Add ECDH support.
[openssl.git] / 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 0 /* defined(_MSC_VER) */
183 #  define ROTATE(a,n)   _lrotl(a,n)
184 # elif defined(__MWERKS__)
185 #  if defined(__POWERPC__)
186 #   define ROTATE(a,n)  __rlwinm(a,n,0,31)
187 #  elif defined(__MC68K__)
188     /* Motorola specific tweak. <appro@fy.chalmers.se> */
189 #   define ROTATE(a,n)  ( n<24 ? __rol(a,n) : __ror(a,32-n) )
190 #  else
191 #   define ROTATE(a,n)  __rol(a,n)
192 #  endif
193 # elif defined(__GNUC__) && __GNUC__>=2 && !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM)
194   /*
195    * Some GNU C inline assembler templates. Note that these are
196    * rotates by *constant* number of bits! But that's exactly
197    * what we need here...
198    *
199    *                                    <appro@fy.chalmers.se>
200    */
201 #  if defined(__i386) || defined(__i386__)
202 #   define ROTATE(a,n)  ({ register unsigned int ret;   \
203                                 asm (                   \
204                                 "roll %1,%0"            \
205                                 : "=r"(ret)             \
206                                 : "I"(n), "0"(a)        \
207                                 : "cc");                \
208                            ret;                         \
209                         })
210 #  elif defined(__powerpc) || defined(__ppc)
211 #   define ROTATE(a,n)  ({ register unsigned int ret;   \
212                                 asm (                   \
213                                 "rlwinm %0,%1,%2,0,31"  \
214                                 : "=r"(ret)             \
215                                 : "r"(a), "I"(n));      \
216                            ret;                         \
217                         })
218 #  endif
219 # endif
220
221 /*
222  * Engage compiler specific "fetch in reverse byte order"
223  * intrinsic function if available.
224  */
225 # if defined(__GNUC__) && __GNUC__>=2 && !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM)
226   /* some GNU C inline assembler templates by <appro@fy.chalmers.se> */
227 #  if (defined(__i386) || defined(__i386__)) && !defined(I386_ONLY)
228 #   define BE_FETCH32(a)        ({ register unsigned int l=(a);\
229                                 asm (                   \
230                                 "bswapl %0"             \
231                                 : "=r"(l) : "0"(l));    \
232                           l;                            \
233                         })
234 #  elif defined(__powerpc)
235 #   define LE_FETCH32(a)        ({ register unsigned int l;     \
236                                 asm (                   \
237                                 "lwbrx %0,0,%1"         \
238                                 : "=r"(l)               \
239                                 : "r"(a));              \
240                            l;                           \
241                         })
242
243 #  elif defined(__sparc) && defined(OPENSSL_SYS_ULTRASPARC)
244 #  define LE_FETCH32(a) ({ register unsigned int l;             \
245                                 asm (                           \
246                                 "lda [%1]#ASI_PRIMARY_LITTLE,%0"\
247                                 : "=r"(l)                       \
248                                 : "r"(a));                      \
249                            l;                                   \
250                         })
251 #  endif
252 # endif
253 #endif /* PEDANTIC */
254
255 #if HASH_LONG_LOG2==2   /* Engage only if sizeof(HASH_LONG)== 4 */
256 /* A nice byte order reversal from Wei Dai <weidai@eskimo.com> */
257 #ifdef ROTATE
258 /* 5 instructions with rotate instruction, else 9 */
259 #define REVERSE_FETCH32(a,l)    (                                       \
260                 l=*(const HASH_LONG *)(a),                              \
261                 ((ROTATE(l,8)&0x00FF00FF)|(ROTATE((l&0x00FF00FF),24)))  \
262                                 )
263 #else
264 /* 6 instructions with rotate instruction, else 8 */
265 #define REVERSE_FETCH32(a,l)    (                               \
266                 l=*(const HASH_LONG *)(a),                      \
267                 l=(((l>>8)&0x00FF00FF)|((l&0x00FF00FF)<<8)),    \
268                 ROTATE(l,16)                                    \
269                                 )
270 /*
271  * Originally the middle line started with l=(((l&0xFF00FF00)>>8)|...
272  * It's rewritten as above for two reasons:
273  *      - RISCs aren't good at long constants and have to explicitely
274  *        compose 'em with several (well, usually 2) instructions in a
275  *        register before performing the actual operation and (as you
276  *        already realized:-) having same constant should inspire the
277  *        compiler to permanently allocate the only register for it;
278  *      - most modern CPUs have two ALUs, but usually only one has
279  *        circuitry for shifts:-( this minor tweak inspires compiler
280  *        to schedule shift instructions in a better way...
281  *
282  *                              <appro@fy.chalmers.se>
283  */
284 #endif
285 #endif
286
287 #ifndef ROTATE
288 #define ROTATE(a,n)     (((a)<<(n))|(((a)&0xffffffff)>>(32-(n))))
289 #endif
290
291 /*
292  * Make some obvious choices. E.g., HASH_BLOCK_DATA_ORDER_ALIGNED
293  * and HASH_BLOCK_HOST_ORDER ought to be the same if input data
294  * and host are of the same "endianess". It's possible to mask
295  * this with blank #define HASH_BLOCK_DATA_ORDER though...
296  *
297  *                              <appro@fy.chalmers.se>
298  */
299 #if defined(B_ENDIAN)
300 #  if defined(DATA_ORDER_IS_BIG_ENDIAN)
301 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
302 #      define HASH_BLOCK_DATA_ORDER_ALIGNED     HASH_BLOCK_HOST_ORDER
303 #    endif
304 #  elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
305 #    ifndef HOST_FETCH32
306 #      ifdef LE_FETCH32
307 #        define HOST_FETCH32(p,l)       LE_FETCH32(p)
308 #      elif defined(REVERSE_FETCH32)
309 #        define HOST_FETCH32(p,l)       REVERSE_FETCH32(p,l)
310 #      endif
311 #    endif
312 #  endif
313 #elif defined(L_ENDIAN)
314 #  if defined(DATA_ORDER_IS_LITTLE_ENDIAN)
315 #    if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED) && HASH_LONG_LOG2==2
316 #      define HASH_BLOCK_DATA_ORDER_ALIGNED     HASH_BLOCK_HOST_ORDER
317 #    endif
318 #  elif defined(DATA_ORDER_IS_BIG_ENDIAN)
319 #    ifndef HOST_FETCH32
320 #      ifdef BE_FETCH32
321 #        define HOST_FETCH32(p,l)       BE_FETCH32(p)
322 #      elif defined(REVERSE_FETCH32)
323 #        define HOST_FETCH32(p,l)       REVERSE_FETCH32(p,l)
324 #      endif
325 #    endif
326 #  endif
327 #endif
328
329 #if !defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
330 #ifndef HASH_BLOCK_DATA_ORDER
331 #error "HASH_BLOCK_DATA_ORDER must be defined!"
332 #endif
333 #endif
334
335 #if defined(DATA_ORDER_IS_BIG_ENDIAN)
336
337 #define HOST_c2l(c,l)   (l =(((unsigned long)(*((c)++)))<<24),          \
338                          l|=(((unsigned long)(*((c)++)))<<16),          \
339                          l|=(((unsigned long)(*((c)++)))<< 8),          \
340                          l|=(((unsigned long)(*((c)++)))    ),          \
341                          l)
342 #define HOST_p_c2l(c,l,n)       {                                       \
343                         switch (n) {                                    \
344                         case 0: l =((unsigned long)(*((c)++)))<<24;     \
345                         case 1: l|=((unsigned long)(*((c)++)))<<16;     \
346                         case 2: l|=((unsigned long)(*((c)++)))<< 8;     \
347                         case 3: l|=((unsigned long)(*((c)++)));         \
348                                 } }
349 #define HOST_p_c2l_p(c,l,sc,len) {                                      \
350                         switch (sc) {                                   \
351                         case 0: l =((unsigned long)(*((c)++)))<<24;     \
352                                 if (--len == 0) break;                  \
353                         case 1: l|=((unsigned long)(*((c)++)))<<16;     \
354                                 if (--len == 0) break;                  \
355                         case 2: l|=((unsigned long)(*((c)++)))<< 8;     \
356                                 } }
357 /* NOTE the pointer is not incremented at the end of this */
358 #define HOST_c2l_p(c,l,n)       {                                       \
359                         l=0; (c)+=n;                                    \
360                         switch (n) {                                    \
361                         case 3: l =((unsigned long)(*(--(c))))<< 8;     \
362                         case 2: l|=((unsigned long)(*(--(c))))<<16;     \
363                         case 1: l|=((unsigned long)(*(--(c))))<<24;     \
364                                 } }
365 #define HOST_l2c(l,c)   (*((c)++)=(unsigned char)(((l)>>24)&0xff),      \
366                          *((c)++)=(unsigned char)(((l)>>16)&0xff),      \
367                          *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \
368                          *((c)++)=(unsigned char)(((l)    )&0xff),      \
369                          l)
370
371 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
372
373 #define HOST_c2l(c,l)   (l =(((unsigned long)(*((c)++)))    ),          \
374                          l|=(((unsigned long)(*((c)++)))<< 8),          \
375                          l|=(((unsigned long)(*((c)++)))<<16),          \
376                          l|=(((unsigned long)(*((c)++)))<<24),          \
377                          l)
378 #define HOST_p_c2l(c,l,n)       {                                       \
379                         switch (n) {                                    \
380                         case 0: l =((unsigned long)(*((c)++)));         \
381                         case 1: l|=((unsigned long)(*((c)++)))<< 8;     \
382                         case 2: l|=((unsigned long)(*((c)++)))<<16;     \
383                         case 3: l|=((unsigned long)(*((c)++)))<<24;     \
384                                 } }
385 #define HOST_p_c2l_p(c,l,sc,len) {                                      \
386                         switch (sc) {                                   \
387                         case 0: l =((unsigned long)(*((c)++)));         \
388                                 if (--len == 0) break;                  \
389                         case 1: l|=((unsigned long)(*((c)++)))<< 8;     \
390                                 if (--len == 0) break;                  \
391                         case 2: l|=((unsigned long)(*((c)++)))<<16;     \
392                                 } }
393 /* NOTE the pointer is not incremented at the end of this */
394 #define HOST_c2l_p(c,l,n)       {                                       \
395                         l=0; (c)+=n;                                    \
396                         switch (n) {                                    \
397                         case 3: l =((unsigned long)(*(--(c))))<<16;     \
398                         case 2: l|=((unsigned long)(*(--(c))))<< 8;     \
399                         case 1: l|=((unsigned long)(*(--(c))));         \
400                                 } }
401 #define HOST_l2c(l,c)   (*((c)++)=(unsigned char)(((l)    )&0xff),      \
402                          *((c)++)=(unsigned char)(((l)>> 8)&0xff),      \
403                          *((c)++)=(unsigned char)(((l)>>16)&0xff),      \
404                          *((c)++)=(unsigned char)(((l)>>24)&0xff),      \
405                          l)
406
407 #endif
408
409 /*
410  * Time for some action:-)
411  */
412
413 int HASH_UPDATE (HASH_CTX *c, const void *data_, unsigned long len)
414         {
415         const unsigned char *data=data_;
416         register HASH_LONG * p;
417         register unsigned long l;
418         int sw,sc,ew,ec;
419
420         if (len==0) return 1;
421
422         l=(c->Nl+(len<<3))&0xffffffffL;
423         /* 95-05-24 eay Fixed a bug with the overflow handling, thanks to
424          * Wei Dai <weidai@eskimo.com> for pointing it out. */
425         if (l < c->Nl) /* overflow */
426                 c->Nh++;
427         c->Nh+=(len>>29);
428         c->Nl=l;
429
430         if (c->num != 0)
431                 {
432                 p=c->data;
433                 sw=c->num>>2;
434                 sc=c->num&0x03;
435
436                 if ((c->num+len) >= HASH_CBLOCK)
437                         {
438                         l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
439                         for (; sw<HASH_LBLOCK; sw++)
440                                 {
441                                 HOST_c2l(data,l); p[sw]=l;
442                                 }
443                         HASH_BLOCK_HOST_ORDER (c,p,1);
444                         len-=(HASH_CBLOCK-c->num);
445                         c->num=0;
446                         /* drop through and do the rest */
447                         }
448                 else
449                         {
450                         c->num+=len;
451                         if ((sc+len) < 4) /* ugly, add char's to a word */
452                                 {
453                                 l=p[sw]; HOST_p_c2l_p(data,l,sc,len); p[sw]=l;
454                                 }
455                         else
456                                 {
457                                 ew=(c->num>>2);
458                                 ec=(c->num&0x03);
459                                 l=p[sw]; HOST_p_c2l(data,l,sc); p[sw++]=l;
460                                 for (; sw < ew; sw++)
461                                         {
462                                         HOST_c2l(data,l); p[sw]=l;
463                                         }
464                                 if (ec)
465                                         {
466                                         HOST_c2l_p(data,l,ec); p[sw]=l;
467                                         }
468                                 }
469                         return 1;
470                         }
471                 }
472
473         sw=len/HASH_CBLOCK;
474         if (sw > 0)
475                 {
476 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
477                 /*
478                  * Note that HASH_BLOCK_DATA_ORDER_ALIGNED gets defined
479                  * only if sizeof(HASH_LONG)==4.
480                  */
481                 if ((((unsigned long)data)%4) == 0)
482                         {
483                         /* data is properly aligned so that we can cast it: */
484                         HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,sw);
485                         sw*=HASH_CBLOCK;
486                         data+=sw;
487                         len-=sw;
488                         }
489                 else
490 #if !defined(HASH_BLOCK_DATA_ORDER)
491                         while (sw--)
492                                 {
493                                 memcpy (p=c->data,data,HASH_CBLOCK);
494                                 HASH_BLOCK_DATA_ORDER_ALIGNED(c,p,1);
495                                 data+=HASH_CBLOCK;
496                                 len-=HASH_CBLOCK;
497                                 }
498 #endif
499 #endif
500 #if defined(HASH_BLOCK_DATA_ORDER)
501                         {
502                         HASH_BLOCK_DATA_ORDER(c,data,sw);
503                         sw*=HASH_CBLOCK;
504                         data+=sw;
505                         len-=sw;
506                         }
507 #endif
508                 }
509
510         if (len!=0)
511                 {
512                 p = c->data;
513                 c->num = len;
514                 ew=len>>2;      /* words to copy */
515                 ec=len&0x03;
516                 for (; ew; ew--,p++)
517                         {
518                         HOST_c2l(data,l); *p=l;
519                         }
520                 HOST_c2l_p(data,l,ec);
521                 *p=l;
522                 }
523         return 1;
524         }
525
526
527 void HASH_TRANSFORM (HASH_CTX *c, const unsigned char *data)
528         {
529 #if defined(HASH_BLOCK_DATA_ORDER_ALIGNED)
530         if ((((unsigned long)data)%4) == 0)
531                 /* data is properly aligned so that we can cast it: */
532                 HASH_BLOCK_DATA_ORDER_ALIGNED (c,(HASH_LONG *)data,1);
533         else
534 #if !defined(HASH_BLOCK_DATA_ORDER)
535                 {
536                 memcpy (c->data,data,HASH_CBLOCK);
537                 HASH_BLOCK_DATA_ORDER_ALIGNED (c,c->data,1);
538                 }
539 #endif
540 #endif
541 #if defined(HASH_BLOCK_DATA_ORDER)
542         HASH_BLOCK_DATA_ORDER (c,data,1);
543 #endif
544         }
545
546
547 int HASH_FINAL (unsigned char *md, HASH_CTX *c)
548         {
549         register HASH_LONG *p;
550         register unsigned long l;
551         register int i,j;
552         static const unsigned char end[4]={0x80,0x00,0x00,0x00};
553         const unsigned char *cp=end;
554
555         /* c->num should definitly have room for at least one more byte. */
556         p=c->data;
557         i=c->num>>2;
558         j=c->num&0x03;
559
560 #if 0
561         /* purify often complains about the following line as an
562          * Uninitialized Memory Read.  While this can be true, the
563          * following p_c2l macro will reset l when that case is true.
564          * This is because j&0x03 contains the number of 'valid' bytes
565          * already in p[i].  If and only if j&0x03 == 0, the UMR will
566          * occur but this is also the only time p_c2l will do
567          * l= *(cp++) instead of l|= *(cp++)
568          * Many thanks to Alex Tang <altitude@cic.net> for pickup this
569          * 'potential bug' */
570 #ifdef PURIFY
571         if (j==0) p[i]=0; /* Yeah, but that's not the way to fix it:-) */
572 #endif
573         l=p[i];
574 #else
575         l = (j==0) ? 0 : p[i];
576 #endif
577         HOST_p_c2l(cp,l,j); p[i++]=l; /* i is the next 'undefined word' */
578
579         if (i>(HASH_LBLOCK-2)) /* save room for Nl and Nh */
580                 {
581                 if (i<HASH_LBLOCK) p[i]=0;
582                 HASH_BLOCK_HOST_ORDER (c,p,1);
583                 i=0;
584                 }
585         for (; i<(HASH_LBLOCK-2); i++)
586                 p[i]=0;
587
588 #if   defined(DATA_ORDER_IS_BIG_ENDIAN)
589         p[HASH_LBLOCK-2]=c->Nh;
590         p[HASH_LBLOCK-1]=c->Nl;
591 #elif defined(DATA_ORDER_IS_LITTLE_ENDIAN)
592         p[HASH_LBLOCK-2]=c->Nl;
593         p[HASH_LBLOCK-1]=c->Nh;
594 #endif
595         HASH_BLOCK_HOST_ORDER (c,p,1);
596
597 #ifndef HASH_MAKE_STRING
598 #error "HASH_MAKE_STRING must be defined!"
599 #else
600         HASH_MAKE_STRING(c,md);
601 #endif
602
603         c->num=0;
604         /* clear stuff, HASH_BLOCK may be leaving some stuff on the stack
605          * but I'm not worried :-)
606         memset((void *)c,0,sizeof(HASH_CTX));
607          */
608         return 1;
609         }