newlib/libc/stdio/asniprintf.c

   1 /* Copyright (C) 2007, 2008 Eric Blake
   2  * Permission to use, copy, modify, and distribute this software
   3  * is freely granted, provided that this notice is preserved.
   4  */
   5 /* This code was derived from asprintf.c */
   6 /* doc in siprintf.c */
   7
   8 #include <_ansi.h>
   9 #include <reent.h>
  10 #include <stdio.h>
  11 #include <stdarg.h>
  12 #include <limits.h>
  13 #include <errno.h>
  14 #include "local.h"
  15
  16 char *
  17 _asniprintf_r (struct _reent *ptr,
  18        char *buf,
  19        size_t *lenp,
  20        const char *fmt, ...)
  21 {
  22   int ret;
  23   va_list ap;
  24   FILE f;
  25   size_t len = *lenp;
  26
  27   if (buf && len)
  28     {
  29       /* mark an existing buffer, but allow allocation of larger string */
  30       f._flags = __SWR | __SSTR | __SOPT;
  31     }
  32   else
  33     {
  34       /* mark a zero-length reallocatable buffer */
  35       f._flags = __SWR | __SSTR | __SMBF;
  36       len = 0;
  37       buf = NULL;
  38     }
  39   f._flags2 = 0;
  40   f._bf._base = f._p = (unsigned char *) buf;
  41   /* For now, inherit the 32-bit signed limit of FILE._bf._size.
  42      FIXME - it would be nice to rewrite sys/reent.h to support size_t
  43      for _size.  */
  44   if (len > INT_MAX)
  45     {
  46       _REENT_ERRNO(ptr) = EOVERFLOW;
  47       return NULL;
  48     }
  49   f._bf._size = f._w = len;
  50   f._file = -1;  /* No file. */
  51   va_start (ap, fmt);
  52   ret = _svfiprintf_r (ptr, &f, fmt, ap);
  53   va_end (ap);
  54   if (ret < 0)
  55     return NULL;
  56   *lenp = ret;
  57   *f._p = '\0';
  58   return (char *) f._bf._base;
  59 }
  60
  61 #ifndef _REENT_ONLY
  62
  63 char *
  64 asniprintf (char *buf,
  65        size_t *lenp,
  66        const char *fmt, ...)
  67 {
  68   int ret;
  69   va_list ap;
  70   FILE f;
  71   size_t len = *lenp;
  72   struct _reent *ptr = _REENT;
  73
  74   if (buf && len)
  75     {
  76       /* mark an existing buffer, but allow allocation of larger string */
  77       f._flags = __SWR | __SSTR | __SOPT;
  78     }
  79   else
  80     {
  81       /* mark a zero-length reallocatable buffer */
  82       f._flags = __SWR | __SSTR | __SMBF;
  83       len = 0;
  84       buf = NULL;
  85     }
  86   f._flags2 = 0;
  87   f._bf._base = f._p = (unsigned char *) buf;
  88   /* For now, inherit the 32-bit signed limit of FILE._bf._size.
  89      FIXME - it would be nice to rewrite sys/reent.h to support size_t
  90      for _size.  */
  91   if (len > INT_MAX)
  92     {
  93       _REENT_ERRNO(ptr) = EOVERFLOW;
  94       return NULL;
  95     }
  96   f._bf._size = f._w = len;
  97   f._file = -1;  /* No file. */
  98   va_start (ap, fmt);
  99   ret = _svfiprintf_r (ptr, &f, fmt, ap);
 100   va_end (ap);
 101   if (ret < 0)
 102     return NULL;
 103   *lenp = ret;
 104   *f._p = '\0';
 105   return (char *) f._bf._base;
 106 }
 107
 108 #endif /* ! _REENT_ONLY */