add circuitpython code

1 files changed, 69 insertions, 0 deletions

diff --git a/circuitpython/extmod/vfs_reader.c b/circuitpython/extmod/vfs_reader.c
new file mode 100644
index 0000000..c87fcd7
--- /dev/null
+++ b/circuitpython/extmod/vfs_reader.c
@@ -0,0 +1,69 @@
+// SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
+// SPDX-FileCopyrightText: Copyright (c) 2013-2017 Damien P. George
+//
+// SPDX-License-Identifier: MIT
+
+#include <stdio.h>
+#include <string.h>
+
+#include "py/runtime.h"
+#include "py/stream.h"
+#include "py/reader.h"
+#include "extmod/vfs.h"
+
+#if MICROPY_READER_VFS
+
+typedef struct _mp_reader_vfs_t {
+    mp_obj_t file;
+    uint16_t len;
+    uint16_t pos;
+    byte buf[24];
+} mp_reader_vfs_t;
+
+STATIC mp_uint_t mp_reader_vfs_readbyte(void *data) {
+    mp_reader_vfs_t *reader = (mp_reader_vfs_t *)data;
+    if (reader->pos >= reader->len) {
+        if (reader->len < sizeof(reader->buf)) {
+            return MP_READER_EOF;
+        } else {
+            int errcode;
+            reader->len = mp_stream_rw(reader->file, reader->buf, sizeof(reader->buf),
+                &errcode, MP_STREAM_RW_READ | MP_STREAM_RW_ONCE);
+            if (errcode != 0) {
+                // TODO handle errors properly
+                return MP_READER_EOF;
+            }
+            if (reader->len == 0) {
+                return MP_READER_EOF;
+            }
+            reader->pos = 0;
+        }
+    }
+    return reader->buf[reader->pos++];
+}
+
+STATIC void mp_reader_vfs_close(void *data) {
+    mp_reader_vfs_t *reader = (mp_reader_vfs_t *)data;
+    mp_stream_close(reader->file);
+    m_del_obj(mp_reader_vfs_t, reader);
+}
+
+void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
+    mp_reader_vfs_t *rf = m_new_obj(mp_reader_vfs_t);
+    mp_obj_t args[2] = {
+        mp_obj_new_str(filename, strlen(filename)),
+        MP_OBJ_NEW_QSTR(MP_QSTR_rb),
+    };
+    rf->file = mp_vfs_open(MP_ARRAY_SIZE(args), &args[0], (mp_map_t *)&mp_const_empty_map);
+    int errcode;
+    rf->len = mp_stream_rw(rf->file, rf->buf, sizeof(rf->buf), &errcode, MP_STREAM_RW_READ | MP_STREAM_RW_ONCE);
+    if (errcode != 0) {
+        mp_raise_OSError(errcode);
+    }
+    rf->pos = 0;
+    reader->data = rf;
+    reader->readbyte = mp_reader_vfs_readbyte;
+    reader->close = mp_reader_vfs_close;
+}
+
+#endif // MICROPY_READER_VFS