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      */
write(const void * buffer,size_t size)27     bool write(const void* buffer, size_t size) override {
28         this->update(reinterpret_cast<const uint8_t*>(buffer), size);
29         return true;
30     }
31 
bytesWritten()32     size_t bytesWritten() const override { return SkToSizeT(this->byteCount); }
33 
34     /** Processes input, adding it to the digest. Calling this after finish is undefined. */
35     void update(const uint8_t* input, size_t length);
36 
37     struct Digest {
38         uint8_t data[16];
39         bool operator ==(Digest const& other) const {
40             return 0 == memcmp(data, other.data, sizeof(data));
41         }
42         bool operator !=(Digest const& other) const {
43             return 0 != memcmp(data, other.data, sizeof(data));
44         }
45     };
46 
47     /** Computes and returns the digest. */
48     void finish(Digest& digest);
49 
50 private:
51     // number of bytes, modulo 2^64
52     uint64_t byteCount;
53 
54     // state (ABCD)
55     uint32_t state[4];
56 
57     // input buffer
58     uint8_t buffer[64];
59 };
60 
61 #endif
62