contrib/bind-9.2.4rc7/lib/lwres/lwbuffer.c

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: lwbuffer.c,v 1.10.2.1 2004/03/09 06:12:34 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <string.h>
  23
  24 #include <lwres/lwbuffer.h>
  25
  26 #include "assert_p.h"
  27
  28 void
  29 lwres_buffer_init(lwres_buffer_t *b, void *base, unsigned int length)
  30 {
  31         /*
  32          * Make 'b' refer to the 'length'-byte region starting at base.
  33          */
  34
  35         REQUIRE(b != NULL);
  36
  37         b->magic = LWRES_BUFFER_MAGIC;
  38         b->base = base;
  39         b->length = length;
  40         b->used = 0;
  41         b->current = 0;
  42         b->active = 0;
  43 }
  44
  45 void
  46 lwres_buffer_invalidate(lwres_buffer_t *b)
  47 {
  48         /*
  49          * Make 'b' an invalid buffer.
  50          */
  51
  52         REQUIRE(LWRES_BUFFER_VALID(b));
  53
  54         b->magic = 0;
  55         b->base = NULL;
  56         b->length = 0;
  57         b->used = 0;
  58         b->current = 0;
  59         b->active = 0;
  60 }
  61
  62 void
  63 lwres_buffer_add(lwres_buffer_t *b, unsigned int n)
  64 {
  65         /*
  66          * Increase the 'used' region of 'b' by 'n' bytes.
  67          */
  68
  69         REQUIRE(LWRES_BUFFER_VALID(b));
  70         REQUIRE(b->used + n <= b->length);
  71
  72         b->used += n;
  73 }
  74
  75 void
  76 lwres_buffer_subtract(lwres_buffer_t *b, unsigned int n)
  77 {
  78         /*
  79          * Decrease the 'used' region of 'b' by 'n' bytes.
  80          */
  81
  82         REQUIRE(LWRES_BUFFER_VALID(b));
  83         REQUIRE(b->used >= n);
  84
  85         b->used -= n;
  86         if (b->current > b->used)
  87                 b->current = b->used;
  88         if (b->active > b->used)
  89                 b->active = b->used;
  90 }
  91
  92 void
  93 lwres_buffer_clear(lwres_buffer_t *b)
  94 {
  95         /*
  96          * Make the used region empty.
  97          */
  98
  99         REQUIRE(LWRES_BUFFER_VALID(b));
 100
 101         b->used = 0;
 102         b->current = 0;
 103         b->active = 0;
 104 }
 105
 106 void
 107 lwres_buffer_first(lwres_buffer_t *b)
 108 {
 109         /*
 110          * Make the consumed region empty.
 111          */
 112
 113         REQUIRE(LWRES_BUFFER_VALID(b));
 114
 115         b->current = 0;
 116 }
 117
 118 void
 119 lwres_buffer_forward(lwres_buffer_t *b, unsigned int n)
 120 {
 121         /*
 122          * Increase the 'consumed' region of 'b' by 'n' bytes.
 123          */
 124
 125         REQUIRE(LWRES_BUFFER_VALID(b));
 126         REQUIRE(b->current + n <= b->used);
 127
 128         b->current += n;
 129 }
 130
 131 void
 132 lwres_buffer_back(lwres_buffer_t *b, unsigned int n)
 133 {
 134         /*
 135          * Decrease the 'consumed' region of 'b' by 'n' bytes.
 136          */
 137
 138         REQUIRE(LWRES_BUFFER_VALID(b));
 139         REQUIRE(n <= b->current);
 140
 141         b->current -= n;
 142 }
 143
 144 lwres_uint8_t
 145 lwres_buffer_getuint8(lwres_buffer_t *b)
 146 {
 147         unsigned char *cp;
 148         lwres_uint8_t result;
 149
 150         /*
 151          * Read an unsigned 8-bit integer from 'b' and return it.
 152          */
 153
 154         REQUIRE(LWRES_BUFFER_VALID(b));
 155         REQUIRE(b->used - b->current >= 1);
 156
 157         cp = b->base;
 158         cp += b->current;
 159         b->current += 1;
 160         result = ((unsigned int)(cp[0]));
 161
 162         return (result);
 163 }
 164
 165 void
 166 lwres_buffer_putuint8(lwres_buffer_t *b, lwres_uint8_t val)
 167 {
 168         unsigned char *cp;
 169
 170         REQUIRE(LWRES_BUFFER_VALID(b));
 171         REQUIRE(b->used + 1 <= b->length);
 172
 173         cp = b->base;
 174         cp += b->used;
 175         b->used += 1;
 176         cp[0] = (val & 0x00ff);
 177 }
 178
 179 lwres_uint16_t
 180 lwres_buffer_getuint16(lwres_buffer_t *b)
 181 {
 182         unsigned char *cp;
 183         lwres_uint16_t result;
 184
 185         /*
 186          * Read an unsigned 16-bit integer in network byte order from 'b',
 187          * convert it to host byte order, and return it.
 188          */
 189
 190         REQUIRE(LWRES_BUFFER_VALID(b));
 191         REQUIRE(b->used - b->current >= 2);
 192
 193         cp = b->base;
 194         cp += b->current;
 195         b->current += 2;
 196         result = ((unsigned int)(cp[0])) << 8;
 197         result |= ((unsigned int)(cp[1]));
 198
 199         return (result);
 200 }
 201
 202 void
 203 lwres_buffer_putuint16(lwres_buffer_t *b, lwres_uint16_t val)
 204 {
 205         unsigned char *cp;
 206
 207         REQUIRE(LWRES_BUFFER_VALID(b));
 208         REQUIRE(b->used + 2 <= b->length);
 209
 210         cp = b->base;
 211         cp += b->used;
 212         b->used += 2;
 213         cp[0] = (val & 0xff00) >> 8;
 214         cp[1] = (val & 0x00ff);
 215 }
 216
 217 lwres_uint32_t
 218 lwres_buffer_getuint32(lwres_buffer_t *b)
 219 {
 220         unsigned char *cp;
 221         lwres_uint32_t result;
 222
 223         /*
 224          * Read an unsigned 32-bit integer in network byte order from 'b',
 225          * convert it to host byte order, and return it.
 226          */
 227
 228         REQUIRE(LWRES_BUFFER_VALID(b));
 229         REQUIRE(b->used - b->current >= 4);
 230
 231         cp = b->base;
 232         cp += b->current;
 233         b->current += 4;
 234         result = ((unsigned int)(cp[0])) << 24;
 235         result |= ((unsigned int)(cp[1])) << 16;
 236         result |= ((unsigned int)(cp[2])) << 8;
 237         result |= ((unsigned int)(cp[3]));
 238
 239         return (result);
 240 }
 241
 242 void
 243 lwres_buffer_putuint32(lwres_buffer_t *b, lwres_uint32_t val)
 244 {
 245         unsigned char *cp;
 246
 247         REQUIRE(LWRES_BUFFER_VALID(b));
 248         REQUIRE(b->used + 4 <= b->length);
 249
 250         cp = b->base;
 251         cp += b->used;
 252         b->used += 4;
 253         cp[0] = (unsigned char)((val & 0xff000000) >> 24);
 254         cp[1] = (unsigned char)((val & 0x00ff0000) >> 16);
 255         cp[2] = (unsigned char)((val & 0x0000ff00) >> 8);
 256         cp[3] = (unsigned char)(val & 0x000000ff);
 257 }
 258
 259 void
 260 lwres_buffer_putmem(lwres_buffer_t *b, const unsigned char *base,
 261                     unsigned int length)
 262 {
 263         unsigned char *cp;
 264
 265         REQUIRE(LWRES_BUFFER_VALID(b));
 266         REQUIRE(b->used + length <= b->length);
 267
 268         cp = (unsigned char *)b->base + b->used;
 269         memcpy(cp, base, length);
 270         b->used += length;
 271 }
 272
 273 void
 274 lwres_buffer_getmem(lwres_buffer_t *b, unsigned char *base,
 275                     unsigned int length)
 276 {
 277         unsigned char *cp;
 278
 279         REQUIRE(LWRES_BUFFER_VALID(b));
 280         REQUIRE(b->used - b->current >= length);
 281
 282         cp = b->base;
 283         cp += b->current;
 284         b->current += length;
 285
 286         memcpy(base, cp, length);
 287 }