diff options
Diffstat (limited to 'extmod')
| -rw-r--r-- | extmod/vfs_fat_file.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/extmod/vfs_fat_file.c b/extmod/vfs_fat_file.c index 75fa2fbd4..1b2bb27f8 100644 --- a/extmod/vfs_fat_file.c +++ b/extmod/vfs_fat_file.c @@ -197,6 +197,23 @@ STATIC mp_obj_t file_open(fs_user_mount_t *vfs, const mp_obj_type_t *type, mp_ar m_del_obj(pyb_file_obj_t, o); mp_raise_OSError(fresult_to_errno_table[res]); } + // If we're reading, turn on fast seek. + if (mode == FA_READ) { + // one call to determine how much space we need. + DWORD temp_table[2]; + temp_table[0] = 2; + o->fp.cltbl = temp_table; + f_lseek(&o->fp, CREATE_LINKMAP); + DWORD size = (temp_table[0] + 1) * 2; + o->fp.cltbl = m_malloc_maybe(size * sizeof(DWORD), false); + if (o->fp.cltbl != NULL) { + o->fp.cltbl[0] = size; + res = f_lseek(&o->fp, CREATE_LINKMAP); + if (res != FR_OK) { + o->fp.cltbl = NULL; + } + } + } // for 'a' mode, we must begin at the end of the file if ((mode & FA_OPEN_ALWAYS) != 0) { |