1 | /* Arduino SdFat Library
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2 | * Copyright (C) 2009 by William Greiman
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3 | *
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4 | * This file is part of the Arduino SdFat Library
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5 | *
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6 | * This Library is free software: you can redistribute it and/or modify
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7 | * it under the terms of the GNU General Public License as published by
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8 | * the Free Software Foundation, either version 3 of the License, or
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9 | * (at your option) any later version.
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10 | *
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11 | * This Library is distributed in the hope that it will be useful,
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 | * GNU General Public License for more details.
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15 | *
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16 | * You should have received a copy of the GNU General Public License
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17 | * along with the Arduino SdFat Library. If not, see
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18 | * <http://www.gnu.org/licenses/>.
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19 | */
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20 | #ifndef FatStructs_h
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21 | #define FatStructs_h
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22 | /**
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23 | * \file
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24 | * FAT file structures
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25 | */
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26 | /*
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27 | * mostly from Microsoft document fatgen103.doc
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28 | * http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx
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29 | */
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30 | //------------------------------------------------------------------------------
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31 | /** Value for byte 510 of boot block or MBR */
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32 | uint8_t const BOOTSIG0 = 0X55;
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33 | /** Value for byte 511 of boot block or MBR */
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34 | uint8_t const BOOTSIG1 = 0XAA;
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35 | //------------------------------------------------------------------------------
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36 | /**
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37 | * \struct partitionTable
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38 | * \brief MBR partition table entry
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39 | *
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40 | * A partition table entry for a MBR formatted storage device.
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41 | * The MBR partition table has four entries.
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42 | */
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43 | struct partitionTable {
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44 | /**
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45 | * Boot Indicator . Indicates whether the volume is the active
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46 | * partition. Legal values include: 0X00. Do not use for booting.
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47 | * 0X80 Active partition.
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48 | */
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49 | uint8_t boot;
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50 | /**
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51 | * Head part of Cylinder-head-sector address of the first block in
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52 | * the partition. Legal values are 0-255. Only used in old PC BIOS.
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53 | */
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54 | uint8_t beginHead;
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55 | /**
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56 | * Sector part of Cylinder-head-sector address of the first block in
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57 | * the partition. Legal values are 1-63. Only used in old PC BIOS.
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58 | */
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59 | unsigned beginSector : 6;
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60 | /** High bits cylinder for first block in partition. */
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61 | unsigned beginCylinderHigh : 2;
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62 | /**
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63 | * Combine beginCylinderLow with beginCylinderHigh. Legal values
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64 | * are 0-1023. Only used in old PC BIOS.
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65 | */
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66 | uint8_t beginCylinderLow;
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67 | /**
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68 | * Partition type. See defines that begin with PART_TYPE_ for
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69 | * some Microsoft partition types.
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70 | */
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71 | uint8_t type;
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72 | /**
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73 | * head part of cylinder-head-sector address of the last sector in the
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74 | * partition. Legal values are 0-255. Only used in old PC BIOS.
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75 | */
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76 | uint8_t endHead;
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77 | /**
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78 | * Sector part of cylinder-head-sector address of the last sector in
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79 | * the partition. Legal values are 1-63. Only used in old PC BIOS.
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80 | */
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81 | unsigned endSector : 6;
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82 | /** High bits of end cylinder */
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83 | unsigned endCylinderHigh : 2;
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84 | /**
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85 | * Combine endCylinderLow with endCylinderHigh. Legal values
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86 | * are 0-1023. Only used in old PC BIOS.
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87 | */
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88 | uint8_t endCylinderLow;
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89 | /** Logical block address of the first block in the partition. */
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90 | uint32_t firstSector;
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91 | /** Length of the partition, in blocks. */
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92 | uint32_t totalSectors;
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93 | } __attribute__((packed));
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94 | /** Type name for partitionTable */
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95 | typedef struct partitionTable part_t;
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96 | //------------------------------------------------------------------------------
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97 | /**
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98 | * \struct masterBootRecord
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99 | *
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100 | * \brief Master Boot Record
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101 | *
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102 | * The first block of a storage device that is formatted with a MBR.
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103 | */
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104 | struct masterBootRecord {
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105 | /** Code Area for master boot program. */
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106 | uint8_t codeArea[440];
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107 | /** Optional WindowsNT disk signature. May contain more boot code. */
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108 | uint32_t diskSignature;
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109 | /** Usually zero but may be more boot code. */
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110 | uint16_t usuallyZero;
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111 | /** Partition tables. */
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112 | part_t part[4];
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113 | /** First MBR signature byte. Must be 0X55 */
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114 | uint8_t mbrSig0;
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115 | /** Second MBR signature byte. Must be 0XAA */
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116 | uint8_t mbrSig1;
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117 | } __attribute__((packed));
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118 | /** Type name for masterBootRecord */
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119 | typedef struct masterBootRecord mbr_t;
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120 | //------------------------------------------------------------------------------
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121 | /**
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122 | * \struct biosParmBlock
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123 | *
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124 | * \brief BIOS parameter block
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125 | *
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126 | * The BIOS parameter block describes the physical layout of a FAT volume.
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127 | */
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128 | struct biosParmBlock {
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129 | /**
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130 | * Count of bytes per sector. This value may take on only the
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131 | * following values: 512, 1024, 2048 or 4096
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132 | */
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133 | uint16_t bytesPerSector;
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134 | /**
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135 | * Number of sectors per allocation unit. This value must be a
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136 | * power of 2 that is greater than 0. The legal values are
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137 | * 1, 2, 4, 8, 16, 32, 64, and 128.
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138 | */
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139 | uint8_t sectorsPerCluster;
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140 | /**
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141 | * Number of sectors before the first FAT.
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142 | * This value must not be zero.
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143 | */
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144 | uint16_t reservedSectorCount;
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145 | /** The count of FAT data structures on the volume. This field should
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146 | * always contain the value 2 for any FAT volume of any type.
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147 | */
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148 | uint8_t fatCount;
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149 | /**
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150 | * For FAT12 and FAT16 volumes, this field contains the count of
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151 | * 32-byte directory entries in the root directory. For FAT32 volumes,
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152 | * this field must be set to 0. For FAT12 and FAT16 volumes, this
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153 | * value should always specify a count that when multiplied by 32
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154 | * results in a multiple of bytesPerSector. FAT16 volumes should
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155 | * use the value 512.
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156 | */
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157 | uint16_t rootDirEntryCount;
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158 | /**
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159 | * This field is the old 16-bit total count of sectors on the volume.
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160 | * This count includes the count of all sectors in all four regions
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161 | * of the volume. This field can be 0; if it is 0, then totalSectors32
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162 | * must be non-zero. For FAT32 volumes, this field must be 0. For
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163 | * FAT12 and FAT16 volumes, this field contains the sector count, and
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164 | * totalSectors32 is 0 if the total sector count fits
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165 | * (is less than 0x10000).
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166 | */
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167 | uint16_t totalSectors16;
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168 | /**
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169 | * This dates back to the old MS-DOS 1.x media determination and is
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170 | * no longer usually used for anything. 0xF8 is the standard value
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171 | * for fixed (non-removable) media. For removable media, 0xF0 is
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172 | * frequently used. Legal values are 0xF0 or 0xF8-0xFF.
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173 | */
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174 | uint8_t mediaType;
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175 | /**
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176 | * Count of sectors occupied by one FAT on FAT12/FAT16 volumes.
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177 | * On FAT32 volumes this field must be 0, and sectorsPerFat32
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178 | * contains the FAT size count.
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179 | */
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180 | uint16_t sectorsPerFat16;
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181 | /** Sectors per track for interrupt 0x13. Not used otherwise. */
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182 | uint16_t sectorsPerTrtack;
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183 | /** Number of heads for interrupt 0x13. Not used otherwise. */
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184 | uint16_t headCount;
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185 | /**
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186 | * Count of hidden sectors preceding the partition that contains this
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187 | * FAT volume. This field is generally only relevant for media
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188 | * visible on interrupt 0x13.
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189 | */
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190 | uint32_t hidddenSectors;
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191 | /**
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192 | * This field is the new 32-bit total count of sectors on the volume.
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193 | * This count includes the count of all sectors in all four regions
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194 | * of the volume. This field can be 0; if it is 0, then
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195 | * totalSectors16 must be non-zero.
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196 | */
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197 | uint32_t totalSectors32;
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198 | /**
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199 | * Count of sectors occupied by one FAT on FAT32 volumes.
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200 | */
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201 | uint32_t sectorsPerFat32;
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202 | /**
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203 | * This field is only defined for FAT32 media and does not exist on
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204 | * FAT12 and FAT16 media.
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205 | * Bits 0-3 -- Zero-based number of active FAT.
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206 | * Only valid if mirroring is disabled.
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207 | * Bits 4-6 -- Reserved.
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208 | * Bit 7 -- 0 means the FAT is mirrored at runtime into all FATs.
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209 | * -- 1 means only one FAT is active; it is the one referenced in bits 0-3.
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210 | * Bits 8-15 -- Reserved.
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211 | */
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212 | uint16_t fat32Flags;
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213 | /**
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214 | * FAT32 version. High byte is major revision number.
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215 | * Low byte is minor revision number. Only 0.0 define.
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216 | */
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217 | uint16_t fat32Version;
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218 | /**
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219 | * Cluster number of the first cluster of the root directory for FAT32.
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220 | * This usually 2 but not required to be 2.
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221 | */
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222 | uint32_t fat32RootCluster;
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223 | /**
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224 | * Sector number of FSINFO structure in the reserved area of the
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225 | * FAT32 volume. Usually 1.
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226 | */
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227 | uint16_t fat32FSInfo;
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228 | /**
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229 | * If non-zero, indicates the sector number in the reserved area
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230 | * of the volume of a copy of the boot record. Usually 6.
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231 | * No value other than 6 is recommended.
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232 | */
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233 | uint16_t fat32BackBootBlock;
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234 | /**
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235 | * Reserved for future expansion. Code that formats FAT32 volumes
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236 | * should always set all of the bytes of this field to 0.
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237 | */
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238 | uint8_t fat32Reserved[12];
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239 | } __attribute__((packed));
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240 | /** Type name for biosParmBlock */
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241 | typedef struct biosParmBlock bpb_t;
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242 | //------------------------------------------------------------------------------
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243 | /**
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244 | * \struct fat32BootSector
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245 | *
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246 | * \brief Boot sector for a FAT16 or FAT32 volume.
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247 | *
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248 | */
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249 | struct fat32BootSector {
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250 | /** X86 jmp to boot program */
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251 | uint8_t jmpToBootCode[3];
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252 | /** informational only - don't depend on it */
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253 | char oemName[8];
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254 | /** BIOS Parameter Block */
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255 | bpb_t bpb;
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256 | /** for int0x13 use value 0X80 for hard drive */
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257 | uint8_t driveNumber;
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258 | /** used by Windows NT - should be zero for FAT */
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259 | uint8_t reserved1;
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260 | /** 0X29 if next three fields are valid */
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261 | uint8_t bootSignature;
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262 | /** usually generated by combining date and time */
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263 | uint32_t volumeSerialNumber;
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264 | /** should match volume label in root dir */
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265 | char volumeLabel[11];
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266 | /** informational only - don't depend on it */
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267 | char fileSystemType[8];
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268 | /** X86 boot code */
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269 | uint8_t bootCode[420];
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270 | /** must be 0X55 */
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271 | uint8_t bootSectorSig0;
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272 | /** must be 0XAA */
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273 | uint8_t bootSectorSig1;
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274 | } __attribute__((packed));
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275 | //------------------------------------------------------------------------------
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276 | // End Of Chain values for FAT entries
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277 | /** FAT16 end of chain value used by Microsoft. */
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278 | uint16_t const FAT16EOC = 0XFFFF;
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279 | /** Minimum value for FAT16 EOC. Use to test for EOC. */
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280 | uint16_t const FAT16EOC_MIN = 0XFFF8;
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281 | /** FAT32 end of chain value used by Microsoft. */
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282 | uint32_t const FAT32EOC = 0X0FFFFFFF;
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283 | /** Minimum value for FAT32 EOC. Use to test for EOC. */
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284 | uint32_t const FAT32EOC_MIN = 0X0FFFFFF8;
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285 | /** Mask a for FAT32 entry. Entries are 28 bits. */
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286 | uint32_t const FAT32MASK = 0X0FFFFFFF;
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287 |
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288 | /** Type name for fat32BootSector */
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289 | typedef struct fat32BootSector fbs_t;
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290 | //------------------------------------------------------------------------------
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291 | /**
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292 | * \struct directoryEntry
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293 | * \brief FAT short directory entry
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294 | *
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295 | * Short means short 8.3 name, not the entry size.
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296 | *
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297 | * Date Format. A FAT directory entry date stamp is a 16-bit field that is
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298 | * basically a date relative to the MS-DOS epoch of 01/01/1980. Here is the
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299 | * format (bit 0 is the LSB of the 16-bit word, bit 15 is the MSB of the
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300 | * 16-bit word):
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301 | *
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302 | * Bits 9-15: Count of years from 1980, valid value range 0-127
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303 | * inclusive (1980-2107).
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304 | *
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305 | * Bits 5-8: Month of year, 1 = January, valid value range 1-12 inclusive.
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306 | *
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307 | * Bits 0-4: Day of month, valid value range 1-31 inclusive.
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308 | *
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309 | * Time Format. A FAT directory entry time stamp is a 16-bit field that has
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310 | * a granularity of 2 seconds. Here is the format (bit 0 is the LSB of the
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311 | * 16-bit word, bit 15 is the MSB of the 16-bit word).
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312 | *
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313 | * Bits 11-15: Hours, valid value range 0-23 inclusive.
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314 | *
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315 | * Bits 5-10: Minutes, valid value range 0-59 inclusive.
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316 | *
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317 | * Bits 0-4: 2-second count, valid value range 0-29 inclusive (0 - 58 seconds).
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318 | *
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319 | * The valid time range is from Midnight 00:00:00 to 23:59:58.
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320 | */
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321 | struct directoryEntry {
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322 | /**
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323 | * Short 8.3 name.
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324 | * The first eight bytes contain the file name with blank fill.
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325 | * The last three bytes contain the file extension with blank fill.
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326 | */
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327 | uint8_t name[11];
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328 | /** Entry attributes.
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329 | *
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330 | * The upper two bits of the attribute byte are reserved and should
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331 | * always be set to 0 when a file is created and never modified or
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332 | * looked at after that. See defines that begin with DIR_ATT_.
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333 | */
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334 | uint8_t attributes;
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335 | /**
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336 | * Reserved for use by Windows NT. Set value to 0 when a file is
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337 | * created and never modify or look at it after that.
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338 | */
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339 | uint8_t reservedNT;
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340 | /**
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341 | * The granularity of the seconds part of creationTime is 2 seconds
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342 | * so this field is a count of tenths of a second and its valid
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343 | * value range is 0-199 inclusive. (WHG note - seems to be hundredths)
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344 | */
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345 | uint8_t creationTimeTenths;
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346 | /** Time file was created. */
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347 | uint16_t creationTime;
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348 | /** Date file was created. */
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349 | uint16_t creationDate;
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350 | /**
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351 | * Last access date. Note that there is no last access time, only
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352 | * a date. This is the date of last read or write. In the case of
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353 | * a write, this should be set to the same date as lastWriteDate.
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354 | */
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355 | uint16_t lastAccessDate;
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356 | /**
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357 | * High word of this entry's first cluster number (always 0 for a
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358 | * FAT12 or FAT16 volume).
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359 | */
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360 | uint16_t firstClusterHigh;
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361 | /** Time of last write. File creation is considered a write. */
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362 | uint16_t lastWriteTime;
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363 | /** Date of last write. File creation is considered a write. */
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364 | uint16_t lastWriteDate;
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365 | /** Low word of this entry's first cluster number. */
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366 | uint16_t firstClusterLow;
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367 | /** 32-bit unsigned holding this file's size in bytes. */
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368 | uint32_t fileSize;
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369 | } __attribute__((packed));
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370 | //------------------------------------------------------------------------------
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371 | // Definitions for directory entries
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372 | //
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373 | /** Type name for directoryEntry */
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374 | typedef struct directoryEntry dir_t;
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375 | /** escape for name[0] = 0XE5 */
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376 | uint8_t const DIR_NAME_0XE5 = 0X05;
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377 | /** name[0] value for entry that is free after being "deleted" */
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378 | uint8_t const DIR_NAME_DELETED = 0XE5;
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379 | /** name[0] value for entry that is free and no allocated entries follow */
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380 | uint8_t const DIR_NAME_FREE = 0X00;
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381 | /** file is read-only */
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382 | uint8_t const DIR_ATT_READ_ONLY = 0X01;
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383 | /** File should hidden in directory listings */
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384 | uint8_t const DIR_ATT_HIDDEN = 0X02;
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385 | /** Entry is for a system file */
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386 | uint8_t const DIR_ATT_SYSTEM = 0X04;
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387 | /** Directory entry contains the volume label */
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388 | uint8_t const DIR_ATT_VOLUME_ID = 0X08;
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389 | /** Entry is for a directory */
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390 | uint8_t const DIR_ATT_DIRECTORY = 0X10;
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391 | /** Old DOS archive bit for backup support */
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392 | uint8_t const DIR_ATT_ARCHIVE = 0X20;
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393 | /** Test value for long name entry. Test is
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394 | (d->attributes & DIR_ATT_LONG_NAME_MASK) == DIR_ATT_LONG_NAME. */
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395 | uint8_t const DIR_ATT_LONG_NAME = 0X0F;
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396 | /** Test mask for long name entry */
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397 | uint8_t const DIR_ATT_LONG_NAME_MASK = 0X3F;
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398 | /** defined attribute bits */
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399 | uint8_t const DIR_ATT_DEFINED_BITS = 0X3F;
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400 | /** Directory entry is part of a long name */
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401 | static inline uint8_t DIR_IS_LONG_NAME(const dir_t* dir) {
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402 | return (dir->attributes & DIR_ATT_LONG_NAME_MASK) == DIR_ATT_LONG_NAME;
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403 | }
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404 | /** Mask for file/subdirectory tests */
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405 | uint8_t const DIR_ATT_FILE_TYPE_MASK = (DIR_ATT_VOLUME_ID | DIR_ATT_DIRECTORY);
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406 | /** Directory entry is for a file */
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407 | static inline uint8_t DIR_IS_FILE(const dir_t* dir) {
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408 | return (dir->attributes & DIR_ATT_FILE_TYPE_MASK) == 0;
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409 | }
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410 | /** Directory entry is for a subdirectory */
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411 | static inline uint8_t DIR_IS_SUBDIR(const dir_t* dir) {
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412 | return (dir->attributes & DIR_ATT_FILE_TYPE_MASK) == DIR_ATT_DIRECTORY;
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413 | }
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414 | /** Directory entry is for a file or subdirectory */
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415 | static inline uint8_t DIR_IS_FILE_OR_SUBDIR(const dir_t* dir) {
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416 | return (dir->attributes & DIR_ATT_VOLUME_ID) == 0;
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417 | }
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418 | #endif // FatStructs_h
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