third_party/WebKit/Source/wtf/text/Base64.cpp

   1 /*
   2    Copyright (C) 2000-2001 Dawit Alemayehu <adawit@kde.org>
   3    Copyright (C) 2006 Alexey Proskuryakov <ap@webkit.org>
   4    Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
   5    Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU Lesser General Public License (LGPL)
   9    version 2 as published by the Free Software Foundation.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19
  20    This code is based on the java implementation in HTTPClient
  21    package by Ronald Tschalaer Copyright (C) 1996-1999.
  22 */
  23
  24 #include "config.h"
  25 #include "Base64.h"
  26
  27 #include <limits.h>
  28 #include "wtf/StringExtras.h"
  29
  30 namespace WTF {
  31
  32 static const char base64EncMap[64] = {
  33     0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
  34     0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
  35     0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
  36     0x59, 0x5A, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
  37     0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E,
  38     0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
  39     0x77, 0x78, 0x79, 0x7A, 0x30, 0x31, 0x32, 0x33,
  40     0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2B, 0x2F
  41 };
  42
  43 static const char base64DecMap[128] = {
  44     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  45     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  46     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  47     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  48     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  49     0x00, 0x00, 0x00, 0x3E, 0x00, 0x00, 0x00, 0x3F,
  50     0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,
  51     0x3C, 0x3D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  52     0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
  53     0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
  54     0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
  55     0x17, 0x18, 0x19, 0x00, 0x00, 0x00, 0x00, 0x00,
  56     0x00, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,
  57     0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
  58     0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
  59     0x31, 0x32, 0x33, 0x00, 0x00, 0x00, 0x00, 0x00
  60 };
  61
  62 String base64Encode(const char* data, unsigned length, Base64EncodePolicy policy)
  63 {
  64     Vector<char> result;
  65     base64Encode(data, length, result, policy);
  66     return String(result.data(), result.size());
  67 }
  68
  69 void base64Encode(const char* data, unsigned len, Vector<char>& out, Base64EncodePolicy policy)
  70 {
  71     out.clear();
  72     if (!len)
  73         return;
  74
  75     // If the input string is pathologically large, just return nothing.
  76     // Note: Keep this in sync with the "outLength" computation below.
  77     // Rather than being perfectly precise, this is a bit conservative.
  78     const unsigned maxInputBufferSize = UINT_MAX / 77 * 76 / 4 * 3 - 2;
  79     if (len > maxInputBufferSize)
  80         return;
  81
  82     unsigned sidx = 0;
  83     unsigned didx = 0;
  84
  85     unsigned outLength = ((len + 2) / 3) * 4;
  86
  87     // Deal with the 76 character per line limit specified in RFC 2045.
  88     bool insertLFs = (policy == Base64InsertLFs && outLength > 76);
  89     if (insertLFs)
  90         outLength += ((outLength - 1) / 76);
  91
  92     int count = 0;
  93     out.grow(outLength);
  94
  95     // 3-byte to 4-byte conversion + 0-63 to ascii printable conversion
  96     if (len > 1) {
  97         while (sidx < len - 2) {
  98             if (insertLFs) {
  99                 if (count && !(count % 76))
 100                     out[didx++] = '\n';
 101                 count += 4;
 102             }
 103             out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
 104             out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
 105             out[didx++] = base64EncMap[((data[sidx + 2] >> 6) & 003) | ((data[sidx + 1] << 2) & 077)];
 106             out[didx++] = base64EncMap[data[sidx + 2] & 077];
 107             sidx += 3;
 108         }
 109     }
 110
 111     if (sidx < len) {
 112         if (insertLFs && (count > 0) && !(count % 76))
 113            out[didx++] = '\n';
 114
 115         out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
 116         if (sidx < len - 1) {
 117             out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
 118             out[didx++] = base64EncMap[(data[sidx + 1] << 2) & 077];
 119         } else
 120             out[didx++] = base64EncMap[(data[sidx] << 4) & 077];
 121     }
 122
 123     // Add padding
 124     while (didx < out.size()) {
 125         out[didx] = '=';
 126         ++didx;
 127     }
 128 }
 129
 130 bool base64Decode(const Vector<char>& in, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 131 {
 132     out.clear();
 133
 134     // If the input string is pathologically large, just return nothing.
 135     if (in.size() > UINT_MAX)
 136         return false;
 137
 138     return base64Decode(in.data(), in.size(), out, shouldIgnoreCharacter, policy);
 139 }
 140
 141 template<typename T>
 142 static inline bool base64DecodeInternal(const T* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 143 {
 144     out.clear();
 145     if (!length)
 146         return true;
 147
 148     out.grow(length);
 149
 150     unsigned equalsSignCount = 0;
 151     unsigned outLength = 0;
 152     bool hadError = false;
 153     for (unsigned idx = 0; idx < length; ++idx) {
 154         UChar ch = data[idx];
 155         if (ch == '=') {
 156             ++equalsSignCount;
 157             // There should never be more than 2 padding characters.
 158             if (policy == Base64ValidatePadding && equalsSignCount > 2) {
 159                 hadError = true;
 160                 break;
 161             }
 162         } else if (('0' <= ch && ch <= '9') || ('A' <= ch && ch <= 'Z') || ('a' <= ch && ch <= 'z') || ch == '+' || ch == '/') {
 163             if (equalsSignCount) {
 164                 hadError = true;
 165                 break;
 166             }
 167             out[outLength++] = base64DecMap[ch];
 168         } else if (!shouldIgnoreCharacter || !shouldIgnoreCharacter(ch)) {
 169             hadError = true;
 170             break;
 171         }
 172     }
 173
 174     if (outLength < out.size())
 175         out.shrink(outLength);
 176
 177     if (hadError)
 178         return false;
 179
 180     if (!outLength)
 181         return !equalsSignCount;
 182
 183     // There should be no padding if length is a multiple of 4.
 184     // We use (outLength + equalsSignCount) instead of length because we don't want to account for ignored characters.
 185     if (policy == Base64ValidatePadding && equalsSignCount && (outLength + equalsSignCount) % 4)
 186         return false;
 187
 188     // Valid data is (n * 4 + [0,2,3]) characters long.
 189     if ((outLength % 4) == 1)
 190         return false;
 191
 192     // 4-byte to 3-byte conversion
 193     outLength -= (outLength + 3) / 4;
 194     if (!outLength)
 195         return false;
 196
 197     unsigned sidx = 0;
 198     unsigned didx = 0;
 199     if (outLength > 1) {
 200         while (didx < outLength - 2) {
 201             out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
 202             out[didx + 1] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
 203             out[didx + 2] = (((out[sidx + 2] << 6) & 255) | (out[sidx + 3] & 077));
 204             sidx += 4;
 205             didx += 3;
 206         }
 207     }
 208
 209     if (didx < outLength)
 210         out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
 211
 212     if (++didx < outLength)
 213         out[didx] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
 214
 215     if (outLength < out.size())
 216         out.shrink(outLength);
 217
 218     return true;
 219 }
 220
 221 bool base64Decode(const char* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 222 {
 223     return base64DecodeInternal<LChar>(reinterpret_cast<const LChar*>(data), length, out, shouldIgnoreCharacter, policy);
 224 }
 225
 226 bool base64Decode(const UChar* data, unsigned length, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 227 {
 228     return base64DecodeInternal<UChar>(data, length, out, shouldIgnoreCharacter, policy);
 229 }
 230
 231 bool base64Decode(const String& in, Vector<char>& out, CharacterMatchFunctionPtr shouldIgnoreCharacter, Base64DecodePolicy policy)
 232 {
 233     if (in.isEmpty())
 234         return base64DecodeInternal<LChar>(0, 0, out, shouldIgnoreCharacter, policy);
 235     if (in.is8Bit())
 236         return base64DecodeInternal<LChar>(in.characters8(), in.length(), out, shouldIgnoreCharacter, policy);
 237     return base64DecodeInternal<UChar>(in.characters16(), in.length(), out, shouldIgnoreCharacter, policy);
 238 }
 239
 240 String base64URLEncode(const char* data, unsigned length, Base64EncodePolicy policy)
 241 {
 242     return base64Encode(data, length, policy).replace('+', '-').replace('/', '_');
 243 }
 244
 245 String normalizeToBase64(const String& encoding)
 246 {
 247     return String(encoding).replace('-', '+').replace('_', '/');
 248 }
 249
 250 } // namespace WTF