1 2 /* 3 * Copyright 2006 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #include "SkBase64.h" 11 12 #define DecodePad -2 13 #define EncodePad 64 14 15 static const char default_encode[] = 16 "ABCDEFGHIJKLMNOPQRSTUVWXYZ" 17 "abcdefghijklmnopqrstuvwxyz" 18 "0123456789+/="; 19 20 static const signed char decodeData[] = { 21 62, -1, -1, -1, 63, 22 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, DecodePad, -1, -1, 23 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 24 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, 25 -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 26 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 27 }; 28 29 SkBase64::SkBase64() : fLength((size_t) -1), fData(NULL) { 30 } 31 32 #if defined _WIN32 && _MSC_VER >= 1300 // disable 'two', etc. may be used without having been initialized 33 #pragma warning ( push ) 34 #pragma warning ( disable : 4701 ) 35 #endif 36 37 SkBase64::Error SkBase64::decode(const void* srcPtr, size_t size, bool writeDestination) { 38 unsigned char* dst = (unsigned char*) fData; 39 const unsigned char* dstStart = (const unsigned char*) fData; 40 const unsigned char* src = (const unsigned char*) srcPtr; 41 bool padTwo = false; 42 bool padThree = false; 43 const unsigned char* end = src + size; 44 while (src < end) { 45 unsigned char bytes[4]; 46 int byte = 0; 47 do { 48 unsigned char srcByte = *src++; 49 if (srcByte == 0) 50 goto goHome; 51 if (srcByte <= ' ') 52 continue; // treat as white space 53 if (srcByte < '+' || srcByte > 'z') 54 return kBadCharError; 55 signed char decoded = decodeData[srcByte - '+']; 56 bytes[byte] = decoded; 57 if (decoded < 0) { 58 if (decoded == DecodePad) 59 goto handlePad; 60 return kBadCharError; 61 } else 62 byte++; 63 if (*src) 64 continue; 65 if (byte == 0) 66 goto goHome; 67 if (byte == 4) 68 break; 69 handlePad: 70 if (byte < 2) 71 return kPadError; 72 padThree = true; 73 if (byte == 2) 74 padTwo = true; 75 break; 76 } while (byte < 4); 77 int two = 0; 78 int three = 0; 79 if (writeDestination) { 80 int one = (uint8_t) (bytes[0] << 2); 81 two = bytes[1]; 82 one |= two >> 4; 83 two = (uint8_t) (two << 4); 84 three = bytes[2]; 85 two |= three >> 2; 86 three = (uint8_t) (three << 6); 87 three |= bytes[3]; 88 SkASSERT(one < 256 && two < 256 && three < 256); 89 *dst = (unsigned char) one; 90 } 91 dst++; 92 if (padTwo) 93 break; 94 if (writeDestination) 95 *dst = (unsigned char) two; 96 dst++; 97 if (padThree) 98 break; 99 if (writeDestination) 100 *dst = (unsigned char) three; 101 dst++; 102 } 103 goHome: 104 fLength = dst - dstStart; 105 return kNoError; 106 } 107 108 #if defined _WIN32 && _MSC_VER >= 1300 109 #pragma warning ( pop ) 110 #endif 111 112 size_t SkBase64::Encode(const void* srcPtr, size_t length, void* dstPtr, const char* encodeMap) { 113 const char* encode; 114 if (NULL == encodeMap) { 115 encode = default_encode; 116 } else { 117 encode = encodeMap; 118 } 119 const unsigned char* src = (const unsigned char*) srcPtr; 120 unsigned char* dst = (unsigned char*) dstPtr; 121 if (dst) { 122 size_t remainder = length % 3; 123 const unsigned char* end = &src[length - remainder]; 124 while (src < end) { 125 unsigned a = *src++; 126 unsigned b = *src++; 127 unsigned c = *src++; 128 int d = c & 0x3F; 129 c = (c >> 6 | b << 2) & 0x3F; 130 b = (b >> 4 | a << 4) & 0x3F; 131 a = a >> 2; 132 *dst++ = encode[a]; 133 *dst++ = encode[b]; 134 *dst++ = encode[c]; 135 *dst++ = encode[d]; 136 } 137 if (remainder > 0) { 138 int k1 = 0; 139 int k2 = EncodePad; 140 int a = (uint8_t) *src++; 141 if (remainder == 2) 142 { 143 int b = *src++; 144 k1 = b >> 4; 145 k2 = (b << 2) & 0x3F; 146 } 147 *dst++ = encode[a >> 2]; 148 *dst++ = encode[(k1 | a << 4) & 0x3F]; 149 *dst++ = encode[k2]; 150 *dst++ = encode[EncodePad]; 151 } 152 } 153 return (length + 2) / 3 * 4; 154 } 155 156 SkBase64::Error SkBase64::decode(const char* src, size_t len) { 157 Error err = decode(src, len, false); 158 SkASSERT(err == kNoError); 159 if (err != kNoError) 160 return err; 161 fData = new char[fLength]; // should use sk_malloc/sk_free 162 decode(src, len, true); 163 return kNoError; 164 } 165
