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add modtrezorutils

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Contains a memcpy helper for zero-cost copying between two buffers (bytearray or memoryview).
This commit is contained in:
Jan Pochyla 2016-10-11 17:09:35 +02:00
parent 9e3102742e
commit 39c2766ae0
1 changed files with 70 additions and 0 deletions
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extmod/modtrezorutils/modtrezorutils.c Normal file
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/*
* Copyright (c) Jan Pochyla, SatoshiLabs
*
* Licensed under TREZOR License
* see LICENSE file for details
*/
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include "py/nlr.h"
#include "py/runtime.h"
#include "py/binary.h"
#include "py/objstr.h"
#if MICROPY_PY_TREZORUTILS
/// def trezor.utils.memcpy(dst: bytearray, dst_ofs: int,
/// src: bytearray, src_ofs: int,
// n: int) -> int:
/// '''
/// Copies at most `n` bytes from `src` at offset `src_ofs` to
/// `dst` at offset `dst_ofs`. Returns the number of actually
/// copied bytes.
/// '''
STATIC mp_obj_t mod_TrezorUtils_memcpy(size_t n_args, const mp_obj_t *args) {
mp_arg_check_num(n_args, 0, 5, 5, false);
mp_buffer_info_t dst;
mp_get_buffer_raise(args[0], &dst, MP_BUFFER_WRITE);
int dst_ofs = mp_obj_get_int(args[1]);
if (dst_ofs < 0) {
mp_raise_ValueError("Invalid dst offset (has to be >= 0)");
}
mp_buffer_info_t src;
mp_get_buffer_raise(args[2], &src, MP_BUFFER_READ);
int src_ofs = mp_obj_get_int(args[3]);
if (src_ofs < 0) {
mp_raise_ValueError("Invalid src offset (has to be >= 0)");
}
int n = mp_obj_get_int(args[4]);
if (n < 0) {
mp_raise_ValueError("Invalid byte count (has to be >= 0)");
}
size_t dst_rem = (dst_ofs < dst.len) ? dst.len - dst_ofs : 0;
size_t src_rem = (src_ofs < src.len) ? src.len - src_ofs : 0;
size_t ncpy = MIN(n, MIN(src_rem, dst_rem));
memmove(((char*)dst.buf) + dst_ofs, ((const char*)src.buf) + src_ofs, ncpy);
return mp_obj_new_int(ncpy);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_TrezorUtils_memcpy_obj, 5, 5, mod_TrezorUtils_memcpy);
STATIC const mp_rom_map_elem_t mp_module_TrezorUtils_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_TrezorUtils) },
{ MP_ROM_QSTR(MP_QSTR_memcpy), MP_ROM_PTR(&mod_TrezorUtils_memcpy_obj) },
};
STATIC MP_DEFINE_CONST_DICT(mp_module_TrezorUtils_globals, mp_module_TrezorUtils_globals_table);
const mp_obj_module_t mp_module_TrezorUtils = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t*)&mp_module_TrezorUtils_globals,
};
#endif // MICROPY_PY_TREZORUTILS