osfmk/corecrypto/ccdigest/src/ccdigest_update.c

   1 /*
   2  *  ccdigest_update.c
   3  *  corecrypto
   4  *
   5  *  Created by Michael Brouwer on 11/30/10.
   6  *  Copyright 2010,2011 Apple Inc. All rights reserved.
   7  *
   8  */
   9
  10 #include <corecrypto/ccdigest.h>
  11 #include <corecrypto/cc_priv.h>
  12
  13 void ccdigest_update(const struct ccdigest_info *di, ccdigest_ctx_t ctx,
  14                      unsigned long len, const void *data) {
  15     char * data_ptr = (char *) data;
  16     while (len > 0) {
  17         if (ccdigest_num(di, ctx) == 0 && len > di->block_size) {
  18             unsigned long nblocks = len / di->block_size;
  19             di->compress(ccdigest_state(di, ctx), nblocks, data_ptr);
  20             unsigned long nbytes = nblocks * di->block_size;
  21             len -= nbytes;
  22             data_ptr += nbytes;
  23             ccdigest_nbits(di, ctx) += nbytes * 8;
  24         } else {
  25             unsigned long n = di->block_size - ccdigest_num(di, ctx);
  26             if (len < n)
  27                 n = len;
  28             CC_MEMCPY(ccdigest_data(di, ctx) + ccdigest_num(di, ctx), data_ptr, n);
  29             /* typecast: less than block size, will always fit into an int */
  30             ccdigest_num(di, ctx) += (unsigned int)n;
  31             len -= n;
  32             data_ptr += n;
  33             if (ccdigest_num(di, ctx) == di->block_size) {
  34                 di->compress(ccdigest_state(di, ctx), 1, ccdigest_data(di, ctx));
  35                 ccdigest_nbits(di, ctx) += ccdigest_num(di, ctx) * 8;
  36                 ccdigest_num(di, ctx) = 0;
  37             }
  38         }
  39     }
  40 }