104 lines
4.5 KiB
C
104 lines
4.5 KiB
C
/*
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* This file is part of the CircuitPython project, https://github.com/adafruit/circuitpython
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2021 Jeff Epler for Adafruit Industries
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "py/obj.h"
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#include "py/runtime.h"
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#include "shared-bindings/bitops/__init__.h"
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//| """Routines for low-level manipulation of binary data"""
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//|
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//|
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//| def bit_transpose(input: ReadableBuffer, output: WriteableBuffer, width:int = 8) -> WriteableBuffer:
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//| """"Transpose" a buffer by assembling each output byte with bits taken from each of ``width`` different input bytes.
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//|
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//| This can be useful to convert a sequence of pixel values into a single
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//| stream of bytes suitable for sending via a parallel conversion method.
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//|
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//| The number of bytes in the input buffer must be a multiple of the width,
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//| and the width can be any value from 2 to 8. If the width is fewer than 8,
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//| then the remaining (less significant) bits of the output are set to zero.
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//|
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//| Let ``stride = len(input)//width``. Then the first byte is made out of the
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//| most significant bits of ``[input[0], input[stride], input[2*stride], ...]``.
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//| The second byte is made out of the second bits, and so on until the 8th output
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//| byte which is made of the first bits of ``input[1], input[1+stride,
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//| input[2*stride], ...]``.
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//|
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//| The required output buffer size is ``len(input) * 8 // width``.
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//|
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//| Returns the output buffer."""
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//| ...
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STATIC mp_obj_t bit_transpose(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
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enum { ARG_input, ARG_output, ARG_width };
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static const mp_arg_t allowed_args[] = {
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{ MP_QSTR_input, MP_ARG_OBJ | MP_ARG_REQUIRED },
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{ MP_QSTR_output, MP_ARG_OBJ | MP_ARG_REQUIRED },
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{ MP_QSTR_width, MP_ARG_INT, { .u_int = 8 } },
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};
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mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
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mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
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int width = args[ARG_width].u_int;
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if (width < 2 || width > 8) {
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mp_raise_ValueError_varg(translate("width must be from 2 to 8 (inclusive), not %d"), width);
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}
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mp_buffer_info_t input_bufinfo;
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mp_get_buffer_raise(args[ARG_input].u_obj, &input_bufinfo, MP_BUFFER_READ);
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int inlen = input_bufinfo.len;
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if (inlen % width != 0) {
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mp_raise_ValueError_varg(translate("Input buffer length (%d) must be a multiple of the strand count (%d)"), inlen, width);
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}
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mp_buffer_info_t output_bufinfo;
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mp_get_buffer_raise(args[ARG_output].u_obj, &output_bufinfo, MP_BUFFER_WRITE);
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int avail = output_bufinfo.len;
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int outlen = 8 * (inlen / width);
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if (avail < outlen) {
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mp_raise_ValueError_varg(translate("Output buffer must be at least %d bytes"), outlen);
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}
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common_hal_bitops_bit_transpose(output_bufinfo.buf, input_bufinfo.buf, inlen, width);
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return args[ARG_output].u_obj;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitops_bit_transpose_obj, 0, bit_transpose);
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STATIC const mp_rom_map_elem_t bitops_module_globals_table[] = {
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{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_bitops) },
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{ MP_ROM_QSTR(MP_QSTR_bit_transpose), MP_ROM_PTR(&bitops_bit_transpose_obj) },
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};
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STATIC MP_DEFINE_CONST_DICT(bitops_module_globals, bitops_module_globals_table);
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const mp_obj_module_t bitops_module = {
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.base = { &mp_type_module },
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.globals = (mp_obj_dict_t *)&bitops_module_globals,
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};
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MP_REGISTER_MODULE(MP_QSTR_bitops, bitops_module, CIRCUITPY_BITOPS);
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