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