1 /* libs/graphics/animator/SkBase64.cpp 2 ** 3 ** Copyright 2006, The Android Open Source Project 4 ** 5 ** Licensed under the Apache License, Version 2.0 (the "License"); 6 ** you may not use this file except in compliance with the License. 7 ** You may obtain a copy of the License at 8 ** 9 ** http://www.apache.org/licenses/LICENSE-2.0 10 ** 11 ** Unless required by applicable law or agreed to in writing, software 12 ** distributed under the License is distributed on an "AS IS" BASIS, 13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 ** See the License for the specific language governing permissions and 15 ** limitations under the License. 16 */ 17 18 #include "SkBase64.h" 19 20 #define DecodePad -2 21 #define EncodePad 64 22 23 static const char encode[] = 24 "ABCDEFGHIJKLMNOPQRSTUVWXYZ" 25 "abcdefghijklmnopqrstuvwxyz" 26 "0123456789+/="; 27 28 static const signed char decodeData[] = { 29 62, -1, -1, -1, 63, 30 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, DecodePad, -1, -1, 31 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 32 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, 33 -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 34 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 35 }; 36 37 SkBase64::SkBase64() : fLength((size_t) -1), fData(NULL) { 38 } 39 40 #if defined _WIN32 && _MSC_VER >= 1300 // disable 'two', etc. may be used without having been initialized 41 #pragma warning ( push ) 42 #pragma warning ( disable : 4701 ) 43 #endif 44 45 SkBase64::Error SkBase64::decode(const void* srcPtr, size_t size, bool writeDestination) { 46 unsigned char* dst = (unsigned char*) fData; 47 const unsigned char* dstStart = (const unsigned char*) fData; 48 const unsigned char* src = (const unsigned char*) srcPtr; 49 bool padTwo = false; 50 bool padThree = false; 51 const unsigned char* end = src + size; 52 while (src < end) { 53 unsigned char bytes[4]; 54 int byte = 0; 55 do { 56 unsigned char srcByte = *src++; 57 if (srcByte == 0) 58 goto goHome; 59 if (srcByte <= ' ') 60 continue; // treat as white space 61 if (srcByte < '+' || srcByte > 'z') 62 return kBadCharError; 63 signed char decoded = decodeData[srcByte - '+']; 64 bytes[byte] = decoded; 65 if (decoded < 0) { 66 if (decoded == DecodePad) 67 goto handlePad; 68 return kBadCharError; 69 } else 70 byte++; 71 if (*src) 72 continue; 73 if (byte == 0) 74 goto goHome; 75 if (byte == 4) 76 break; 77 handlePad: 78 if (byte < 2) 79 return kPadError; 80 padThree = true; 81 if (byte == 2) 82 padTwo = true; 83 break; 84 } while (byte < 4); 85 int two, three; 86 if (writeDestination) { 87 int one = (uint8_t) (bytes[0] << 2); 88 two = bytes[1]; 89 one |= two >> 4; 90 two = (uint8_t) (two << 4); 91 three = bytes[2]; 92 two |= three >> 2; 93 three = (uint8_t) (three << 6); 94 three |= bytes[3]; 95 SkASSERT(one < 256 && two < 256 && three < 256); 96 *dst = (unsigned char) one; 97 } 98 dst++; 99 if (padTwo) 100 break; 101 if (writeDestination) 102 *dst = (unsigned char) two; 103 dst++; 104 if (padThree) 105 break; 106 if (writeDestination) 107 *dst = (unsigned char) three; 108 dst++; 109 } 110 goHome: 111 fLength = dst - dstStart; 112 return kNoError; 113 } 114 115 #if defined _WIN32 && _MSC_VER >= 1300 116 #pragma warning ( pop ) 117 #endif 118 119 size_t SkBase64::Encode(const void* srcPtr, size_t length, void* dstPtr) { 120 const unsigned char* src = (const unsigned char*) srcPtr; 121 unsigned char* dst = (unsigned char*) dstPtr; 122 if (dst) { 123 size_t remainder = length % 3; 124 const unsigned char* end = &src[length - remainder]; 125 while (src < end) { 126 unsigned a = *src++; 127 unsigned b = *src++; 128 unsigned c = *src++; 129 int d = c & 0x3F; 130 c = (c >> 6 | b << 2) & 0x3F; 131 b = (b >> 4 | a << 4) & 0x3F; 132 a = a >> 2; 133 *dst++ = encode[a]; 134 *dst++ = encode[b]; 135 *dst++ = encode[c]; 136 *dst++ = encode[d]; 137 } 138 if (remainder > 0) { 139 int k1 = 0; 140 int k2 = EncodePad; 141 int a = (uint8_t) *src++; 142 if (remainder == 2) 143 { 144 int b = *src++; 145 k1 = b >> 4; 146 k2 = (b << 2) & 0x3F; 147 } 148 *dst++ = encode[a >> 2]; 149 *dst++ = encode[(k1 | a << 4) & 0x3F]; 150 *dst++ = encode[k2]; 151 *dst++ = encode[EncodePad]; 152 } 153 } 154 return (length + 2) / 3 * 4; 155 } 156 157 SkBase64::Error SkBase64::decode(const char* src, size_t len) { 158 Error err = decode(src, len, false); 159 SkASSERT(err == kNoError); 160 if (err != kNoError) 161 return err; 162 fData = new char[fLength]; // should use sk_malloc/sk_free 163 decode(src, len, true); 164 return kNoError; 165 } 166 167 #ifdef SK_SUPPORT_UNITTEST 168 void SkBase64::UnitTest() { 169 signed char all[256]; 170 for (int index = 0; index < 256; index++) 171 all[index] = (signed char) (index + 1); 172 for (int offset = 0; offset < 6; offset++) { 173 size_t length = 256 - offset; 174 size_t encodeLength = Encode(all + offset, length, NULL); 175 char* src = (char*)sk_malloc_throw(encodeLength + 1); 176 Encode(all + offset, length, src); 177 src[encodeLength] = '\0'; 178 SkBase64 tryMe; 179 tryMe.decode(src, encodeLength); 180 SkASSERT(length == tryMe.fLength); 181 SkASSERT(strcmp((const char*) (all + offset), tryMe.fData) == 0); 182 sk_free(src); 183 delete[] tryMe.fData; 184 } 185 } 186 #endif 187 188 189
