text: /*
     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.
  
     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 "config.h"
  #include "Base64.h"
  
  #include <limits.h>
  
  #include <wtf/Platform.h>
  #include <wtf/StringExtras.h>
  
  namespace WebCore {
  
  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
  };
  
  void base64Encode(const Vector<char>& in, Vector<char>& out, bool insertLFs)
  {
      out.clear();
      if (in.isEmpty())
          return;
  
      // If the input string is pathologically large, just return nothing.
      // Note: Keep this in sync with the "out_len" computation below.
      // Rather than being perfectly precise, this is a bit conservative.
      const unsigned maxInputBufferSize = UINT_MAX / 77 * 76 / 4 * 3 - 2;
      if (in.size() > maxInputBufferSize)
          return;
  
      unsigned sidx = 0;
      unsigned didx = 0;
      const char* data = in.data();
      const unsigned len = in.size();
  
      unsigned out_len = ((len + 2) / 3) * 4;
  
      // Deal with the 76 character per line limit specified in RFC 2045.
      insertLFs = (insertLFs && out_len > 76);
      if (insertLFs)
          out_len += ((out_len - 1) / 76);
  
      int count = 0;
      out.grow(out_len);
  
      // 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) == 0)
                      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) == 0)
             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)
  {
      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);
  }
  
  bool base64Decode(const char* data, unsigned len, Vector<char>& out)
  {
      out.clear();
      if (len == 0)
          return true;
  
      while (len && data[len-1] == '=')
          --len;
  
      out.grow(len);
      for (unsigned idx = 0; idx < len; idx++) {
          unsigned char ch = data[idx];
          if ((ch > 47 && ch < 58) || (ch > 64 && ch < 91) || (ch > 96 && ch < 123) || ch == '+' || ch == '/' || ch == '=')
              out[idx] = base64DecMap[ch];
          else
              return false;
      }
  
      // 4-byte to 3-byte conversion
      unsigned outLen = len - ((len + 3) / 4);
      if (!outLen || ((outLen + 2) / 3) * 4 < len)
          return false;
  
      unsigned sidx = 0;
      unsigned didx = 0;
      if (outLen > 1) {
          while (didx < outLen - 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 < outLen)
          out[didx] = (((out[sidx] << 2) & 255) | ((out[sidx + 1] >> 4) & 003));
  
      if (++didx < outLen)
          out[didx] = (((out[sidx + 1] << 4) & 255) | ((out[sidx + 2] >> 2) & 017));
  
      if (outLen < out.size())
          out.shrink(outLen);
  
      return true;
  }
  
  }
  