libc/stdio/vsnprintf.c

   1 /* Copyright (C) 2004       Manuel Novoa III    <mjn3@codepoet.org>
   2  *
   3  * GNU Library General Public License (LGPL) version 2 or later.
   4  *
   5  * Dedicated to Toni.  See uClibc/DEDICATION.mjn3 for details.
   6  */
   7
   8 #include "_stdio.h"
   9 #include <stdarg.h>
  10
  11 #ifdef __STDIO_BUFFERS
  12 /* NB: we can still have __USE_OLD_VFPRINTF__ defined in this case! */
  13
  14 int vsnprintf(char *__restrict buf, size_t size,
  15                           const char * __restrict format, va_list arg)
  16 {
  17         FILE f;
  18         int rv;
  19
  20         f.__filedes = __STDIO_STREAM_FAKE_VSNPRINTF_FILEDES;
  21         f.__modeflags = (__FLAG_NARROW|__FLAG_WRITEONLY|__FLAG_WRITING);
  22
  23 #ifdef __UCLIBC_HAS_WCHAR__
  24         f.__ungot_width[0] = 0;
  25 #endif /* __UCLIBC_HAS_WCHAR__ */
  26 #ifdef __STDIO_MBSTATE
  27         __INIT_MBSTATE(&(f.__state));
  28 #endif /* __STDIO_MBSTATE */
  29
  30 #if (defined(__STDIO_BUFFERS) || defined(__USE_OLD_VFPRINTF__)) && defined(__UCLIBC_HAS_THREADS__)
  31         f.__user_locking = 1;           /* Set user locking. */
  32         STDIO_INIT_MUTEX(f.__lock);
  33 #endif
  34         f.__nextopen = NULL;
  35
  36         if (size > SIZE_MAX - (size_t) buf) {
  37                 size = SIZE_MAX - (size_t) buf;
  38         }
  39
  40 /* TODO: this comment seems to be wrong */
  41         /* Set these last since __bufputc initialization depends on
  42          * __user_locking and only gets set if user locking is on. */
  43         f.__bufstart = (unsigned char *) buf;
  44         f.__bufend = (unsigned char *) buf + size;
  45         __STDIO_STREAM_INIT_BUFREAD_BUFPOS(&f);
  46         __STDIO_STREAM_DISABLE_GETC(&f);
  47         __STDIO_STREAM_ENABLE_PUTC(&f);
  48
  49 #ifdef __USE_OLD_VFPRINTF__
  50         rv = vfprintf(&f, format, arg);
  51 #else
  52         rv = _vfprintf_internal(&f, format, arg);
  53 #endif
  54         if (size) {
  55                 if (f.__bufpos == f.__bufend) {
  56                         --f.__bufpos;
  57                 }
  58                 *f.__bufpos = 0;
  59         }
  60         return rv;
  61 }
  62 libc_hidden_def(vsnprintf)
  63
  64 #elif defined(__USE_OLD_VFPRINTF__)
  65
  66 typedef struct {
  67         FILE f;
  68         unsigned char *bufend;          /* pointer to 1 past end of buffer */
  69         unsigned char *bufpos;
  70 } __FILE_vsnprintf;
  71
  72 int vsnprintf(char *__restrict buf, size_t size,
  73                           const char * __restrict format, va_list arg)
  74 {
  75         __FILE_vsnprintf f;
  76         int rv;
  77
  78         f.bufpos = buf;
  79
  80         if (size > SIZE_MAX - (size_t) buf) {
  81                 size = SIZE_MAX - (size_t) buf;
  82         }
  83         f.bufend = buf + size;
  84
  85         f.f.__filedes = __STDIO_STREAM_FAKE_VSNPRINTF_FILEDES_NB;
  86         f.f.__modeflags = (__FLAG_NARROW|__FLAG_WRITEONLY|__FLAG_WRITING);
  87
  88 #ifdef __UCLIBC_HAS_WCHAR__
  89         f.f.__ungot_width[0] = 0;
  90 #endif /* __UCLIBC_HAS_WCHAR__ */
  91 #ifdef __STDIO_MBSTATE
  92         __INIT_MBSTATE(&(f.f.__state));
  93 #endif /* __STDIO_MBSTATE */
  94
  95 #ifdef __UCLIBC_HAS_THREADS__
  96         f.f.__user_locking = 1;         /* Set user locking. */
  97         STDIO_INIT_MUTEX(f.f.__lock);
  98 #endif
  99         f.f.__nextopen = NULL;
 100
 101         rv = vfprintf((FILE *) &f, format, arg);
 102         if (size) {
 103                 if (f.bufpos == f.bufend) {
 104                         --f.bufpos;
 105                 }
 106                 *f.bufpos = 0;
 107         }
 108         return rv;
 109 }
 110 libc_hidden_def(vsnprintf)
 111
 112 #elif defined(__UCLIBC_HAS_GLIBC_CUSTOM_STREAMS__)
 113
 114 typedef struct {
 115         size_t pos;
 116         size_t len;
 117         char *buf;
 118         FILE *fp;
 119 } __snpf_cookie;
 120
 121 #define COOKIE ((__snpf_cookie *) cookie)
 122
 123 static ssize_t snpf_write(register void *cookie, const char *buf,
 124                                                   size_t bufsize)
 125 {
 126         size_t count;
 127         register char *p;
 128
 129         /* Note: bufsize < SSIZE_MAX because of _stdio_WRITE. */
 130
 131         if (COOKIE->len > COOKIE->pos) {
 132                 count = COOKIE->len - COOKIE->pos - 1; /* Leave space for nul. */
 133                 if (count > bufsize) {
 134                         count = bufsize;
 135                 }
 136
 137                 p = COOKIE->buf + COOKIE->pos;
 138                 while (count) {
 139                         *p++ = *buf++;
 140                         --count;
 141                 }
 142                 *p = 0;
 143         }
 144
 145         COOKIE->pos += bufsize;
 146
 147         return bufsize;
 148 }
 149
 150 #undef COOKIE
 151
 152 int vsnprintf(char *__restrict buf, size_t size,
 153                           const char * __restrict format, va_list arg)
 154 {
 155         _IO_cookie_file_t cf;
 156         __snpf_cookie cookie;
 157         int rv;
 158
 159         cookie.buf = buf;
 160         cookie.len = size;
 161         cookie.pos = 0;
 162         cookie.fp = &cf.__fp;
 163
 164         cf.__cookie = &cookie;
 165         cf.__gcs.write = snpf_write;
 166         cf.__gcs.read = NULL;
 167         cf.__gcs.seek = NULL;
 168         cf.__gcs.close = NULL;
 169
 170         cf.__fp.__filedes = __STDIO_STREAM_GLIBC_CUSTOM_FILEDES;
 171         cf.__fp.__modeflags = (__FLAG_NARROW|__FLAG_WRITEONLY|__FLAG_WRITING);
 172
 173 #ifdef __UCLIBC_HAS_WCHAR__
 174         cf.__fp.__ungot_width[0] = 0;
 175 #endif /* __UCLIBC_HAS_WCHAR__ */
 176 #ifdef __STDIO_MBSTATE
 177         __INIT_MBSTATE(&(cf.__fp.__state));
 178 #endif /* __STDIO_MBSTATE */
 179
 180         cf.__fp.__nextopen = NULL;
 181
 182         rv = _vfprintf_internal(&cf.__fp, format, arg);
 183
 184         return rv;
 185 }
 186 libc_hidden_def(vsnprintf)
 187
 188 #else
 189 #warning Skipping vsnprintf since no buffering, no custom streams, and not old vfprintf!
 190 #ifdef __STDIO_HAS_VSNPRINTF
 191 #error WHOA! __STDIO_HAS_VSNPRINTF is defined!
 192 #endif
 193 #endif