1 
2 //*********************************************************************
3 //* C_Base64 - a simple base64 encoder and decoder.
4 //*
5 //*     Copyright (c) 1999, Bob Withers - bwit@pobox.com
6 //*
7 //* This code may be freely used for any purpose, either personal
8 //* or commercial, provided the authors copyright notice remains
9 //* intact.
10 //*********************************************************************
11 
12 #ifndef TALK_BASE_BASE64_H__
13 #define TALK_BASE_BASE64_H__
14 
15 #include <string>
16 #include <vector>
17 
18 namespace talk_base {
19 
20 class Base64
21 {
22 public:
23   enum DecodeOption {
24     DO_PARSE_STRICT =  1,  // Parse only base64 characters
25     DO_PARSE_WHITE  =  2,  // Parse only base64 and whitespace characters
26     DO_PARSE_ANY    =  3,  // Parse all characters
27     DO_PARSE_MASK   =  3,
28 
29     DO_PAD_YES      =  4,  // Padding is required
30     DO_PAD_ANY      =  8,  // Padding is optional
31     DO_PAD_NO       = 12,  // Padding is disallowed
32     DO_PAD_MASK     = 12,
33 
34     DO_TERM_BUFFER  = 16,  // Must termiante at end of buffer
35     DO_TERM_CHAR    = 32,  // May terminate at any character boundary
36     DO_TERM_ANY     = 48,  // May terminate at a sub-character bit offset
37     DO_TERM_MASK    = 48,
38 
39     // Strictest interpretation
40     DO_STRICT = DO_PARSE_STRICT | DO_PAD_YES | DO_TERM_BUFFER,
41 
42     DO_LAX    = DO_PARSE_ANY | DO_PAD_ANY | DO_TERM_CHAR,
43   };
44   typedef int DecodeFlags;
45 
46   static bool IsBase64Char(char ch);
47 
48   // Determines whether the given string consists entirely of valid base64
49   // encoded characters.
50   static bool IsBase64Encoded(const std::string& str);
51 
52   static void EncodeFromArray(const void* data, size_t len,
53                               std::string* result);
54   static bool DecodeFromArray(const char* data, size_t len, DecodeFlags flags,
55                               std::string* result, size_t* data_used);
56   static bool DecodeFromArray(const char* data, size_t len, DecodeFlags flags,
57                               std::vector<char>* result, size_t* data_used);
58 
59   // Convenience Methods
Encode(const std::string & data)60   static inline std::string Encode(const std::string& data) {
61     std::string result;
62     EncodeFromArray(data.data(), data.size(), &result);
63     return result;
64   }
Decode(const std::string & data,DecodeFlags flags)65   static inline std::string Decode(const std::string& data, DecodeFlags flags) {
66     std::string result;
67     DecodeFromArray(data.data(), data.size(), flags, &result, NULL);
68     return result;
69   }
Decode(const std::string & data,DecodeFlags flags,std::string * result,size_t * data_used)70   static inline bool Decode(const std::string& data, DecodeFlags flags,
71                             std::string* result, size_t* data_used)
72   {
73     return DecodeFromArray(data.data(), data.size(), flags, result, data_used);
74   }
Decode(const std::string & data,DecodeFlags flags,std::vector<char> * result,size_t * data_used)75   static inline bool Decode(const std::string& data, DecodeFlags flags,
76                             std::vector<char>* result, size_t* data_used)
77   {
78     return DecodeFromArray(data.data(), data.size(), flags, result, data_used);
79   }
80 
81 private:
82   static const char Base64Table[];
83   static const unsigned char DecodeTable[];
84 
85   static size_t GetNextQuantum(DecodeFlags parse_flags, bool illegal_pads,
86                                const char* data, size_t len, size_t* dpos,
87                                unsigned char qbuf[4], bool* padded);
88   template<typename T>
89   static bool DecodeFromArrayTemplate(const char* data, size_t len,
90                                       DecodeFlags flags, T* result,
91                                       size_t* data_used);
92 };
93 
94 } // namespace talk_base
95 
96 #endif // TALK_BASE_BASE64_H__
97