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  *
  98  * Optional macros:
  99  *
 100  * B_ENDIAN or L_ENDIAN
 101  *      defines host byte-order.
 102  * HASH_LONG_LOG2
 103  *      defaults to 2 if not states otherwise.
 104  * HASH_LBLOCK
 105  *      assumed to be HASH_CBLOCK/4 if not stated otherwise.
 106  * HASH_BLOCK_DATA_ORDER_ALIGNED
 107  *      alternative "block" function capable of treating
 108  *      aligned input message in original (data) order,
 109  *      implemented externally.
 110  *
 111  * MD5 example:
 112  *
 113  *      #define DATA_ORDER_IS_LITTLE_ENDIAN
 114  *
 115  *      #define HASH_LONG               MD5_LONG
 116  *      #define HASH_LONG_LOG2          MD5_LONG_LOG2
 117  *      #define HASH_CTX                MD5_CTX
 118  *      #define HASH_CBLOCK             MD5_CBLOCK
 119  *      #define HASH_LBLOCK             MD5_LBLOCK
 120  *      #define HASH_UPDATE             MD5_Update
 121  *      #define HASH_TRANSFORM          MD5_Transform
 122  *      #define HASH_FINAL              MD5_Final
 123  *      #define HASH_BLOCK_HOST_ORDER   md5_block_host_order
 124  *      #define HASH_BLOCK_DATA_ORDER   md5_block_data_order
 125  *
 126  *                                      <appro@fy.chalmers.se>
 127  */
 128
 129 #if !defined(DATA_ORDER_IS_BIG_ENDIAN) && !defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 130 #error "DATA_ORDER must be defined!"
 131 #endif
 132
 133 #ifndef HASH_CBLOCK
 134 #error "HASH_CBLOCK must be defined!"
 135 #endif
 136 #ifndef HASH_LONG
 137 #error "HASH_LONG must be defined!"
 138 #endif
 139 #ifndef HASH_CTX
 140 #error "HASH_CTX must be defined!"
 141 #endif
 142
 143 #ifndef HASH_UPDATE
 144 #error "HASH_UPDATE must be defined!"
 145 #endif
 146 #ifndef HASH_TRANSFORM
 147 #error "HASH_TRANSFORM must be defined!"
 148 #endif
 149 #ifndef HASH_FINAL
 150 #error "HASH_FINAL must be defined!"
 151 #endif
 152
 153 #ifndef HASH_BLOCK_HOST_ORDER
 154 #error "HASH_BLOCK_HOST_ORDER must be defined!"
 155 #endif
 156
 157 #if 0
 158 /*
 159  * Moved below as it's required only if HASH_BLOCK_DATA_ORDER_ALIGNED
 160  * isn't defined.
 161  */
 162 #ifndef HASH_BLOCK_DATA_ORDER
 163 #error "HASH_BLOCK_DATA_ORDER must be defined!"
 164 #endif
 165 #endif
 166
 167 #ifndef HASH_LBLOCK
 168 #define HASH_LBLOCK     (HASH_CBLOCK/4)
 169 #endif
 170
 171 #ifndef HASH_LONG_LOG2
 172 #define HASH_LONG_LOG2  2
 173 #endif
 174
 175 /*
 176  * Engage compiler specific rotate intrinsic function if available.
 177  */
 178 #undef ROTATE
 179 #ifndef PEDANTIC
 180 # if defined(_MSC_VER)
 181 #  define ROTATE(a,n)     _lrotl(a,n)
 182 # elif defined(__GNUC__) && __GNUC__>=2
 183   /*
 184    * Some GNU C inline assembler templates. Note that these are
 185    * rotates by *constant* number of bits! But that's exactly
 186    * what we need here...
 187    *
 188    *                                    <appro@fy.chalmers.se>
 189    */
 190 #  if defined(__i386)
 191 #   define ROTATE(a,n)  ({ register unsigned int ret;   \
 192                                 asm volatile (          \
 193                                 "roll %1,%0"            \
 194                                 : "=r"(ret)             \
 195                                 : "I"(n), "0"(a)        \
 196                                 : "cc");                \
 197                            ret;                         \
 198                         })
 199 #  elif defined(__powerpc)
 200 #   define ROTATE(a,n)  ({ register unsigned int ret;   \
 201                                 asm volatile (          \
 202                                 "rlwinm %0,%1,%2,0,31"  \
 203                                 : "=r"(ret)             \
 204                                 : "r"(a), "I"(n));      \
 205                            ret;                         \
 206                         })
 207 #  endif
 208 # endif
 209
 210 /*
 211  * Engage compiler specific "fetch in reverse byte order"
 212  * intrinsic function if available.
 213  */
 214 # if defined(__GNUC__) && __GNUC__>=2
 215   /* some GNU C inline assembler templates by <appro@fy.chalmers.se> */
 216 #  if defined(__i386) && !defined(I386_ONLY)
 217 #   define BE_FETCH32(a)        ({ register unsigned int l=(a);\
 218                                 asm volatile (          \
 219                                 "bswapl %0"             \
 220                                 : "=r"(l) : "0"(l));    \
 221                           l;                            \
 222                         })
 223 #  elif defined(__powerpc)
 224 #   define LE_FETCH32(a)        ({ register unsigned int l;     \
 225                                 asm volatile (          \
 226                                 "lwbrx %0,0,%1"         \
 227                                 : "=r"(l)               \
 228                                 : "r"(a));              \
 229                            l;                           \
 230                         })
 231
 232 #  elif defined(__sparc) && defined(ULTRASPARC)
 233 #  define LE_FETCH32(a) ({ register unsigned int l;             \
 234                                 asm volatile (                  \
 235                                 "lda [%1]#ASI_PRIMARY_LITTLE,%0"\
 236                                 : "=r"(l)                       \
 237                                 : "r"(a));                      \
 238                            l;                                   \
 239                         })
 240 #  endif
 241 # endif
 242 #endif /* PEDANTIC */
 243
 244 #if HASH_LONG_LOG2==2   /* Engage only if sizeof(HASH_LONG)== 4 */
 245 /* A nice byte order reversal from Wei Dai <weidai@eskimo.com> */
 246 #ifdef ROTATE
 247 /* 5 instructions with rotate instruction, else 9 */
 248 #define REVERSE_FETCH32(a,l)    (                                       \
 249                 l=*(const HASH_LONG *)(a),                              \
 250                 ((ROTATE(l,8)&0x00FF00FF)|(ROTATE((l&0x00FF00FF),24)))  \
 251                                 )
 252 #else
 253 /* 6 instructions with rotate instruction, else 8 */
 254 #define REVERSE_FETCH32(a,l)    (                               \
 255                 l=*(const HASH_LONG *)(a),                      \
 256                 l=(((l>>8)&0x00FF00FF)|((l&0x00FF00FF)<<8)),    \
 257                 ROTATE(l,16)                                    \
 258                                 )
 259 /*
 260  * Originally the middle line started with l=(((l&0xFF00FF00)>>8)|...
 261  * It's rewritten as above for two reasons:
 262  *      - RISCs aren't good at long constants and have to explicitely
 263  *        compose 'em with several (well, usually 2) instructions in a
 264  *        register before performing the actual operation and (as you
 265  *        already realized:-) having same constant should inspire the
 266  *        compiler to permanently allocate the only register for it;
 267  *      - most modern CPUs have two ALUs, but usually only one has
 268  *        circuitry for shifts:-( this minor tweak inspires compiler
 269  *        to schedule shift instructions in a better way...
 270  *
 271  *                              <appro@fy.chalmers.se>
 272  */
 273 #endif
 274 #endif
 275
 276 #ifndef ROTATE
 277 #define ROTATE(a,n)     (((a)<<(n))|(((a)&0xffffffff)>>(32-(n))))
 278 #endif
 279
 280 /*
 281  * Make some obvious choices. E.g., HASH_BLOCK_DATA_ORDER_ALIGNED
 282  * and HASH_BLOCK_HOST_ORDER ought to be the same if input data
 283  * and host are of the same "endianess". It's possible to mask
 284  * this with blank #define HASH_BLOCK_DATA_ORDER though...
 285  *
 286  *                              <appro@fy.chalmers.se>
 287  */
 288 #if defined(B_ENDIAN)
 289 #  if defined(DATA_ORDER_IS_BIG_ENDIAN)
 290 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
 291 #      define HASH_BLOCK_DATA_ORDER_ALIGNED     HASH_BLOCK_HOST_ORDER
 292 #    endif
 293 #  elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 294 #    ifndef HOST_FETCH32
 295 #      ifdef LE_FETCH32
 296 #        define HOST_FETCH32(p,l)       LE_FETCH32(p)
 297 #      elif defined(REVERSE_FETCH32)
 298 #        define HOST_FETCH32(p,l)       REVERSE_FETCH32(p,l)
 299 #      endif
 300 #    endif
 301 #  endif
 302 #elif defined(L_ENDIAN)
 303 #  if defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 304 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
 305 #      define HASH_BLOCK_DATA_ORDER_ALIGNED     HASH_BLOCK_HOST_ORDER
 306 #    endif
 307 #  elif defined(DATA_ORDER_IS_BIG_ENDIAN)
 308 #    ifndef HOST_FETCH32
 309 #      ifdef BE_FETCH32
 310 #        define HOST_FETCH32(p,l)       BE_FETCH32(p)
 311 #      elif defined(REVERSE_FETCH32)
 312 #        define HOST_FETCH32(p,l)       REVERSE_FETCH32(p,l)
 313 #      endif
 314 #    endif
 315 #  endif
 316 #endif
 317
 318 #if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
 319 #ifndef HASH_BLOCK_DATA_ORDER
 320 #error "HASH_BLOCK_DATA_ORDER must be defined!"
 321 #endif
 322 #endif
 323
 324 #if defined(DATA_ORDER_IS_BIG_ENDIAN)
 325
 326 #define HOST_c2l(c,l)   (l =(((unsigned long)(*((c)++)))<<24),          \
 327                          l|=(((unsigned long)(*((c)++)))<<16),          \
 328                          l|=(((unsigned long)(*((c)++)))<< 8),          \
 329                          l|=(((unsigned long)(*((c)++)))    ),          \
 330                          l)
 331 #define HOST_p_c2l(c,l,n)       {                                       \
 332                         switch (n) {                                    \
 333                         case 0: l =((unsigned long)(*((c)++)))<<24;     \
 334                         case 1: l|=((unsigned long)(*((c)++)))<<16;     \
 335                         case 2: l|=((unsigned long)(*((c)++)))<< 8;     \
 336                         case 3: l|=((unsigned long)(*((c)++)));         \
 337                                 } }
 338 #define HOST_p_c2l_p(c,l,sc,len) {                                      \
 339                         switch (sc) {                                   \
 340                         case 0: l =((unsigned long)(*((c)++)))<<24;     \
 341                                 if (--len == 0) break;                  \
 342                         case 1: l|=((unsigned long)(*((c)++)))<<16;     \
 343                                 if (--len == 0) break;                  \
 344                         case 2: l|=((unsigned long)(*((c)++)))<< 8;     \
 345                                 } }
 346 /* NOTE the pointer is not incremented at the end of this */
 347 #define HOST_c2l_p(c,l,n)       {                                       \
 348                         l=0; (c)+=n;                                    \
 349                         switch (n) {                                    \
 350                         case 3: l =((unsigned long)(*(--(c))))<< 8;     \
 351                         case 2: l|=((unsigned long)(*(--(c))))<<16;     \
 352                         case 1: l|=((unsigned long)(*(--(c))))<<24;     \
 353                                 } }
 354 #define HOST_l2c(l,c)   (*((c)++)=(unsigned char)(((l)>>24)&0xff),      \
 355                          *((c)++)=(unsigned char)(((l)>>16)&0xff),      \
 356                          *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \
 357                          *((c)++)=(unsigned char)(((l)    )&0xff),      \
 358                          l)
 359
 360 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 361
 362 #define HOST_c2l(c,l)   (l =(((unsigned long)(*((c)++)))    ),          \
 363                          l|=(((unsigned long)(*((c)++)))<< 8),          \
 364                          l|=(((unsigned long)(*((c)++)))<<16),          \
 365                          l|=(((unsigned long)(*((c)++)))<<24),          \
 366                          l)
 367 #define HOST_p_c2l(c,l,n)       {                                       \
 368                         switch (n) {                                    \
 369                         case 0: l =((unsigned long)(*((c)++)));         \
 370                         case 1: l|=((unsigned long)(*((c)++)))<< 8;     \
 371                         case 2: l|=((unsigned long)(*((c)++)))<<16;     \
 372                         case 3: l|=((unsigned long)(*((c)++)))<<24;     \
 373                                 } }
 374 #define HOST_p_c2l_p(c,l,sc,len) {                                      \
 375                         switch (sc) {                                   \
 376                         case 0: l =((unsigned long)(*((c)++)));         \
 377                                 if (--len == 0) break;                  \
 378                         case 1: l|=((unsigned long)(*((c)++)))<< 8;     \
 379                                 if (--len == 0) break;                  \
 380                         case 2: l|=((unsigned long)(*((c)++)))<<16;     \
 381                                 } }
 382 /* NOTE the pointer is not incremented at the end of this */
 383 #define HOST_c2l_p(c,l,n)       {                                       \
 384                         l=0; (c)+=n;                                    \
 385                         switch (n) {                                    \
 386                         case 3: l =((unsigned long)(*(--(c))))<<16;     \
 387                         case 2: l|=((unsigned long)(*(--(c))))<< 8;     \
 388                         case 1: l|=((unsigned long)(*(--(c))));         \
 389                                 } }
 390 #define HOST_l2c(l,c)   (*((c)++)=(unsigned char)(((l)    )&0xff),      \
 391                          *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \
 392                          *((c)++)=(unsigned char)(((l)>>16)&0xff),      \
 393                          *((c)++)=(unsigned char)(((l)>>24)&0xff),      \
 394                          l)
 395
 396 #endif
 397
 398 /*
 399  * Time for some action:-)
 400  */
 401
 402 void HASH_UPDATE (HASH_CTX *c, const unsigned char *data, unsigned long len)
 403         {
 404         register HASH_LONG * p;
 405         register unsigned long l;
 406         int sw,sc,ew,ec;
 407
 408         if (len==0) return;
 409
 410         l=(c->Nl+(len<<3))&0xffffffffL;
 411         /* 95-05-24 eay Fixed a bug with the overflow handling, thanks to
 412          * Wei Dai <weidai@eskimo.com> for pointing it out. */
 413         if (l < c->Nl) /* overflow */
 414                 c->Nh++;
 415         c->Nh+=(len>>29);
 416         c->Nl=l;
 417
 418         if (c->num != 0)
 419                 {
 420                 p=c->data;
 421                 sw=c->num>>2;
 422                 sc=c->num&0x03;
 423
 424                 if ((c->num+len) >= HASH_CBLOCK)
 425                         {
 426                         l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
 427                         for (; sw<HASH_LBLOCK; sw++)
 428                                 {
 429                                 HOST_c2l(data,l); p[sw]=l;
 430                                 }
 431                         HASH_BLOCK_HOST_ORDER (c,p,1);
 432                         len-=(HASH_CBLOCK-c->num);
 433                         c->num=0;
 434                         /* drop through and do the rest */
 435                         }
 436                 else
 437                         {
 438                         c->num+=len;
 439                         if ((sc+len) < 4) /* ugly, add char's to a word */
 440                                 {
 441                                 l=p[sw]; HOST_p_c2l_p(data,l,sc,len); p[sw]=l;
 442                                 }
 443                         else
 444                                 {
 445                                 ew=(c->num>>2);
 446                                 ec=(c->num&0x03);
 447                                 l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
 448                                 for (; sw < ew; sw++)
 449                                         {
 450                                         HOST_c2l(data,l); p[sw]=l;
 451                                         }
 452                                 if (ec)
 453                                         {
 454                                         HOST_c2l_p(data,l,ec); p[sw]=l;
 455                                         }
 456                                 }
 457                         return;
 458                         }
 459                 }
 460
 461         sw=len/HASH_CBLOCK;
 462         if (sw > 0)
 463                 {
 464 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
 465                 /*
 466                  * Note that HASH_BLOCK_DATA_ORDER_ALIGNED gets defined
 467                  * only if sizeof(HASH_LONG)==4.
 468                  */
 469                 if ((((unsigned long)data)%4) == 0)
 470                         {
 471                         /* data is properly aligned so that we can cast it: */
 472                         HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,sw);
 473                         sw*=HASH_CBLOCK;
 474                         data+=sw;
 475                         len-=sw;
 476                         }
 477                 else
 478 #if !defined(HASH_BLOCK_DATA_ORDER)
 479                         while (sw--)
 480                                 {
 481                                 memcpy (p=c->data,data,HASH_CBLOCK);
 482                                 HASH_BLOCK_DATA_ORDER_ALIGNED(c,p,1);
 483                                 data+=HASH_CBLOCK;
 484                                 len-=HASH_CBLOCK;
 485                                 }
 486 #endif
 487 #endif
 488 #if defined(HASH_BLOCK_DATA_ORDER)
 489                         {
 490                         HASH_BLOCK_DATA_ORDER(c,data,sw);
 491                         sw*=HASH_CBLOCK;
 492                         data+=sw;
 493                         len-=sw;
 494                         }
 495 #endif
 496                 }
 497
 498         if (len!=0)
 499                 {
 500                 p = c->data;
 501                 c->num = len;
 502                 ew=len>>2;      /* words to copy */
 503                 ec=len&0x03;
 504                 for (; ew; ew--,p++)
 505                         {
 506                         HOST_c2l(data,l); *p=l;
 507                         }
 508                 HOST_c2l_p(data,l,ec);
 509                 *p=l;
 510                 }
 511         }
 512
 513
 514 void HASH_TRANSFORM (HASH_CTX *c, const unsigned char *data)
 515         {
 516 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
 517         if ((((unsigned long)data)%4) == 0)
 518                 /* data is properly aligned so that we can cast it: */
 519                 HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,1);
 520         else
 521 #if !defined(HASH_BLOCK_DATA_ORDER)
 522                 {
 523                 memcpy (c->data,data,HASH_CBLOCK);
 524                 HASH_BLOCK_DATA_ORDER_ALIGNED (c,c->data,1);
 525                 }
 526 #endif
 527 #endif
 528 #if defined(HASH_BLOCK_DATA_ORDER)
 529         HASH_BLOCK_DATA_ORDER (c,data,1);
 530 #endif
 531         }
 532
 533
 534 void HASH_FINAL (unsigned char *md, HASH_CTX *c)
 535         {
 536         register HASH_LONG *p;
 537         register unsigned long l;
 538         register int i,j;
 539         static const unsigned char end[4]={0x80,0x00,0x00,0x00};
 540         const unsigned char *cp=end;
 541
 542         /* c->num should definitly have room for at least one more byte. */
 543         p=c->data;
 544         i=c->num>>2;
 545         j=c->num&0x03;
 546
 547 #if 0
 548         /* purify often complains about the following line as an
 549          * Uninitialized Memory Read.  While this can be true, the
 550          * following p_c2l macro will reset l when that case is true.
 551          * This is because j&0x03 contains the number of 'valid' bytes
 552          * already in p[i].  If and only if j&0x03 == 0, the UMR will
 553          * occur but this is also the only time p_c2l will do
 554          * l= *(cp++) instead of l|= *(cp++)
 555          * Many thanks to Alex Tang <altitude@cic.net> for pickup this
 556          * 'potential bug' */
 557 #ifdef PURIFY
 558         if (j==0) p[i]=0; /* Yeah, but that's not the way to fix it:-) */
 559 #endif
 560         l=p[i];
 561 #else
 562         l = (j==0) ? 0 : p[i];
 563 #endif
 564         HOST_p_c2l(cp,l,j); p[i++]=l; /* i is the next 'undefined word' */
 565
 566         if (i>(HASH_LBLOCK-2)) /* save room for Nl and Nh */
 567                 {
 568                 if (i<HASH_LBLOCK) p[i]=0;
 569                 HASH_BLOCK_HOST_ORDER (c,p,1);
 570                 i=0;
 571                 }
 572         for (; i<(HASH_LBLOCK-2); i++)
 573                 p[i]=0;
 574
 575 #if   defined(DATA_ORDER_IS_BIG_ENDIAN)
 576         p[HASH_LBLOCK-2]=c->Nh;
 577         p[HASH_LBLOCK-1]=c->Nl;
 578 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
 579         p[HASH_LBLOCK-2]=c->Nl;
 580         p[HASH_LBLOCK-1]=c->Nh;
 581 #endif
 582         HASH_BLOCK_HOST_ORDER (c,p,1);
 583
 584         l=c->A; HOST_l2c(l,md);
 585         l=c->B; HOST_l2c(l,md);
 586         l=c->C; HOST_l2c(l,md);
 587         l=c->D; HOST_l2c(l,md);
 588
 589         c->num=0;
 590         /* clear stuff, HASH_BLOCK may be leaving some stuff on the stack
 591          * but I'm not worried :-)
 592         memset((void *)c,0,sizeof(HASH_CTX));
 593          */
 594         }