Improved comments and moved internal stuff to special header file

fat16.c

@@ -706,13 +706,13 @@ void fat16_first(FAT16_FILE* file)
 
 
 /** Open a directory denoted by the file. */
-bool fat16_opendir(FAT16_FILE* file)
+bool fat16_opendir(FAT16_FILE* dir)
 {
 	// Don't open non-dirs and "." directory.
-	if (!(file->attribs & FA_DIR) || file->type == FT_SELF)
+	if (!(dir->attribs & FA_DIR) || dir->type == FT_SELF)
 		return false;
 
-	open_file(file->fat, file, file->clu_start, 0);
+	open_file(dir->fat, dir, dir->clu_start, 0);
 	return true;
 }
 

fat16.h

@@ -1,6 +1,10 @@
 #pragma once
 
-/** Abstract block device interface */
+/**
+ * Abstract block device interface
+ *
+ * Populate this with pointers to your I/O functions.
+ */
 typedef struct
 {
 	// Sequential read
@@ -20,7 +24,10 @@ typedef struct
 
 // -------------------------------
 
-/** file types (values don't matter) */
+/**
+ * File types (values can be used for debug printing).
+ * Accessible using file->type
+ */
 typedef enum
 {
 	FT_NONE = '-',
@@ -29,102 +36,73 @@ typedef enum
 	FT_PARENT = 'P',
 	FT_LABEL = 'L',
 	FT_LFN = '~',
-	FT_INVALID = 'i', // not recognized weird file
+	FT_INVALID = '?', // not recognized weird file
 	FT_SELF = '.',
 	FT_FILE = 'F'
 } FAT16_FT;
 
 
-// File Attributes (bit flags)
+// Include definitions of fully internal structs
-#define FA_READONLY 0x01 // read only file
+#include "fat16_internal.h"
-#define FA_HIDDEN   0x02 // hidden file
-#define FA_SYSTEM   0x04 // system file
-#define FA_LABEL    0x08 // volume label entry, found only in root directory.
-#define FA_DIR      0x10 // subdirectory
-#define FA_ARCHIVE  0x20 // archive flag
-
-
-/** Boot Sector structure - INTERNAL! */
-typedef struct __attribute__((packed))
-{
-
-	// Fields loaded directly from disk:
 
-	// 13 bytes skipped
-	uint8_t sectors_per_cluster;
-	uint16_t reserved_sectors;
-	uint8_t num_fats;
-	uint16_t root_entries;
-	// 3 bytes skipped
-	uint16_t fat_size_sectors;
-	// 8 bytes skipped
-	uint32_t total_sectors; // if "short size sectors" is used, it's copied here too
-	// 7 bytes skipped
-	char volume_label[11]; // space padded, no terminator
 
-	// Added fields:
+/**
-
+ * File handle struct.
-	uint32_t bytes_per_cluster;
+ *
-
+ * File handle contains cursor, file name, type, size etc.
-}
+ * Everything (files, dirs) is accessed using this.
-Fat16BootSector;
+ */
-
-
-/** FAT filesystem handle - private fields! */
 typedef struct __attribute__((packed))
 {
-	// Backing block device
+	/**
-	const BLOCKDEV* dev;
+	 * Raw file name. Starting 0x05 was converted to 0xE5.
-
+	 * To get PRINTABLE file name, use fat16_dispname()
-	// Root directory sector start
+	 */
-	uint32_t rd_addr;
+	uint8_t name[11];
-
-	// Start of first cluster (number "2")
-	uint32_t data_addr;
-
-	// Start of fat table
-	uint32_t fat_addr;
-
-	// Boot sector data struct
-	Fat16BootSector bs;
-}
-FAT16;
 
+	/**
+	 * File attributes - bit field composed of FA_* flags
+	 * (internal)
+	 */
+	uint8_t attribs;
 
-/** File handle struct */
+	// 14 bytes skipped (10 reserved, date, time)
-typedef struct __attribute__((packed))
-{
-	// Fields loaded directly from disk:
 
-	uint8_t name[11]; // Starting 0x05 converted to 0xE5, other "magic chars" left intact
+	/** First cluster of the file. (internal) */
-	uint8_t attribs; // composed of FA_* constants
-	// 14 bytes skipped
 	uint16_t clu_start;
+
+	/**
+	 * File size in bytes.
+	 * This is the current allocated and readable file size.
+	 */
 	uint32_t size;
 
-	// Added fields:
 
+	// --- the following fields are added when reading ---
+
+	/** File type. */
 	FAT16_FT type;
 
-	// --- Private fields ---
 
-	// Cursor
+	// --- INTERNAL FIELDS ---
+
+	// Cursor variables. (internal)
 	uint32_t cur_abs; // absolute position in device
 	uint32_t cur_rel; // relative position in file
 	uint16_t cur_clu; // cluster where the cursor is
 	uint16_t cur_ofs; // offset within the active cluster
 
-	// File position in the directory
+	// File position in the directory. (internal)
 	uint16_t clu; // first cluster of directory
-	uint16_t num; // fiel entry number
+	uint16_t num; // file entry number
 
-	// pointer to FAT
+	// Pointer to the FAT16 handle. (internal)
 	const FAT16* fat;
 }
 FAT16_FILE;
 
 
-/** Initialize a filesystem */
+/** Initialize the file system - store into "fat" */
 void fat16_init(const BLOCKDEV* dev, FAT16* fat);
 
 
@@ -132,14 +110,13 @@ void fat16_init(const BLOCKDEV* dev, FAT16* fat);
  * Open the first file of the root directory.
  * The file may be invalid (eg. a volume label, deleted etc),
  * or blank (type FT_NONE) if the filesystem is empty.
- *
- * Either way, the prev and next functions will work as expected.
  */
 void fat16_root(const FAT16* fat, FAT16_FILE* file);
 
 
 /**
  * Resolve the disk label.
+ * That can be in the Boot Sector, or in the first root directory entry.
  */
 char* fat16_disk_label(const FAT16* fat, char* label_out);
 
@@ -185,29 +162,29 @@ bool fat16_mkdir(FAT16_FILE* file, const char* name);
 
 
 /**
- * Write new file size (also to the disk).
+ * Set new file size.
- * Allocates / frees needed clusters, does not erase them.
+ * Allocates / frees needed clusters, does NOT erase them.
+ *
+ * Useful mainly for shrinking.
  */
 void fat16_resize(FAT16_FILE* file, uint32_t size);
 
 
 /**
- * Delete a file entry and free clusters.
+ * Delete a *FILE* and free it's clusters.
- * Does NOT work on folders.
  */
 bool fat16_rmfile(FAT16_FILE* file);
 
 
 /**
- * Delete an empty directory.
+ * Delete an empty *DIRECTORY* and free it's clusters.
- * Calling with non-subfolder entry or non-empty directory will cause error.
  */
 bool fat16_rmdir(FAT16_FILE* file);
 
 
 /**
- * Delete a file or directory, regardless of type.
+ * Delete a file or directory, even FT_LFN and FT_INVALID.
- * Directories are deleted recursively.
+ * Directories are deleted recursively (!)
  */
 bool fat16_delete(FAT16_FILE* file);
 
@@ -226,17 +203,19 @@ bool fat16_next(FAT16_FILE* file);
 
 /**
  * Open a subdirectory denoted by the file.
- * Provided handle changes to first entry of the directory.
+ * Provided handle changes to the first entry of the directory.
  */
-bool fat16_opendir(FAT16_FILE* file);
+bool fat16_opendir(FAT16_FILE* dir);
+
 
 /**
  * Open a parent directory. Fails in root.
+ * Provided handle changes to the first entry of the parent directory.
  */
 bool fat16_parent(FAT16_FILE* file);
 
 
-/** Rewind to first file in directory */
+/** Jump to first file in this directory */
 void fat16_first(FAT16_FILE* file);
 
 

fat16_internal.h

@@ -0,0 +1,62 @@
+#pragma once
+
+// Internal types and stuff that is needed in the header for declarations,
+// but is not a part of the public API.
+
+/** Boot Sector structure */
+typedef struct __attribute__((packed))
+{
+
+	// Fields loaded directly from disk:
+
+	// 13 bytes skipped
+	uint8_t sectors_per_cluster;
+	uint16_t reserved_sectors;
+	uint8_t num_fats;
+	uint16_t root_entries;
+	// 3 bytes skipped
+	uint16_t fat_size_sectors;
+	// 8 bytes skipped
+	uint32_t total_sectors; // if "short size sectors" is used, it's copied here too
+	// 7 bytes skipped
+	char volume_label[11]; // space padded, no terminator
+
+	// Added fields:
+
+	uint32_t bytes_per_cluster;
+
+}
+Fat16BootSector;
+
+
+/** FAT filesystem handle */
+typedef struct __attribute__((packed))
+{
+	// Backing block device
+	const BLOCKDEV* dev;
+
+	// Root directory sector start
+	uint32_t rd_addr;
+
+	// Start of first cluster (number "2")
+	uint32_t data_addr;
+
+	// Start of fat table
+	uint32_t fat_addr;
+
+	// Boot sector data struct
+	Fat16BootSector bs;
+}
+FAT16;
+
+
+/**
+ * File Attributes (bit flags)
+ * Accessible using file->attribs
+ */
+#define FA_READONLY 0x01 // read only file
+#define FA_HIDDEN   0x02 // hidden file
+#define FA_SYSTEM   0x04 // system file
+#define FA_LABEL    0x08 // volume label entry, found only in root directory.
+#define FA_DIR      0x10 // subdirectory
+#define FA_ARCHIVE  0x20 // archive flag