Add different seek modes

1 files changed, 19 insertions, 2 deletions

diff --git a/src/filesystem.c b/src/filesystem.c
index 3fe95ab..327b613 100644
--- a/src/filesystem.c
+++ b/src/filesystem.c
@@ -274,10 +274,27 @@ _fs_write_to_block(u8 *src, u16 n_bytes, u16 blk_offset,
     _fs_write(&block, block_pos, sizeof(FileBlock));
 }
 
+typedef enum {
+    FS_SEEK_SET,
+    FS_SEEK_CUR,
+    FS_SEEK_END,
+} SeekMode;
+
 int
-fs_seek(File *file, int offset) {
+fs_seek(File *file, int offset, SeekMode mode) {
     u16 file_size = fs_file_size(file);
-    u16 new_offset = MAX((int)file->offset + offset, 0);
+    u16 new_offset = 0;
+    switch (mode) {
+        case FS_SEEK_SET: {
+            new_offset = offset;
+        } break;
+        case FS_SEEK_CUR: {
+            new_offset = MAX((int)file->offset + offset, 0);
+        } break;
+        case FS_SEEK_END: {
+            new_offset = MAX((int)file_size - 1 + offset, 0);
+        } break;
+    }
     if (new_offset >= file_size) {
         return -1;
     }