michael@0: 
michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #include "SkBase64.h"
michael@0: 
michael@0: #define DecodePad -2
michael@0: #define EncodePad 64
michael@0: 
michael@0: static const char default_encode[] =
michael@0:     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
michael@0:     "abcdefghijklmnopqrstuvwxyz"
michael@0:     "0123456789+/=";
michael@0: 
michael@0: static const signed char decodeData[] = {
michael@0:     62, -1, -1, -1, 63,
michael@0:     52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, DecodePad, -1, -1,
michael@0:     -1,  0,  1,  2,  3,  4,  5,  6, 7,  8,  9, 10, 11, 12, 13, 14,
michael@0:     15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
michael@0:     -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
michael@0:     41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
michael@0: };
michael@0: 
michael@0: SkBase64::SkBase64() : fLength((size_t) -1), fData(NULL) {
michael@0: }
michael@0: 
michael@0: #if defined _WIN32 && _MSC_VER >= 1300  // disable 'two', etc. may be used without having been initialized
michael@0: #pragma warning ( push )
michael@0: #pragma warning ( disable : 4701 )
michael@0: #endif
michael@0: 
michael@0: SkBase64::Error SkBase64::decode(const void* srcPtr, size_t size, bool writeDestination) {
michael@0:     unsigned char* dst = (unsigned char*) fData;
michael@0:     const unsigned char* dstStart = (const unsigned char*) fData;
michael@0:     const unsigned char* src = (const unsigned char*) srcPtr;
michael@0:     bool padTwo = false;
michael@0:     bool padThree = false;
michael@0:     const unsigned char* end = src + size;
michael@0:     while (src < end) {
michael@0:         unsigned char bytes[4];
michael@0:         int byte = 0;
michael@0:         do {
michael@0:             unsigned char srcByte = *src++;
michael@0:             if (srcByte == 0)
michael@0:                 goto goHome;
michael@0:             if (srcByte <= ' ')
michael@0:                 continue; // treat as white space
michael@0:             if (srcByte < '+' || srcByte > 'z')
michael@0:                 return kBadCharError;
michael@0:             signed char decoded = decodeData[srcByte - '+'];
michael@0:             bytes[byte] = decoded;
michael@0:             if (decoded < 0) {
michael@0:                 if (decoded == DecodePad)
michael@0:                     goto handlePad;
michael@0:                 return kBadCharError;
michael@0:             } else
michael@0:                 byte++;
michael@0:             if (*src)
michael@0:                 continue;
michael@0:             if (byte == 0)
michael@0:                 goto goHome;
michael@0:             if (byte == 4)
michael@0:                 break;
michael@0: handlePad:
michael@0:             if (byte < 2)
michael@0:                 return kPadError;
michael@0:             padThree = true;
michael@0:             if (byte == 2)
michael@0:                 padTwo = true;
michael@0:             break;
michael@0:         } while (byte < 4);
michael@0:         int two = 0;
michael@0:         int three = 0;
michael@0:         if (writeDestination) {
michael@0:             int one = (uint8_t) (bytes[0] << 2);
michael@0:             two = bytes[1];
michael@0:             one |= two >> 4;
michael@0:             two = (uint8_t) (two << 4);
michael@0:             three = bytes[2];
michael@0:             two |= three >> 2;
michael@0:             three = (uint8_t) (three << 6);
michael@0:             three |= bytes[3];
michael@0:             SkASSERT(one < 256 && two < 256 && three < 256);
michael@0:             *dst = (unsigned char) one;
michael@0:         }
michael@0:         dst++;
michael@0:         if (padTwo)
michael@0:             break;
michael@0:         if (writeDestination)
michael@0:             *dst = (unsigned char) two;
michael@0:         dst++;
michael@0:         if (padThree)
michael@0:             break;
michael@0:         if (writeDestination)
michael@0:             *dst = (unsigned char) three;
michael@0:         dst++;
michael@0:     }
michael@0: goHome:
michael@0:     fLength = dst - dstStart;
michael@0:     return kNoError;
michael@0: }
michael@0: 
michael@0: #if defined _WIN32 && _MSC_VER >= 1300
michael@0: #pragma warning ( pop )
michael@0: #endif
michael@0: 
michael@0: size_t SkBase64::Encode(const void* srcPtr, size_t length, void* dstPtr, const char* encodeMap) {
michael@0:     const char* encode;
michael@0:     if (NULL == encodeMap) {
michael@0:         encode = default_encode;
michael@0:     } else {
michael@0:         encode = encodeMap;
michael@0:     }
michael@0:     const unsigned char* src = (const unsigned char*) srcPtr;
michael@0:     unsigned char* dst = (unsigned char*) dstPtr;
michael@0:     if (dst) {
michael@0:         size_t remainder = length % 3;
michael@0:         const unsigned char* end = &src[length - remainder];
michael@0:         while (src < end) {
michael@0:             unsigned a = *src++;
michael@0:             unsigned b = *src++;
michael@0:             unsigned c = *src++;
michael@0:             int      d = c & 0x3F;
michael@0:             c = (c >> 6 | b << 2) & 0x3F;
michael@0:             b = (b >> 4 | a << 4) & 0x3F;
michael@0:             a = a >> 2;
michael@0:             *dst++ = encode[a];
michael@0:             *dst++ = encode[b];
michael@0:             *dst++ = encode[c];
michael@0:             *dst++ = encode[d];
michael@0:         }
michael@0:         if (remainder > 0) {
michael@0:             int k1 = 0;
michael@0:             int k2 = EncodePad;
michael@0:             int a = (uint8_t) *src++;
michael@0:             if (remainder == 2)
michael@0:             {
michael@0:                 int b = *src++;
michael@0:                 k1 = b >> 4;
michael@0:                 k2 = (b << 2) & 0x3F;
michael@0:             }
michael@0:             *dst++ = encode[a >> 2];
michael@0:             *dst++ = encode[(k1 | a << 4) & 0x3F];
michael@0:             *dst++ = encode[k2];
michael@0:             *dst++ = encode[EncodePad];
michael@0:         }
michael@0:     }
michael@0:     return (length + 2) / 3 * 4;
michael@0: }
michael@0: 
michael@0: SkBase64::Error SkBase64::decode(const char* src, size_t len) {
michael@0:     Error err = decode(src, len, false);
michael@0:     SkASSERT(err == kNoError);
michael@0:     if (err != kNoError)
michael@0:         return err;
michael@0:     fData = new char[fLength];  // should use sk_malloc/sk_free
michael@0:     decode(src, len, true);
michael@0:     return kNoError;
michael@0: }