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author | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:24:06 +0300 |
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committer | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:41:34 +0300 |
commit | e0e3e1717e3d33762ce61950504f9637a6e669ed (patch) | |
tree | bca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Python/mysnprintf.c | |
parent | 38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff) | |
download | ydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz |
add ydb deps
Diffstat (limited to 'contrib/tools/python3/src/Python/mysnprintf.c')
-rw-r--r-- | contrib/tools/python3/src/Python/mysnprintf.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/contrib/tools/python3/src/Python/mysnprintf.c b/contrib/tools/python3/src/Python/mysnprintf.c new file mode 100644 index 0000000000..2a505d14f8 --- /dev/null +++ b/contrib/tools/python3/src/Python/mysnprintf.c @@ -0,0 +1,80 @@ +#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. + + PyOS_snprintf and PyOS_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 + PyMem_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 +PyOS_snprintf(char *str, size_t size, const char *format, ...) +{ + int rc; + va_list va; + + va_start(va, format); + rc = PyOS_vsnprintf(str, size, format, va); + va_end(va); + return rc; +} + +int +PyOS_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; +} |