mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
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103 lines
3.8 KiB
C++
103 lines
3.8 KiB
C++
/*
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* Copyright (C) 2023 Mark Thompson
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#include "io_convert.hpp"
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#include "complex.hpp"
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namespace fs = std::filesystem;
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static const fs::path c8_ext = u".C8";
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namespace file_convert {
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// Convert buffer contents from c16 to c8.
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// Same buffer used for input & output; input size is bytes; output size is bytes/2.
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void c16_to_c8(const void* buffer, File::Size bytes) {
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complex16_t* src = (complex16_t*)buffer;
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complex8_t* dest = (complex8_t*)buffer;
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// Shift isn't used here because it would amplify noise at center freq since it's a signed number
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// i.e. ((-1 >> 8) << 8) = -256, whereas (-1 / 256) * 256 = 0
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for (File::Size i = 0; i < bytes / sizeof(complex16_t); i++) {
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auto re_out = src[i].real() / 256;
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auto im_out = src[i].imag() / 256;
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dest[i] = {(int8_t)re_out, (int8_t)im_out};
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}
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}
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// Convert c8 buffer to c16 buffer.
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// Same buffer used for input & output; input size is bytes; output size is 2*bytes.
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void c8_to_c16(const void* buffer, File::Size bytes) {
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complex8_t* src = (complex8_t*)buffer;
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complex16_t* dest = (complex16_t*)buffer;
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uint32_t i = bytes / sizeof(complex8_t);
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if (i != 0) {
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do {
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i--;
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auto re_out = (int16_t)src[i].real() * 256; // C8 to C16 conversion;
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auto im_out = (int16_t)src[i].imag() * 256; // Can't shift signed numbers left, so using multiply
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dest[i] = {(int16_t)re_out, (int16_t)im_out};
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} while (i != 0);
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}
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}
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} /* namespace file_convert */
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// Automatically enables C8/C16 conversion based on file extension
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Optional<File::Error> FileConvertReader::open(const std::filesystem::path& filename) {
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convert_c8_to_c16 = path_iequal(filename.extension(), c8_ext);
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return file_.open(filename);
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}
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// If C8 conversion enabled, half the number of bytes are read from the file & expanded to fill the whole buffer.
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File::Result<File::Size> FileConvertReader::read(void* const buffer, const File::Size bytes) {
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auto read_result = file_.read(buffer, convert_c8_to_c16 ? bytes / 2 : bytes);
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if (read_result.is_ok()) {
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if (convert_c8_to_c16) {
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file_convert::c8_to_c16(buffer, read_result.value());
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read_result = read_result.value() * 2;
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}
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bytes_read_ += read_result.value();
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}
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return read_result;
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}
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// Automatically enables C8/C16 conversion based on file extension
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Optional<File::Error> FileConvertWriter::create(const std::filesystem::path& filename) {
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convert_c16_to_c8 = path_iequal(filename.extension(), c8_ext);
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return file_.create(filename);
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}
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// If C8 conversion is enabled, half the number of bytes are written to the file.
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File::Result<File::Size> FileConvertWriter::write(const void* const buffer, const File::Size bytes) {
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if (convert_c16_to_c8) {
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file_convert::c16_to_c8(buffer, bytes);
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}
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auto write_result = file_.write(buffer, convert_c16_to_c8 ? bytes / 2 : bytes);
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if (write_result.is_ok()) {
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if (convert_c16_to_c8) {
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write_result = write_result.value() * 2;
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}
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bytes_written_ += write_result.value();
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}
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return write_result;
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}
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