From de20d7430df08731d9108acb83e1234ba7f1fe16 Mon Sep 17 00:00:00 2001
From: Benji Dial <benji6283@gmail.com>
Date: Sat, 19 Sep 2020 14:53:29 -0400
Subject: file manager

---
 src/kernel/fat.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

(limited to 'src/kernel/fat.c')

diff --git a/src/kernel/fat.c b/src/kernel/fat.c
index c4461de..362539c 100644
--- a/src/kernel/fat.c
+++ b/src/kernel/fat.c
@@ -365,6 +365,72 @@ static uint32_t fat_enumerate_dir(const struct drive *d, const char *path, struc
   }
 }
 
+static uint32_t n_root_entries(const struct drive *d) {
+  uint32_t sect = infos[d->drive_id].root_start - 1;
+  struct directory_entry *entry = (struct directory_entry *)(fat_driver_buffer + 512);
+
+  uint32_t count = 0;
+
+  while (true) {
+    if (entry == (struct directory_entry *)(fat_driver_buffer + 512)) {
+      entry = (struct directory_entry *)fat_driver_buffer;
+      ++sect;
+      d->read_sectors(d, sect, 1, entry);
+    }
+
+    if (!*(uint8_t *)entry) {
+      d->done(d);
+      return count;
+    }
+
+    if (entry-> attrib & FA_LABEL) {
+      ++entry;
+      continue;
+    }
+
+    ++entry;
+    ++count;
+  }
+}
+
+static uint32_t fat_n_dir_entries(const struct drive *d, const char *path) {
+  d->ready(d);
+
+  if (!*path)
+    return n_root_entries(d);
+
+  if (!try_load_from_path(d, path)) {
+    d->done(d);
+    return 0;
+  }
+
+  uint16_t cluster = cur_dir->first_cluster;
+  load_cluster(cluster, fat_driver_buffer);
+  struct directory_entry *entry = (struct directory_entry *)fat_driver_buffer;
+
+  uint32_t count = 0;
+
+  while (true) {
+    if (entry == (struct directory_entry *)(fat_driver_buffer + 512)) {
+      entry = (struct directory_entry *)fat_driver_buffer;
+      load_cluster(cluster = next_cluster(cluster), fat_driver_buffer);
+    }
+
+    if (!*(uint8_t *)entry) {
+      d->done(d);
+      return count;
+    }
+
+    if (check_fat_names(entry->name, this_dir) || check_fat_names(entry->name, parent_dir)) {
+      ++entry;
+      continue;
+    }
+
+    ++entry;
+    ++count;
+  }
+}
+
 void init_fat() {
   next_fi = allocate_kernel_pages(1);
   next_id = 0;
@@ -388,6 +454,7 @@ bool try_fat_init_drive(struct drive *d) {
   d->load_sector = &fat_load_sector;
   d->get_file_length = &fat_get_file_length;
   d->enumerate_dir = &fat_enumerate_dir;
+  d->n_dir_entries = &fat_n_dir_entries;
   d->get_free_sectors = &fat_get_free_sectors;
 
   d->fs_id = next_id;
-- 
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