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1 /* |
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2 * Copyright (c) 2004 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: This class implements the base64 en/decoding. |
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15 * |
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16 */ |
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17 |
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18 |
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19 #include <e32base.h> |
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20 #include "base64.h" |
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21 |
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22 /* 6 LOCAL DEFINITIONS */ |
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23 |
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24 /* 6.1 Local include files */ |
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25 |
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26 /* 6.2 Local constants */ |
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27 |
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28 LOCAL_C const TUint8 pBase64[] = |
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29 { |
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30 0x3e, 0x7f, 0x7f, 0x7f, 0x3f, 0x34, 0x35, 0x36, |
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31 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x7f, |
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32 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x00, 0x01, |
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33 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, |
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34 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, |
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35 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, |
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36 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x1a, 0x1b, |
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37 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, |
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38 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, |
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39 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33 |
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40 }; |
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41 |
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42 /* 6.3 Local macros */ |
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43 #define b64blocks(l) (((l) + 2) / 3 * 4) |
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44 /* #define b64octets(l) ((l) / 4 * 3) */ |
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45 |
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46 /* 6.4 Local data types */ |
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47 |
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48 /* 6.5 Local data structures */ |
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49 |
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50 /* 6.6 Local function prototypes */ |
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51 |
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52 LOCAL_C TInt b64valid(TUint8 *); |
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53 |
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54 /* 7 MODULE CODE */ |
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55 |
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56 /* ========================================================================= */ |
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57 |
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58 /* 7.2 */ |
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59 |
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60 /* Functional description |
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61 * |
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62 * This function does base64 decoding. As the outputted buffer is always 33% shorter than |
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63 * the input buffer, the caller may want to reallocate the buffer after calling this function. |
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64 * |
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65 * Parameters |
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66 * |
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67 * Pointer to source containing data to decode |
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68 * |
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69 source |
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70 * |
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71 * Length of source buffer |
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72 * |
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73 length |
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74 * |
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75 * pointer to the destination buffer |
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76 * Note: the user must allocate memory for this buffer that its length at least can not be shorter than |
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77 * the length of source. The user also can use same buffer for both source and destination. |
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78 * |
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79 destination |
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80 * |
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81 * length of the buffer allocated |
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82 * |
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83 destination_length |
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84 * |
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85 * Return values |
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86 * |
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87 * byte 0 if OK else > 0 |
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88 */ |
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89 |
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90 /* ---------------------------------------------------------------------- */ |
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91 |
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92 TInt b64decode(TUint8 *source, TUint32 length, TUint8 *destination, TUint32 *destination_length) |
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93 { |
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94 /* Data structures */ |
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95 |
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96 /* Code */ |
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97 |
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98 TUint8 *buf/*, *pbuf*/; /* Decoding buffer pointers. */ |
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99 register TUint32 x = 0; /* General purpose integers. */ |
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100 TUint32 buf_index = 0; /* current index in destination buffer */ |
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101 |
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102 |
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103 /* buffer to avoid allocating wholly new buffer for output */ |
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104 TUint8 localBuffer[4] = {0,0,0,0}; |
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105 TUint8* pLocalBufferOutPointer = 0; |
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106 |
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107 register TUint32 i = 0; |
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108 TUint32 num; |
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109 |
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110 TUint8 c = 0; /* Character to decode. */ |
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111 TUint8 localBufferIndex = 0; |
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112 |
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113 /* int32 buf_length = 0; */ /* new length of destination buf */ |
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114 const TUint8 pad = 0x3d; /* '=' */ |
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115 |
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116 if(!source || length == 0 || !destination || !destination_length) |
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117 { |
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118 return KErrArgument; |
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119 } |
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120 |
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121 /* Collating sequence independant "===". */ |
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122 |
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123 /* Calculate the amount of '=' in the end of the source */ |
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124 for(x=0, buf=source + (length-1); *buf == pad; buf --) |
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125 { |
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126 x++; |
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127 } |
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128 |
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129 /* max allow 3 "===" in the end of content */ |
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130 if (x > 3) |
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131 { |
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132 return KErrArgument; |
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133 } |
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134 |
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135 /* Save the encoded string pointer. */ |
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136 // pbuf = destination; |
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137 |
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138 /* save address for first output block */ |
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139 pLocalBufferOutPointer = destination; |
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140 x = 0; /* Initialize index. */ |
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141 |
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142 localBufferIndex = 0; |
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143 |
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144 |
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145 Mem::Copy(localBuffer, source, 4); |
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146 |
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147 for (i = length; i != 0; i-- ) /* Decode every byte of the base 64 string */ |
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148 { |
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149 /* c = *pbuf++; */ |
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150 c = localBuffer[localBufferIndex++]; |
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151 |
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152 if(localBufferIndex == 4) |
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153 { |
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154 localBufferIndex = 0; |
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155 |
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156 source = source + 4; |
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157 |
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158 /* INPUT: copy next input block to local buffer */ |
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159 num = i > 4 ? 4 : i - 1; |
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160 if(num > 0) |
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161 { |
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162 Mem::Copy(localBuffer, source, num); |
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163 } |
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164 } |
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165 |
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166 /* Ignore "=". */ |
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167 if (c == pad) |
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168 { |
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169 break; /* this must be the end of the buffer, or else ve have a invalid character */ |
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170 } |
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171 |
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172 if (c == '\n' || c == '\r' || c == '\t') /* ignore linefeed tab and cr */ |
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173 { |
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174 continue; |
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175 } |
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176 |
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177 /* Valid Base64 Index? */ |
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178 if (!b64valid(&c)) |
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179 { |
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180 /* b64free(buf); */ |
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181 return KErrArgument; |
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182 } |
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183 |
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184 /* Decode 4 byte words into 3 byte octets.*/ |
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185 switch(x % 4) |
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186 { |
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187 case 0: /* Byte 0 of word.*/ |
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188 pLocalBufferOutPointer[buf_index] = (TInt8)(c << 2); |
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189 break; |
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190 case 1: /* Byte 1 of word. */ |
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191 pLocalBufferOutPointer[buf_index] |= c >> 4; |
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192 buf_index ++; |
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193 pLocalBufferOutPointer[buf_index] = (TInt8)( (c & 0x0f) << 4 ); |
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194 break; |
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195 case 2: /* Byte 2 of word. */ |
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196 pLocalBufferOutPointer[buf_index] |= c >> 2; |
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197 buf_index ++; |
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198 pLocalBufferOutPointer[buf_index] = (TInt8)( (c & 0x03) << 6 ); |
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199 break; |
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200 case 3: /* Byte 3 of word. */ |
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201 pLocalBufferOutPointer[buf_index] |= c; |
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202 buf_index ++; |
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203 break; |
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204 default: /* useless, just to depress warnings */ |
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205 break; |
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206 } |
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207 |
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208 x++; /* Increment word byte. */ |
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209 |
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210 |
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211 } /* while */ |
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212 |
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213 |
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214 /* make sure that there is zero at the end of the buffer |
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215 though buf[buf_index] shoule be zero after decoding |
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216 */ |
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217 |
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218 |
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219 /* pbuf[buf_index+1] = 0; */ |
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220 |
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221 /*buf[buf_index+1]=0*/ |
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222 /* don't return the size of the buffer (buf_length), but the data size we put in (buf_index)*/ |
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223 *destination_length = buf_index; |
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224 return KErrNone; |
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225 } |
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226 |
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227 /* 7.3 */ |
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228 |
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229 /* Functional description |
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230 * |
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231 * This function validates the character according to the base64 rules, |
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232 * and changes it to the corresponding value in the table. |
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233 * |
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234 * Parameters |
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235 * |
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236 * Pointer to character to validate |
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237 * |
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238 c |
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239 * |
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240 * Return values |
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241 * |
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242 * TRUE if character is valid else FALSE. |
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243 */ |
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244 |
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245 /* ---------------------------------------------------------------------- */ |
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246 |
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247 LOCAL_C TInt b64valid(TUint8 *c) |
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248 { |
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249 /* Data structures */ |
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250 |
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251 /* Code */ |
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252 |
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253 /* If not within the range of the table, return false. */ |
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254 if ((*c < 0x2b) || (*c > 0x7a)) |
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255 { |
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256 return 0; |
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257 } |
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258 /* If it falls within one of the gaps, return false. */ |
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259 if ((*c = pBase64[*c - 0x2b]) == 0x7f) |
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260 { |
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261 return 0; |
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262 } |
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263 |
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264 return 1; /* Otherwise, return true. */ |
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265 } |
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266 |
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267 /* 7.4 */ |
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268 |
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269 /* Functional description |
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270 * |
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271 * This function allocates a buffer in the size of the parameter. |
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272 * |
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273 * Parameters |
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274 * |
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275 * Size of buffer to allocate |
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276 * |
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277 length |
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278 * |
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279 * Return values |
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280 * |
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281 * pointer to buffer |
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282 */ |
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283 |
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284 /* ---------------------------------------------------------------------- */ |
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285 #ifdef BUILD_BASE64_ENCODE |
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286 |
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287 LOCAL TUint8 *b64buffer(TUint32 length) |
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288 { |
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289 /* Data structures */ |
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290 |
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291 /* Code */ |
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292 |
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293 TUint8 *buf; /* buffer pointers. */ |
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294 |
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295 if (!length) /* dont allow buf size 0 */ |
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296 { |
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297 return NULL; |
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298 } |
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299 |
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300 buf = (TUint8 *) DRM_BLOCK_ALLOC(length); |
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301 |
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302 return buf; /* Return the pointer or null. */ |
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303 } |
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304 #endif /* #ifdef BUILD_BASE64_ENCODE */ |
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305 |
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306 /* End of File */ |
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307 |