Python/mysnprintf.c

   1
   2 #include "Python.h"
   3
   4 /* snprintf() emulation for platforms which don't have it (yet).
   5
   6    Return value
   7
   8        The number of characters printed (not including the trailing
   9        `\0' used to end output to strings) or a negative number in
  10        case of an error.
  11
  12        PyOS_snprintf and PyOS_vsnprintf do not write more than size
  13        bytes (including the trailing '\0').
  14
  15        If the output would have been truncated, they return the number
  16        of characters (excluding the trailing '\0') which would have
  17        been written to the final string if enough space had been
  18        available. This is inline with the C99 standard.
  19
  20 */
  21
  22 #include <ctype.h>
  23
  24 #ifndef HAVE_SNPRINTF
  25
  26 static
  27 int myvsnprintf(char *str, size_t size, const char  *format, va_list va)
  28 {
  29     char *buffer = PyMem_Malloc(size + 512);
  30     int len;
  31
  32     if (buffer == NULL)
  33         return -1;
  34     len = vsprintf(buffer, format, va);
  35     if (len < 0) {
  36         PyMem_Free(buffer);
  37         return len;
  38     }
  39     len++;
  40     assert(len >= 0);
  41     if ((size_t)len > size + 512)
  42         Py_FatalError("Buffer overflow in PyOS_snprintf/PyOS_vsnprintf");
  43     if ((size_t)len > size) {
  44         PyMem_Free(buffer);
  45         return len - 1;
  46     }
  47     memcpy(str, buffer, len);
  48     PyMem_Free(buffer);
  49     return len - 1;
  50 }
  51
  52 int PyOS_snprintf(char *str, size_t size, const  char  *format, ...)
  53 {
  54     int rc;
  55     va_list va;
  56
  57     va_start(va, format);
  58     rc = myvsnprintf(str, size, format, va);
  59     va_end(va);
  60     return rc;
  61 }
  62
  63 int PyOS_vsnprintf(char *str, size_t size, const char  *format, va_list va)
  64 {
  65     return myvsnprintf(str, size, format, va);
  66 }
  67
  68 #else
  69
  70 /* Make sure that a C API is included in the lib */
  71
  72 #ifdef PyOS_snprintf
  73 # undef PyOS_snprintf
  74 #endif
  75
  76 int PyOS_snprintf(char *str, size_t size, const  char  *format, ...)
  77 {
  78     int rc;
  79     va_list va;
  80
  81     va_start(va, format);
  82     rc = vsnprintf(str, size, format, va);
  83     va_end(va);
  84     return rc;
  85 }
  86
  87 #ifdef PyOS_vsnprintf
  88 # undef PyOS_vsnprintf
  89 #endif
  90
  91 int PyOS_vsnprintf(char *str, size_t size, const char  *format, va_list va)
  92 {
  93     return vsnprintf(str, size, format, va);
  94 }
  95
  96 #endif
  97