Fix the dev version of the PPAPI video decoder plugin.
[chromium-blink-merge.git] / base / md5.h
blob0a87fcf7c4aa56c1ed6eaece425a6e49a71735c7
1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef BASE_MD5_H_
6 #define BASE_MD5_H_
8 #include "base/base_export.h"
9 #include "base/strings/string_piece.h"
11 namespace base {
13 // MD5 stands for Message Digest algorithm 5.
14 // MD5 is a robust hash function, designed for cyptography, but often used
15 // for file checksums. The code is complex and slow, but has few
16 // collisions.
17 // See Also:
18 // http://en.wikipedia.org/wiki/MD5
20 // These functions perform MD5 operations. The simplest call is MD5Sum() to
21 // generate the MD5 sum of the given data.
23 // You can also compute the MD5 sum of data incrementally by making multiple
24 // calls to MD5Update():
25 // MD5Context ctx; // intermediate MD5 data: do not use
26 // MD5Init(&ctx);
27 // MD5Update(&ctx, data1, length1);
28 // MD5Update(&ctx, data2, length2);
29 // ...
31 // MD5Digest digest; // the result of the computation
32 // MD5Final(&digest, &ctx);
34 // You can call MD5DigestToBase16() to generate a string of the digest.
36 // The output of an MD5 operation.
37 struct MD5Digest {
38 unsigned char a[16];
41 // Used for storing intermediate data during an MD5 computation. Callers
42 // should not access the data.
43 typedef char MD5Context[88];
45 // Computes the MD5 sum of the given data buffer with the given length.
46 // The given 'digest' structure will be filled with the result data.
47 BASE_EXPORT void MD5Sum(const void* data, size_t length, MD5Digest* digest);
49 // Initializes the given MD5 context structure for subsequent calls to
50 // MD5Update().
51 BASE_EXPORT void MD5Init(MD5Context* context);
53 // For the given buffer of |data| as a StringPiece, updates the given MD5
54 // context with the sum of the data. You can call this any number of times
55 // during the computation, except that MD5Init() must have been called first.
56 BASE_EXPORT void MD5Update(MD5Context* context, const StringPiece& data);
58 // Finalizes the MD5 operation and fills the buffer with the digest.
59 BASE_EXPORT void MD5Final(MD5Digest* digest, MD5Context* context);
61 // MD5IntermediateFinal() generates a digest without finalizing the MD5
62 // operation. Can be used to generate digests for the input seen thus far,
63 // without affecting the digest generated for the entire input.
64 BASE_EXPORT void MD5IntermediateFinal(MD5Digest* digest,
65 const MD5Context* context);
67 // Converts a digest into human-readable hexadecimal.
68 BASE_EXPORT std::string MD5DigestToBase16(const MD5Digest& digest);
70 // Returns the MD5 (in hexadecimal) of a string.
71 BASE_EXPORT std::string MD5String(const StringPiece& str);
73 } // namespace base
75 #endif // BASE_MD5_H_