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