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hekate/bdk/libs/compr/blz.c
CTCaer 185526d134 Introducing Bootloader Development Kit (BDK)
BDK will allow developers to use the full collection of drivers,
with limited editing, if any, for making payloads for Nintendo Switch.

Using a single source for everything will also help decoupling
Switch specific code and easily port it to other Tegra X1/X1+ platforms.
And maybe even to lower targets.

Everything is now centrilized into bdk folder.
Every module or project can utilize it by simply including it.

This is just the start and it will continue to improve.
2020-06-14 15:25:21 +03:00

98 lines
3.1 KiB
C

/*
* Copyright (c) 2018 rajkosto
* Copyright (c) 2018 SciresM
*
* 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 <stdlib.h>
#include <string.h>
#include "blz.h"
const blz_footer *blz_get_footer(const unsigned char *compData, unsigned int compDataLen, blz_footer *outFooter)
{
if (compDataLen < sizeof(blz_footer))
return NULL;
const blz_footer *srcFooter = (const blz_footer*)&compData[compDataLen - sizeof(blz_footer)];
if (outFooter != NULL)
memcpy(outFooter, srcFooter, sizeof(blz_footer)); // Must be a memcpy because no umaligned accesses on ARMv4.
return srcFooter;
}
// From https://github.com/SciresM/hactool/blob/master/kip.c which is exactly how kernel does it, thanks SciresM!
int blz_uncompress_inplace(unsigned char *dataBuf, unsigned int compSize, const blz_footer *footer)
{
u32 addl_size = footer->addl_size;
u32 header_size = footer->header_size;
u32 cmp_and_hdr_size = footer->cmp_and_hdr_size;
unsigned char* cmp_start = &dataBuf[compSize] - cmp_and_hdr_size;
u32 cmp_ofs = cmp_and_hdr_size - header_size;
u32 out_ofs = cmp_and_hdr_size + addl_size;
while (out_ofs)
{
unsigned char control = cmp_start[--cmp_ofs];
for (unsigned int i=0; i<8; i++)
{
if (control & 0x80)
{
if (cmp_ofs < 2)
return 0; // Out of bounds.
cmp_ofs -= 2;
u16 seg_val = ((unsigned int)(cmp_start[cmp_ofs + 1]) << 8) | cmp_start[cmp_ofs];
u32 seg_size = ((seg_val >> 12) & 0xF) + 3;
u32 seg_ofs = (seg_val & 0x0FFF) + 3;
if (out_ofs < seg_size) // Kernel restricts segment copy to stay in bounds.
seg_size = out_ofs;
out_ofs -= seg_size;
for (unsigned int j = 0; j < seg_size; j++)
cmp_start[out_ofs + j] = cmp_start[out_ofs + j + seg_ofs];
}
else
{
// Copy directly.
if (cmp_ofs < 1)
return 0; //out of bounds
cmp_start[--out_ofs] = cmp_start[--cmp_ofs];
}
control <<= 1;
if (out_ofs == 0) // Blz works backwards, so if it reaches byte 0, it's done.
return 1;
}
}
return 1;
}
int blz_uncompress_srcdest(const unsigned char *compData, unsigned int compDataLen, unsigned char *dstData, unsigned int dstSize)
{
blz_footer footer;
const blz_footer *compFooterPtr = blz_get_footer(compData, compDataLen, &footer);
if (compFooterPtr == NULL)
return 0;
// Decompression must be done in-place, so need to copy the relevant compressed data first.
unsigned int numCompBytes = (const unsigned char*)(compFooterPtr)-compData;
memcpy(dstData, compData, numCompBytes);
memset(&dstData[numCompBytes], 0, dstSize - numCompBytes);
return blz_uncompress_inplace(dstData, compDataLen, &footer);
}