */
    0,                                 /* tp_clear */
    0,                                 /* tp_richcompare */
    0,                                 /* tp_weaklistoffset */
    PyObject_SelfIter,                 /* tp_iter */
    (iternextfunc)bytearrayiter_next,  /* tp_iternext */
    bytearrayiter_methods,             /* tp_methods */
    0,
};

static PyObject *
bytearray_iter(PyObject *seq)
{
    bytesiterobject *it;

    if (!PyByteArray_Check(seq)) {
        PyErr_BadInternalCall();
        return NULL;
    }
    it = PyObject_GC_New(bytesiterobject, &PyByteArrayIter_Type);
    if (it == NULL)
        return NULL;
    it->it_index = 0;
    Py_INCREF(seq);
    it->it_seq = (PyByteArrayObject *)seq;
    _PyObject_GC_TRACK(it);
    return (PyObject *)it;
}