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flutter_flutter/sky/engine/wtf/text/Base64.cpp

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/*
Copyright (C) 2000-2001 Dawit Alemayehu <adawit@kde.org>
Copyright (C) 2006 Alexey Proskuryakov <ap@webkit.org>
Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License (LGPL)
version 2 as published by the Free Software Foundation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
This code is based on the java implementation in HTTPClient
package by Ronald Tschalär Copyright (C) 1996-1999.
*/
#include "sky/engine/wtf/text/Base64.h"
#include <limits.h>
#include "sky/engine/wtf/StringExtras.h"
namespace WTF {
static const char base64EncMap[64] = {
0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5A, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E,
0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
0x77, 0x78, 0x79, 0x7A, 0x30, 0x31, 0x32, 0x33,
0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2B, 0x2F
};
static const char base64DecMap[128] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x3E, 0x00, 0x00, 0x00, 0x3F,
0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,
0x3C, 0x3D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
0x17, 0x18, 0x19, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,
0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
0x31, 0x32, 0x33, 0x00, 0x00, 0x00, 0x00, 0x00
};
String base64Encode(const char* data, unsigned length, Base64EncodePolicy policy)
{
Vector<char> result;
base64Encode(data, length, result, policy);
return String(result.data(), result.size());
}
void base64Encode(const char* data, unsigned len, Vector<char>& out, Base64EncodePolicy policy)
{
out.clear();
if (!len)
return;
// If the input string is pathologically large, just return nothing.
// Note: Keep this in sync with the "outLength" computation below.
// Rather than being perfectly precise, this is a bit conservative.
const unsigned maxInputBufferSize = UINT_MAX / 77 * 76 / 4 * 3 - 2;
if (len > maxInputBufferSize)
return;
unsigned sidx = 0;
unsigned didx = 0;
unsigned outLength = ((len + 2) / 3) * 4;
// Deal with the 76 character per line limit specified in RFC 2045.
bool insertLFs = (policy == Base64InsertLFs && outLength > 76);
if (insertLFs)
outLength += ((outLength - 1) / 76);
int count = 0;
out.grow(outLength);
// 3-byte to 4-byte conversion + 0-63 to ascii printable conversion
if (len > 1) {
while (sidx < len - 2) {
if (insertLFs) {
if (count && !(count % 76))
out[didx++] = '\n';
count += 4;
}
out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
out[didx++] = base64EncMap[((data[sidx + 2] >> 6) & 003) | ((data[sidx + 1] << 2) & 077)];
out[didx++] = base64EncMap[data[sidx + 2] & 077];
sidx += 3;
}
}
if (sidx < len) {
if (insertLFs && (count > 0) && !(count % 76))
out[didx++] = '\n';
out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
if (sidx < len - 1) {
out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
out[didx++] = base64EncMap[(data[sidx + 1] << 2) & 077];
} else
out[didx++] = base64EncMap[(data[sidx] << 4) & 077];
}
// Add padding
while (didx < out.size()) {
out[didx] = '=';
++didx;
}
}
bool base64Decode(const Vector<char>& in, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
{
out.clear();
// If the input string is pathologically large, just return nothing.
if (in.size() > UINT_MAX)
return false;
return base64Decode(in.data(), in.size(), out, shouldIgnoreCharacter, policy);
}
template<typename T>
static inline bool base64DecodeInternal(const T* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
{
out.clear();
if (!length)
return true;
out.grow(length);
unsigned equalsSignCount = 0;
unsigned outLength = 0;
bool hadError = false;
for (unsigned idx = 0; idx < length; ++idx) {
unsigned ch = data[idx];
if (ch == '=') {
++equalsSignCount;
// There should never be more than 2 padding characters.
if (policy == Base64ValidatePadding && equalsSignCount > 2) {
hadError = true;
break;
}
} else if (('0' <= ch && ch <= '9') || ('A' <= ch && ch <= 'Z') || ('a' <= ch && ch <= 'z') || ch == '+' || ch == '/') {
if (equalsSignCount) {
hadError = true;
break;
}
out[outLength++] = base64DecMap[ch];
} else if (!shouldIgnoreCharacter || !shouldIgnoreCharacter(ch)) {
hadError = true;
break;
}
}
if (outLength < out.size())
out.shrink(outLength);
if (hadError)
return false;
if (!outLength)
return !equalsSignCount;
// There should be no padding if length is a multiple of 4.
// We use (outLength + equalsSignCount) instead of length because we don't want to account for ignored characters.
if (policy == Base64ValidatePadding && equalsSignCount && (outLength + equalsSignCount) % 4)
return false;
// Valid data is (n * 4 + [0,2,3]) characters long.
if ((outLength % 4) == 1)
return false;
// 4-byte to 3-byte conversion
outLength -= (outLength + 3) / 4;
if (!outLength)
return false;
unsigned sidx = 0;
unsigned didx = 0;
if (outLength > 1) {
while (didx < outLength - 2) {
out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
out[didx + 1] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
out[didx + 2] = (((out[sidx + 2] << 6) & 255) | (out[sidx + 3] & 077));
sidx += 4;
didx += 3;
}
}
if (didx < outLength)
out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
if (++didx < outLength)
out[didx] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
if (outLength < out.size())
out.shrink(outLength);
return true;
}
bool base64Decode(const char* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
{
return base64DecodeInternal<LChar>(reinterpret_cast<const LChar*>(data), length, out, shouldIgnoreCharacter, policy);
}
bool base64Decode(const UChar* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
{
return base64DecodeInternal<UChar>(data, length, out, shouldIgnoreCharacter, policy);
}
bool base64Decode(const String& in, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
{
if (in.isEmpty())
return base64DecodeInternal<LChar>(0, 0, out, shouldIgnoreCharacter, policy);
if (in.is8Bit())
return base64DecodeInternal<LChar>(in.characters8(), in.length(), out, shouldIgnoreCharacter, policy);
return base64DecodeInternal<UChar>(in.characters16(), in.length(), out, shouldIgnoreCharacter, policy);
}
} // namespace WTF
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