Files
typthon/Python/mysnprintf.c
copilot-swe-agent[bot] b198f511d2 Rename Py_ to Ty_ throughout C API
Massive automated renaming of all Py_/PyObject/etc. prefixes to Ty_/TyObject/etc.
This includes:
- All public API types (TyObject, TyTypeObject, etc.)
- All public API functions (Ty_Initialize, Ty_BuildValue, etc.)
- All internal API (_Ty_ prefixes)
- Reference counting macros (Ty_INCREF, Ty_DECREF, etc.)
- Type flags (Ty_TPFLAGS_*)
- Debug flags (Ty_DEBUG, Ty_TRACE_REFS, etc.)
- All object type APIs (TyList_, TyDict_, TyUnicode_, etc.)

This changes over 60,000 occurrences across 1000+ files.

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>
2025-12-29 17:37:49 +00:00

81 lines
2.5 KiB
C

#include "Python.h"
/* snprintf() and vsnprintf() wrappers.
If the platform has vsnprintf, we use it, else we
emulate it in a half-hearted way. Even if the platform has it, we wrap
it because platforms differ in what vsnprintf does in case the buffer
is too small: C99 behavior is to return the number of characters that
would have been written had the buffer not been too small, and to set
the last byte of the buffer to \0. At least MS _vsnprintf returns a
negative value instead, and fills the entire buffer with non-\0 data.
Unlike C99, our wrappers do not support passing a null buffer.
The wrappers ensure that str[size-1] is always \0 upon return.
TyOS_snprintf and TyOS_vsnprintf never write more than size bytes
(including the trailing '\0') into str.
Return value (rv):
When 0 <= rv < size, the output conversion was unexceptional, and
rv characters were written to str (excluding a trailing \0 byte at
str[rv]).
When rv >= size, output conversion was truncated, and a buffer of
size rv+1 would have been needed to avoid truncation. str[size-1]
is \0 in this case.
When rv < 0, "something bad happened". str[size-1] is \0 in this
case too, but the rest of str is unreliable. It could be that
an error in format codes was detected by libc, or on platforms
with a non-C99 vsnprintf simply that the buffer wasn't big enough
to avoid truncation, or on platforms without any vsnprintf that
TyMem_Malloc couldn't obtain space for a temp buffer.
CAUTION: Unlike C99, str != NULL and size > 0 are required.
Also, size must be smaller than INT_MAX.
*/
int
TyOS_snprintf(char *str, size_t size, const char *format, ...)
{
int rc;
va_list va;
va_start(va, format);
rc = TyOS_vsnprintf(str, size, format, va);
va_end(va);
return rc;
}
int
TyOS_vsnprintf(char *str, size_t size, const char *format, va_list va)
{
assert(str != NULL);
assert(size > 0);
assert(size <= (INT_MAX - 1));
assert(format != NULL);
int len; /* # bytes written, excluding \0 */
/* We take a size_t as input but return an int. Sanity check
* our input so that it won't cause an overflow in the
* vsnprintf return value. */
if (size > INT_MAX - 1) {
len = -666;
goto Done;
}
#if defined(_MSC_VER)
len = _vsnprintf(str, size, format, va);
#else
len = vsnprintf(str, size, format, va);
#endif
Done:
if (size > 0) {
str[size-1] = '\0';
}
return len;
}