mpd/src/util/ByteReverse.cxx

117 lines
2.4 KiB
C++

// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project
#include "ByteReverse.hxx"
#include "util/ByteOrder.hxx"
#include "Compiler.h"
#include <cassert>
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);
}
}