traverseda
/
cpython
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Optimize _Py_strhex_impl() (GH-19535) 

Avoid a temporary buffer to create a bytes string: use
PyBytes_FromStringAndSize() to directly allocate a bytes object.

Cleanup also the code: PEP 7 formatting, move variable definitions
closer to where they are used. Fix assertion checking "j" index.
This commit is contained in:
Victor Stinner 2020-04-15 14:05:24 +02:00 committed by GitHub
parent a86b522d8f
commit 455df97798
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 27 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
Python/pystrhex.c
View File

@ -8,12 +8,9 @@ static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
const PyObject* sep, int bytes_per_sep_group,
const int return_bytes)
{
PyObject *retval;
Py_UCS1* retbuf;
Py_ssize_t i, j, resultlen = 0;
Py_UCS1 sep_char = 0;
unsigned int abs_bytes_per_sep;
assert(arglen >= 0);
Py_UCS1 sep_char = 0;
if (sep) {
Py_ssize_t seplen = PyObject_Length((PyObject*)sep);
if (seplen < 0) {
@ -31,9 +28,11 @@ static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
return NULL;
}
sep_char = PyUnicode_READ_CHAR(sep, 0);
} else if (PyBytes_Check(sep)) {
}
else if (PyBytes_Check(sep)) {
sep_char = PyBytes_AS_STRING(sep)[0];
} else {
}
else {
PyErr_SetString(PyExc_TypeError, "sep must be str or bytes.");
return NULL;
}
@ -41,12 +40,13 @@ static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
PyErr_SetString(PyExc_ValueError, "sep must be ASCII.");
return NULL;
}
} else {
}
else {
bytes_per_sep_group = 0;
}
assert(arglen >= 0);
abs_bytes_per_sep = abs(bytes_per_sep_group);
unsigned int abs_bytes_per_sep = abs(bytes_per_sep_group);
Py_ssize_t resultlen = 0;
if (bytes_per_sep_group && arglen > 0) {
/* How many sep characters we'll be inserting. */
resultlen = (arglen - 1) / abs_bytes_per_sep;
@ -62,26 +62,32 @@ static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
abs_bytes_per_sep = 0;
}
PyObject *retval;
Py_UCS1 *retbuf;
if (return_bytes) {
/* If _PyBytes_FromSize() were public we could avoid malloc+copy. */
retbuf = (Py_UCS1*) PyMem_Malloc(resultlen);
if (!retbuf)
return PyErr_NoMemory();
retval = NULL; /* silence a compiler warning, assigned later. */
} else {
retval = PyUnicode_New(resultlen, 127);
if (!retval)
retval = PyBytes_FromStringAndSize(NULL, resultlen);
if (!retval) {
return NULL;
}
retbuf = (Py_UCS1 *)PyBytes_AS_STRING(retval);
}
else {
retval = PyUnicode_New(resultlen, 127);
if (!retval) {
return NULL;
}
retbuf = PyUnicode_1BYTE_DATA(retval);
}
/* Hexlify */
Py_ssize_t i, j;
for (i=j=0; i < arglen; ++i) {
assert(j < resultlen);
assert((j + 1) < resultlen);
unsigned char c;
c = (argbuf[i] >> 4) & 0xf;
c = (argbuf[i] >> 4) & 0x0f;
retbuf[j++] = Py_hexdigits[c];
c = argbuf[i] & 0xf;
c = argbuf[i] & 0x0f;
retbuf[j++] = Py_hexdigits[c];
if (bytes_per_sep_group && i < arglen - 1) {
Py_ssize_t anchor;
@ -93,12 +99,8 @@ static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
}
assert(j == resultlen);
if (return_bytes) {
retval = PyBytes_FromStringAndSize((const char *)retbuf, resultlen);
PyMem_Free(retbuf);
}
#ifdef Py_DEBUG
else {
if (!return_bytes) {
assert(_PyUnicode_CheckConsistency(retval, 1));
}
#endif