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