src/main/io/asyncfatfs/fat_standard.c

   1 /*
   2  * This file is part of Cleanflight.
   3  *
   4  * Cleanflight is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Cleanflight is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <ctype.h>
  19
  20 #include "fat_standard.h"
  21
  22 bool fat16_isEndOfChainMarker(uint16_t clusterNumber)
  23 {
  24     return clusterNumber >= 0xFFF8;
  25 }
  26
  27 // Pass the cluster number after fat32_decodeClusterNumber().
  28 bool fat32_isEndOfChainMarker(uint32_t clusterNumber)
  29 {
  30     return clusterNumber >= 0x0FFFFFF8;
  31 }
  32
  33 /**
  34  * FAT32 cluster numbers are really only 28 bits, and the top 4 bits must be left alone and not treated as part of the
  35  * cluster number (so various FAT drivers can use those bits for their own purposes, or they can be used in later
  36  * extensions)
  37  */
  38 uint32_t fat32_decodeClusterNumber(uint32_t clusterNumber)
  39 {
  40     return clusterNumber & 0x0FFFFFFF;
  41 }
  42
  43 // fat32 needs fat32_decodeClusterNumber() applied first.
  44 bool fat_isFreeSpace(uint32_t clusterNumber)
  45 {
  46     return clusterNumber == 0;
  47 }
  48
  49 bool fat_isDirectoryEntryTerminator(fatDirectoryEntry_t *entry)
  50 {
  51     return entry->filename[0] == 0x00;
  52 }
  53
  54 bool fat_isDirectoryEntryEmpty(fatDirectoryEntry_t *entry)
  55 {
  56     return (unsigned char) entry->filename[0] == FAT_DELETED_FILE_MARKER;
  57 }
  58
  59 /**
  60  * Convert the given "prefix.ext" style filename to the FAT format to be stored on disk.
  61  *
  62  * fatFilename must point to a buffer which is FAT_FILENAME_LENGTH bytes long. The buffer is not null-terminated.
  63  */
  64 void fat_convertFilenameToFATStyle(const char *filename, uint8_t *fatFilename)
  65 {
  66     for (int i = 0; i < 8; i++) {
  67         if (*filename == '\0' || *filename == '.') {
  68             *fatFilename = ' ';
  69         } else {
  70             *fatFilename = toupper((unsigned char)*filename);
  71             filename++;
  72         }
  73         fatFilename++;
  74     }
  75
  76     if (*filename == '.') {
  77         filename++;
  78     }
  79
  80     for (int i = 0; i < 3; i++) {
  81          if (*filename == '\0') {
  82              *fatFilename = ' ';
  83          } else {
  84              *fatFilename = toupper((unsigned char)*filename);
  85              filename++;
  86          }
  87          fatFilename++;
  88      }
  89 }