diff --git a/Modules/_json.c b/Modules/_json.c
index 2e77f1c..d75a019 100644
--- a/Modules/_json.c
+++ b/Modules/_json.c
@@ -1,19 +1,164 @@
 #include "Python.h"
+#include "structmember.h"
+#if PY_VERSION_HEX < 0x02060000 && !defined(Py_TYPE)
+#define Py_TYPE(ob)     (((PyObject*)(ob))->ob_type)
+#endif
+#if PY_VERSION_HEX < 0x02050000 && !defined(PY_SSIZE_T_MIN)
+typedef int Py_ssize_t;
+#define PY_SSIZE_T_MAX INT_MAX
+#define PY_SSIZE_T_MIN INT_MIN
+#define PyInt_FromSsize_t PyInt_FromLong
+#define PyInt_AsSsize_t PyInt_AsLong
+#endif
+#ifndef Py_IS_FINITE
+#define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
+#endif
+
+#ifdef __GNUC__
+#define UNUSED __attribute__((__unused__))
+#else
+#define UNUSED
+#endif
 
 #define DEFAULT_ENCODING "utf-8"
-#define S_CHAR(c) (c >= ' ' && c <= '~' && c != '\\' && c != '"')
-#define MIN_EXPANSION 6
 
+#define PyScanner_Check(op) PyObject_TypeCheck(op, &PyScannerType)
+#define PyScanner_CheckExact(op) (Py_TYPE(op) == &PyScannerType)
+#define PyEncoder_Check(op) PyObject_TypeCheck(op, &PyEncoderType)
+#define PyEncoder_CheckExact(op) (Py_TYPE(op) == &PyEncoderType)
+
+static PyTypeObject PyScannerType;
+static PyTypeObject PyEncoderType;
+
+typedef struct _PyScannerObject {
+    PyObject_HEAD
+    PyObject *encoding;
+    PyObject *strict;
+    PyObject *object_hook;
+    PyObject *parse_float;
+    PyObject *parse_int;
+    PyObject *parse_constant;
+} PyScannerObject;
+
+static PyMemberDef scanner_members[] = {
+    {"encoding", T_OBJECT, offsetof(PyScannerObject, encoding), READONLY, "encoding"},
+    {"strict", T_OBJECT, offsetof(PyScannerObject, strict), READONLY, "strict"},
+    {"object_hook", T_OBJECT, offsetof(PyScannerObject, object_hook), READONLY, "object_hook"},
+    {"parse_float", T_OBJECT, offsetof(PyScannerObject, parse_float), READONLY, "parse_float"},
+    {"parse_int", T_OBJECT, offsetof(PyScannerObject, parse_int), READONLY, "parse_int"},
+    {"parse_constant", T_OBJECT, offsetof(PyScannerObject, parse_constant), READONLY, "parse_constant"},
+    {NULL}
+};
+
+typedef struct _PyEncoderObject {
+    PyObject_HEAD
+    PyObject *markers;
+    PyObject *defaultfn;
+    PyObject *encoder;
+    PyObject *indent;
+    PyObject *key_separator;
+    PyObject *item_separator;
+    PyObject *sort_keys;
+    PyObject *skipkeys;
+    int fast_encode;
+    int allow_nan;
+} PyEncoderObject;
+
+static PyMemberDef encoder_members[] = {
+    {"markers", T_OBJECT, offsetof(PyEncoderObject, markers), READONLY, "markers"},
+    {"default", T_OBJECT, offsetof(PyEncoderObject, defaultfn), READONLY, "default"},
+    {"encoder", T_OBJECT, offsetof(PyEncoderObject, encoder), READONLY, "encoder"},
+    {"indent", T_OBJECT, offsetof(PyEncoderObject, indent), READONLY, "indent"},
+    {"key_separator", T_OBJECT, offsetof(PyEncoderObject, key_separator), READONLY, "key_separator"},
+    {"item_separator", T_OBJECT, offsetof(PyEncoderObject, item_separator), READONLY, "item_separator"},
+    {"sort_keys", T_OBJECT, offsetof(PyEncoderObject, sort_keys), READONLY, "sort_keys"},
+    {"skipkeys", T_OBJECT, offsetof(PyEncoderObject, skipkeys), READONLY, "skipkeys"},
+    {NULL}
+};
+
+static Py_ssize_t
+ascii_escape_char(Py_UNICODE c, char *output, Py_ssize_t chars);
+static PyObject *
+ascii_escape_unicode(PyObject *pystr);
+static PyObject *
+ascii_escape_str(PyObject *pystr);
+static PyObject *
+py_encode_basestring_ascii(PyObject* self UNUSED, PyObject *pystr);
+void init_json(void);
+static PyObject *
+scan_once_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr);
+static PyObject *
+scan_once_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr);
+static PyObject *
+_build_rval_index_tuple(PyObject *rval, Py_ssize_t idx);
+static PyObject *
+scanner_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
+static int
+scanner_init(PyObject *self, PyObject *args, PyObject *kwds);
+static void
+scanner_dealloc(PyObject *self);
+static int
+scanner_clear(PyObject *self);
+static PyObject *
+encoder_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
+static int
+encoder_init(PyObject *self, PyObject *args, PyObject *kwds);
+static void
+encoder_dealloc(PyObject *self);
+static int
+encoder_clear(PyObject *self);
+static int
+encoder_listencode_list(PyEncoderObject *s, PyObject *rval, PyObject *seq, Py_ssize_t indent_level);
+static int
+encoder_listencode_obj(PyEncoderObject *s, PyObject *rval, PyObject *obj, Py_ssize_t indent_level);
+static int
+encoder_listencode_dict(PyEncoderObject *s, PyObject *rval, PyObject *dct, Py_ssize_t indent_level);
+static PyObject *
+_encoded_const(PyObject *const);
+static void
+raise_errmsg(char *msg, PyObject *s, Py_ssize_t end);
+static PyObject *
+encoder_encode_string(PyEncoderObject *s, PyObject *obj);
+static int
+_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr);
+static PyObject *
+_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr);
+static PyObject *
+encoder_encode_float(PyEncoderObject *s, PyObject *obj);
+
+#define S_CHAR(c) (c >= ' ' && c <= '~' && c != '\\' && c != '"')
+#define IS_WHITESPACE(c) (((c) == ' ') || ((c) == '\t') || ((c) == '\n') || ((c) == '\r'))
+
+#define MIN_EXPANSION 6
 #ifdef Py_UNICODE_WIDE
 #define MAX_EXPANSION (2 * MIN_EXPANSION)
 #else
 #define MAX_EXPANSION MIN_EXPANSION
 #endif
 
+static int
+_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr)
+{
+    /* PyObject to Py_ssize_t converter */
+    *size_ptr = PyInt_AsSsize_t(o);
+    if (*size_ptr == -1 && PyErr_Occurred());
+        return 1;
+    return 0;
+}
+
+static PyObject *
+_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr)
+{
+    /* Py_ssize_t to PyObject converter */
+    return PyInt_FromSsize_t(*size_ptr);
+}
+
 static Py_ssize_t
 ascii_escape_char(Py_UNICODE c, char *output, Py_ssize_t chars)
 {
-    Py_UNICODE x;
+    /* Escape unicode code point c to ASCII escape sequences
+    in char *output. output must have at least 12 bytes unused to
+    accommodate an escaped surrogate pair "\uXXXX\uXXXX" */
     output[chars++] = '\\';
     switch (c) {
         case '\\': output[chars++] = (char)c; break;
@@ -30,27 +175,19 @@
                 Py_UNICODE v = c - 0x10000;
                 c = 0xd800 | ((v >> 10) & 0x3ff);
                 output[chars++] = 'u';
-                x = (c & 0xf000) >> 12;
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-                x = (c & 0x0f00) >> 8;
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-                x = (c & 0x00f0) >> 4;
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-                x = (c & 0x000f);
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
+                output[chars++] = "0123456789abcdef"[(c >> 12) & 0xf];
+                output[chars++] = "0123456789abcdef"[(c >>  8) & 0xf];
+                output[chars++] = "0123456789abcdef"[(c >>  4) & 0xf];
+                output[chars++] = "0123456789abcdef"[(c      ) & 0xf];
                 c = 0xdc00 | (v & 0x3ff);
                 output[chars++] = '\\';
             }
 #endif
             output[chars++] = 'u';
-            x = (c & 0xf000) >> 12;
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-            x = (c & 0x0f00) >> 8;
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-            x = (c & 0x00f0) >> 4;
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-            x = (c & 0x000f);
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
+            output[chars++] = "0123456789abcdef"[(c >> 12) & 0xf];
+            output[chars++] = "0123456789abcdef"[(c >>  8) & 0xf];
+            output[chars++] = "0123456789abcdef"[(c >>  4) & 0xf];
+            output[chars++] = "0123456789abcdef"[(c      ) & 0xf];
     }
     return chars;
 }
@@ -58,9 +195,11 @@
 static PyObject *
 ascii_escape_unicode(PyObject *pystr)
 {
+    /* Take a PyUnicode pystr and return a new ASCII-only escaped PyString */
     Py_ssize_t i;
     Py_ssize_t input_chars;
     Py_ssize_t output_size;
+    Py_ssize_t max_output_size;
     Py_ssize_t chars;
     PyObject *rval;
     char *output;
@@ -68,8 +207,10 @@
 
     input_chars = PyUnicode_GET_SIZE(pystr);
     input_unicode = PyUnicode_AS_UNICODE(pystr);
+
     /* One char input can be up to 6 chars output, estimate 4 of these */
     output_size = 2 + (MIN_EXPANSION * 4) + input_chars;
+    max_output_size = 2 + (input_chars * MAX_EXPANSION);
     rval = PyString_FromStringAndSize(NULL, output_size);
     if (rval == NULL) {
         return NULL;
@@ -82,20 +223,24 @@
         if (S_CHAR(c)) {
             output[chars++] = (char)c;
         }
-	else {
+        else {
             chars = ascii_escape_char(c, output, chars);
         }
         if (output_size - chars < (1 + MAX_EXPANSION)) {
             /* There's more than four, so let's resize by a lot */
-            output_size *= 2;
+            Py_ssize_t new_output_size = output_size * 2;
             /* This is an upper bound */
-            if (output_size > 2 + (input_chars * MAX_EXPANSION)) {
-                output_size = 2 + (input_chars * MAX_EXPANSION);
+            if (new_output_size > max_output_size) {
+                new_output_size = max_output_size;
             }
-            if (_PyString_Resize(&rval, output_size) == -1) {
-                return NULL;
+            /* Make sure that the output size changed before resizing */
+            if (new_output_size != output_size) {
+                output_size = new_output_size;
+                if (_PyString_Resize(&rval, output_size) == -1) {
+                    return NULL;
+                }
+                output = PyString_AS_STRING(rval);
             }
-            output = PyString_AS_STRING(rval);
         }
     }
     output[chars++] = '"';
@@ -108,6 +253,7 @@
 static PyObject *
 ascii_escape_str(PyObject *pystr)
 {
+    /* Take a PyString pystr and return a new ASCII-only escaped PyString */
     Py_ssize_t i;
     Py_ssize_t input_chars;
     Py_ssize_t output_size;
@@ -118,33 +264,56 @@
 
     input_chars = PyString_GET_SIZE(pystr);
     input_str = PyString_AS_STRING(pystr);
-    /* One char input can be up to 6 chars output, estimate 4 of these */
-    output_size = 2 + (MIN_EXPANSION * 4) + input_chars;
+
+    /* Fast path for a string that's already ASCII */
+    for (i = 0; i < input_chars; i++) {
+        Py_UNICODE c = (Py_UNICODE)(unsigned char)input_str[i];
+        if (!S_CHAR(c)) {
+            /* If we have to escape something, scan the string for unicode */
+            Py_ssize_t j;
+            for (j = i; j < input_chars; j++) {
+                c = (Py_UNICODE)(unsigned char)input_str[j];
+                if (c > 0x7f) {
+                    /* We hit a non-ASCII character, bail to unicode mode */
+                    PyObject *uni;
+                    uni = PyUnicode_DecodeUTF8(input_str, input_chars, "strict");
+                    if (uni == NULL) {
+                        return NULL;
+                    }
+                    rval = ascii_escape_unicode(uni);
+                    Py_DECREF(uni);
+                    return rval;
+                }
+            }
+            break;
+        }
+    }
+
+    if (i == input_chars) {
+        /* Input is already ASCII */
+        output_size = 2 + input_chars;
+    }
+    else {
+        /* One char input can be up to 6 chars output, estimate 4 of these */
+        output_size = 2 + (MIN_EXPANSION * 4) + input_chars;
+    }
     rval = PyString_FromStringAndSize(NULL, output_size);
     if (rval == NULL) {
         return NULL;
     }
     output = PyString_AS_STRING(rval);
-    chars = 0;
-    output[chars++] = '"';
-    for (i = 0; i < input_chars; i++) {
-        Py_UNICODE c = (Py_UNICODE)input_str[i];
+    output[0] = '"';
+
+    /* We know that everything up to i is ASCII already */
+    chars = i + 1;
+    memcpy(&output[1], input_str, i);
+
+    for (; i < input_chars; i++) {
+        Py_UNICODE c = (Py_UNICODE)(unsigned char)input_str[i];
         if (S_CHAR(c)) {
             output[chars++] = (char)c;
         }
-	else if (c > 0x7F) {
-            /* We hit a non-ASCII character, bail to unicode mode */
-            PyObject *uni;
-            Py_DECREF(rval);
-            uni = PyUnicode_DecodeUTF8(input_str, input_chars, "strict");
-            if (uni == NULL) {
-                return NULL;
-            }
-            rval = ascii_escape_unicode(uni);
-            Py_DECREF(uni);
-            return rval;
-        }
-	else {
+        else {
             chars = ascii_escape_char(c, output, chars);
         }
         /* An ASCII char can't possibly expand to a surrogate! */
@@ -167,9 +336,11 @@
     return rval;
 }
 
-void
+static void
 raise_errmsg(char *msg, PyObject *s, Py_ssize_t end)
 {
+    /* Use the Python function json.decoder.errmsg to raise a nice
+    looking ValueError exception */
     static PyObject *errmsg_fn = NULL;
     PyObject *pymsg;
     if (errmsg_fn == NULL) {
@@ -177,61 +348,97 @@
         if (decoder == NULL)
             return;
         errmsg_fn = PyObject_GetAttrString(decoder, "errmsg");
+        Py_DECREF(decoder);
         if (errmsg_fn == NULL)
             return;
-        Py_DECREF(decoder);
     }
-    pymsg = PyObject_CallFunction(errmsg_fn, "(zOn)", msg, s, end);
+    pymsg = PyObject_CallFunction(errmsg_fn, "(zOO&)", msg, s, _convertPyInt_FromSsize_t, &end);
     if (pymsg) {
         PyErr_SetObject(PyExc_ValueError, pymsg);
         Py_DECREF(pymsg);
     }
-/*
-
-def linecol(doc, pos):
-    lineno = doc.count('\n', 0, pos) + 1
-    if lineno == 1:
-        colno = pos
-    else:
-        colno = pos - doc.rindex('\n', 0, pos)
-    return lineno, colno
-
-def errmsg(msg, doc, pos, end=None):
-    lineno, colno = linecol(doc, pos)
-    if end is None:
-        return '%s: line %d column %d (char %d)' % (msg, lineno, colno, pos)
-    endlineno, endcolno = linecol(doc, end)
-    return '%s: line %d column %d - line %d column %d (char %d - %d)' % (
-        msg, lineno, colno, endlineno, endcolno, pos, end)
-
-*/
 }
 
 static PyObject *
 join_list_unicode(PyObject *lst)
 {
-    static PyObject *ustr = NULL;
-    static PyObject *joinstr = NULL;
-    if (ustr == NULL) {
-        Py_UNICODE c = 0;
-        ustr = PyUnicode_FromUnicode(&c, 0);
+    /* return u''.join(lst) */
+    static PyObject *joinfn = NULL;
+    if (joinfn == NULL) {
+        PyObject *ustr = PyUnicode_FromUnicode(NULL, 0);
+        if (ustr == NULL)
+            return NULL;
+
+        joinfn = PyObject_GetAttrString(ustr, "join");
+        Py_DECREF(ustr);
+        if (joinfn == NULL)
+            return NULL;
     }
-    if (joinstr == NULL) {
-        joinstr = PyString_InternFromString("join");
-    }
-    if (joinstr == NULL || ustr == NULL) {
-        return NULL;
-    }
-    return PyObject_CallMethodObjArgs(ustr, joinstr, lst, NULL);
+    return PyObject_CallFunctionObjArgs(joinfn, lst, NULL);
 }
 
 static PyObject *
-scanstring_str(PyObject *pystr, Py_ssize_t end, char *encoding, int strict)
+join_list_string(PyObject *lst)
 {
+    /* return ''.join(lst) */
+    static PyObject *joinfn = NULL;
+    if (joinfn == NULL) {
+        PyObject *ustr = PyString_FromStringAndSize(NULL, 0);
+        if (ustr == NULL)
+            return NULL;
+
+        joinfn = PyObject_GetAttrString(ustr, "join");
+        Py_DECREF(ustr);
+        if (joinfn == NULL)
+            return NULL;
+    }
+    return PyObject_CallFunctionObjArgs(joinfn, lst, NULL);
+}
+
+static PyObject *
+_build_rval_index_tuple(PyObject *rval, Py_ssize_t idx) {
+    /* return (rval, idx) tuple, stealing reference to rval */
+    PyObject *tpl;
+    PyObject *pyidx;
+    /*
+    steal a reference to rval, returns (rval, idx)
+    */
+    if (rval == NULL) {
+        return NULL;
+    }
+    pyidx = PyInt_FromSsize_t(idx);
+    if (pyidx == NULL) {
+        Py_DECREF(rval);
+        return NULL;
+    }
+    tpl = PyTuple_New(2);
+    if (tpl == NULL) {
+        Py_DECREF(pyidx);
+        Py_DECREF(rval);
+        return NULL;
+    }
+    PyTuple_SET_ITEM(tpl, 0, rval);
+    PyTuple_SET_ITEM(tpl, 1, pyidx);
+    return tpl;
+}
+
+static PyObject *
+scanstring_str(PyObject *pystr, Py_ssize_t end, char *encoding, int strict, Py_ssize_t *next_end_ptr)
+{
+    /* Read the JSON string from PyString pystr.
+    end is the index of the first character after the quote.
+    encoding is the encoding of pystr (must be an ASCII superset)
+    if strict is zero then literal control characters are allowed
+    *next_end_ptr is a return-by-reference index of the character
+        after the end quote
+
+    Return value is a new PyString (if ASCII-only) or PyUnicode
+    */
     PyObject *rval;
     Py_ssize_t len = PyString_GET_SIZE(pystr);
     Py_ssize_t begin = end - 1;
     Py_ssize_t next = begin;
+    int has_unicode = 0;
     char *buf = PyString_AS_STRING(pystr);
     PyObject *chunks = PyList_New(0);
     if (chunks == NULL) {
@@ -246,7 +453,7 @@
         Py_UNICODE c = 0;
         PyObject *chunk = NULL;
         for (next = end; next < len; next++) {
-            c = buf[next];
+            c = (unsigned char)buf[next];
             if (c == '"' || c == '\\') {
                 break;
             }
@@ -254,6 +461,9 @@
                 raise_errmsg("Invalid control character at", pystr, next);
                 goto bail;
             }
+            else if (c > 0x7f) {
+                has_unicode = 1;
+            }
         }
         if (!(c == '"' || c == '\\')) {
             raise_errmsg("Unterminated string starting at", pystr, begin);
@@ -261,14 +471,19 @@
         }
         /* Pick up this chunk if it's not zero length */
         if (next != end) {
-            PyObject *strchunk = PyBuffer_FromMemory(&buf[end], next - end);
+            PyObject *strchunk = PyString_FromStringAndSize(&buf[end], next - end);
             if (strchunk == NULL) {
                 goto bail;
             }
-            chunk = PyUnicode_FromEncodedObject(strchunk, encoding, NULL);
-            Py_DECREF(strchunk);
-            if (chunk == NULL) {
-                goto bail;
+            if (has_unicode) {
+                chunk = PyUnicode_FromEncodedObject(strchunk, encoding, NULL);
+                Py_DECREF(strchunk);
+                if (chunk == NULL) {
+                    goto bail;
+                }
+            }
+            else {
+                chunk = strchunk;
             }
             if (PyList_Append(chunks, chunk)) {
                 Py_DECREF(chunk);
@@ -315,18 +530,18 @@
             }
             /* Decode 4 hex digits */
             for (; next < end; next++) {
-                Py_ssize_t shl = (end - next - 1) << 2;
                 Py_UNICODE digit = buf[next];
+                c <<= 4;
                 switch (digit) {
                     case '0': case '1': case '2': case '3': case '4':
                     case '5': case '6': case '7': case '8': case '9':
-                        c |= (digit - '0') << shl; break;
+                        c |= (digit - '0'); break;
                     case 'a': case 'b': case 'c': case 'd': case 'e':
                     case 'f':
-                        c |= (digit - 'a' + 10) << shl; break;
+                        c |= (digit - 'a' + 10); break;
                     case 'A': case 'B': case 'C': case 'D': case 'E':
                     case 'F':
-                        c |= (digit - 'A' + 10) << shl; break;
+                        c |= (digit - 'A' + 10); break;
                     default:
                         raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                         goto bail;
@@ -334,43 +549,63 @@
             }
 #ifdef Py_UNICODE_WIDE
             /* Surrogate pair */
-            if (c >= 0xd800 && c <= 0xdbff) {
+            if ((c & 0xfc00) == 0xd800) {
                 Py_UNICODE c2 = 0;
                 if (end + 6 >= len) {
-                    raise_errmsg("Invalid \\uXXXX\\uXXXX surrogate pair", pystr,
-                        end - 5);
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
                 }
                 if (buf[next++] != '\\' || buf[next++] != 'u') {
-                    raise_errmsg("Invalid \\uXXXX\\uXXXX surrogate pair", pystr,
-                        end - 5);
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
                 }
                 end += 6;
                 /* Decode 4 hex digits */
                 for (; next < end; next++) {
-                    Py_ssize_t shl = (end - next - 1) << 2;
+                    c2 <<= 4;
                     Py_UNICODE digit = buf[next];
                     switch (digit) {
                         case '0': case '1': case '2': case '3': case '4':
                         case '5': case '6': case '7': case '8': case '9':
-                            c2 |= (digit - '0') << shl; break;
+                            c2 |= (digit - '0'); break;
                         case 'a': case 'b': case 'c': case 'd': case 'e':
                         case 'f':
-                            c2 |= (digit - 'a' + 10) << shl; break;
+                            c2 |= (digit - 'a' + 10); break;
                         case 'A': case 'B': case 'C': case 'D': case 'E':
                         case 'F':
-                            c2 |= (digit - 'A' + 10) << shl; break;
+                            c2 |= (digit - 'A' + 10); break;
                         default:
                             raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                             goto bail;
                     }
                 }
+                if ((c2 & 0xfc00) != 0xdc00) {
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
+                }
                 c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
             }
+            else if ((c & 0xfc00) == 0xdc00) {
+                raise_errmsg("Unpaired low surrogate", pystr, end - 5);
+                goto bail;
+            }
 #endif
         }
-        chunk = PyUnicode_FromUnicode(&c, 1);
-        if (chunk == NULL) {
-            goto bail;
+        if (c > 0x7f) {
+            has_unicode = 1;
+        }
+        if (has_unicode) {
+            chunk = PyUnicode_FromUnicode(&c, 1);
+            if (chunk == NULL) {
+                goto bail;
+            }
+        }
+        else {
+            char c_char = Py_CHARMASK(c);
+            chunk = PyString_FromStringAndSize(&c_char, 1);
+            if (chunk == NULL) {
+                goto bail;
+            }
         }
         if (PyList_Append(chunks, chunk)) {
             Py_DECREF(chunk);
@@ -379,21 +614,31 @@
         Py_DECREF(chunk);
     }
 
-    rval = join_list_unicode(chunks);
+    rval = join_list_string(chunks);
     if (rval == NULL) {
         goto bail;
     }
     Py_CLEAR(chunks);
-    return Py_BuildValue("(Nn)", rval, end);
+    *next_end_ptr = end;
+    return rval;
 bail:
+    *next_end_ptr = -1;
     Py_XDECREF(chunks);
     return NULL;
 }
 
 
 static PyObject *
-scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict)
+scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next_end_ptr)
 {
+    /* Read the JSON string from PyUnicode pystr.
+    end is the index of the first character after the quote.
+    if strict is zero then literal control characters are allowed
+    *next_end_ptr is a return-by-reference index of the character
+        after the end quote
+
+    Return value is a new PyUnicode
+    */
     PyObject *rval;
     Py_ssize_t len = PyUnicode_GET_SIZE(pystr);
     Py_ssize_t begin = end - 1;
@@ -476,18 +721,18 @@
             }
             /* Decode 4 hex digits */
             for (; next < end; next++) {
-                Py_ssize_t shl = (end - next - 1) << 2;
                 Py_UNICODE digit = buf[next];
+                c <<= 4;
                 switch (digit) {
                     case '0': case '1': case '2': case '3': case '4':
                     case '5': case '6': case '7': case '8': case '9':
-                        c |= (digit - '0') << shl; break;
+                        c |= (digit - '0'); break;
                     case 'a': case 'b': case 'c': case 'd': case 'e':
                     case 'f':
-                        c |= (digit - 'a' + 10) << shl; break;
+                        c |= (digit - 'a' + 10); break;
                     case 'A': case 'B': case 'C': case 'D': case 'E':
                     case 'F':
-                        c |= (digit - 'A' + 10) << shl; break;
+                        c |= (digit - 'A' + 10); break;
                     default:
                         raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                         goto bail;
@@ -495,38 +740,46 @@
             }
 #ifdef Py_UNICODE_WIDE
             /* Surrogate pair */
-            if (c >= 0xd800 && c <= 0xdbff) {
+            if ((c & 0xfc00) == 0xd800) {
                 Py_UNICODE c2 = 0;
                 if (end + 6 >= len) {
-                    raise_errmsg("Invalid \\uXXXX\\uXXXX surrogate pair", pystr,
-                        end - 5);
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
                 }
                 if (buf[next++] != '\\' || buf[next++] != 'u') {
-                    raise_errmsg("Invalid \\uXXXX\\uXXXX surrogate pair", pystr,
-                        end - 5);
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
                 }
                 end += 6;
                 /* Decode 4 hex digits */
                 for (; next < end; next++) {
-                    Py_ssize_t shl = (end - next - 1) << 2;
+                    c2 <<= 4;
                     Py_UNICODE digit = buf[next];
                     switch (digit) {
                         case '0': case '1': case '2': case '3': case '4':
                         case '5': case '6': case '7': case '8': case '9':
-                            c2 |= (digit - '0') << shl; break;
+                            c2 |= (digit - '0'); break;
                         case 'a': case 'b': case 'c': case 'd': case 'e':
                         case 'f':
-                            c2 |= (digit - 'a' + 10) << shl; break;
+                            c2 |= (digit - 'a' + 10); break;
                         case 'A': case 'B': case 'C': case 'D': case 'E':
                         case 'F':
-                            c2 |= (digit - 'A' + 10) << shl; break;
+                            c2 |= (digit - 'A' + 10); break;
                         default:
                             raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                             goto bail;
                     }
                 }
+                if ((c2 & 0xfc00) != 0xdc00) {
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
+                }
                 c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
             }
+            else if ((c & 0xfc00) == 0xdc00) {
+                raise_errmsg("Unpaired low surrogate", pystr, end - 5);
+                goto bail;
+            }
 #endif
         }
         chunk = PyUnicode_FromUnicode(&c, 1);
@@ -544,49 +797,68 @@
     if (rval == NULL) {
         goto bail;
     }
-    Py_CLEAR(chunks);
-    return Py_BuildValue("(Nn)", rval, end);
+    Py_DECREF(chunks);
+    *next_end_ptr = end;
+    return rval;
 bail:
+    *next_end_ptr = -1;
     Py_XDECREF(chunks);
     return NULL;
 }
 
 PyDoc_STRVAR(pydoc_scanstring,
-"scanstring(basestring, end, encoding) -> (str, end)\n");
+    "scanstring(basestring, end, encoding, strict=True) -> (str, end)\n"
+    "\n"
+    "Scan the string s for a JSON string. End is the index of the\n"
+    "character in s after the quote that started the JSON string.\n"
+    "Unescapes all valid JSON string escape sequences and raises ValueError\n"
+    "on attempt to decode an invalid string. If strict is False then literal\n"
+    "control characters are allowed in the string.\n"
+    "\n"
+    "Returns a tuple of the decoded string and the index of the character in s\n"
+    "after the end quote."
+);
 
 static PyObject *
-py_scanstring(PyObject* self, PyObject *args)
+py_scanstring(PyObject* self UNUSED, PyObject *args)
 {
     PyObject *pystr;
+    PyObject *rval;
     Py_ssize_t end;
+    Py_ssize_t next_end = -1;
     char *encoding = NULL;
-    int strict = 0;
-    if (!PyArg_ParseTuple(args, "On|zi:scanstring", &pystr, &end, &encoding, &strict)) {
+    int strict = 1;
+    if (!PyArg_ParseTuple(args, "OO&|zi:scanstring", &pystr, _convertPyInt_AsSsize_t, &end, &encoding, &strict)) {
         return NULL;
     }
     if (encoding == NULL) {
         encoding = DEFAULT_ENCODING;
     }
     if (PyString_Check(pystr)) {
-        return scanstring_str(pystr, end, encoding, strict);
+        rval = scanstring_str(pystr, end, encoding, strict, &next_end);
     }
     else if (PyUnicode_Check(pystr)) {
-        return scanstring_unicode(pystr, end, strict);
+        rval = scanstring_unicode(pystr, end, strict, &next_end);
     }
     else {
-        PyErr_Format(PyExc_TypeError, 
-                     "first argument must be a string or unicode, not %.80s",
+        PyErr_Format(PyExc_TypeError,
+                     "first argument must be a string, not %.80s",
                      Py_TYPE(pystr)->tp_name);
         return NULL;
     }
+    return _build_rval_index_tuple(rval, next_end);
 }
 
 PyDoc_STRVAR(pydoc_encode_basestring_ascii,
-"encode_basestring_ascii(basestring) -> str\n");
+    "encode_basestring_ascii(basestring) -> str\n"
+    "\n"
+    "Return an ASCII-only JSON representation of a Python string"
+);
 
 static PyObject *
-py_encode_basestring_ascii(PyObject* self, PyObject *pystr)
+py_encode_basestring_ascii(PyObject* self UNUSED, PyObject *pystr)
 {
+    /* Return an ASCII-only JSON representation of a Python string */
     /* METH_O */
     if (PyString_Check(pystr)) {
         return ascii_escape_str(pystr);
@@ -595,18 +867,1444 @@
         return ascii_escape_unicode(pystr);
     }
     else {
-        PyErr_Format(PyExc_TypeError, 
-                     "first argument must be a string or unicode, not %.80s",
+        PyErr_Format(PyExc_TypeError,
+                     "first argument must be a string, not %.80s",
                      Py_TYPE(pystr)->tp_name);
         return NULL;
     }
 }
 
-static PyMethodDef json_methods[] = {
-    {"encode_basestring_ascii", (PyCFunction)py_encode_basestring_ascii,
-     METH_O, pydoc_encode_basestring_ascii},
-    {"scanstring", (PyCFunction)py_scanstring, METH_VARARGS,
-     pydoc_scanstring},
+static void
+scanner_dealloc(PyObject *self)
+{
+    /* Deallocate scanner object */
+    scanner_clear(self);
+    Py_TYPE(self)->tp_free(self);
+}
+
+static int
+scanner_traverse(PyObject *self, visitproc visit, void *arg)
+{
+    PyScannerObject *s;
+    assert(PyScanner_Check(self));
+    s = (PyScannerObject *)self;
+    Py_VISIT(s->encoding);
+    Py_VISIT(s->strict);
+    Py_VISIT(s->object_hook);
+    Py_VISIT(s->parse_float);
+    Py_VISIT(s->parse_int);
+    Py_VISIT(s->parse_constant);
+    return 0;
+}
+
+static int
+scanner_clear(PyObject *self)
+{
+    PyScannerObject *s;
+    assert(PyScanner_Check(self));
+    s = (PyScannerObject *)self;
+    Py_CLEAR(s->encoding);
+    Py_CLEAR(s->strict);
+    Py_CLEAR(s->object_hook);
+    Py_CLEAR(s->parse_float);
+    Py_CLEAR(s->parse_int);
+    Py_CLEAR(s->parse_constant);
+    return 0;
+}
+
+static PyObject *
+_parse_object_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
+    /* Read a JSON object from PyString pystr.
+    idx is the index of the first character after the opening curly brace.
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the closing curly brace.
+
+    Returns a new PyObject (usually a dict, but object_hook can change that)
+    */
+    char *str = PyString_AS_STRING(pystr);
+    Py_ssize_t end_idx = PyString_GET_SIZE(pystr) - 1;
+    PyObject *rval = PyDict_New();
+    PyObject *key = NULL;
+    PyObject *val = NULL;
+    char *encoding = PyString_AS_STRING(s->encoding);
+    int strict = PyObject_IsTrue(s->strict);
+    Py_ssize_t next_idx;
+    if (rval == NULL)
+        return NULL;
+
+    /* skip whitespace after { */
+    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+    /* only loop if the object is non-empty */
+    if (idx <= end_idx && str[idx] != '}') {
+        while (idx <= end_idx) {
+            /* read key */
+            if (str[idx] != '"') {
+                raise_errmsg("Expecting property name", pystr, idx);
+                goto bail;
+            }
+            key = scanstring_str(pystr, idx + 1, encoding, strict, &next_idx);
+            if (key == NULL)
+                goto bail;
+            idx = next_idx;
+
+            /* skip whitespace between key and : delimiter, read :, skip whitespace */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+            if (idx > end_idx || str[idx] != ':') {
+                raise_errmsg("Expecting : delimiter", pystr, idx);
+                goto bail;
+            }
+            idx++;
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+            /* read any JSON data type */
+            val = scan_once_str(s, pystr, idx, &next_idx);
+            if (val == NULL)
+                goto bail;
+
+            if (PyDict_SetItem(rval, key, val) == -1)
+                goto bail;
+
+            Py_CLEAR(key);
+            Py_CLEAR(val);
+            idx = next_idx;
+
+            /* skip whitespace before } or , */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+            /* bail if the object is closed or we didn't get the , delimiter */
+            if (idx > end_idx) break;
+            if (str[idx] == '}') {
+                break;
+            }
+            else if (str[idx] != ',') {
+                raise_errmsg("Expecting , delimiter", pystr, idx);
+                goto bail;
+            }
+            idx++;
+
+            /* skip whitespace after , delimiter */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+        }
+    }
+    /* verify that idx < end_idx, str[idx] should be '}' */
+    if (idx > end_idx || str[idx] != '}') {
+        raise_errmsg("Expecting object", pystr, end_idx);
+        goto bail;
+    }
+    /* if object_hook is not None: rval = object_hook(rval) */
+    if (s->object_hook != Py_None) {
+        val = PyObject_CallFunctionObjArgs(s->object_hook, rval, NULL);
+        if (val == NULL)
+            goto bail;
+        Py_DECREF(rval);
+        rval = val;
+        val = NULL;
+    }
+    *next_idx_ptr = idx + 1;
+    return rval;
+bail:
+    Py_XDECREF(key);
+    Py_XDECREF(val);
+    Py_DECREF(rval);
+    return NULL;
+}
+
+static PyObject *
+_parse_object_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
+    /* Read a JSON object from PyUnicode pystr.
+    idx is the index of the first character after the opening curly brace.
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the closing curly brace.
+
+    Returns a new PyObject (usually a dict, but object_hook can change that)
+    */
+    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
+    Py_ssize_t end_idx = PyUnicode_GET_SIZE(pystr) - 1;
+    PyObject *val = NULL;
+    PyObject *rval = PyDict_New();
+    PyObject *key = NULL;
+    int strict = PyObject_IsTrue(s->strict);
+    Py_ssize_t next_idx;
+    if (rval == NULL)
+        return NULL;
+
+    /* skip whitespace after { */
+    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+    /* only loop if the object is non-empty */
+    if (idx <= end_idx && str[idx] != '}') {
+        while (idx <= end_idx) {
+            /* read key */
+            if (str[idx] != '"') {
+                raise_errmsg("Expecting property name", pystr, idx);
+                goto bail;
+            }
+            key = scanstring_unicode(pystr, idx + 1, strict, &next_idx);
+            if (key == NULL)
+                goto bail;
+            idx = next_idx;
+
+            /* skip whitespace between key and : delimiter, read :, skip whitespace */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+            if (idx > end_idx || str[idx] != ':') {
+                raise_errmsg("Expecting : delimiter", pystr, idx);
+                goto bail;
+            }
+            idx++;
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+            /* read any JSON term */
+            val = scan_once_unicode(s, pystr, idx, &next_idx);
+            if (val == NULL)
+                goto bail;
+
+            if (PyDict_SetItem(rval, key, val) == -1)
+                goto bail;
+
+            Py_CLEAR(key);
+            Py_CLEAR(val);
+            idx = next_idx;
+
+            /* skip whitespace before } or , */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+            /* bail if the object is closed or we didn't get the , delimiter */
+            if (idx > end_idx) break;
+            if (str[idx] == '}') {
+                break;
+            }
+            else if (str[idx] != ',') {
+                raise_errmsg("Expecting , delimiter", pystr, idx);
+                goto bail;
+            }
+            idx++;
+
+            /* skip whitespace after , delimiter */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+        }
+    }
+
+    /* verify that idx < end_idx, str[idx] should be '}' */
+    if (idx > end_idx || str[idx] != '}') {
+        raise_errmsg("Expecting object", pystr, end_idx);
+        goto bail;
+    }
+
+    /* if object_hook is not None: rval = object_hook(rval) */
+    if (s->object_hook != Py_None) {
+        val = PyObject_CallFunctionObjArgs(s->object_hook, rval, NULL);
+        if (val == NULL)
+            goto bail;
+        Py_DECREF(rval);
+        rval = val;
+        val = NULL;
+    }
+    *next_idx_ptr = idx + 1;
+    return rval;
+bail:
+    Py_XDECREF(key);
+    Py_XDECREF(val);
+    Py_DECREF(rval);
+    return NULL;
+}
+
+static PyObject *
+_parse_array_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
+    /* Read a JSON array from PyString pystr.
+    idx is the index of the first character after the opening brace.
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the closing brace.
+
+    Returns a new PyList
+    */
+    char *str = PyString_AS_STRING(pystr);
+    Py_ssize_t end_idx = PyString_GET_SIZE(pystr) - 1;
+    PyObject *val = NULL;
+    PyObject *rval = PyList_New(0);
+    Py_ssize_t next_idx;
+    if (rval == NULL)
+        return NULL;
+
+    /* skip whitespace after [ */
+    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+    /* only loop if the array is non-empty */
+    if (idx <= end_idx && str[idx] != ']') {
+        while (idx <= end_idx) {
+
+            /* read any JSON term and de-tuplefy the (rval, idx) */
+            val = scan_once_str(s, pystr, idx, &next_idx);
+            if (val == NULL)
+                goto bail;
+
+            if (PyList_Append(rval, val) == -1)
+                goto bail;
+
+            Py_CLEAR(val);
+            idx = next_idx;
+
+            /* skip whitespace between term and , */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+            /* bail if the array is closed or we didn't get the , delimiter */
+            if (idx > end_idx) break;
+            if (str[idx] == ']') {
+                break;
+            }
+            else if (str[idx] != ',') {
+                raise_errmsg("Expecting , delimiter", pystr, idx);
+                goto bail;
+            }
+            idx++;
+
+            /* skip whitespace after , */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+        }
+    }
+
+    /* verify that idx < end_idx, str[idx] should be ']' */
+    if (idx > end_idx || str[idx] != ']') {
+        raise_errmsg("Expecting object", pystr, end_idx);
+        goto bail;
+    }
+    *next_idx_ptr = idx + 1;
+    return rval;
+bail:
+    Py_XDECREF(val);
+    Py_DECREF(rval);
+    return NULL;
+}
+
+static PyObject *
+_parse_array_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
+    /* Read a JSON array from PyString pystr.
+    idx is the index of the first character after the opening brace.
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the closing brace.
+
+    Returns a new PyList
+    */
+    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
+    Py_ssize_t end_idx = PyUnicode_GET_SIZE(pystr) - 1;
+    PyObject *val = NULL;
+    PyObject *rval = PyList_New(0);
+    Py_ssize_t next_idx;
+    if (rval == NULL)
+        return NULL;
+
+    /* skip whitespace after [ */
+    while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+    /* only loop if the array is non-empty */
+    if (idx <= end_idx && str[idx] != ']') {
+        while (idx <= end_idx) {
+
+            /* read any JSON term  */
+            val = scan_once_unicode(s, pystr, idx, &next_idx);
+            if (val == NULL)
+                goto bail;
+
+            if (PyList_Append(rval, val) == -1)
+                goto bail;
+
+            Py_CLEAR(val);
+            idx = next_idx;
+
+            /* skip whitespace between term and , */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+
+            /* bail if the array is closed or we didn't get the , delimiter */
+            if (idx > end_idx) break;
+            if (str[idx] == ']') {
+                break;
+            }
+            else if (str[idx] != ',') {
+                raise_errmsg("Expecting , delimiter", pystr, idx);
+                goto bail;
+            }
+            idx++;
+
+            /* skip whitespace after , */
+            while (idx <= end_idx && IS_WHITESPACE(str[idx])) idx++;
+        }
+    }
+
+    /* verify that idx < end_idx, str[idx] should be ']' */
+    if (idx > end_idx || str[idx] != ']') {
+        raise_errmsg("Expecting object", pystr, end_idx);
+        goto bail;
+    }
+    *next_idx_ptr = idx + 1;
+    return rval;
+bail:
+    Py_XDECREF(val);
+    Py_DECREF(rval);
+    return NULL;
+}
+
+static PyObject *
+_parse_constant(PyScannerObject *s, char *constant, Py_ssize_t idx, Py_ssize_t *next_idx_ptr) {
+    /* Read a JSON constant from PyString pystr.
+    constant is the constant string that was found
+        ("NaN", "Infinity", "-Infinity").
+    idx is the index of the first character of the constant
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the constant.
+
+    Returns the result of parse_constant
+    */
+    PyObject *cstr;
+    PyObject *rval;
+    /* constant is "NaN", "Infinity", or "-Infinity" */
+    cstr = PyString_InternFromString(constant);
+    if (cstr == NULL)
+        return NULL;
+
+    /* rval = parse_constant(constant) */
+    rval = PyObject_CallFunctionObjArgs(s->parse_constant, cstr, NULL);
+    idx += PyString_GET_SIZE(cstr);
+    Py_DECREF(cstr);
+    *next_idx_ptr = idx;
+    return rval;
+}
+
+static PyObject *
+_match_number_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t start, Py_ssize_t *next_idx_ptr) {
+    /* Read a JSON number from PyString pystr.
+    idx is the index of the first character of the number
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the number.
+
+    Returns a new PyObject representation of that number:
+        PyInt, PyLong, or PyFloat.
+        May return other types if parse_int or parse_float are set
+    */
+    char *str = PyString_AS_STRING(pystr);
+    Py_ssize_t end_idx = PyString_GET_SIZE(pystr) - 1;
+    Py_ssize_t idx = start;
+    int is_float = 0;
+    PyObject *rval;
+    PyObject *numstr;
+
+    /* read a sign if it's there, make sure it's not the end of the string */
+    if (str[idx] == '-') {
+        idx++;
+        if (idx > end_idx) {
+            PyErr_SetNone(PyExc_StopIteration);
+            return NULL;
+        }
+    }
+
+    /* read as many integer digits as we find as long as it doesn't start with 0 */
+    if (str[idx] >= '1' && str[idx] <= '9') {
+        idx++;
+        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
+    }
+    /* if it starts with 0 we only expect one integer digit */
+    else if (str[idx] == '0') {
+        idx++;
+    }
+    /* no integer digits, error */
+    else {
+        PyErr_SetNone(PyExc_StopIteration);
+        return NULL;
+    }
+
+    /* if the next char is '.' followed by a digit then read all float digits */
+    if (idx < end_idx && str[idx] == '.' && str[idx + 1] >= '0' && str[idx + 1] <= '9') {
+        is_float = 1;
+        idx += 2;
+        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
+    }
+
+    /* if the next char is 'e' or 'E' then maybe read the exponent (or backtrack) */
+    if (idx < end_idx && (str[idx] == 'e' || str[idx] == 'E')) {
+
+        /* save the index of the 'e' or 'E' just in case we need to backtrack */
+        Py_ssize_t e_start = idx;
+        idx++;
+
+        /* read an exponent sign if present */
+        if (idx < end_idx && (str[idx] == '-' || str[idx] == '+')) idx++;
+
+        /* read all digits */
+        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
+
+        /* if we got a digit, then parse as float. if not, backtrack */
+        if (str[idx - 1] >= '0' && str[idx - 1] <= '9') {
+            is_float = 1;
+        }
+        else {
+            idx = e_start;
+        }
+    }
+
+    /* copy the section we determined to be a number */
+    numstr = PyString_FromStringAndSize(&str[start], idx - start);
+    if (numstr == NULL)
+        return NULL;
+    if (is_float) {
+        /* parse as a float using a fast path if available, otherwise call user defined method */
+        if (s->parse_float != (PyObject *)&PyFloat_Type) {
+            rval = PyObject_CallFunctionObjArgs(s->parse_float, numstr, NULL);
+        }
+        else {
+            rval = PyFloat_FromDouble(PyOS_ascii_atof(PyString_AS_STRING(numstr)));
+        }
+    }
+    else {
+        /* parse as an int using a fast path if available, otherwise call user defined method */
+        if (s->parse_int != (PyObject *)&PyInt_Type) {
+            rval = PyObject_CallFunctionObjArgs(s->parse_int, numstr, NULL);
+        }
+        else {
+            rval = PyInt_FromString(PyString_AS_STRING(numstr), NULL, 10);
+        }
+    }
+    Py_DECREF(numstr);
+    *next_idx_ptr = idx;
+    return rval;
+}
+
+static PyObject *
+_match_number_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t start, Py_ssize_t *next_idx_ptr) {
+    /* Read a JSON number from PyUnicode pystr.
+    idx is the index of the first character of the number
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the number.
+
+    Returns a new PyObject representation of that number:
+        PyInt, PyLong, or PyFloat.
+        May return other types if parse_int or parse_float are set
+    */
+    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
+    Py_ssize_t end_idx = PyUnicode_GET_SIZE(pystr) - 1;
+    Py_ssize_t idx = start;
+    int is_float = 0;
+    PyObject *rval;
+    PyObject *numstr;
+
+    /* read a sign if it's there, make sure it's not the end of the string */
+    if (str[idx] == '-') {
+        idx++;
+        if (idx > end_idx) {
+            PyErr_SetNone(PyExc_StopIteration);
+            return NULL;
+        }
+    }
+
+    /* read as many integer digits as we find as long as it doesn't start with 0 */
+    if (str[idx] >= '1' && str[idx] <= '9') {
+        idx++;
+        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
+    }
+    /* if it starts with 0 we only expect one integer digit */
+    else if (str[idx] == '0') {
+        idx++;
+    }
+    /* no integer digits, error */
+    else {
+        PyErr_SetNone(PyExc_StopIteration);
+        return NULL;
+    }
+
+    /* if the next char is '.' followed by a digit then read all float digits */
+    if (idx < end_idx && str[idx] == '.' && str[idx + 1] >= '0' && str[idx + 1] <= '9') {
+        is_float = 1;
+        idx += 2;
+        while (idx < end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
+    }
+
+    /* if the next char is 'e' or 'E' then maybe read the exponent (or backtrack) */
+    if (idx < end_idx && (str[idx] == 'e' || str[idx] == 'E')) {
+        Py_ssize_t e_start = idx;
+        idx++;
+
+        /* read an exponent sign if present */
+        if (idx < end_idx && (str[idx] == '-' || str[idx] == '+')) idx++;
+
+        /* read all digits */
+        while (idx <= end_idx && str[idx] >= '0' && str[idx] <= '9') idx++;
+
+        /* if we got a digit, then parse as float. if not, backtrack */
+        if (str[idx - 1] >= '0' && str[idx - 1] <= '9') {
+            is_float = 1;
+        }
+        else {
+            idx = e_start;
+        }
+    }
+
+    /* copy the section we determined to be a number */
+    numstr = PyUnicode_FromUnicode(&str[start], idx - start);
+    if (numstr == NULL)
+        return NULL;
+    if (is_float) {
+        /* parse as a float using a fast path if available, otherwise call user defined method */
+        if (s->parse_float != (PyObject *)&PyFloat_Type) {
+            rval = PyObject_CallFunctionObjArgs(s->parse_float, numstr, NULL);
+        }
+        else {
+            rval = PyFloat_FromString(numstr, NULL);
+        }
+    }
+    else {
+        /* no fast path for unicode -> int, just call */
+        rval = PyObject_CallFunctionObjArgs(s->parse_int, numstr, NULL);
+    }
+    Py_DECREF(numstr);
+    *next_idx_ptr = idx;
+    return rval;
+}
+
+static PyObject *
+scan_once_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr)
+{
+    /* Read one JSON term (of any kind) from PyString pystr.
+    idx is the index of the first character of the term
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the number.
+
+    Returns a new PyObject representation of the term.
+    */
+    char *str = PyString_AS_STRING(pystr);
+    Py_ssize_t length = PyString_GET_SIZE(pystr);
+    if (idx >= length) {
+        PyErr_SetNone(PyExc_StopIteration);
+        return NULL;
+    }
+    switch (str[idx]) {
+        case '"':
+            /* string */
+            return scanstring_str(pystr, idx + 1,
+                PyString_AS_STRING(s->encoding),
+                PyObject_IsTrue(s->strict),
+                next_idx_ptr);
+        case '{':
+            /* object */
+            return _parse_object_str(s, pystr, idx + 1, next_idx_ptr);
+        case '[':
+            /* array */
+            return _parse_array_str(s, pystr, idx + 1, next_idx_ptr);
+        case 'n':
+            /* null */
+            if ((idx + 3 < length) && str[idx + 1] == 'u' && str[idx + 2] == 'l' && str[idx + 3] == 'l') {
+                Py_INCREF(Py_None);
+                *next_idx_ptr = idx + 4;
+                return Py_None;
+            }
+            break;
+        case 't':
+            /* true */
+            if ((idx + 3 < length) && str[idx + 1] == 'r' && str[idx + 2] == 'u' && str[idx + 3] == 'e') {
+                Py_INCREF(Py_True);
+                *next_idx_ptr = idx + 4;
+                return Py_True;
+            }
+            break;
+        case 'f':
+            /* false */
+            if ((idx + 4 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'l' && str[idx + 3] == 's' && str[idx + 4] == 'e') {
+                Py_INCREF(Py_False);
+                *next_idx_ptr = idx + 5;
+                return Py_False;
+            }
+            break;
+        case 'N':
+            /* NaN */
+            if ((idx + 2 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'N') {
+                return _parse_constant(s, "NaN", idx, next_idx_ptr);
+            }
+            break;
+        case 'I':
+            /* Infinity */
+            if ((idx + 7 < length) && str[idx + 1] == 'n' && str[idx + 2] == 'f' && str[idx + 3] == 'i' && str[idx + 4] == 'n' && str[idx + 5] == 'i' && str[idx + 6] == 't' && str[idx + 7] == 'y') {
+                return _parse_constant(s, "Infinity", idx, next_idx_ptr);
+            }
+            break;
+        case '-':
+            /* -Infinity */
+            if ((idx + 8 < length) && str[idx + 1] == 'I' && str[idx + 2] == 'n' && str[idx + 3] == 'f' && str[idx + 4] == 'i' && str[idx + 5] == 'n' && str[idx + 6] == 'i' && str[idx + 7] == 't' && str[idx + 8] == 'y') {
+                return _parse_constant(s, "-Infinity", idx, next_idx_ptr);
+            }
+            break;
+    }
+    /* Didn't find a string, object, array, or named constant. Look for a number. */
+    return _match_number_str(s, pystr, idx, next_idx_ptr);
+}
+
+static PyObject *
+scan_once_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr)
+{
+    /* Read one JSON term (of any kind) from PyUnicode pystr.
+    idx is the index of the first character of the term
+    *next_idx_ptr is a return-by-reference index to the first character after
+        the number.
+
+    Returns a new PyObject representation of the term.
+    */
+    Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
+    Py_ssize_t length = PyUnicode_GET_SIZE(pystr);
+    if (idx >= length) {
+        PyErr_SetNone(PyExc_StopIteration);
+        return NULL;
+    }
+    switch (str[idx]) {
+        case '"':
+            /* string */
+            return scanstring_unicode(pystr, idx + 1,
+                PyObject_IsTrue(s->strict),
+                next_idx_ptr);
+        case '{':
+            /* object */
+            return _parse_object_unicode(s, pystr, idx + 1, next_idx_ptr);
+        case '[':
+            /* array */
+            return _parse_array_unicode(s, pystr, idx + 1, next_idx_ptr);
+        case 'n':
+            /* null */
+            if ((idx + 3 < length) && str[idx + 1] == 'u' && str[idx + 2] == 'l' && str[idx + 3] == 'l') {
+                Py_INCREF(Py_None);
+                *next_idx_ptr = idx + 4;
+                return Py_None;
+            }
+            break;
+        case 't':
+            /* true */
+            if ((idx + 3 < length) && str[idx + 1] == 'r' && str[idx + 2] == 'u' && str[idx + 3] == 'e') {
+                Py_INCREF(Py_True);
+                *next_idx_ptr = idx + 4;
+                return Py_True;
+            }
+            break;
+        case 'f':
+            /* false */
+            if ((idx + 4 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'l' && str[idx + 3] == 's' && str[idx + 4] == 'e') {
+                Py_INCREF(Py_False);
+                *next_idx_ptr = idx + 5;
+                return Py_False;
+            }
+            break;
+        case 'N':
+            /* NaN */
+            if ((idx + 2 < length) && str[idx + 1] == 'a' && str[idx + 2] == 'N') {
+                return _parse_constant(s, "NaN", idx, next_idx_ptr);
+            }
+            break;
+        case 'I':
+            /* Infinity */
+            if ((idx + 7 < length) && str[idx + 1] == 'n' && str[idx + 2] == 'f' && str[idx + 3] == 'i' && str[idx + 4] == 'n' && str[idx + 5] == 'i' && str[idx + 6] == 't' && str[idx + 7] == 'y') {
+                return _parse_constant(s, "Infinity", idx, next_idx_ptr);
+            }
+            break;
+        case '-':
+            /* -Infinity */
+            if ((idx + 8 < length) && str[idx + 1] == 'I' && str[idx + 2] == 'n' && str[idx + 3] == 'f' && str[idx + 4] == 'i' && str[idx + 5] == 'n' && str[idx + 6] == 'i' && str[idx + 7] == 't' && str[idx + 8] == 'y') {
+                return _parse_constant(s, "-Infinity", idx, next_idx_ptr);
+            }
+            break;
+    }
+    /* Didn't find a string, object, array, or named constant. Look for a number. */
+    return _match_number_unicode(s, pystr, idx, next_idx_ptr);
+}
+
+static PyObject *
+scanner_call(PyObject *self, PyObject *args, PyObject *kwds)
+{
+    /* Python callable interface to scan_once_{str,unicode} */
+    PyObject *pystr;
+    PyObject *rval;
+    Py_ssize_t idx;
+    Py_ssize_t next_idx = -1;
+    static char *kwlist[] = {"string", "idx", NULL};
+    PyScannerObject *s;
+    assert(PyScanner_Check(self));
+    s = (PyScannerObject *)self;
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO&:scan_once", kwlist, &pystr, _convertPyInt_AsSsize_t, &idx))
+        return NULL;
+
+    if (PyString_Check(pystr)) {
+        rval = scan_once_str(s, pystr, idx, &next_idx);
+    }
+    else if (PyUnicode_Check(pystr)) {
+        rval = scan_once_unicode(s, pystr, idx, &next_idx);
+    }
+    else {
+        PyErr_Format(PyExc_TypeError,
+                 "first argument must be a string, not %.80s",
+                 Py_TYPE(pystr)->tp_name);
+        return NULL;
+    }
+    return _build_rval_index_tuple(rval, next_idx);
+}
+
+static PyObject *
+scanner_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+    PyScannerObject *s;
+    s = (PyScannerObject *)type->tp_alloc(type, 0);
+    if (s != NULL) {
+        s->encoding = NULL;
+        s->strict = NULL;
+        s->object_hook = NULL;
+        s->parse_float = NULL;
+        s->parse_int = NULL;
+        s->parse_constant = NULL;
+    }
+    return (PyObject *)s;
+}
+
+static int
+scanner_init(PyObject *self, PyObject *args, PyObject *kwds)
+{
+    /* Initialize Scanner object */
+    PyObject *ctx;
+    static char *kwlist[] = {"context", NULL};
+    PyScannerObject *s;
+
+    assert(PyScanner_Check(self));
+    s = (PyScannerObject *)self;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:make_scanner", kwlist, &ctx))
+        return -1;
+
+    /* PyString_AS_STRING is used on encoding */
+    s->encoding = PyObject_GetAttrString(ctx, "encoding");
+    if (s->encoding == Py_None) {
+        Py_DECREF(Py_None);
+        s->encoding = PyString_InternFromString(DEFAULT_ENCODING);
+    }
+    else if (PyUnicode_Check(s->encoding)) {
+        PyObject *tmp = PyUnicode_AsEncodedString(s->encoding, NULL, NULL);
+        Py_DECREF(s->encoding);
+        s->encoding = tmp;
+    }
+    if (s->encoding == NULL || !PyString_Check(s->encoding))
+        goto bail;
+
+    /* All of these will fail "gracefully" so we don't need to verify them */
+    s->strict = PyObject_GetAttrString(ctx, "strict");
+    if (s->strict == NULL)
+        goto bail;
+    s->object_hook = PyObject_GetAttrString(ctx, "object_hook");
+    if (s->object_hook == NULL)
+        goto bail;
+    s->parse_float = PyObject_GetAttrString(ctx, "parse_float");
+    if (s->parse_float == NULL)
+        goto bail;
+    s->parse_int = PyObject_GetAttrString(ctx, "parse_int");
+    if (s->parse_int == NULL)
+        goto bail;
+    s->parse_constant = PyObject_GetAttrString(ctx, "parse_constant");
+    if (s->parse_constant == NULL)
+        goto bail;
+
+    return 0;
+
+bail:
+    Py_CLEAR(s->encoding);
+    Py_CLEAR(s->strict);
+    Py_CLEAR(s->object_hook);
+    Py_CLEAR(s->parse_float);
+    Py_CLEAR(s->parse_int);
+    Py_CLEAR(s->parse_constant);
+    return -1;
+}
+
+PyDoc_STRVAR(scanner_doc, "JSON scanner object");
+
+static
+PyTypeObject PyScannerType = {
+    PyObject_HEAD_INIT(NULL)
+    0,                    /* tp_internal */
+    "_json.Scanner",       /* tp_name */
+    sizeof(PyScannerObject), /* tp_basicsize */
+    0,                    /* tp_itemsize */
+    scanner_dealloc, /* tp_dealloc */
+    0,                    /* tp_print */
+    0,                    /* tp_getattr */
+    0,                    /* tp_setattr */
+    0,                    /* tp_compare */
+    0,                    /* tp_repr */
+    0,                    /* tp_as_number */
+    0,                    /* tp_as_sequence */
+    0,                    /* tp_as_mapping */
+    0,                    /* tp_hash */
+    scanner_call,         /* tp_call */
+    0,                    /* tp_str */
+    0,/* PyObject_GenericGetAttr, */                    /* tp_getattro */
+    0,/* PyObject_GenericSetAttr, */                    /* tp_setattro */
+    0,                    /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,   /* tp_flags */
+    scanner_doc,          /* tp_doc */
+    scanner_traverse,                    /* tp_traverse */
+    scanner_clear,                    /* tp_clear */
+    0,                    /* tp_richcompare */
+    0,                    /* tp_weaklistoffset */
+    0,                    /* tp_iter */
+    0,                    /* tp_iternext */
+    0,                    /* tp_methods */
+    scanner_members,                    /* tp_members */
+    0,                    /* tp_getset */
+    0,                    /* tp_base */
+    0,                    /* tp_dict */
+    0,                    /* tp_descr_get */
+    0,                    /* tp_descr_set */
+    0,                    /* tp_dictoffset */
+    scanner_init,                    /* tp_init */
+    0,/* PyType_GenericAlloc, */        /* tp_alloc */
+    scanner_new,          /* tp_new */
+    0,/* PyObject_GC_Del, */              /* tp_free */
+};
+
+static PyObject *
+encoder_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+    PyEncoderObject *s;
+    s = (PyEncoderObject *)type->tp_alloc(type, 0);
+    if (s != NULL) {
+        s->markers = NULL;
+        s->defaultfn = NULL;
+        s->encoder = NULL;
+        s->indent = NULL;
+        s->key_separator = NULL;
+        s->item_separator = NULL;
+        s->sort_keys = NULL;
+        s->skipkeys = NULL;
+    }
+    return (PyObject *)s;
+}
+
+static int
+encoder_init(PyObject *self, PyObject *args, PyObject *kwds)
+{
+    /* initialize Encoder object */
+    static char *kwlist[] = {"markers", "default", "encoder", "indent", "key_separator", "item_separator", "sort_keys", "skipkeys", "allow_nan", NULL};
+
+    PyEncoderObject *s;
+    PyObject *allow_nan;
+
+    assert(PyEncoder_Check(self));
+    s = (PyEncoderObject *)self;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOOOOOOOO:make_encoder", kwlist,
+        &s->markers, &s->defaultfn, &s->encoder, &s->indent, &s->key_separator, &s->item_separator, &s->sort_keys, &s->skipkeys, &allow_nan))
+        return -1;
+
+    Py_INCREF(s->markers);
+    Py_INCREF(s->defaultfn);
+    Py_INCREF(s->encoder);
+    Py_INCREF(s->indent);
+    Py_INCREF(s->key_separator);
+    Py_INCREF(s->item_separator);
+    Py_INCREF(s->sort_keys);
+    Py_INCREF(s->skipkeys);
+    s->fast_encode = (PyCFunction_Check(s->encoder) && PyCFunction_GetFunction(s->encoder) == (PyCFunction)py_encode_basestring_ascii);
+    s->allow_nan = PyObject_IsTrue(allow_nan);
+    return 0;
+}
+
+static PyObject *
+encoder_call(PyObject *self, PyObject *args, PyObject *kwds)
+{
+    /* Python callable interface to encode_listencode_obj */
+    static char *kwlist[] = {"obj", "_current_indent_level", NULL};
+    PyObject *obj;
+    PyObject *rval;
+    Py_ssize_t indent_level;
+    PyEncoderObject *s;
+    assert(PyEncoder_Check(self));
+    s = (PyEncoderObject *)self;
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO&:_iterencode", kwlist,
+        &obj, _convertPyInt_AsSsize_t, &indent_level))
+        return NULL;
+    rval = PyList_New(0);
+    if (rval == NULL)
+        return NULL;
+    if (encoder_listencode_obj(s, rval, obj, indent_level)) {
+        Py_DECREF(rval);
+        return NULL;
+    }
+    return rval;
+}
+
+static PyObject *
+_encoded_const(PyObject *obj)
+{
+    /* Return the JSON string representation of None, True, False */
+    if (obj == Py_None) {
+        static PyObject *s_null = NULL;
+        if (s_null == NULL) {
+            s_null = PyString_InternFromString("null");
+        }
+        Py_INCREF(s_null);
+        return s_null;
+    }
+    else if (obj == Py_True) {
+        static PyObject *s_true = NULL;
+        if (s_true == NULL) {
+            s_true = PyString_InternFromString("true");
+        }
+        Py_INCREF(s_true);
+        return s_true;
+    }
+    else if (obj == Py_False) {
+        static PyObject *s_false = NULL;
+        if (s_false == NULL) {
+            s_false = PyString_InternFromString("false");
+        }
+        Py_INCREF(s_false);
+        return s_false;
+    }
+    else {
+        PyErr_SetString(PyExc_ValueError, "not a const");
+        return NULL;
+    }
+}
+
+static PyObject *
+encoder_encode_float(PyEncoderObject *s, PyObject *obj)
+{
+    /* Return the JSON representation of a PyFloat */
+    double i = PyFloat_AS_DOUBLE(obj);
+    if (!Py_IS_FINITE(i)) {
+        if (!s->allow_nan) {
+            PyErr_SetString(PyExc_ValueError, "Out of range float values are not JSON compliant");
+            return NULL;
+        }
+        if (i > 0) {
+            return PyString_FromString("Infinity");
+        }
+        else if (i < 0) {
+            return PyString_FromString("-Infinity");
+        }
+        else {
+            return PyString_FromString("NaN");
+        }
+    }
+    /* Use a better float format here? */
+    return PyObject_Repr(obj);
+}
+
+static PyObject *
+encoder_encode_string(PyEncoderObject *s, PyObject *obj)
+{
+    /* Return the JSON representation of a string */
+    if (s->fast_encode)
+        return py_encode_basestring_ascii(NULL, obj);
+    else
+        return PyObject_CallFunctionObjArgs(s->encoder, obj, NULL);
+}
+
+static int
+_steal_list_append(PyObject *lst, PyObject *stolen)
+{
+    /* Append stolen and then decrement its reference count */
+    int rval = PyList_Append(lst, stolen);
+    Py_DECREF(stolen);
+    return rval;
+}
+
+static int
+encoder_listencode_obj(PyEncoderObject *s, PyObject *rval, PyObject *obj, Py_ssize_t indent_level)
+{
+    /* Encode Python object obj to a JSON term, rval is a PyList */
+    PyObject *newobj;
+    int rv;
+
+    if (obj == Py_None || obj == Py_True || obj == Py_False) {
+        PyObject *cstr = _encoded_const(obj);
+        if (cstr == NULL)
+            return -1;
+        return _steal_list_append(rval, cstr);
+    }
+    else if (PyString_Check(obj) || PyUnicode_Check(obj))
+    {
+        PyObject *encoded = encoder_encode_string(s, obj);
+        if (encoded == NULL)
+            return -1;
+        return _steal_list_append(rval, encoded);
+    }
+    else if (PyInt_Check(obj) || PyLong_Check(obj)) {
+        PyObject *encoded = PyObject_Str(obj);
+        if (encoded == NULL)
+            return -1;
+        return _steal_list_append(rval, encoded);
+    }
+    else if (PyFloat_Check(obj)) {
+        PyObject *encoded = encoder_encode_float(s, obj);
+        if (encoded == NULL)
+            return -1;
+        return _steal_list_append(rval, encoded);
+    }
+    else if (PyList_Check(obj) || PyTuple_Check(obj)) {
+        return encoder_listencode_list(s, rval, obj, indent_level);
+    }
+    else if (PyDict_Check(obj)) {
+        return encoder_listencode_dict(s, rval, obj, indent_level);
+    }
+    else {
+        PyObject *ident = NULL;
+        if (s->markers != Py_None) {
+            int has_key;
+            ident = PyLong_FromVoidPtr(obj);
+            if (ident == NULL)
+                return -1;
+            has_key = PyDict_Contains(s->markers, ident);
+            if (has_key) {
+                if (has_key != -1)
+                    PyErr_SetString(PyExc_ValueError, "Circular reference detected");
+                Py_DECREF(ident);
+                return -1;
+            }
+            if (PyDict_SetItem(s->markers, ident, obj)) {
+                Py_DECREF(ident);
+                return -1;
+            }
+        }
+        newobj = PyObject_CallFunctionObjArgs(s->defaultfn, obj, NULL);
+        if (newobj == NULL) {
+            Py_XDECREF(ident);
+            return -1;
+        }
+        rv = encoder_listencode_obj(s, rval, newobj, indent_level);
+        Py_DECREF(newobj);
+        if (rv) {
+            Py_XDECREF(ident);
+            return -1;
+        }
+        if (ident != NULL) {
+            if (PyDict_DelItem(s->markers, ident)) {
+                Py_XDECREF(ident);
+                return -1;
+            }
+            Py_XDECREF(ident);
+        }
+        return rv;
+    }
+}
+
+static int
+encoder_listencode_dict(PyEncoderObject *s, PyObject *rval, PyObject *dct, Py_ssize_t indent_level)
+{
+    /* Encode Python dict dct a JSON term, rval is a PyList */
+    static PyObject *open_dict = NULL;
+    static PyObject *close_dict = NULL;
+    static PyObject *empty_dict = NULL;
+    PyObject *kstr = NULL;
+    PyObject *ident = NULL;
+    PyObject *key, *value;
+    Py_ssize_t pos;
+    int skipkeys;
+    Py_ssize_t idx;
+
+    if (open_dict == NULL || close_dict == NULL || empty_dict == NULL) {
+        open_dict = PyString_InternFromString("{");
+        close_dict = PyString_InternFromString("}");
+        empty_dict = PyString_InternFromString("{}");
+        if (open_dict == NULL || close_dict == NULL || empty_dict == NULL)
+            return -1;
+    }
+    if (PyDict_Size(dct) == 0)
+        return PyList_Append(rval, empty_dict);
+
+    if (s->markers != Py_None) {
+        int has_key;
+        ident = PyLong_FromVoidPtr(dct);
+        if (ident == NULL)
+            goto bail;
+        has_key = PyDict_Contains(s->markers, ident);
+        if (has_key) {
+            if (has_key != -1)
+                PyErr_SetString(PyExc_ValueError, "Circular reference detected");
+            goto bail;
+        }
+        if (PyDict_SetItem(s->markers, ident, dct)) {
+            goto bail;
+        }
+    }
+
+    if (PyList_Append(rval, open_dict))
+        goto bail;
+
+    if (s->indent != Py_None) {
+        /* TODO: DOES NOT RUN */
+        indent_level += 1;
+        /*
+            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
+            separator = _item_separator + newline_indent
+            buf += newline_indent
+        */
+    }
+
+    /* TODO: C speedup not implemented for sort_keys */
+
+    pos = 0;
+    skipkeys = PyObject_IsTrue(s->skipkeys);
+    idx = 0;
+    while (PyDict_Next(dct, &pos, &key, &value)) {
+        PyObject *encoded;
+
+        if (PyString_Check(key) || PyUnicode_Check(key)) {
+            Py_INCREF(key);
+            kstr = key;
+        }
+        else if (PyFloat_Check(key)) {
+            kstr = encoder_encode_float(s, key);
+            if (kstr == NULL)
+                goto bail;
+        }
+        else if (PyInt_Check(key) || PyLong_Check(key)) {
+            kstr = PyObject_Str(key);
+            if (kstr == NULL)
+                goto bail;
+        }
+        else if (key == Py_True || key == Py_False || key == Py_None) {
+            kstr = _encoded_const(key);
+            if (kstr == NULL)
+                goto bail;
+        }
+        else if (skipkeys) {
+            continue;
+        }
+        else {
+            /* TODO: include repr of key */
+            PyErr_SetString(PyExc_ValueError, "keys must be a string");
+            goto bail;
+        }
+
+        if (idx) {
+            if (PyList_Append(rval, s->item_separator))
+                goto bail;
+        }
+
+        encoded = encoder_encode_string(s, kstr);
+        Py_CLEAR(kstr);
+        if (encoded == NULL)
+            goto bail;
+        if (PyList_Append(rval, encoded)) {
+            Py_DECREF(encoded);
+            goto bail;
+        }
+        Py_DECREF(encoded);
+        if (PyList_Append(rval, s->key_separator))
+            goto bail;
+        if (encoder_listencode_obj(s, rval, value, indent_level))
+            goto bail;
+        idx += 1;
+    }
+    if (ident != NULL) {
+        if (PyDict_DelItem(s->markers, ident))
+            goto bail;
+        Py_CLEAR(ident);
+    }
+    if (s->indent != Py_None) {
+        /* TODO: DOES NOT RUN */
+        indent_level -= 1;
+        /*
+            yield '\n' + (' ' * (_indent * _current_indent_level))
+        */
+    }
+    if (PyList_Append(rval, close_dict))
+        goto bail;
+    return 0;
+
+bail:
+    Py_XDECREF(kstr);
+    Py_XDECREF(ident);
+    return -1;
+}
+
+
+static int
+encoder_listencode_list(PyEncoderObject *s, PyObject *rval, PyObject *seq, Py_ssize_t indent_level)
+{
+    /* Encode Python list seq to a JSON term, rval is a PyList */
+    static PyObject *open_array = NULL;
+    static PyObject *close_array = NULL;
+    static PyObject *empty_array = NULL;
+    PyObject *ident = NULL;
+    PyObject *s_fast = NULL;
+    Py_ssize_t num_items;
+    PyObject **seq_items;
+    Py_ssize_t i;
+
+    if (open_array == NULL || close_array == NULL || empty_array == NULL) {
+        open_array = PyString_InternFromString("[");
+        close_array = PyString_InternFromString("]");
+        empty_array = PyString_InternFromString("[]");
+        if (open_array == NULL || close_array == NULL || empty_array == NULL)
+            return -1;
+    }
+    ident = NULL;
+    s_fast = PySequence_Fast(seq, "_iterencode_list needs a sequence");
+    if (s_fast == NULL)
+        return -1;
+    num_items = PySequence_Fast_GET_SIZE(s_fast);
+    if (num_items == 0) {
+        Py_DECREF(s_fast);
+        return PyList_Append(rval, empty_array);
+    }
+
+    if (s->markers != Py_None) {
+        int has_key;
+        ident = PyLong_FromVoidPtr(seq);
+        if (ident == NULL)
+            goto bail;
+        has_key = PyDict_Contains(s->markers, ident);
+        if (has_key) {
+            if (has_key != -1)
+                PyErr_SetString(PyExc_ValueError, "Circular reference detected");
+            goto bail;
+        }
+        if (PyDict_SetItem(s->markers, ident, seq)) {
+            goto bail;
+        }
+    }
+
+    seq_items = PySequence_Fast_ITEMS(s_fast);
+    if (PyList_Append(rval, open_array))
+        goto bail;
+    if (s->indent != Py_None) {
+        /* TODO: DOES NOT RUN */
+        indent_level += 1;
+        /*
+            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
+            separator = _item_separator + newline_indent
+            buf += newline_indent
+        */
+    }
+    for (i = 0; i < num_items; i++) {
+        PyObject *obj = seq_items[i];
+        if (i) {
+            if (PyList_Append(rval, s->item_separator))
+                goto bail;
+        }
+        if (encoder_listencode_obj(s, rval, obj, indent_level))
+            goto bail;
+    }
+    if (ident != NULL) {
+        if (PyDict_DelItem(s->markers, ident))
+            goto bail;
+        Py_CLEAR(ident);
+    }
+    if (s->indent != Py_None) {
+        /* TODO: DOES NOT RUN */
+        indent_level -= 1;
+        /*
+            yield '\n' + (' ' * (_indent * _current_indent_level))
+        */
+    }
+    if (PyList_Append(rval, close_array))
+        goto bail;
+    Py_DECREF(s_fast);
+    return 0;
+
+bail:
+    Py_XDECREF(ident);
+    Py_DECREF(s_fast);
+    return -1;
+}
+
+static void
+encoder_dealloc(PyObject *self)
+{
+    /* Deallocate Encoder */
+    encoder_clear(self);
+    Py_TYPE(self)->tp_free(self);
+}
+
+static int
+encoder_traverse(PyObject *self, visitproc visit, void *arg)
+{
+    PyEncoderObject *s;
+    assert(PyEncoder_Check(self));
+    s = (PyEncoderObject *)self;
+    Py_VISIT(s->markers);
+    Py_VISIT(s->defaultfn);
+    Py_VISIT(s->encoder);
+    Py_VISIT(s->indent);
+    Py_VISIT(s->key_separator);
+    Py_VISIT(s->item_separator);
+    Py_VISIT(s->sort_keys);
+    Py_VISIT(s->skipkeys);
+    return 0;
+}
+
+static int
+encoder_clear(PyObject *self)
+{
+    /* Deallocate Encoder */
+    PyEncoderObject *s;
+    assert(PyEncoder_Check(self));
+    s = (PyEncoderObject *)self;
+    Py_CLEAR(s->markers);
+    Py_CLEAR(s->defaultfn);
+    Py_CLEAR(s->encoder);
+    Py_CLEAR(s->indent);
+    Py_CLEAR(s->key_separator);
+    Py_CLEAR(s->item_separator);
+    Py_CLEAR(s->sort_keys);
+    Py_CLEAR(s->skipkeys);
+    return 0;
+}
+
+PyDoc_STRVAR(encoder_doc, "_iterencode(obj, _current_indent_level) -> iterable");
+
+static
+PyTypeObject PyEncoderType = {
+    PyObject_HEAD_INIT(NULL)
+    0,                    /* tp_internal */
+    "_json.Encoder",       /* tp_name */
+    sizeof(PyEncoderObject), /* tp_basicsize */
+    0,                    /* tp_itemsize */
+    encoder_dealloc, /* tp_dealloc */
+    0,                    /* tp_print */
+    0,                    /* tp_getattr */
+    0,                    /* tp_setattr */
+    0,                    /* tp_compare */
+    0,                    /* tp_repr */
+    0,                    /* tp_as_number */
+    0,                    /* tp_as_sequence */
+    0,                    /* tp_as_mapping */
+    0,                    /* tp_hash */
+    encoder_call,         /* tp_call */
+    0,                    /* tp_str */
+    0,                    /* tp_getattro */
+    0,                    /* tp_setattro */
+    0,                    /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,   /* tp_flags */
+    encoder_doc,          /* tp_doc */
+    encoder_traverse,     /* tp_traverse */
+    encoder_clear,        /* tp_clear */
+    0,                    /* tp_richcompare */
+    0,                    /* tp_weaklistoffset */
+    0,                    /* tp_iter */
+    0,                    /* tp_iternext */
+    0,                    /* tp_methods */
+    encoder_members,      /* tp_members */
+    0,                    /* tp_getset */
+    0,                    /* tp_base */
+    0,                    /* tp_dict */
+    0,                    /* tp_descr_get */
+    0,                    /* tp_descr_set */
+    0,                    /* tp_dictoffset */
+    encoder_init,         /* tp_init */
+    0,                    /* tp_alloc */
+    encoder_new,          /* tp_new */
+    0,                    /* tp_free */
+};
+
+static PyMethodDef speedups_methods[] = {
+    {"encode_basestring_ascii",
+        (PyCFunction)py_encode_basestring_ascii,
+        METH_O,
+        pydoc_encode_basestring_ascii},
+    {"scanstring",
+        (PyCFunction)py_scanstring,
+        METH_VARARGS,
+        pydoc_scanstring},
     {NULL, NULL, 0, NULL}
 };
 
@@ -617,5 +2315,15 @@
 init_json(void)
 {
     PyObject *m;
-    m = Py_InitModule3("_json", json_methods, module_doc);
+    PyScannerType.tp_new = PyType_GenericNew;
+    if (PyType_Ready(&PyScannerType) < 0)
+        return;
+    PyEncoderType.tp_new = PyType_GenericNew;
+    if (PyType_Ready(&PyEncoderType) < 0)
+        return;
+    m = Py_InitModule3("_json", speedups_methods, module_doc);
+    Py_INCREF((PyObject*)&PyScannerType);
+    PyModule_AddObject(m, "make_scanner", (PyObject*)&PyScannerType);
+    Py_INCREF((PyObject*)&PyEncoderType);
+    PyModule_AddObject(m, "make_encoder", (PyObject*)&PyEncoderType);
 }