osfmk/corecrypto/ccdigest/src/ccdigest_update.c

   1 /*
   2  *  ccdigest_update.c
   3  *  corecrypto
   4  *
   5  *  Created on 11/30/2010
   6  *
   7  *  Copyright (c) 2010,2011,2014,2015 Apple Inc. All rights reserved.
   8  *
   9  */
  10
  11 #include <corecrypto/ccdigest.h>
  12 #include <corecrypto/cc_priv.h>
  13
  14 void ccdigest_update(const struct ccdigest_info *di, ccdigest_ctx_t ctx,
  15                      size_t len, const void *data) {
  16     const char * data_ptr = data;
  17     size_t nblocks, nbytes;
  18
  19     while (len > 0) {
  20         if (ccdigest_num(di, ctx) == 0 && len > di->block_size) {
  21             //low-end processors are slow on divison
  22             if(di->block_size == 1<<6 ){ //sha256
  23                 nblocks = len >> 6;
  24                 nbytes = len & 0xFFFFffC0;
  25             }else if(di->block_size == 1<<7 ){ //sha512
  26                 nblocks = len >> 7;
  27                 nbytes = len & 0xFFFFff80;
  28             }else {
  29                 nblocks = len / di->block_size;
  30                 nbytes = nblocks * di->block_size;
  31             }
  32
  33             di->compress(ccdigest_state(di, ctx), nblocks, data_ptr);
  34             len -= nbytes;
  35             data_ptr += nbytes;
  36             ccdigest_nbits(di, ctx) += nbytes * 8;
  37         } else {
  38             size_t n = di->block_size - ccdigest_num(di, ctx);
  39             if (len < n)
  40                 n = len;
  41             CC_MEMCPY(ccdigest_data(di, ctx) + ccdigest_num(di, ctx), data_ptr, n);
  42             /* typecast: less than block size, will always fit into an int */
  43             ccdigest_num(di, ctx) += (unsigned int)n;
  44             len -= n;
  45             data_ptr += n;
  46             if (ccdigest_num(di, ctx) == di->block_size) {
  47                 di->compress(ccdigest_state(di, ctx), 1, ccdigest_data(di, ctx));
  48                 ccdigest_nbits(di, ctx) += ccdigest_num(di, ctx) * 8;
  49                 ccdigest_num(di, ctx) = 0;
  50             }
  51         }
  52     }
  53 }