sd-reader_source_20081121.zip

/* * Copyright (c) 2006-2008 by Roland Riegel <feedback@roland-riegel.de> * * This file is free software; you can redistribute it and/or modify * it under the terms of either the GNU General Public License version 2 * or the GNU Lesser General Public License version 2.1, both as * published by the Free Software Foundation. */ #include "byteordering.h" #include "partition.h" #include "fat.h" #include "fat_config.h" #include "sd-reader_config.h" #include <string.h> #if USE_DYNAMIC_MEMORY #include <stdlib.h> #endif /** * \addtogroup fat FAT support * * This module implements FAT16/FAT32 read and write access. * * The following features are supported: * - File names up to 31 characters long. * - Unlimited depth of subdirectories. * - Short 8.3 and long filenames. * - Creating and deleting files. * - Reading and writing from and to files. * - File resizing. * - File sizes of up to 4 gigabytes. * * @{ */ /** * \file * FAT implementation (license: GPLv2 or LGPLv2.1) * * \author Roland Riegel */ /** * \addtogroup fat_config FAT configuration * Preprocessor defines to configure the FAT implementation. */ /** * \addtogroup fat_fs FAT access * Basic functions for handling a FAT filesystem. */ /** * \addtogroup fat_file FAT file functions * Functions for managing files. */ /** * \addtogroup fat_dir FAT directory functions * Functions for managing directories. */ /** * @} */ #define FAT16_CLUSTER_FREE 0x0000 #define FAT16_CLUSTER_RESERVED_MIN 0xfff0 #define FAT16_CLUSTER_RESERVED_MAX 0xfff6 #define FAT16_CLUSTER_BAD 0xfff7 #define FAT16_CLUSTER_LAST_MIN 0xfff8 #define FAT16_CLUSTER_LAST_MAX 0xffff #define FAT32_CLUSTER_FREE 0x00000000 #define FAT32_CLUSTER_RESERVED_MIN 0x0ffffff0 #define FAT32_CLUSTER_RESERVED_MAX 0x0ffffff6 #define FAT32_CLUSTER_BAD 0x0ffffff7 #define FAT32_CLUSTER_LAST_MIN 0x0ffffff8 #define FAT32_CLUSTER_LAST_MAX 0x0fffffff #define FAT_DIRENTRY_DELETED 0xe5 #define FAT_DIRENTRY_LFNLAST (1 << 6) #define FAT_DIRENTRY_LFNSEQMASK ((1 << 6) - 1) /* Each entry within the directory table has a size of 32 bytes * and either contains a 8.3 DOS-style file name or a part of a * long file name, which may consist of several directory table * entries at once. * * multi-byte integer values are stored little-endian! * * 8.3 file name entry: * ==================== * offset length description * 0 8 name (space padded) * 8 3 extension (space padded) * 11 1 attributes (FAT_ATTRIB_*) * * long file name (lfn) entry ordering for a single file name: * =========================================================== * LFN entry n * ... * LFN entry 2 * LFN entry 1 * 8.3 entry (see above) * * lfn entry: * ========== * offset length description * 0 1 ordinal field * 1 2 unicode character 1 * 3 3 unicode character 2 * 5 3 unicode character 3 * 7 3 unicode character 4 * 9 3 unicode character 5 * 11 1 attribute (always 0x0f) * 12 1 type (reserved, always 0) * 13 1 checksum * 14 2 unicode character 6 * 16 2 unicode character 7 * 18 2 unicode character 8 * 20 2 unicode character 9 * 22 2 unicode character 10 * 24 2 unicode character 11 * 26 2 cluster (unused, always 0) * 28 2 unicode character 12 * 30 2 unicode character 13 * * The ordinal field contains a descending number, from n to 1. * For the n'th lfn entry the ordinal field is or'ed with 0x40. * For deleted lfn entries, the ordinal field is set to 0xe5. */ struct fat_header_struct { offset_t size; offset_t fat_offset; uint32_t fat_size; uint16_t sector_size; uint16_t cluster_size; offset_t cluster_zero_offset; offset_t root_dir_offset; #if FAT_FAT32_SUPPORT cluster_t root_dir_cluster; #endif }; struct fat_fs_struct { struct partition_struct* partition; struct fat_header_struct header; }; struct fat_file_struct { struct fat_fs_struct* fs; struct fat_dir_entry_struct dir_entry; offset_t pos; cluster_t pos_cluster; }; struct fat_dir_struct { struct fat_fs_struct* fs; struct fat_dir_entry_struct dir_entry; cluster_t entry_cluster; uint16_t entry_offset; }; struct fat_read_dir_callback_arg { struct fat_dir_entry_struct* dir_entry; uintptr_t bytes_read; uint8_t finished; }; struct fat_usage_count_callback_arg { cluster_t cluster_count; uintptr_t buffer_size; }; #if !USE_DYNAMIC_MEMORY static struct fat_fs_struct fat_fs_handles[FAT_FS_COUNT]; static struct fat_file_struct fat_file_handles[FAT_FILE_COUNT]; static struct fat_dir_struct fat_dir_handles[FAT_DIR_COUNT]; #endif static uint8_t fat_read_header(struct fat_fs_struct* fs); static cluster_t fat_get_next_cluster(const struct fat_fs_struct* fs, cluster_t cluster_num); static offset_t fat_cluster_offset(const struct fat_fs_struct* fs, cluster_t cluster_num); static uint8_t fat_dir_entry_read_callback(uint8_t* buffer, offset_t offset, void* p); static uint8_t fat_interpret_dir_entry(struct fat_dir_entry_struct* dir_entry, const uint8_t* raw_entry); static uint8_t fat_get_fs_free_16_callback(uint8_t* buffer, offset_t offset, void* p); #if FAT_FAT32_SUPPORT static uint8_t fat_get_fs_free_32_callback(uint8_t* buffer, offset_t offset, void* p); #endif #if FAT_WRITE_SUPPORT static cluster_t fat_append_clusters(const struct fat_fs_struct* fs, cluster_t cluster_num, cluster_t count); static uint8_t fat_free_clusters(const struct fat_fs_struct* fs, cluster_t cluster_num); static uint8_t fat_terminate_clusters(const struct fat_fs_struct* fs, cluster_t cluster_num); static uint8_t fat_clear_cluster(const struct fat_fs_struct* fs, cluster_t cluster_num); static uintptr_t fat_clear_cluster_callback(uint8_t* buffer, offset_t offset, void* p); static offset_t fat_find_offset_for_dir_entry(const struct fat_fs_struct* fs, const struct fat_dir_struct* parent, const struct fat_dir_entry_struct* dir_entry); static uint8_t fat_write_dir_entry(const struct fat_fs_struct* fs, struct fat_dir_entry_struct* dir_entry); #if FAT_DATETIME_SUPPORT static void fat_set_file_modification_date(struct fat_dir_entry_struct* dir_entry, uint16_t year, uint8_t month, uint8_t day); static void fat_set_file_modification_time(struct fat_dir_entry_struct* dir_entry, uint8_t hour, uint8_t min, uint8_t sec); #endif #endif /** * \ingroup fat_fs * Opens a FAT filesystem. * * \param[in] partition Discriptor of partition on which the filesystem resides. * \returns 0 on error, a FAT filesystem descriptor on success. * \see fat_close */ struct fat_fs_struct* fat_open(struct partition_struct* partition) { if(!partition || #if FAT_WRITE_SUPPORT !partition->device_write || !partition->device_write_interval #else 0 #endif ) return 0; #if USE_DYNAMIC_MEMORY struct fat_fs_struct* fs = malloc(sizeof(*fs)); if(!fs) return 0; #else struct fat_fs_struct* fs = fat_fs_handles; uint8_t i; for(i = 0; i < FAT_FS_COUNT; ++i) { if(!fs->partition) break; ++fs; } if(i >= FAT_FS_COUNT) return 0; #endif memset(fs, 0, sizeof(*fs)); fs->partition = partition; if(!fat_read_header(fs)) { #if USE_DYNAMIC_MEMORY free(fs); #else fs->partition = 0; #endif return 0; } return fs; } /** * \ingroup fat_fs * Closes a FAT filesystem. * * When this function returns, the given filesystem descriptor * will be invalid. * * \param[in] fs The filesystem to close. * \see fat_open */ void fat_close(struct fat_fs_struct* fs) { if(!fs) return; #if USE_DYNAMIC_MEMORY free(fs); #else fs->partition = 0; #endif } /** * \ingroup fat_fs * Reads and parses the header of a FAT filesystem. * * \param[inout] fs The