1 /*
2  * Copyright 2013 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 SkSHA1_DEFINED
9 #define SkSHA1_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 SHA1 code generated.
16 //SK_SHA1_CLEAR_DATA causes all intermediate state to be overwritten with 0's.
17 //SK_CPU_BENDIAN 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_BENDIAN.
19 
20 class SkSHA1 : public SkWStream {
21 public:
22     SkSHA1();
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         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[20];
39     };
40 
41     /** Computes and returns the digest. */
42     void finish(Digest& digest);
43 
44 private:
45     // number of bytes, modulo 2^64
46     uint64_t byteCount;
47 
48     // state (ABCDE)
49     uint32_t state[5];
50 
51     // input buffer
52     uint8_t buffer[64];
53 };
54 
55 #endif
56