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      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 
     13 /**
     14    @file hash_filehandle.c
     15    Hash open files, Tom St Denis
     16 */
     17 
     18 /**
     19   Hash data from an open file handle.
     20   @param hash   The index of the hash you want to use
     21   @param in     The FILE* handle of the file you want to hash
     22   @param out    [out] The destination of the digest
     23   @param outlen [in/out] The max size and resulting size of the digest
     24   @result CRYPT_OK if successful
     25 */
     26 int hash_filehandle(int hash, FILE *in, unsigned char *out, unsigned long *outlen)
     27 {
     28 #ifdef LTC_NO_FILE
     29     return CRYPT_NOP;
     30 #else
     31     hash_state md;
     32     unsigned char buf[512];
     33     size_t x;
     34     int err;
     35 
     36     LTC_ARGCHK(out    != NULL);
     37     LTC_ARGCHK(outlen != NULL);
     38     LTC_ARGCHK(in     != NULL);
     39 
     40     if ((err = hash_is_valid(hash)) != CRYPT_OK) {
     41         return err;
     42     }
     43 
     44     if (*outlen < hash_descriptor[hash].hashsize) {
     45        *outlen = hash_descriptor[hash].hashsize;
     46        return CRYPT_BUFFER_OVERFLOW;
     47     }
     48     if ((err = hash_descriptor[hash].init(&md)) != CRYPT_OK) {
     49        return err;
     50     }
     51 
     52     *outlen = hash_descriptor[hash].hashsize;
     53     do {
     54         x = fread(buf, 1, sizeof(buf), in);
     55         if ((err = hash_descriptor[hash].process(&md, buf, x)) != CRYPT_OK) {
     56            return err;
     57         }
     58     } while (x == sizeof(buf));
     59     err = hash_descriptor[hash].done(&md, out);
     60 
     61 #ifdef LTC_CLEAN_STACK
     62     zeromem(buf, sizeof(buf));
     63 #endif
     64     return err;
     65 #endif
     66 }
     67 
     68 
     69 /* $Source: /cvs/libtom/libtomcrypt/src/hashes/helper/hash_filehandle.c,v $ */
     70 /* $Revision: 1.5 $ */
     71 /* $Date: 2006/06/16 21:53:41 $ */
     72