crypto/md32_common.h

   1 /* crypto/md32_common.h */
   2 /* ====================================================================
   3  * Copyright (c) 1999 The OpenSSL Project.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this
  18  *    software must display the following acknowledgment:
  19  *    "This product includes software developed by the OpenSSL Project
  20  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  21  *
  22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  23  *    endorse or promote products derived from this software without
  24  *    prior written permission. For written permission, please contact
  25  *    licensing@OpenSSL.org.
  26  *
  27  * 5. Products derived from this software may not be called "OpenSSL"
  28  *    nor may "OpenSSL" appear in their names without prior written
  29  *    permission of the OpenSSL Project.
  30  *
  31  * 6. Redistributions of any form whatsoever must retain the following
  32  *    acknowledgment:
  33  *    "This product includes software developed by the OpenSSL Project
  34  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  47  * OF THE POSSIBILITY OF SUCH DAMAGE.
  48  * ====================================================================
  49  *
  50  * This product includes cryptographic software written by Eric Young
  51  * (eay@cryptsoft.com).  This product includes software written by Tim
  52  * Hudson (tjh@cryptsoft.com).
  53  *
  54  */
  55
  56 /*
  57  * This is a generic 32 bit "collector" for message digest algorithms.
  58  * Whenever needed it collects input character stream into chunks of
  59  * 32 bit values and invokes a block function that performs actual hash
  60  * calculations.
  61  *
  62  * Porting guide.
  63  *
  64  * Obligatory macros:
  65  *
  66  * DATA_ORDER_IS_BIG_ENDIAN or DATA_ORDER_IS_LITTLE_ENDIAN
  67  *      this macro defines byte order of input stream.
  68  * HASH_CBLOCK
  69  *      size of a unit chunk HASH_BLOCK operates on.
  70  * HASH_LONG
  71  *      has to be at lest 32 bit wide, if it's wider, then
  72  *      HASH_LONG_LOG2 *has to* be defined along
  73  * HASH_CTX
  74  *      context structure that at least contains following
  75  *      members:
  76  *              typedef struct {
  77  *                      ...
  78  *                      HASH_LONG       Nl,Nh;
  79  *                      HASH_LONG       data[HASH_LBLOCK];
  80  *                      int             num;
  81  *                      ...
  82  *                      } HASH_CTX;
  83  * HASH_UPDATE
  84  *      name of "Update" function, implemented here.
  85  * HASH_TRANSFORM
  86  *      name of "Transform" function, implemented here.
  87  * HASH_FINAL
  88  *      name of "Final" function, implemented here.
  89  * HASH_BLOCK_HOST_ORDER
  90  *      name of "block" function treating *aligned* input message
  91  *      in host byte order, implemented externally.
  92  * HASH_BLOCK_DATA_ORDER
  93  *      name of "block" function treating *unaligned* input message
  94  *      in original (data) byte order, implemented externally (it
  95  *      actually is optional if data and host are of the same
  96  *      "endianess").
  97  * HASH_MAKE_STRING
  98  *      macro convering context variables to an ASCII hash string.
  99  *
 100  * Optional macros:
 101  *
 102  * B_ENDIAN or L_ENDIAN
 103  *      defines host byte-order.
 104  * HASH_LONG_LOG2
 105  *      defaults to 2 if not states otherwise.
 106  * HASH_LBLOCK
 107  *      assumed to be HASH_CBLOCK/4 if not stated otherwise.
 108  * HASH_BLOCK_DATA_ORDER_ALIGNED
 109  *      alternative "block" function capable of treating
 110  *      aligned input message in original (data) order,
 111  *      implemented externally.
 112  *
 113  * MD5 example:
 114  *
 115  *      #define DATA_ORDER_IS_LITTLE_ENDIAN
 116  *
 117  *      #define HASH_LONG               MD5_LONG
 118  *      #define HASH_LONG_LOG2          MD5_LONG_LOG2
 119  *      #define HASH_CTX                MD5_CTX
 120  *      #define HASH_CBLOCK             MD5_CBLOCK
 121  *      #define HASH_LBLOCK             MD5_LBLOCK
 122  *      #define HASH_UPDATE             MD5_Update
 123  *      #define HASH_TRANSFORM          MD5_Transform
 124  *      #define HASH_FINAL              MD5_Final
 125  *      #define HASH_BLOCK_HOST_ORDER   md5_block_host_order
 126  *      #define HASH_BLOCK_DATA_ORDER   md5_block_data_order
 127  *
 128  *                                      <appro@fy.chalmers.se>
 129  */
 130
 131 #if !defined(DATA_ORDER_IS_BIG_ENDIAN) && !defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 132 #error "DATA_ORDER must be defined!"
 133 #endif
 134
 135 #ifndef HASH_CBLOCK
 136 #error "HASH_CBLOCK must be defined!"
 137 #endif
 138 #ifndef HASH_LONG
 139 #error "HASH_LONG must be defined!"
 140 #endif
 141 #ifndef HASH_CTX
 142 #error "HASH_CTX must be defined!"
 143 #endif
 144
 145 #ifndef HASH_UPDATE
 146 #error "HASH_UPDATE must be defined!"
 147 #endif
 148 #ifndef HASH_TRANSFORM
 149 #error "HASH_TRANSFORM must be defined!"
 150 #endif
 151 #ifndef HASH_FINAL
 152 #error "HASH_FINAL must be defined!"
 153 #endif
 154
 155 #ifndef HASH_BLOCK_HOST_ORDER
 156 #error "HASH_BLOCK_HOST_ORDER must be defined!"
 157 #endif
 158
 159 #if 0
 160 /*
 161  * Moved below as it's required only if HASH_BLOCK_DATA_ORDER_ALIGNED
 162  * isn't defined.
 163  */
 164 #ifndef HASH_BLOCK_DATA_ORDER
 165 #error "HASH_BLOCK_DATA_ORDER must be defined!"
 166 #endif
 167 #endif
 168
 169 #ifndef HASH_LBLOCK
 170 #define HASH_LBLOCK     (HASH_CBLOCK/4)
 171 #endif
 172
 173 #ifndef HASH_LONG_LOG2
 174 #define HASH_LONG_LOG2  2
 175 #endif
 176
 177 /*
 178  * Engage compiler specific rotate intrinsic function if available.
 179  */
 180 #undef ROTATE
 181 #ifndef PEDANTIC
 182 # if defined(_MSC_VER)
 183 #  define ROTATE(a,n)   _lrotl(a,n)
 184 # elif defined(__MWERKS__)
 185 #  define ROTATE(a,n)   __rol(a,n)
 186 # elif defined(__GNUC__) && __GNUC__>=2 && !defined(NO_ASM)
 187   /*
 188    * Some GNU C inline assembler templates. Note that these are
 189    * rotates by *constant* number of bits! But that's exactly
 190    * what we need here...
 191    *
 192    *                                    <appro@fy.chalmers.se>
 193    */
 194 #  if defined(__i386)
 195 #   define ROTATE(a,n)  ({ register unsigned int ret;   \
 196                                 asm volatile (          \
 197                                 "roll %1,%0"            \
 198                                 : "=r"(ret)             \
 199                                 : "I"(n), "0"(a)        \
 200                                 : "cc");                \
 201                            ret;                         \
 202                         })
 203 #  elif defined(__powerpc)
 204 #   define ROTATE(a,n)  ({ register unsigned int ret;   \
 205                                 asm volatile (          \
 206                                 "rlwinm %0,%1,%2,0,31"  \
 207                                 : "=r"(ret)             \
 208                                 : "r"(a), "I"(n));      \
 209                            ret;                         \
 210                         })
 211 #  endif
 212 # endif
 213
 214 /*
 215  * Engage compiler specific "fetch in reverse byte order"
 216  * intrinsic function if available.
 217  */
 218 # if defined(__GNUC__) && __GNUC__>=2 && !defined(NO_ASM)
 219   /* some GNU C inline assembler templates by <appro@fy.chalmers.se> */
 220 #  if defined(__i386) && !defined(I386_ONLY)
 221 #   define BE_FETCH32(a)        ({ register unsigned int l=(a);\
 222                                 asm volatile (          \
 223                                 "bswapl %0"             \
 224                                 : "=r"(l) : "0"(l));    \
 225                           l;                            \
 226                         })
 227 #  elif defined(__powerpc)
 228 #   define LE_FETCH32(a)        ({ register unsigned int l;     \
 229                                 asm volatile (          \
 230                                 "lwbrx %0,0,%1"         \
 231                                 : "=r"(l)               \
 232                                 : "r"(a));              \
 233                            l;                           \
 234                         })
 235
 236 #  elif defined(__sparc) && defined(ULTRASPARC)
 237 #  define LE_FETCH32(a) ({ register unsigned int l;             \
 238                                 asm volatile (                  \
 239                                 "lda [%1]#ASI_PRIMARY_LITTLE,%0"\
 240                                 : "=r"(l)                       \
 241                                 : "r"(a));                      \
 242                            l;                                   \
 243                         })
 244 #  endif
 245 # endif
 246 #endif /* PEDANTIC */
 247
 248 #if HASH_LONG_LOG2==2   /* Engage only if sizeof(HASH_LONG)== 4 */
 249 /* A nice byte order reversal from Wei Dai <weidai@eskimo.com> */
 250 #ifdef ROTATE
 251 /* 5 instructions with rotate instruction, else 9 */
 252 #define REVERSE_FETCH32(a,l)    (                                       \
 253                 l=*(const HASH_LONG *)(a),                              \
 254                 ((ROTATE(l,8)&0x00FF00FF)|(ROTATE((l&0x00FF00FF),24)))  \
 255                                 )
 256 #else
 257 /* 6 instructions with rotate instruction, else 8 */
 258 #define REVERSE_FETCH32(a,l)    (                               \
 259                 l=*(const HASH_LONG *)(a),                      \
 260                 l=(((l>>8)&0x00FF00FF)|((l&0x00FF00FF)<<8)),    \
 261                 ROTATE(l,16)                                    \
 262                                 )
 263 /*
 264  * Originally the middle line started with l=(((l&0xFF00FF00)>>8)|...
 265  * It's rewritten as above for two reasons:
 266  *      - RISCs aren't good at long constants and have to explicitely
 267  *        compose 'em with several (well, usually 2) instructions in a
 268  *        register before performing the actual operation and (as you
 269  *        already realized:-) having same constant should inspire the
 270  *        compiler to permanently allocate the only register for it;
 271  *      - most modern CPUs have two ALUs, but usually only one has
 272  *        circuitry for shifts:-( this minor tweak inspires compiler
 273  *        to schedule shift instructions in a better way...
 274  *
 275  *                              <appro@fy.chalmers.se>
 276  */
 277 #endif
 278 #endif
 279
 280 #ifndef ROTATE
 281 #define ROTATE(a,n)     (((a)<<(n))|(((a)&0xffffffff)>>(32-(n))))
 282 #endif
 283
 284 /*
 285  * Make some obvious choices. E.g., HASH_BLOCK_DATA_ORDER_ALIGNED
 286  * and HASH_BLOCK_HOST_ORDER ought to be the same if input data
 287  * and host are of the same "endianess". It's possible to mask
 288  * this with blank #define HASH_BLOCK_DATA_ORDER though...
 289  *
 290  *                              <appro@fy.chalmers.se>
 291  */
 292 #if defined(B_ENDIAN)
 293 #  if defined(DATA_ORDER_IS_BIG_ENDIAN)
 294 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
 295 #      define HASH_BLOCK_DATA_ORDER_ALIGNED     HASH_BLOCK_HOST_ORDER
 296 #    endif
 297 #  elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 298 #    ifndef HOST_FETCH32
 299 #      ifdef LE_FETCH32
 300 #        define HOST_FETCH32(p,l)       LE_FETCH32(p)
 301 #      elif defined(REVERSE_FETCH32)
 302 #        define HOST_FETCH32(p,l)       REVERSE_FETCH32(p,l)
 303 #      endif
 304 #    endif
 305 #  endif
 306 #elif defined(L_ENDIAN)
 307 #  if defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 308 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
 309 #      define HASH_BLOCK_DATA_ORDER_ALIGNED     HASH_BLOCK_HOST_ORDER
 310 #    endif
 311 #  elif defined(DATA_ORDER_IS_BIG_ENDIAN)
 312 #    ifndef HOST_FETCH32
 313 #      ifdef BE_FETCH32
 314 #        define HOST_FETCH32(p,l)       BE_FETCH32(p)
 315 #      elif defined(REVERSE_FETCH32)
 316 #        define HOST_FETCH32(p,l)       REVERSE_FETCH32(p,l)
 317 #      endif
 318 #    endif
 319 #  endif
 320 #endif
 321
 322 #if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
 323 #ifndef HASH_BLOCK_DATA_ORDER
 324 #error "HASH_BLOCK_DATA_ORDER must be defined!"
 325 #endif
 326 #endif
 327
 328 #if defined(DATA_ORDER_IS_BIG_ENDIAN)
 329
 330 #define HOST_c2l(c,l)   (l =(((unsigned long)(*((c)++)))<<24),          \
 331                          l|=(((unsigned long)(*((c)++)))<<16),          \
 332                          l|=(((unsigned long)(*((c)++)))<< 8),          \
 333                          l|=(((unsigned long)(*((c)++)))    ),          \
 334                          l)
 335 #define HOST_p_c2l(c,l,n)       {                                       \
 336                         switch (n) {                                    \
 337                         case 0: l =((unsigned long)(*((c)++)))<<24;     \
 338                         case 1: l|=((unsigned long)(*((c)++)))<<16;     \
 339                         case 2: l|=((unsigned long)(*((c)++)))<< 8;     \
 340                         case 3: l|=((unsigned long)(*((c)++)));         \
 341                                 } }
 342 #define HOST_p_c2l_p(c,l,sc,len) {                                      \
 343                         switch (sc) {                                   \
 344                         case 0: l =((unsigned long)(*((c)++)))<<24;     \
 345                                 if (--len == 0) break;                  \
 346                         case 1: l|=((unsigned long)(*((c)++)))<<16;     \
 347                                 if (--len == 0) break;                  \
 348                         case 2: l|=((unsigned long)(*((c)++)))<< 8;     \
 349                                 } }
 350 /* NOTE the pointer is not incremented at the end of this */
 351 #define HOST_c2l_p(c,l,n)       {                                       \
 352                         l=0; (c)+=n;                                    \
 353                         switch (n) {                                    \
 354                         case 3: l =((unsigned long)(*(--(c))))<< 8;     \
 355                         case 2: l|=((unsigned long)(*(--(c))))<<16;     \
 356                         case 1: l|=((unsigned long)(*(--(c))))<<24;     \
 357                                 } }
 358 #define HOST_l2c(l,c)   (*((c)++)=(unsigned char)(((l)>>24)&0xff),      \
 359                          *((c)++)=(unsigned char)(((l)>>16)&0xff),      \
 360                          *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \
 361                          *((c)++)=(unsigned char)(((l)    )&0xff),      \
 362                          l)
 363
 364 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 365
 366 #define HOST_c2l(c,l)   (l =(((unsigned long)(*((c)++)))    ),          \
 367                          l|=(((unsigned long)(*((c)++)))<< 8),          \
 368                          l|=(((unsigned long)(*((c)++)))<<16),          \
 369                          l|=(((unsigned long)(*((c)++)))<<24),          \
 370                          l)
 371 #define HOST_p_c2l(c,l,n)       {                                       \
 372                         switch (n) {                                    \
 373                         case 0: l =((unsigned long)(*((c)++)));         \
 374                         case 1: l|=((unsigned long)(*((c)++)))<< 8;     \
 375                         case 2: l|=((unsigned long)(*((c)++)))<<16;     \
 376                         case 3: l|=((unsigned long)(*((c)++)))<<24;     \
 377                                 } }
 378 #define HOST_p_c2l_p(c,l,sc,len) {                                      \
 379                         switch (sc) {                                   \
 380                         case 0: l =((unsigned long)(*((c)++)));         \
 381                                 if (--len == 0) break;                  \
 382                         case 1: l|=((unsigned long)(*((c)++)))<< 8;     \
 383                                 if (--len == 0) break;                  \
 384                         case 2: l|=((unsigned long)(*((c)++)))<<16;     \
 385                                 } }
 386 /* NOTE the pointer is not incremented at the end of this */
 387 #define HOST_c2l_p(c,l,n)       {                                       \
 388                         l=0; (c)+=n;                                    \
 389                         switch (n) {                                    \
 390                         case 3: l =((unsigned long)(*(--(c))))<<16;     \
 391                         case 2: l|=((unsigned long)(*(--(c))))<< 8;     \
 392                         case 1: l|=((unsigned long)(*(--(c))));         \
 393                                 } }
 394 #define HOST_l2c(l,c)   (*((c)++)=(unsigned char)(((l)    )&0xff),      \
 395                          *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \
 396                          *((c)++)=(unsigned char)(((l)>>16)&0xff),      \
 397                          *((c)++)=(unsigned char)(((l)>>24)&0xff),      \
 398                          l)
 399
 400 #endif
 401
 402 /*
 403  * Time for some action:-)
 404  */
 405
 406 void HASH_UPDATE (HASH_CTX *c, const unsigned char *data, unsigned long len)
 407         {
 408         register HASH_LONG * p;
 409         register unsigned long l;
 410         int sw,sc,ew,ec;
 411
 412         if (len==0) return;
 413
 414         l=(c->Nl+(len<<3))&0xffffffffL;
 415         /* 95-05-24 eay Fixed a bug with the overflow handling, thanks to
 416          * Wei Dai <weidai@eskimo.com> for pointing it out. */
 417         if (l < c->Nl) /* overflow */
 418                 c->Nh++;
 419         c->Nh+=(len>>29);
 420         c->Nl=l;
 421
 422         if (c->num != 0)
 423                 {
 424                 p=c->data;
 425                 sw=c->num>>2;
 426                 sc=c->num&0x03;
 427
 428                 if ((c->num+len) >= HASH_CBLOCK)
 429                         {
 430                         l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
 431                         for (; sw<HASH_LBLOCK; sw++)
 432                                 {
 433                                 HOST_c2l(data,l); p[sw]=l;
 434                                 }
 435                         HASH_BLOCK_HOST_ORDER (c,p,1);
 436                         len-=(HASH_CBLOCK-c->num);
 437                         c->num=0;
 438                         /* drop through and do the rest */
 439                         }
 440                 else
 441                         {
 442                         c->num+=len;
 443                         if ((sc+len) < 4) /* ugly, add char's to a word */
 444                                 {
 445                                 l=p[sw]; HOST_p_c2l_p(data,l,sc,len); p[sw]=l;
 446                                 }
 447                         else
 448                                 {
 449                                 ew=(c->num>>2);
 450                                 ec=(c->num&0x03);
 451                                 l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
 452                                 for (; sw < ew; sw++)
 453                                         {
 454                                         HOST_c2l(data,l); p[sw]=l;
 455                                         }
 456                                 if (ec)
 457                                         {
 458                                         HOST_c2l_p(data,l,ec); p[sw]=l;
 459                                         }
 460                                 }
 461                         return;
 462                         }
 463                 }
 464
 465         sw=len/HASH_CBLOCK;
 466         if (sw > 0)
 467                 {
 468 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
 469                 /*
 470                  * Note that HASH_BLOCK_DATA_ORDER_ALIGNED gets defined
 471                  * only if sizeof(HASH_LONG)==4.
 472                  */
 473                 if ((((unsigned long)data)%4) == 0)
 474                         {
 475                         /* data is properly aligned so that we can cast it: */
 476                         HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,sw);
 477                         sw*=HASH_CBLOCK;
 478                         data+=sw;
 479                         len-=sw;
 480                         }
 481                 else
 482 #if !defined(HASH_BLOCK_DATA_ORDER)
 483                         while (sw--)
 484                                 {
 485                                 memcpy (p=c->data,data,HASH_CBLOCK);
 486                                 HASH_BLOCK_DATA_ORDER_ALIGNED(c,p,1);
 487                                 data+=HASH_CBLOCK;
 488                                 len-=HASH_CBLOCK;
 489                                 }
 490 #endif
 491 #endif
 492 #if defined(HASH_BLOCK_DATA_ORDER)
 493                         {
 494                         HASH_BLOCK_DATA_ORDER(c,data,sw);
 495                         sw*=HASH_CBLOCK;
 496                         data+=sw;
 497                         len-=sw;
 498                         }
 499 #endif
 500                 }
 501
 502         if (len!=0)
 503                 {
 504                 p = c->data;
 505                 c->num = len;
 506                 ew=len>>2;      /* words to copy */
 507                 ec=len&0x03;
 508                 for (; ew; ew--,p++)
 509                         {
 510                         HOST_c2l(data,l); *p=l;
 511                         }
 512                 HOST_c2l_p(data,l,ec);
 513                 *p=l;
 514                 }
 515         }
 516
 517
 518 void HASH_TRANSFORM (HASH_CTX *c, const unsigned char *data)
 519         {
 520 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
 521         if ((((unsigned long)data)%4) == 0)
 522                 /* data is properly aligned so that we can cast it: */
 523                 HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,1);
 524         else
 525 #if !defined(HASH_BLOCK_DATA_ORDER)
 526                 {
 527                 memcpy (c->data,data,HASH_CBLOCK);
 528                 HASH_BLOCK_DATA_ORDER_ALIGNED (c,c->data,1);
 529                 }
 530 #endif
 531 #endif
 532 #if defined(HASH_BLOCK_DATA_ORDER)
 533         HASH_BLOCK_DATA_ORDER (c,data,1);
 534 #endif
 535         }
 536
 537
 538 void HASH_FINAL (unsigned char *md, HASH_CTX *c)
 539         {
 540         register HASH_LONG *p;
 541         register unsigned long l;
 542         register int i,j;
 543         static const unsigned char end[4]={0x80,0x00,0x00,0x00};
 544         const unsigned char *cp=end;
 545
 546         /* c->num should definitly have room for at least one more byte. */
 547         p=c->data;
 548         i=c->num>>2;
 549         j=c->num&0x03;
 550
 551 #if 0
 552         /* purify often complains about the following line as an
 553          * Uninitialized Memory Read.  While this can be true, the
 554          * following p_c2l macro will reset l when that case is true.
 555          * This is because j&0x03 contains the number of 'valid' bytes
 556          * already in p[i].  If and only if j&0x03 == 0, the UMR will
 557          * occur but this is also the only time p_c2l will do
 558          * l= *(cp++) instead of l|= *(cp++)
 559          * Many thanks to Alex Tang <altitude@cic.net> for pickup this
 560          * 'potential bug' */
 561 #ifdef PURIFY
 562         if (j==0) p[i]=0; /* Yeah, but that's not the way to fix it:-) */
 563 #endif
 564         l=p[i];
 565 #else
 566         l = (j==0) ? 0 : p[i];
 567 #endif
 568         HOST_p_c2l(cp,l,j); p[i++]=l; /* i is the next 'undefined word' */
 569
 570         if (i>(HASH_LBLOCK-2)) /* save room for Nl and Nh */
 571                 {
 572                 if (i<HASH_LBLOCK) p[i]=0;
 573                 HASH_BLOCK_HOST_ORDER (c,p,1);
 574                 i=0;
 575                 }
 576         for (; i<(HASH_LBLOCK-2); i++)
 577                 p[i]=0;
 578
 579 #if   defined(DATA_ORDER_IS_BIG_ENDIAN)
 580         p[HASH_LBLOCK-2]=c->Nh;
 581         p[HASH_LBLOCK-1]=c->Nl;
 582 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 583         p[HASH_LBLOCK-2]=c->Nl;
 584         p[HASH_LBLOCK-1]=c->Nh;
 585 #endif
 586         HASH_BLOCK_HOST_ORDER (c,p,1);
 587
 588 #ifndef HASH_MAKE_STRING
 589 #error "HASH_MAKE_STRING must be defined!"
 590 #else
 591         HASH_MAKE_STRING(c,md);
 592 #endif
 593
 594         c->num=0;
 595         /* clear stuff, HASH_BLOCK may be leaving some stuff on the stack
 596          * but I'm not worried :-)
 597         memset((void *)c,0,sizeof(HASH_CTX));
 598          */
 599         }