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pystrhex.c
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172 lines (155 loc) · 5.24 KB
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/* bytes to hex implementation */
#include "Python.h"
#include "pystrhex.h"
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)
{
assert(arglen >= 0);
Py_UCS1 sep_char = 0;
if (sep) {
Py_ssize_t seplen = PyObject_Length((PyObject*)sep);
if (seplen < 0) {
return NULL;
}
if (seplen != 1) {
PyErr_SetString(PyExc_ValueError, "sep must be length 1.");
return NULL;
}
if (PyUnicode_Check(sep)) {
if (PyUnicode_READY(sep))
return NULL;
if (PyUnicode_KIND(sep) != PyUnicode_1BYTE_KIND) {
PyErr_SetString(PyExc_ValueError, "sep must be ASCII.");
return NULL;
}
sep_char = PyUnicode_READ_CHAR(sep, 0);
}
else if (PyBytes_Check(sep)) {
sep_char = PyBytes_AS_STRING(sep)[0];
}
else {
PyErr_SetString(PyExc_TypeError, "sep must be str or bytes.");
return NULL;
}
if (sep_char > 127 && !return_bytes) {
PyErr_SetString(PyExc_ValueError, "sep must be ASCII.");
return NULL;
}
}
else {
bytes_per_sep_group = 0;
}
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;
}
/* Bounds checking for our Py_ssize_t indices. */
if (arglen >= PY_SSIZE_T_MAX / 2 - resultlen) {
return PyErr_NoMemory();
}
resultlen += arglen * 2;
if ((size_t)abs_bytes_per_sep >= (size_t)arglen) {
bytes_per_sep_group = 0;
abs_bytes_per_sep = 0;
}
PyObject *retval;
Py_UCS1 *retbuf;
if (return_bytes) {
/* If _PyBytes_FromSize() were public we could avoid malloc+copy. */
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;
unsigned char c;
if (bytes_per_sep_group == 0) {
for (i = j = 0; i < arglen; ++i) {
assert((j + 1) < resultlen);
c = argbuf[i];
retbuf[j++] = Py_hexdigits[c >> 4];
retbuf[j++] = Py_hexdigits[c & 0x0f];
}
assert(j == resultlen);
}
else {
/* The number of complete chunk+sep periods */
Py_ssize_t chunks = (arglen - 1) / abs_bytes_per_sep;
Py_ssize_t chunk;
unsigned int k;
if (bytes_per_sep_group < 0) {
i = j = 0;
for (chunk = 0; chunk < chunks; chunk++) {
for (k = 0; k < abs_bytes_per_sep; k++) {
c = argbuf[i++];
retbuf[j++] = Py_hexdigits[c >> 4];
retbuf[j++] = Py_hexdigits[c & 0x0f];
}
retbuf[j++] = sep_char;
}
while (i < arglen) {
c = argbuf[i++];
retbuf[j++] = Py_hexdigits[c >> 4];
retbuf[j++] = Py_hexdigits[c & 0x0f];
}
assert(j == resultlen);
}
else {
i = arglen - 1;
j = resultlen - 1;
for (chunk = 0; chunk < chunks; chunk++) {
for (k = 0; k < abs_bytes_per_sep; k++) {
c = argbuf[i--];
retbuf[j--] = Py_hexdigits[c & 0x0f];
retbuf[j--] = Py_hexdigits[c >> 4];
}
retbuf[j--] = sep_char;
}
while (i >= 0) {
c = argbuf[i--];
retbuf[j--] = Py_hexdigits[c & 0x0f];
retbuf[j--] = Py_hexdigits[c >> 4];
}
assert(j == -1);
}
}
#ifdef Py_DEBUG
if (!return_bytes) {
assert(_PyUnicode_CheckConsistency(retval, 1));
}
#endif
return retval;
}
PyObject * _Py_strhex(const char* argbuf, const Py_ssize_t arglen)
{
return _Py_strhex_impl(argbuf, arglen, NULL, 0, 0);
}
/* Same as above but returns a bytes() instead of str() to avoid the
* need to decode the str() when bytes are needed. */
PyObject * _Py_strhex_bytes(const char* argbuf, const Py_ssize_t arglen)
{
return _Py_strhex_impl(argbuf, arglen, NULL, 0, 1);
}
/* These variants include support for a separator between every N bytes: */
PyObject * _Py_strhex_with_sep(const char* argbuf, const Py_ssize_t arglen, const PyObject* sep, const int bytes_per_group)
{
return _Py_strhex_impl(argbuf, arglen, sep, bytes_per_group, 0);
}
/* Same as above but returns a bytes() instead of str() to avoid the
* need to decode the str() when bytes are needed. */
PyObject * _Py_strhex_bytes_with_sep(const char* argbuf, const Py_ssize_t arglen, const PyObject* sep, const int bytes_per_group)
{
return _Py_strhex_impl(argbuf, arglen, sep, bytes_per_group, 1);
}