aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/tools/python3/src/Python/mysnprintf.c
diff options
context:
space:
mode:
authornkozlovskiy <nmk@ydb.tech>2023-09-29 12:24:06 +0300
committernkozlovskiy <nmk@ydb.tech>2023-09-29 12:41:34 +0300
commite0e3e1717e3d33762ce61950504f9637a6e669ed (patch)
treebca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Python/mysnprintf.c
parent38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff)
downloadydb-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.c80
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;
+}