circuitpython/extmod/vfs_reader.c

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2020-06-03 18:40:05 -04:00
// 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) {
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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) {
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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 arg = mp_obj_new_str(filename, strlen(filename));
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rf->file = mp_vfs_open(1, &arg, (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