mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-12-18 16:32:05 +00:00
103 lines
No EOL
3.8 KiB
C++
103 lines
No EOL
3.8 KiB
C++
/*
|
|
* Copyright (c) 2018-2020 Atmosphère-NX
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include <exosphere.hpp>
|
|
#include "fusee_uncompress.hpp"
|
|
|
|
namespace ams::nxboot {
|
|
|
|
namespace {
|
|
|
|
class Lz4Uncompressor {
|
|
private:
|
|
const u8 *src;
|
|
size_t src_size;
|
|
size_t src_offset;
|
|
u8 *dst;
|
|
size_t dst_size;
|
|
size_t dst_offset;
|
|
public:
|
|
Lz4Uncompressor(void *dst, size_t dst_size, const void *src, size_t src_size) : src(static_cast<const u8 *>(src)), src_size(src_size), src_offset(0), dst(static_cast<u8 *>(dst)), dst_size(dst_size), dst_offset(0) {
|
|
/* ... */
|
|
}
|
|
|
|
void Uncompress() {
|
|
while (true) {
|
|
/* Read a control byte. */
|
|
const u8 control = this->ReadByte();
|
|
|
|
/* Copy what it specifies we should copy. */
|
|
this->Copy(this->GetCopySize(control >> 4));
|
|
|
|
/* If we've exceeded size, we're done. */
|
|
if (this->src_offset >= this->src_size) {
|
|
break;
|
|
}
|
|
|
|
/* Read the wide copy offset. */
|
|
u16 wide_offset = this->ReadByte();
|
|
AMS_ABORT_UNLESS(this->CanRead());
|
|
wide_offset |= (this->ReadByte() << 8);
|
|
|
|
/* Determine the copy size. */
|
|
const size_t wide_copy_size = this->GetCopySize(control & 0xF);
|
|
|
|
/* Copy bytes. */
|
|
const size_t end_offset = this->dst_offset + wide_copy_size + 4;
|
|
for (size_t cur_offset = this->dst_offset; cur_offset < end_offset; this->dst_offset = (++cur_offset)) {
|
|
AMS_ABORT_UNLESS(wide_offset <= cur_offset);
|
|
|
|
this->dst[cur_offset] = this->dst[cur_offset - wide_offset];
|
|
}
|
|
}
|
|
}
|
|
private:
|
|
u8 ReadByte() {
|
|
return this->src[this->src_offset++];
|
|
}
|
|
|
|
bool CanRead() const {
|
|
return this->src_offset < this->src_size;
|
|
}
|
|
|
|
size_t GetCopySize(u8 control) {
|
|
size_t size = control;
|
|
|
|
if (control >= 0xF) {
|
|
do {
|
|
AMS_ABORT_UNLESS(this->CanRead());
|
|
control = this->ReadByte();
|
|
size += control;
|
|
} while (control == 0xFF);
|
|
}
|
|
|
|
return size;
|
|
}
|
|
|
|
void Copy(size_t size) {
|
|
__builtin_memcpy(this->dst + this->dst_offset, this->src + this->src_offset, size);
|
|
this->dst_offset += size;
|
|
this->src_offset += size;
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
void Uncompress(void *dst, size_t dst_size, const void *src, size_t src_size) {
|
|
/* Create an execute a decompressor. */
|
|
Lz4Uncompressor(dst, dst_size, src, src_size).Uncompress();
|
|
}
|
|
|
|
} |