bpo-39939: Add str.removeprefix and str.removesuffix (GH-18939)
Added str.removeprefix and str.removesuffix methods and corresponding
bytes, bytearray, and collections.UserString methods to remove affixes
from a string if present. See PEP 616 for a full description.
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 06ead2b..25d9814 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -2182,6 +2182,81 @@
/** End DALKE **/
+/*[clinic input]
+bytes.removeprefix as bytes_removeprefix
+
+ prefix: Py_buffer
+ /
+
+Return a bytes object with the given prefix string removed if present.
+
+If the bytes starts with the prefix string, return bytes[len(prefix):].
+Otherwise, return a copy of the original bytes.
+[clinic start generated code]*/
+
+static PyObject *
+bytes_removeprefix_impl(PyBytesObject *self, Py_buffer *prefix)
+/*[clinic end generated code: output=f006865331a06ab6 input=0c93bac817a8502c]*/
+{
+ const char *self_start = PyBytes_AS_STRING(self);
+ Py_ssize_t self_len = PyBytes_GET_SIZE(self);
+ const char *prefix_start = prefix->buf;
+ Py_ssize_t prefix_len = prefix->len;
+
+ if (self_len >= prefix_len
+ && prefix_len > 0
+ && memcmp(self_start, prefix_start, prefix_len) == 0)
+ {
+ return PyBytes_FromStringAndSize(self_start + prefix_len,
+ self_len - prefix_len);
+ }
+
+ if (PyBytes_CheckExact(self)) {
+ Py_INCREF(self);
+ return (PyObject *)self;
+ }
+
+ return PyBytes_FromStringAndSize(self_start, self_len);
+}
+
+/*[clinic input]
+bytes.removesuffix as bytes_removesuffix
+
+ suffix: Py_buffer
+ /
+
+Return a bytes object with the given suffix string removed if present.
+
+If the bytes ends with the suffix string and that suffix is not empty,
+return bytes[:-len(prefix)]. Otherwise, return a copy of the original
+bytes.
+[clinic start generated code]*/
+
+static PyObject *
+bytes_removesuffix_impl(PyBytesObject *self, Py_buffer *suffix)
+/*[clinic end generated code: output=d887d308e3242eeb input=9f4e1da8c637bbf1]*/
+{
+ const char *self_start = PyBytes_AS_STRING(self);
+ Py_ssize_t self_len = PyBytes_GET_SIZE(self);
+ const char *suffix_start = suffix->buf;
+ Py_ssize_t suffix_len = suffix->len;
+
+ if (self_len >= suffix_len
+ && suffix_len > 0
+ && memcmp(self_start + self_len - suffix_len,
+ suffix_start, suffix_len) == 0)
+ {
+ return PyBytes_FromStringAndSize(self_start,
+ self_len - suffix_len);
+ }
+
+ if (PyBytes_CheckExact(self)) {
+ Py_INCREF(self);
+ return (PyObject *)self;
+ }
+
+ return PyBytes_FromStringAndSize(self_start, self_len);
+}
static PyObject *
bytes_startswith(PyBytesObject *self, PyObject *args)
@@ -2421,6 +2496,8 @@
BYTES_MAKETRANS_METHODDEF
BYTES_PARTITION_METHODDEF
BYTES_REPLACE_METHODDEF
+ BYTES_REMOVEPREFIX_METHODDEF
+ BYTES_REMOVESUFFIX_METHODDEF
{"rfind", (PyCFunction)bytes_rfind, METH_VARARGS, _Py_rfind__doc__},
{"rindex", (PyCFunction)bytes_rindex, METH_VARARGS, _Py_rindex__doc__},
STRINGLIB_RJUST_METHODDEF