fat12: add ls_callback function

Signed-off-by: Sean Cross <sean@xobs.io>

include/fat12.h

@@ -4,16 +4,28 @@
 #include <stdint.h>
 
 struct fat12_partition;
+struct fat12_dirent {
+    char filename[256];
+    uint32_t first_cluster;
+    uint32_t size;
+    uint32_t file_attributes;
+    uint32_t ctime;
+    uint32_t mtime;
+};
 
 struct fat12_partition * fat12_alloc(void);
 int fat12_open(struct fat12_partition *part, const char *filename);
 int fat12_close(struct fat12_partition *part);
 void fat12_free(struct fat12_partition **part);
 
+int fat12_ls_foreach(struct fat12_partition *part, uint32_t dir_cluster, void *data, int (*callback)(void *data, const struct fat12_dirent *dirent));
+
 void fat12_write_u8(void *ptr, uint8_t val);
 uint8_t fat12_read_u8(void *ptr);
 void fat12_write_u16(void *ptr, uint16_t val);
 uint16_t fat12_read_u16(void *ptr);
+void fat12_write_u32(void *ptr, uint32_t val);
+uint32_t fat12_read_u32(void *ptr);
 void fat12_set_cluster(void *fat, uint32_t cluster, uint32_t value);
 uint32_t fat12_get_cluster(void *fat, uint32_t cluster);
 

src/fat12.c

@@ -50,6 +50,22 @@ uint16_t fat12_read_u16(void *ptr) {
     return val;
 }
 
+void fat12_write_u32(void *ptr, uint32_t val) {
+    ((uint8_t *)ptr)[0] = (val >> 0) & 0xff;
+    ((uint8_t *)ptr)[1] = (val >> 8) & 0xff;
+    ((uint8_t *)ptr)[2] = (val >> 16) & 0xff;
+    ((uint8_t *)ptr)[3] = (val >> 24) & 0xff;
+}
+
+uint32_t fat12_read_u32(void *ptr) {
+    uint16_t val = 0;
+    val |= (((uint8_t *)ptr)[0] << 0)  & 0x000000ff;
+    val |= (((uint8_t *)ptr)[1] << 8)  & 0x0000ff00;
+    val |= (((uint8_t *)ptr)[2] << 16) & 0x00ff0000;
+    val |= (((uint8_t *)ptr)[3] << 24) & 0xff000000;
+    return val;
+}
+
 void fat12_set_cluster(void *fat, uint32_t cluster, uint32_t value) {
     uint32_t offset = (cluster * 3) / 2;
     if (cluster&1) {
@@ -119,6 +135,9 @@ int fat12_open(struct fat12_partition *part, const char *filename) {
     part->cluster_count = bytes / part->sector_size / part->cluster_size;
     part->cluster_bytes = (part->cluster_count * 3) / 2;
 
+    // Move to the root directory
+    part->current_cluster = part->first_offset;
+
 ///
     fprintf(stderr, "part->sector_size: %d\n", part->sector_size);
 
@@ -141,6 +160,53 @@ int fat12_open(struct fat12_partition *part, const char *filename) {
     return 0;
 }
 
+static int fat12_ls_foreach_sector(struct fat12_partition *part, uint32_t sector, uint32_t count,
+                                    void *data, int (*callback)(void *data, const struct fat12_dirent *dirent)) {
+    struct fat12_dirent dirent;
+    uint8_t buf[part->sector_size];
+    uint32_t offset;
+    pang_seek(part->fd, sector * part->sector_size, SEEK_SET);
+    pang_read(part->fd, buf, sizeof(buf));
+
+    for (offset = 0; offset < count; offset++) {
+        struct fat_directory_entry *entry = &((struct fat_directory_entry *)buf)[offset];
+        memset(&dirent, 0, sizeof(dirent));
+        memcpy(dirent.filename, entry->file_name, 8);
+        memcpy(dirent.filename + 8, entry->extension, 3);
+        dirent.first_cluster = fat12_read_u16(&entry->first_cluster);
+        dirent.size = fat12_read_u32(&entry->file_size);
+
+        if ((entry->file_name[0] != 0xe5) && (entry->file_name[0] != 0x00))
+            callback(data, &dirent);
+    }
+    return 0;
+}
+
+int fat12_ls_foreach(struct fat12_partition *part, uint32_t dir_cluster, void *data, int (*callback)(void *data, const struct fat12_dirent *dirent)) {
+    uint32_t sector;
+    if (dir_cluster < 2) {
+        sector = part->root_offset;
+        uint32_t dir_entries;
+        uint32_t max_entries = part->root_entries;
+        uint32_t entries_per_sector = part->sector_size / sizeof(struct fat_directory_entry);
+        uint32_t loop = 0;
+        for (dir_entries = 0; dir_entries < max_entries; dir_entries += entries_per_sector) {
+            uint32_t entries_to_list = entries_per_sector;
+            if (max_entries - dir_entries < entries_to_list)
+                entries_to_list = max_entries - dir_entries;
+            fat12_ls_foreach_sector(part, part->root_offset + loop++, entries_to_list, data, callback);
+        }
+    }
+    else {
+        sector = dir_cluster * part->cluster_size + part->first_offset;
+        while (dir_cluster > 1 && dir_cluster < 0xff0) {
+            // dir_cluster = fat12_get_cluster(part->fd, dir_cluster);
+        }
+    }
+
+    return 0;
+}
+
 int fat12_close(struct fat12_partition *part) {
     if (!part)
         return -1;

tests/fragment-file.c

@@ -25,22 +25,29 @@ static int make_image(const char *name, uint32_t size) {
     return 0;
 }
 
+static int list_directory(void *data, const struct fat12_dirent *dirent) {
+    printf("%d  %d  %x  %d  %d  %s\n", dirent->ctime, dirent->mtime, dirent->file_attributes, dirent->size, dirent->first_cluster, dirent->filename);
+}
+
 int main(int argc, char **argv) {
-    const char *img_name = "build/fat12-1800k.img";
+    // const char *img_name = "build/fat12-1800k.img";
+    const char *img_name = "disk-image";
     int ret = 0;
     int fd;
     struct fat12_partition *part = fat12_alloc();
     
-    ret = make_image(img_name, 1800 * 1024);
-    if (ret == -1) {
-        return 1;
-    }
+    // ret = make_image(img_name, 1800 * 1024);
+    // if (ret == -1) {
+    //     return 1;
+    // }
 
     if (-1 == fat12_open(part, img_name)) {
         fprintf(stderr, "couldn't open fat12 on %s: %s\n", img_name, strerror(errno));
         return 1;
     }
 
+    fat12_ls_foreach(part, 0, NULL, list_directory);
+
     fat12_close(part);
     fat12_free(&part);