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      1 /*
      2  * Copyright 2012 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkMD5_DEFINED
      9 #define SkMD5_DEFINED
     10 
     11 #include "SkTypes.h"
     12 #include "SkEndian.h"
     13 #include "SkStream.h"
     14 
     15 //The following macros can be defined to affect the MD5 code generated.
     16 //SK_MD5_CLEAR_DATA causes all intermediate state to be overwritten with 0's.
     17 //SK_CPU_LENDIAN allows 32 bit <=> 8 bit conversions without copies (if alligned).
     18 //SK_CPU_FAST_UNALIGNED_ACCESS allows 32 bit <=> 8 bit conversions without copies if SK_CPU_LENDIAN.
     19 
     20 class SkMD5 : public SkWStream {
     21 public:
     22     SkMD5();
     23 
     24     /** Processes input, adding it to the digest.
     25      *  Note that this treats the buffer as a series of uint8_t values.
     26      */
     27     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE {
     28         update(reinterpret_cast<const uint8_t*>(buffer), size);
     29         return true;
     30     }
     31 
     32     /** Processes input, adding it to the digest. Calling this after finish is undefined. */
     33     void update(const uint8_t* input, size_t length);
     34 
     35     struct Digest {
     36         uint8_t data[16];
     37     };
     38 
     39     /** Computes and returns the digest. */
     40     void finish(Digest& digest);
     41 
     42 private:
     43     // number of bytes, modulo 2^64
     44     uint64_t byteCount;
     45 
     46     // state (ABCD)
     47     uint32_t state[4];
     48 
     49     // input buffer
     50     uint8_t buffer[64];
     51 };
     52 
     53 #endif
     54