mpd/src/util/ByteReverse.cxx
2019-03-08 10:21:10 +01:00

133 lines
3.1 KiB
C++

/*
* Copyright 2003-2018 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "ByteReverse.hxx"
#include "util/ByteOrder.hxx"
#include "Compiler.h"
#include <assert.h>
void
reverse_bytes_16(uint16_t *gcc_restrict dest,
const uint16_t *gcc_restrict src,
const uint16_t *src_end) noexcept
{
assert(dest != nullptr);
assert(src != nullptr);
assert(src_end >= src);
while (src < src_end) {
const uint16_t x = *src++;
*dest++ = ByteSwap16(x);
}
}
void
reverse_bytes_32(uint32_t *gcc_restrict dest,
const uint32_t *gcc_restrict src,
const uint32_t *src_end) noexcept
{
assert(dest != nullptr);
assert(src != nullptr);
assert(src_end >= src);
while (src < src_end) {
const uint32_t x = *src++;
*dest++ = ByteSwap32(x);
}
}
void
reverse_bytes_64(uint64_t *gcc_restrict dest,
const uint64_t *gcc_restrict src,
const uint64_t *src_end) noexcept
{
assert(dest != nullptr);
assert(src != nullptr);
assert(src_end >= src);
while (src < src_end) {
const uint64_t x = *src++;
*dest++ = ByteSwap64(x);
}
}
static void
reverse_bytes_linear(uint8_t *gcc_restrict dest,
const uint8_t *gcc_restrict src, size_t n) noexcept
{
src += n;
while (n-- > 0)
*dest++ = *--src;
}
static void
reverse_bytes_generic(uint8_t *gcc_restrict dest,
const uint8_t *gcc_restrict src, const uint8_t *src_end,
size_t frame_size) noexcept
{
assert(dest != nullptr);
assert(src != nullptr);
assert(src_end >= src);
assert(frame_size > 0);
assert((src_end - src) % frame_size == 0);
while (src < src_end) {
reverse_bytes_linear(dest, src, frame_size);
dest += frame_size;
src += frame_size;
}
}
void
reverse_bytes(uint8_t *gcc_restrict dest,
const uint8_t *gcc_restrict src, const uint8_t *src_end,
size_t frame_size) noexcept
{
assert(dest != nullptr);
assert(src != nullptr);
assert(src_end >= src);
assert(frame_size > 0);
assert((src_end - src) % frame_size == 0);
switch (frame_size) {
case 2:
reverse_bytes_16((uint16_t *)dest,
(const uint16_t *)src,
(const uint16_t *)src_end);
break;
case 4:
reverse_bytes_32((uint32_t *)dest,
(const uint32_t *)src,
(const uint32_t *)src_end);
break;
case 8:
reverse_bytes_64((uint64_t *)dest,
(const uint64_t *)src,
(const uint64_t *)src_end);
break;
default:
reverse_bytes_generic(dest, src, src_end, frame_size);
}
}