Home | History | Annotate | Download | only in text
      1 /*
      2    Copyright (C) 2000-2001 Dawit Alemayehu <adawit (at) kde.org>
      3    Copyright (C) 2006 Alexey Proskuryakov <ap (at) webkit.org>
      4    Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
      5    Copyright (C) 2010 Patrick Gansterer <paroga (at) 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 Tschalr 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 #include <wtf/text/WTFString.h>
     30 
     31 namespace WebCore {
     32 
     33 static const char base64EncMap[64] = {
     34     0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
     35     0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
     36     0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
     37     0x59, 0x5A, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
     38     0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E,
     39     0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
     40     0x77, 0x78, 0x79, 0x7A, 0x30, 0x31, 0x32, 0x33,
     41     0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2B, 0x2F
     42 };
     43 
     44 static const char base64DecMap[128] = {
     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, 0x00, 0x00, 0x00, 0x00, 0x00,
     50     0x00, 0x00, 0x00, 0x3E, 0x00, 0x00, 0x00, 0x3F,
     51     0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,
     52     0x3C, 0x3D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     53     0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
     54     0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
     55     0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
     56     0x17, 0x18, 0x19, 0x00, 0x00, 0x00, 0x00, 0x00,
     57     0x00, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,
     58     0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
     59     0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
     60     0x31, 0x32, 0x33, 0x00, 0x00, 0x00, 0x00, 0x00
     61 };
     62 
     63 String base64Encode(const char* data, unsigned length, bool insertLFs)
     64 {
     65     Vector<char> result;
     66     base64Encode(data, length, result, insertLFs);
     67     return String(result.data(), result.size());
     68 }
     69 
     70 void base64Encode(const char* data, unsigned len, Vector<char>& out, bool insertLFs)
     71 {
     72     out.clear();
     73     if (!len)
     74         return;
     75 
     76     // If the input string is pathologically large, just return nothing.
     77     // Note: Keep this in sync with the "outLength" computation below.
     78     // Rather than being perfectly precise, this is a bit conservative.
     79     const unsigned maxInputBufferSize = UINT_MAX / 77 * 76 / 4 * 3 - 2;
     80     if (len > maxInputBufferSize)
     81         return;
     82 
     83     unsigned sidx = 0;
     84     unsigned didx = 0;
     85 
     86     unsigned outLength = ((len + 2) / 3) * 4;
     87 
     88     // Deal with the 76 character per line limit specified in RFC 2045.
     89     insertLFs = (insertLFs && outLength > 76);
     90     if (insertLFs)
     91         outLength += ((outLength - 1) / 76);
     92 
     93     int count = 0;
     94     out.grow(outLength);
     95 
     96     // 3-byte to 4-byte conversion + 0-63 to ascii printable conversion
     97     if (len > 1) {
     98         while (sidx < len - 2) {
     99             if (insertLFs) {
    100                 if (count && !(count % 76))
    101                     out[didx++] = '\n';
    102                 count += 4;
    103             }
    104             out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
    105             out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
    106             out[didx++] = base64EncMap[((data[sidx + 2] >> 6) & 003) | ((data[sidx + 1] << 2) & 077)];
    107             out[didx++] = base64EncMap[data[sidx + 2] & 077];
    108             sidx += 3;
    109         }
    110     }
    111 
    112     if (sidx < len) {
    113         if (insertLFs && (count > 0) && !(count % 76))
    114            out[didx++] = '\n';
    115 
    116         out[didx++] = base64EncMap[(data[sidx] >> 2) & 077];
    117         if (sidx < len - 1) {
    118             out[didx++] = base64EncMap[((data[sidx + 1] >> 4) & 017) | ((data[sidx] << 4) & 077)];
    119             out[didx++] = base64EncMap[(data[sidx + 1] << 2) & 077];
    120         } else
    121             out[didx++] = base64EncMap[(data[sidx] << 4) & 077];
    122     }
    123 
    124     // Add padding
    125     while (didx < out.size()) {
    126         out[didx] = '=';
    127         didx++;
    128     }
    129 }
    130 
    131 bool base64Decode(const Vector<char>& in, Vector<char>& out, Base64DecodePolicy policy)
    132 {
    133     out.clear();
    134 
    135     // If the input string is pathologically large, just return nothing.
    136     if (in.size() > UINT_MAX)
    137         return false;
    138 
    139     return base64Decode(in.data(), in.size(), out, policy);
    140 }
    141 
    142 template<typename T>
    143 static inline bool base64DecodeInternal(const T* data, unsigned len, Vector<char>& out, Base64DecodePolicy policy)
    144 {
    145     out.clear();
    146     if (!len)
    147         return true;
    148 
    149     out.grow(len);
    150 
    151     bool sawEqualsSign = false;
    152     unsigned outLength = 0;
    153     for (unsigned idx = 0; idx < len; idx++) {
    154         unsigned ch = data[idx];
    155         if (ch == '=')
    156             sawEqualsSign = true;
    157         else if (('0' <= ch && ch <= '9') || ('A' <= ch && ch <= 'Z') || ('a' <= ch && ch <= 'z') || ch == '+' || ch == '/') {
    158             if (sawEqualsSign)
    159                 return false;
    160             out[outLength] = base64DecMap[ch];
    161             outLength++;
    162         } else if (policy == FailOnInvalidCharacter || (policy == IgnoreWhitespace && !isSpaceOrNewline(ch)))
    163             return false;
    164     }
    165 
    166     if (!outLength)
    167         return !sawEqualsSign;
    168 
    169     // Valid data is (n * 4 + [0,2,3]) characters long.
    170     if ((outLength % 4) == 1)
    171         return false;
    172 
    173     // 4-byte to 3-byte conversion
    174     outLength -= (outLength + 3) / 4;
    175     if (!outLength)
    176         return false;
    177 
    178     unsigned sidx = 0;
    179     unsigned didx = 0;
    180     if (outLength > 1) {
    181         while (didx < outLength - 2) {
    182             out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
    183             out[didx + 1] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
    184             out[didx + 2] = (((out[sidx + 2] << 6) & 255) | (out[sidx + 3] & 077));
    185             sidx += 4;
    186             didx += 3;
    187         }
    188     }
    189 
    190     if (didx < outLength)
    191         out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
    192 
    193     if (++didx < outLength)
    194         out[didx] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
    195 
    196     if (outLength < out.size())
    197         out.shrink(outLength);
    198 
    199     return true;
    200 }
    201 
    202 bool base64Decode(const char* data, unsigned len, Vector<char>& out, Base64DecodePolicy policy)
    203 {
    204     return base64DecodeInternal<char>(data, len, out, policy);
    205 }
    206 
    207 bool base64Decode(const String& in, Vector<char>& out, Base64DecodePolicy policy)
    208 {
    209     return base64DecodeInternal<UChar>(in.characters(), in.length(), out, policy);
    210 }
    211 
    212 } // namespace WebCore
    213