git.distorted.org.uk Git - u/mdw/catacomb/blob - buf.h

   1 /* -*-c-*-
   2  *
   3  * $Id: buf.h,v 1.2 2003/11/10 22:18:30 mdw Exp $
   4  *
   5  * Reading and writing packet buffers
   6  *
   7  * (c) 2001 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: buf.h,v $
  33  * Revision 1.2  2003/11/10 22:18:30  mdw
  34  * Build fixes.
  35  *
  36  * Revision 1.1  2003/10/11 21:02:33  mdw
  37  * Import buf stuff from tripe.
  38  *
  39  * Revision 1.1  2001/06/19 22:09:54  mdw
  40  * Expose interface, for use in the proxy.
  41  *
  42  */
  43
  44 #ifndef CATACOMB_BUF_H
  45 #define CATACOMB_BUF_H
  46
  47 #ifdef __cplusplus
  48   extern "C" {
  49 #endif
  50
  51 /*----- Header files ------------------------------------------------------*/
  52
  53 #include <stddef.h>
  54
  55 #include <mLib/bits.h>
  56
  57 #ifndef CATACOMB_MP_H
  58 #  include "mp.h"
  59 #endif
  60
  61 /*----- Data structures ---------------------------------------------------*/
  62
  63 /* --- Buffers --- *
  64  *
  65  * Buffers provide a simple stream-like interface for building and parsing
  66  * packets.
  67  */
  68
  69 typedef struct buf {
  70   octet *base, *p, *limit;              /* Pointers to the buffer */
  71   unsigned f;                           /* Various flags */
  72 } buf;
  73
  74 #define BF_BROKEN 1u                    /* Buffer is broken */
  75
  76 /*----- Useful macros -----------------------------------------------------*/
  77
  78 #define BBASE(b) ((b)->base)
  79 #define BLIM(b) ((b)->limit)
  80 #define BCUR(b) ((b)->p)
  81 #define BSZ(b) ((b)->limit - (b)->base)
  82 #define BLEN(b) ((b)->p - (b)->base)
  83 #define BLEFT(b) ((b)->limit - (b)->p)
  84 #define BSTEP(b, sz) ((b)->p += (sz))
  85 #define BBAD(b) ((b)->f & BF_BROKEN)
  86 #define BOK(b) (!BBAD(b))
  87
  88 #define BENSURE(b, sz)                                                  \
  89   (BBAD(b) ? -1 : (sz) > BLEFT(b) ? (b)->f |= BF_BROKEN, -1 : 0)
  90
  91 /*----- Functions provided ------------------------------------------------*/
  92
  93 /* --- @buf_init@ --- *
  94  *
  95  * Arguments:   @buf *b@ = pointer to a buffer block
  96  *              @void *p@ = pointer to a buffer
  97  *              @size_t sz@ = size of the buffer
  98  *
  99  * Returns:     ---
 100  *
 101  * Use:         Initializes the buffer block appropriately.
 102  */
 103
 104 extern void buf_init(buf */*b*/, void */*p*/, size_t /*sz*/);
 105
 106 /* --- @buf_break@ --- *
 107  *
 108  * Arguments:   @buf *b@ = pointer to a buffer block
 109  *
 110  * Returns:     Some negative value.
 111  *
 112  * Use:         Marks a buffer as broken.
 113  */
 114
 115 extern int buf_break(buf */*b*/);
 116
 117 /* --- @buf_flip@ --- *
 118  *
 119  * Arguments:   @buf *b@ = pointer to a buffer block
 120  *
 121  * Returns:     ---
 122  *
 123  * Use:         Flips a buffer so that if you've just been writing to it,
 124  *              you can now read from the bit you've written.
 125  */
 126
 127 extern void buf_flip(buf */*b*/);
 128
 129 /* --- @buf_ensure@ --- *
 130  *
 131  * Arguments:   @buf *b@ = pointer to a buffer block
 132  *              @size_t sz@ = size of data wanted
 133  *
 134  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 135  *
 136  * Use:         Ensures that there are @sz@ bytes still in the buffer.
 137  */
 138
 139 extern int buf_ensure(buf */*b*/, size_t /*sz*/);
 140
 141 /* --- @buf_get@ --- *
 142  *
 143  * Arguments:   @buf *b@ = pointer to a buffer block
 144  *              @size_t sz@ = size of the buffer
 145  *
 146  * Returns:     Pointer to the place in the buffer.
 147  *
 148  * Use:         Reserves a space in the buffer of the requested size, and
 149  *              returns its start address.
 150  */
 151
 152 extern void *buf_get(buf */*b*/, size_t /*sz*/);
 153
 154 /* --- @buf_put@ --- *
 155  *
 156  * Arguments:   @buf *b@ = pointer to a buffer block
 157  *              @const void *p@ = pointer to a buffer
 158  *              @size_t sz@ = size of the buffer
 159  *
 160  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 161  *
 162  * Use:         Fetches data from some place and puts it in the buffer
 163  */
 164
 165 extern int buf_put(buf */*b*/, const void */*p*/, size_t /*sz*/);
 166
 167 /* --- @buf_getbyte@ --- *
 168  *
 169  * Arguments:   @buf *b@ = pointer to a buffer block
 170  *
 171  * Returns:     A byte, or less than zero if there wasn't a byte there.
 172  *
 173  * Use:         Gets a single byte from a buffer.
 174  */
 175
 176 extern int buf_getbyte(buf */*b*/);
 177
 178 /* --- @buf_putbyte@ --- *
 179  *
 180  * Arguments:   @buf *b@ = pointer to a buffer block
 181  *              @int ch@ = byte to write
 182  *
 183  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 184  *
 185  * Use:         Puts a single byte in a buffer.
 186  */
 187
 188 extern int buf_putbyte(buf */*b*/, int /*ch*/);
 189
 190 /* --- @buf_getu16@ --- *
 191  *
 192  * Arguments:   @buf *b@ = pointer to a buffer block
 193  *              @uint16 *w@ = where to put the word
 194  *
 195  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 196  *
 197  * Use:         Gets a 16-bit word from a buffer.
 198  */
 199
 200 extern int buf_getu16(buf */*b*/, uint16 */*w*/);
 201
 202 /* --- @buf_putu16@ --- *
 203  *
 204  * Arguments:   @buf *b@ = pointer to a buffer block
 205  *              @uint16 w@ = word to write
 206  *
 207  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 208  *
 209  * Use:         Puts a 16-but word in a buffer.
 210  */
 211
 212 extern int buf_putu16(buf */*b*/, uint16 /*w*/);
 213
 214 /* --- @buf_getu32@ --- *
 215  *
 216  * Arguments:   @buf *b@ = pointer to a buffer block
 217  *              @uint32 *w@ = where to put the word
 218  *
 219  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 220  *
 221  * Use:         Gets a 32-bit word from a buffer.
 222  */
 223
 224 extern int buf_getu32(buf */*b*/, uint32 */*w*/);
 225
 226 /* --- @buf_putu32@ --- *
 227  *
 228  * Arguments:   @buf *b@ = pointer to a buffer block
 229  *              @uint32 w@ = word to write
 230  *
 231  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 232  *
 233  * Use:         Puts a 32-but word in a buffer.
 234  */
 235
 236 extern int buf_putu32(buf */*b*/, uint32 /*w*/);
 237
 238 /* --- @buf_getmp@ --- *
 239  *
 240  * Arguments:   @buf *b@ = pointer to a buffer block
 241  *
 242  * Returns:     A multiprecision integer, or null if there wasn't one there.
 243  *
 244  * Use:         Gets a multiprecision integer from a buffer.
 245  */
 246
 247 extern mp *buf_getmp(buf */*b*/);
 248
 249 /* --- @buf_putmp@ --- *
 250  *
 251  * Arguments:   @buf *b@ = pointer to a buffer block
 252  *              @mp *m@ = a multiprecision integer
 253  *
 254  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 255  *
 256  * Use:         Puts a multiprecision integer to a buffer.
 257  */
 258
 259 extern int buf_putmp(buf */*b*/, mp */*m*/);
 260
 261 /*----- That's all, folks -------------------------------------------------*/
 262
 263 #ifdef __cplusplus
 264   }
 265 #endif
 266
 267 #endif