Home | History | Annotate | Download | only in helper 
      1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
      2  *
      3  * LibTomCrypt is a library that provides various cryptographic
      4  * algorithms in a highly modular and flexible manner.
      5  *
      6  * The library is free for all purposes without any express
      7  * guarantee it works.
      8  *
      9  * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com
     10  */
     11 #include "tomcrypt.h"
     12 #include <stdarg.h>
     13 /**
     14   @file hash_memory_multi.c
     15   Hash (multiple buffers) memory helper, Tom St Denis
     16 */
     17 
     18 /**
     19   Hash multiple (non-adjacent) blocks of memory at once.
     20   @param hash   The index of the hash you wish to use
     21   @param out    [out] Where to store the digest
     22   @param outlen [in/out] Max size and resulting size of the digest
     23   @param in     The data you wish to hash
     24   @param inlen  The length of the data to hash (octets)
     25   @param ...    tuples of (data,len) pairs to hash, terminated with a (NULL,x) (x=don't care)
     26   @return CRYPT_OK if successful
     27 */
     28 int hash_memory_multi(int hash, unsigned char *out, unsigned long *outlen,
     29                       const unsigned char *in, unsigned long inlen, ...)
     30 {
     31     hash_state          *md;
     32     int                  err;
     33     va_list              args;
     34     const unsigned char *curptr;
     35     unsigned long        curlen;
     36 
     37     LTC_ARGCHK(in     != NULL);
     38     LTC_ARGCHK(out    != NULL);
     39     LTC_ARGCHK(outlen != NULL);
     40 
     41     if ((err = hash_is_valid(hash)) != CRYPT_OK) {
     42         return err;
     43     }
     44 
     45     if (*outlen < hash_descriptor[hash].hashsize) {
     46        *outlen = hash_descriptor[hash].hashsize;
     47        return CRYPT_BUFFER_OVERFLOW;
     48     }
     49 
     50     md = XMALLOC(sizeof(hash_state));
     51     if (md == NULL) {
     52        return CRYPT_MEM;
     53     }
     54 
     55     if ((err = hash_descriptor[hash].init(md)) != CRYPT_OK) {
     56        goto LBL_ERR;
     57     }
     58 
     59     va_start(args, inlen);
     60     curptr = in;
     61     curlen = inlen;
     62     for (;;) {
     63        /* process buf */
     64        if ((err = hash_descriptor[hash].process(md, curptr, curlen)) != CRYPT_OK) {
     65           goto LBL_ERR;
     66        }
     67        /* step to next */
     68        curptr = va_arg(args, const unsigned char*);
     69        if (curptr == NULL) {
     70           break;
     71        }
     72        curlen = va_arg(args, unsigned long);
     73     }
     74     err = hash_descriptor[hash].done(md, out);
     75     *outlen = hash_descriptor[hash].hashsize;
     76 LBL_ERR:
     77 #ifdef LTC_CLEAN_STACK
     78     zeromem(md, sizeof(hash_state));
     79 #endif
     80     XFREE(md);
     81     va_end(args);
     82     return err;
     83 }
     84 
     85 /* $Source: /cvs/libtom/libtomcrypt/src/hashes/helper/hash_memory_multi.c,v $ */
     86 /* $Revision: 1.5 $ */
     87 /* $Date: 2006/06/16 21:53:41 $ */
     88