mdw@git.distorted.org.uk Git - mLib/blob - struct/buf.c

   1 /* -*-c-*-
   2  *
   3  * Buffer handling
   4  *
   5  * (c) 2001 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <assert.h>
  31 #include <string.h>
  32
  33 #include "buf.h"
  34 #include "macros.h"
  35
  36 /*----- Main code ---------------------------------------------------------*/
  37
  38 /* --- @buf_init@ --- *
  39  *
  40  * Arguments:   @buf *b@ = pointer to a buffer block
  41  *              @void *p@ = pointer to a buffer
  42  *              @size_t sz@ = size of the buffer
  43  *
  44  * Returns:     ---
  45  *
  46  * Use:         Initializes the buffer block appropriately.
  47  */
  48
  49 void buf_init(buf *b, void *p, size_t sz)
  50 {
  51   b->base = b->p = p;
  52   b->limit = b->p + sz;
  53   b->f = 0;
  54 }
  55
  56 /* --- @buf_break@ --- *
  57  *
  58  * Arguments:   @buf *b@ = pointer to a buffer block
  59  *
  60  * Returns:     Some negative value.
  61  *
  62  * Use:         Marks a buffer as broken.
  63  */
  64
  65 int buf_break(buf *b) { b->f |= BF_BROKEN; return (-1); }
  66
  67 /* --- @buf_flip@ --- *
  68  *
  69  * Arguments:   @buf *b@ = pointer to a buffer block
  70  *
  71  * Returns:     ---
  72  *
  73  * Use:         Flips a buffer so that if you've just been writing to it,
  74  *              you can now read from the bit you've written.
  75  */
  76
  77 void buf_flip(buf *b)
  78 {
  79   b->limit = b->p;
  80   b->p = b->base;
  81 }
  82
  83 /* --- @buf_ensure@ --- *
  84  *
  85  * Arguments:   @buf *b@ = pointer to a buffer block
  86  *              @size_t sz@ = size of data wanted
  87  *
  88  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
  89  *
  90  * Use:         Ensures that there are @sz@ bytes still in the buffer.
  91  */
  92
  93 int buf_ensure(buf *b, size_t sz) { return (BENSURE(b, sz)); }
  94
  95 /* --- @buf_get@ --- *
  96  *
  97  * Arguments:   @buf *b@ = pointer to a buffer block
  98  *              @size_t sz@ = size of the buffer
  99  *
 100  * Returns:     Pointer to the place in the buffer.
 101  *
 102  * Use:         Reserves a space in the buffer of the requested size, and
 103  *              returns its start address.
 104  */
 105
 106 void *buf_get(buf *b, size_t sz)
 107 {
 108   void *p;
 109   if (BENSURE(b, sz))
 110     return (0);
 111   p = BCUR(b);
 112   BSTEP(b, sz);
 113   return (p);
 114 }
 115
 116 /* --- @buf_put@ --- *
 117  *
 118  * Arguments:   @buf *b@ = pointer to a buffer block
 119  *              @const void *p@ = pointer to a buffer
 120  *              @size_t sz@ = size of the buffer
 121  *
 122  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 123  *
 124  * Use:         Fetches data from some place and puts it in the buffer
 125  */
 126
 127 int buf_put(buf *b, const void *p, size_t sz)
 128 {
 129   if (BENSURE(b, sz))
 130     return (-1);
 131   memcpy(BCUR(b), p, sz);
 132   BSTEP(b, sz);
 133   return (0);
 134 }
 135
 136 /* --- @buf_getbyte@ --- *
 137  *
 138  * Arguments:   @buf *b@ = pointer to a buffer block
 139  *
 140  * Returns:     A byte, or less than zero if there wasn't a byte there.
 141  *
 142  * Use:         Gets a single byte from a buffer.
 143  */
 144
 145 int buf_getbyte(buf *b)
 146 {
 147   if (BENSURE(b, 1))
 148     return (-1);
 149   return (*b->p++);
 150 }
 151
 152 /* --- @buf_putbyte@ --- *
 153  *
 154  * Arguments:   @buf *b@ = pointer to a buffer block
 155  *              @int ch@ = byte to write
 156  *
 157  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 158  *
 159  * Use:         Puts a single byte in a buffer.
 160  */
 161
 162 int buf_putbyte(buf *b, int ch)
 163 {
 164   if (BENSURE(b, 1))
 165     return (-1);
 166   *b->p++ = ch;
 167   return (0);
 168 }
 169
 170 /* --- @buf_getu{8,{16,24,32,64}{,l,b}}@ --- *
 171  *
 172  * Arguments:   @buf *b@ = pointer to a buffer block
 173  *              @uintSZ *w@ = where to put the word
 174  *
 175  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 176  *
 177  * Use:         Gets a word of appropriate size and order from a buffer.
 178  */
 179
 180 #define BUF_GETU_(n, W, w)                                              \
 181   int buf_getu##w(buf *b, uint##n *ww)                                  \
 182   {                                                                     \
 183     if (BENSURE(b, SZ_##W)) return (-1);                                \
 184     *ww = LOAD##W(b->p);                                                \
 185     BSTEP(b, SZ_##W);                                                   \
 186     return (0);                                                         \
 187   }
 188 DOUINTCONV(BUF_GETU_)
 189
 190 /* --- @buf_putu{8,{16,24,32,64}{,l,b}}@ --- *
 191  *
 192  * Arguments:   @buf *b@ = pointer to a buffer block
 193  *              @uintSZ w@ = word to write
 194  *
 195  * Returns:     Zero if OK, or nonzero if there wasn't enough space
 196  *
 197  * Use:         Puts a word into a buffer with appropriate size and order.
 198  */
 199
 200 #define BUF_PUTU_(n, W, w)                                              \
 201   int buf_putu##w(buf *b, uint##n ww)                                   \
 202   {                                                                     \
 203     if (BENSURE(b, SZ_##W)) return (-1);                                \
 204     STORE##W(b->p, ww);                                                 \
 205     BSTEP(b, SZ_##W);                                                   \
 206     return (0);                                                         \
 207   }
 208 DOUINTCONV(BUF_PUTU_)
 209
 210 /* --- @findz@ --- *
 211  *
 212  * Arguments:   @buf *b@ = pointer to a buffer block
 213  *              @size_t *nn@ = where to put the length
 214  *
 215  * Returns:     Zero if OK, nonzero if there wasn't a null byte to be found.
 216  *
 217  * Use:         Finds a terminating null byte.  The length includes this
 218  *              terminator.
 219  */
 220
 221 static int findz(buf *b, size_t *nn)
 222 {
 223   octet *p;
 224
 225   if ((p = memchr(BCUR(b), 0, BLEFT(b))) == 0) {
 226     buf_break(b);
 227     return (-1);
 228   }
 229   *nn = p - BCUR(b) + 1;
 230   return (0);
 231 }
 232
 233 /* --- @buf_getmem{8,{16,24,32,64}{,l,b},z} --- *
 234  *
 235  * Arguments:   @buf *b@ = pointer to a buffer block
 236  *              @size_t *nn@ = where to put the length
 237  *
 238  * Returns:     Pointer to the buffer data, or null.
 239  *
 240  * Use:         Gets a chunk of memory from a buffer.  The suffix is the
 241  *              width and byte order of the length; @z@ means null-
 242  *              terminated.
 243  */
 244
 245 #define BUF_GETMEM_(n, W, w)                                            \
 246   void *buf_getmem##w(buf *b, size_t *nn)                               \
 247   {                                                                     \
 248     uint##n sz;                                                         \
 249     if (buf_getu##w(b, &sz)) return (0);                                \
 250     if (BENSURE(b, sz)) return (0);                                     \
 251     *nn = sz;                                                           \
 252     return (buf_get(b, sz));                                            \
 253   }
 254 DOUINTCONV(BUF_GETMEM_)
 255
 256 void *buf_getmemz(buf *b, size_t *nn)
 257 {
 258   if (findz(b, nn)) return (0);
 259   return (buf_get(b, *nn));
 260 }
 261
 262 /* --- @buf_putmem{8,{16,24,32,64}{,l,b},z} --- *
 263  *
 264  * Arguments:   @buf *b@ = pointer to a buffer block
 265  *              @const void *p@ = pointer to data to write
 266  *              @size_t n@ = length to write
 267  *
 268  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 269  *
 270  * Use:         Writes a chunk of data to a buffer.  The suffix is the
 271  *              width and byte order of the length; @z@ means null-
 272  *              terminated.
 273  */
 274
 275 #define BUF_PUTMEM_(n, W, w)                                            \
 276   int buf_putmem##w(buf *b, const void *p, size_t sz)                   \
 277   {                                                                     \
 278     MUFFLE_WARNINGS_STMT                                                \
 279       (CLANG_WARNING("-Wtautological-constant-out-of-range-compare"),   \
 280        { assert(sz <= MASK##W); });                                     \
 281     if (buf_putu##w(b, sz) || buf_put(b, p, sz))                        \
 282       return (-1);                                                      \
 283     return (0);                                                         \
 284   }
 285 DOUINTCONV(BUF_PUTMEM_)
 286
 287 int buf_putmemz(buf *b, const void *p, size_t n)
 288 {
 289   octet *q;
 290
 291   assert(!memchr(p, 0, n));
 292   if ((q = buf_get(b, n + 1)) == 0)
 293     return (-1);
 294   memcpy(q, p, n);
 295   q[n] = 0;
 296   return (0);
 297 }
 298
 299 /* --- @buf_getbuf{8,{16,24,32,64}{,l,b},z} --- *
 300  *
 301  * Arguments:   @buf *b@ = pointer to a buffer block
 302  *              @buf *bb@ = where to put the result
 303  *
 304  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 305  *
 306  * Use:         Gets a block of data from a buffer, and writes its bounds to
 307  *              another buffer.
 308  */
 309
 310 #define BUF_GETBUF_(n, W, w)                                            \
 311   int buf_getbuf##w(buf *b, buf *bb)                                    \
 312   {                                                                     \
 313     void *p;                                                            \
 314     size_t sz;                                                          \
 315                                                                         \
 316     if ((p = buf_getmem##w(b, &sz)) == 0)                               \
 317       return (-1);                                                      \
 318     buf_init(bb, p, sz);                                                \
 319     return (0);                                                         \
 320   }
 321 BUF_DOSUFFIXES(BUF_GETBUF_)
 322
 323 /* --- @buf_putbuf{8,{16,24,32,64}{,l,b},z} --- *
 324  *
 325  * Arguments:   @buf *b@ = pointer to a buffer block
 326  *              @buf *bb@ = buffer to write
 327  *
 328  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 329  *
 330  * Use:         Puts the contents of a buffer to a buffer.
 331  */
 332
 333 #define BUF_PUTBUF_(n, W, w)                                            \
 334   int buf_putbuf##w(buf *b, buf *bb)                                    \
 335     { return (buf_putmem##w(b, BBASE(bb), BLEN(bb))); }
 336 BUF_DOSUFFIXES(BUF_PUTBUF_)
 337
 338 /* --- @buf_putstr{8,{16,24,32,64}{,l,b},z} --- *
 339  *
 340  * Arguments:   @buf *b@ = pointer to a buffer block
 341  *              @const char *p@ = string to write
 342  *
 343  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 344  *
 345  * Use:         Puts a null-terminated string to a buffer.
 346  */
 347
 348 #define BUF_PUTSTR_(n, W, w)                                            \
 349   int buf_putstr##w(buf *b, const char *p)                              \
 350     { return (buf_putmem##w(b, p, strlen(p))); }
 351 BUF_DOSUFFIXES(BUF_PUTSTR_)
 352
 353 /*----- That's all, folks -------------------------------------------------*/