mirror of
https://github.com/trezor/trezor-firmware.git
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39c2766ae0
Contains a memcpy helper for zero-cost copying between two buffers (bytearray or memoryview).
71 lines
2.2 KiB
C
71 lines
2.2 KiB
C
/*
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* Copyright (c) Jan Pochyla, SatoshiLabs
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*
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* Licensed under TREZOR License
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* see LICENSE file for details
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*/
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#include <stdio.h>
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#include <string.h>
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#include <stdint.h>
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#include "py/nlr.h"
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#include "py/runtime.h"
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#include "py/binary.h"
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#include "py/objstr.h"
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#if MICROPY_PY_TREZORUTILS
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/// def trezor.utils.memcpy(dst: bytearray, dst_ofs: int,
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/// src: bytearray, src_ofs: int,
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// n: int) -> int:
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/// '''
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/// Copies at most `n` bytes from `src` at offset `src_ofs` to
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/// `dst` at offset `dst_ofs`. Returns the number of actually
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/// copied bytes.
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/// '''
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STATIC mp_obj_t mod_TrezorUtils_memcpy(size_t n_args, const mp_obj_t *args) {
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mp_arg_check_num(n_args, 0, 5, 5, false);
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mp_buffer_info_t dst;
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mp_get_buffer_raise(args[0], &dst, MP_BUFFER_WRITE);
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int dst_ofs = mp_obj_get_int(args[1]);
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if (dst_ofs < 0) {
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mp_raise_ValueError("Invalid dst offset (has to be >= 0)");
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}
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mp_buffer_info_t src;
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mp_get_buffer_raise(args[2], &src, MP_BUFFER_READ);
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int src_ofs = mp_obj_get_int(args[3]);
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if (src_ofs < 0) {
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mp_raise_ValueError("Invalid src offset (has to be >= 0)");
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}
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int n = mp_obj_get_int(args[4]);
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if (n < 0) {
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mp_raise_ValueError("Invalid byte count (has to be >= 0)");
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}
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size_t dst_rem = (dst_ofs < dst.len) ? dst.len - dst_ofs : 0;
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size_t src_rem = (src_ofs < src.len) ? src.len - src_ofs : 0;
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size_t ncpy = MIN(n, MIN(src_rem, dst_rem));
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memmove(((char*)dst.buf) + dst_ofs, ((const char*)src.buf) + src_ofs, ncpy);
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return mp_obj_new_int(ncpy);
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_TrezorUtils_memcpy_obj, 5, 5, mod_TrezorUtils_memcpy);
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STATIC const mp_rom_map_elem_t mp_module_TrezorUtils_globals_table[] = {
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{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_TrezorUtils) },
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{ MP_ROM_QSTR(MP_QSTR_memcpy), MP_ROM_PTR(&mod_TrezorUtils_memcpy_obj) },
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};
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STATIC MP_DEFINE_CONST_DICT(mp_module_TrezorUtils_globals, mp_module_TrezorUtils_globals_table);
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const mp_obj_module_t mp_module_TrezorUtils = {
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.base = { &mp_type_module },
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.globals = (mp_obj_dict_t*)&mp_module_TrezorUtils_globals,
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};
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#endif // MICROPY_PY_TREZORUTILS
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