asn1/per_support.c

   1 /*
   2  * Copyright (c) 2005, 2006, 2007 Lev Walkin <vlm@lionet.info>.
   3  * All rights reserved.
   4  * Redistribution and modifications are permitted subject to BSD license.
   5  */
   6 #include <asn_system.h>
   7 #include <asn_internal.h>
   8 #include <per_support.h>
   9
  10 char *
  11 per_data_string(asn_per_data_t *pd) {
  12         static char buf[2][32];
  13         static int n;
  14         n = (n+1) % 2;
  15         snprintf(buf[n], sizeof(buf),
  16                 "{m=%ld span %+ld[%d..%d] (%d)}",
  17                 (long)pd->moved,
  18                 (((long)pd->buffer) & 0xf),
  19                 (int)pd->nboff, (int)pd->nbits,
  20                 (int)(pd->nbits - pd->nboff));
  21         return buf[n];
  22 }
  23
  24 void
  25 per_get_undo(asn_per_data_t *pd, int nbits) {
  26         if((ssize_t)pd->nboff < nbits) {
  27                 assert((ssize_t)pd->nboff < nbits);
  28         } else {
  29                 pd->nboff -= nbits;
  30                 pd->moved -= nbits;
  31         }
  32 }
  33
  34 /*
  35  * Extract a small number of bits (<= 31) from the specified PER data pointer.
  36  */
  37 int32_t
  38 per_get_few_bits(asn_per_data_t *pd, int nbits) {
  39         size_t off;     /* Next after last bit offset */
  40         ssize_t nleft;  /* Number of bits left in this stream */
  41         uint32_t accum;
  42         const uint8_t *buf;
  43
  44         if(nbits < 0)
  45                 return -1;
  46
  47         nleft = pd->nbits - pd->nboff;
  48         if(nbits > nleft) {
  49                 int32_t tailv, vhead;
  50                 if(!pd->refill || nbits > 31) return -1;
  51                 /* Accumulate unused bytes before refill */
  52                 ASN_DEBUG("Obtain the rest %d bits (want %d)",
  53                         (int)nleft, (int)nbits);
  54                 tailv = per_get_few_bits(pd, nleft);
  55                 if(tailv < 0) return -1;
  56                 /* Refill (replace pd contents with new data) */
  57                 if(pd->refill(pd))
  58                         return -1;
  59                 nbits -= nleft;
  60                 vhead = per_get_few_bits(pd, nbits);
  61                 /* Combine the rest of previous pd with the head of new one */
  62                 tailv = (tailv << nbits) | vhead;  /* Could == -1 */
  63                 return tailv;
  64         }
  65
  66         /*
  67          * Normalize position indicator.
  68          */
  69         if(pd->nboff >= 8) {
  70                 pd->buffer += (pd->nboff >> 3);
  71                 pd->nbits  -= (pd->nboff & ~0x07);
  72                 pd->nboff  &= 0x07;
  73         }
  74         pd->moved += nbits;
  75         pd->nboff += nbits;
  76         off = pd->nboff;
  77         buf = pd->buffer;
  78
  79         /*
  80          * Extract specified number of bits.
  81          */
  82         if(off <= 8)
  83                 accum = nbits ? (buf[0]) >> (8 - off) : 0;
  84         else if(off <= 16)
  85                 accum = ((buf[0] << 8) + buf[1]) >> (16 - off);
  86         else if(off <= 24)
  87                 accum = ((buf[0] << 16) + (buf[1] << 8) + buf[2]) >> (24 - off);
  88         else if(off <= 31)
  89                 accum = ((buf[0] << 24) + (buf[1] << 16)
  90                         + (buf[2] << 8) + (buf[3])) >> (32 - off);
  91         else if(nbits <= 31) {
  92                 asn_per_data_t tpd = *pd;
  93                 /* Here are we with our 31-bits limit plus 1..7 bits offset. */
  94                 per_get_undo(&tpd, nbits);
  95                 /* The number of available bits in the stream allow
  96                  * for the following operations to take place without
  97                  * invoking the ->refill() function */
  98                 accum  = per_get_few_bits(&tpd, nbits - 24) << 24;
  99                 accum |= per_get_few_bits(&tpd, 24);
 100         } else {
 101                 per_get_undo(pd, nbits);
 102                 return -1;
 103         }
 104
 105         accum &= (((uint32_t)1 << nbits) - 1);
 106
 107         ASN_DEBUG("  [PER got %2d<=%2d bits => span %d %+ld[%d..%d]:%02x (%d) => 0x%x]",
 108                 (int)nbits, (int)nleft,
 109                 (int)pd->moved,
 110                 (((long)pd->buffer) & 0xf),
 111                 (int)pd->nboff, (int)pd->nbits,
 112                 pd->buffer[0],
 113                 (int)(pd->nbits - pd->nboff),
 114                 (int)accum);
 115
 116         return accum;
 117 }
 118
 119 /*
 120  * Extract a large number of bits from the specified PER data pointer.
 121  */
 122 int
 123 per_get_many_bits(asn_per_data_t *pd, uint8_t *dst, int alright, int nbits) {
 124         int32_t value;
 125
 126         if(alright && (nbits & 7)) {
 127                 /* Perform right alignment of a first few bits */
 128                 value = per_get_few_bits(pd, nbits & 0x07);
 129                 if(value < 0) return -1;
 130                 *dst++ = value; /* value is already right-aligned */
 131                 nbits &= ~7;
 132         }
 133
 134         while(nbits) {
 135                 if(nbits >= 24) {
 136                         value = per_get_few_bits(pd, 24);
 137                         if(value < 0) return -1;
 138                         *(dst++) = value >> 16;
 139                         *(dst++) = value >> 8;
 140                         *(dst++) = value;
 141                         nbits -= 24;
 142                 } else {
 143                         value = per_get_few_bits(pd, nbits);
 144                         if(value < 0) return -1;
 145                         if(nbits & 7) { /* implies left alignment */
 146                                 value <<= 8 - (nbits & 7),
 147                                 nbits += 8 - (nbits & 7);
 148                                 if(nbits > 24)
 149                                         *dst++ = value >> 24;
 150                         }
 151                         if(nbits > 16)
 152                                 *dst++ = value >> 16;
 153                         if(nbits > 8)
 154                                 *dst++ = value >> 8;
 155                         *dst++ = value;
 156                         break;
 157                 }
 158         }
 159
 160         return 0;
 161 }
 162
 163 /*
 164  * Get the length "n" from the stream.
 165  */
 166 ssize_t
 167 uper_get_length(asn_per_data_t *pd, int ebits, int *repeat) {
 168         ssize_t value;
 169
 170         *repeat = 0;
 171
 172         if(ebits >= 0) return per_get_few_bits(pd, ebits);
 173
 174         value = per_get_few_bits(pd, 8);
 175         if(value < 0) return -1;
 176         if((value & 128) == 0)  /* #10.9.3.6 */
 177                 return (value & 0x7F);
 178         if((value & 64) == 0) { /* #10.9.3.7 */
 179                 value = ((value & 63) << 8) | per_get_few_bits(pd, 8);
 180                 if(value < 0) return -1;
 181                 return value;
 182         }
 183         value &= 63;    /* this is "m" from X.691, #10.9.3.8 */
 184         if(value < 1 || value > 4)
 185                 return -1;
 186         *repeat = 1;
 187         return (16384 * value);
 188 }
 189
 190 /*
 191  * Get the normally small length "n".
 192  * This procedure used to decode length of extensions bit-maps
 193  * for SET and SEQUENCE types.
 194  */
 195 ssize_t
 196 uper_get_nslength(asn_per_data_t *pd) {
 197         ssize_t length;
 198
 199         ASN_DEBUG("Getting normally small length");
 200
 201         if(per_get_few_bits(pd, 1) == 0) {
 202                 length = per_get_few_bits(pd, 6) + 1;
 203                 if(length <= 0) return -1;
 204                 ASN_DEBUG("l=%d", (int)length);
 205                 return length;
 206         } else {
 207                 int repeat;
 208                 length = uper_get_length(pd, -1, &repeat);
 209                 if(length >= 0 && !repeat) return length;
 210                 return -1; /* Error, or do not support >16K extensions */
 211         }
 212 }
 213
 214 /*
 215  * Get the normally small non-negative whole number.
 216  * X.691, #10.6
 217  */
 218 ssize_t
 219 uper_get_nsnnwn(asn_per_data_t *pd) {
 220         ssize_t value;
 221
 222         value = per_get_few_bits(pd, 7);
 223         if(value & 64) {        /* implicit (value < 0) */
 224                 value &= 63;
 225                 value <<= 2;
 226                 value |= per_get_few_bits(pd, 2);
 227                 if(value & 128) /* implicit (value < 0) */
 228                         return -1;
 229                 if(value == 0)
 230                         return 0;
 231                 if(value >= 3)
 232                         return -1;
 233                 value = per_get_few_bits(pd, 8 * value);
 234                 return value;
 235         }
 236
 237         return value;
 238 }
 239
 240 /*
 241  * Put the normally small non-negative whole number.
 242  * X.691, #10.6
 243  */
 244 int
 245 uper_put_nsnnwn(asn_per_outp_t *po, int n) {
 246         int bytes;
 247
 248         if(n <= 63) {
 249                 if(n < 0) return -1;
 250                 return per_put_few_bits(po, n, 7);
 251         }
 252         if(n < 256)
 253                 bytes = 1;
 254         else if(n < 65536)
 255                 bytes = 2;
 256         else if(n < 256 * 65536)
 257                 bytes = 3;
 258         else
 259                 return -1;      /* This is not a "normally small" value */
 260         if(per_put_few_bits(po, bytes, 8))
 261                 return -1;
 262
 263         return per_put_few_bits(po, n, 8 * bytes);
 264 }
 265
 266
 267 /*
 268  * Put a small number of bits (<= 31).
 269  */
 270 int
 271 per_put_few_bits(asn_per_outp_t *po, uint32_t bits, int obits) {
 272         size_t off;     /* Next after last bit offset */
 273         size_t omsk;    /* Existing last byte meaningful bits mask */
 274         uint8_t *buf;
 275
 276         if(obits <= 0 || obits >= 32) return obits ? -1 : 0;
 277
 278         ASN_DEBUG("[PER put %d bits %x to %p+%d bits]",
 279                         obits, (int)bits, po->buffer, (int)po->nboff);
 280
 281         /*
 282          * Normalize position indicator.
 283          */
 284         if(po->nboff >= 8) {
 285                 po->buffer += (po->nboff >> 3);
 286                 po->nbits  -= (po->nboff & ~0x07);
 287                 po->nboff  &= 0x07;
 288         }
 289
 290         /*
 291          * Flush whole-bytes output, if necessary.
 292          */
 293         if(po->nboff + obits > po->nbits) {
 294                 int complete_bytes = (po->buffer - po->tmpspace);
 295                 ASN_DEBUG("[PER output %ld complete + %ld]",
 296                         (long)complete_bytes, (long)po->flushed_bytes);
 297                 if(po->outper(po->tmpspace, complete_bytes, po->op_key) < 0)
 298                         return -1;
 299                 if(po->nboff)
 300                         po->tmpspace[0] = po->buffer[0];
 301                 po->buffer = po->tmpspace;
 302                 po->nbits = 8 * sizeof(po->tmpspace);
 303                 po->flushed_bytes += complete_bytes;
 304         }
 305
 306         /*
 307          * Now, due to sizeof(tmpspace), we are guaranteed large enough space.
 308          */
 309         buf = po->buffer;
 310         omsk = ~((1 << (8 - po->nboff)) - 1);
 311         off = (po->nboff + obits);
 312
 313         /* Clear data of debris before meaningful bits */
 314         bits &= (((uint32_t)1 << obits) - 1);
 315
 316         ASN_DEBUG("[PER out %d %u/%x (t=%d,o=%d) %x&%x=%x]", obits,
 317                 (int)bits, (int)bits,
 318                 (int)po->nboff, (int)off,
 319                 buf[0], (int)(omsk&0xff),
 320                 (int)(buf[0] & omsk));
 321
 322         if(off <= 8)    /* Completely within 1 byte */
 323                 po->nboff = off,
 324                 bits <<= (8 - off),
 325                 buf[0] = (buf[0] & omsk) | bits;
 326         else if(off <= 16)
 327                 po->nboff = off,
 328                 bits <<= (16 - off),
 329                 buf[0] = (buf[0] & omsk) | (bits >> 8),
 330                 buf[1] = bits;
 331         else if(off <= 24)
 332                 po->nboff = off,
 333                 bits <<= (24 - off),
 334                 buf[0] = (buf[0] & omsk) | (bits >> 16),
 335                 buf[1] = bits >> 8,
 336                 buf[2] = bits;
 337         else if(off <= 31)
 338                 po->nboff = off,
 339                 bits <<= (32 - off),
 340                 buf[0] = (buf[0] & omsk) | (bits >> 24),
 341                 buf[1] = bits >> 16,
 342                 buf[2] = bits >> 8,
 343                 buf[3] = bits;
 344         else {
 345                 per_put_few_bits(po, bits >> (obits - 24), 24);
 346                 per_put_few_bits(po, bits, obits - 24);
 347         }
 348
 349         ASN_DEBUG("[PER out %u/%x => %02x buf+%ld]",
 350                 (int)bits, (int)bits, buf[0],
 351                 (long)(po->buffer - po->tmpspace));
 352
 353         return 0;
 354 }
 355
 356
 357 /*
 358  * Output a large number of bits.
 359  */
 360 int
 361 per_put_many_bits(asn_per_outp_t *po, const uint8_t *src, int nbits) {
 362
 363         while(nbits) {
 364                 uint32_t value;
 365
 366                 if(nbits >= 24) {
 367                         value = (src[0] << 16) | (src[1] << 8) | src[2];
 368                         src += 3;
 369                         nbits -= 24;
 370                         if(per_put_few_bits(po, value, 24))
 371                                 return -1;
 372                 } else {
 373                         value = src[0];
 374                         if(nbits > 8)
 375                                 value = (value << 8) | src[1];
 376                         if(nbits > 16)
 377                                 value = (value << 8) | src[2];
 378                         if(nbits & 0x07)
 379                                 value >>= (8 - (nbits & 0x07));
 380                         if(per_put_few_bits(po, value, nbits))
 381                                 return -1;
 382                         break;
 383                 }
 384         }
 385
 386         return 0;
 387 }
 388
 389 /*
 390  * Put the length "n" (or part of it) into the stream.
 391  */
 392 ssize_t
 393 uper_put_length(asn_per_outp_t *po, size_t length) {
 394
 395         if(length <= 127)       /* #10.9.3.6 */
 396                 return per_put_few_bits(po, length, 8)
 397                         ? -1 : (ssize_t)length;
 398         else if(length < 16384) /* #10.9.3.7 */
 399                 return per_put_few_bits(po, length|0x8000, 16)
 400                         ? -1 : (ssize_t)length;
 401
 402         length >>= 14;
 403         if(length > 4) length = 4;
 404
 405         return per_put_few_bits(po, 0xC0 | length, 8)
 406                         ? -1 : (ssize_t)(length << 14);
 407 }
 408
 409
 410 /*
 411  * Put the normally small length "n" into the stream.
 412  * This procedure used to encode length of extensions bit-maps
 413  * for SET and SEQUENCE types.
 414  */
 415 int
 416 uper_put_nslength(asn_per_outp_t *po, size_t length) {
 417
 418         if(length <= 64) {
 419                 /* #10.9.3.4 */
 420                 if(length == 0) return -1;
 421                 return per_put_few_bits(po, length-1, 7) ? -1 : 0;
 422         } else {
 423                 if(uper_put_length(po, length) != (ssize_t)length) {
 424                         /* This might happen in case of >16K extensions */
 425                         return -1;
 426                 }
 427         }
 428
 429         return 0;
 430 }
 431