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/* Standalone version of ucl_nrv2e_decompress_8 from UCL library
* Original copyright notice:
*/
/* n2e_d.c -- implementation of the NRV2E decompression algorithm
This file is part of the UCL data compression library.
Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
All Rights Reserved.
The UCL library 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.
The UCL library 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 the UCL library; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Markus F.X.J. Oberhumer
<markus@oberhumer.com>
http://www.oberhumer.com/opensource/ucl/
*/
#include "ucl_decompress.h"
#define UCL_UINT32_C(c) c ## U
#define fail(x, r) do if(x) { *dst_len = olen; return r; } while(0)
#define getbit(bb) \
(((bb = bb & 0x7f ? bb*2 : ((unsigned)src[ilen++]*2+1)) >> 8) & 1)
int ucl_nrv2e_decompress_8(const uint8_t* src, uint32_t src_len,
uint8_t* dst, uint32_t* dst_len)
{
uint32_t bb = 0;
uint32_t ilen = 0, olen = 0, last_m_off = 1;
uint32_t oend = *dst_len;
for (;;)
{
uint32_t m_off, m_len;
while (getbit(bb))
{
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
fail(olen >= oend, UCL_E_OUTPUT_OVERRUN);
dst[olen++] = src[ilen++];
}
m_off = 1;
for (;;)
{
m_off = m_off*2 + getbit(bb);
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
fail(m_off > UCL_UINT32_C(0xffffff) + 3, UCL_E_LOOKBEHIND_OVERRUN);
if (getbit(bb)) break;
m_off = (m_off-1)*2 + getbit(bb);
}
if (m_off == 2)
{
m_off = last_m_off;
m_len = getbit(bb);
}
else
{
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
m_off = (m_off-3)*256 + src[ilen++];
if (m_off == UCL_UINT32_C(0xffffffff))
break;
m_len = (m_off ^ UCL_UINT32_C(0xffffffff)) & 1;
m_off >>= 1;
last_m_off = ++m_off;
}
if (m_len)
m_len = 1 + getbit(bb);
else if (getbit(bb))
m_len = 3 + getbit(bb);
else
{
m_len++;
do {
m_len = m_len*2 + getbit(bb);
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
fail(m_len >= oend, UCL_E_OUTPUT_OVERRUN);
} while (!getbit(bb));
m_len += 3;
}
m_len += (m_off > 0x500);
fail(olen + m_len > oend, UCL_E_OUTPUT_OVERRUN);
fail(m_off > olen, UCL_E_LOOKBEHIND_OVERRUN);
{
const uint8_t *m_pos;
m_pos = dst + olen - m_off;
dst[olen++] = *m_pos++;
do dst[olen++] = *m_pos++; while (--m_len > 0);
}
}
*dst_len = olen;
return ilen == src_len ? UCL_E_OK : (ilen < src_len ? UCL_E_INPUT_NOT_CONSUMED : UCL_E_INPUT_OVERRUN);
}
static uint32_t xread32(const uint8_t* d)
{
uint32_t r = 0;
r |= d[0] << 24;
r |= d[1] << 16;
r |= d[2] << 8;
r |= d[3] << 0;
return r;
}
/* From uclpack.c */
int ucl_unpack(const uint8_t* src, uint32_t src_len,
uint8_t* dst, uint32_t* dst_len)
{
static const uint8_t magic[8] =
{0x00, 0xe9, 0x55, 0x43, 0x4c, 0xff, 0x01, 0x1a};
/* make sure there are enough bytes for the header */
if(src_len < 18)
return UCL_E_BAD_MAGIC;
/* avoid memcmp for reasons of code size */
for(size_t i = 0; i < sizeof(magic); ++i)
if(src[i] != magic[i])
return UCL_E_BAD_MAGIC;
/* read the other header fields */
/* uint32_t flags = xread32(&src[8]); */
uint8_t method = src[12];
/* uint8_t level = src[13]; */
uint32_t block_size = xread32(&src[14]);
/* check supported compression method */
if(method != 0x2e)
return UCL_E_UNSUPPORTED_METHOD;
/* validate */
if(block_size < 1024 || block_size > 8*1024*1024)
return UCL_E_BAD_BLOCK_SIZE;
/* process the blocks */
src += 18;
src_len -= 18;
uint32_t dst_ilen = *dst_len;
while(1) {
if(src_len < 4)
return UCL_E_TRUNCATED;
uint32_t out_len = xread32(src); src += 4, src_len -= 4;
if(out_len == 0)
break;
if(src_len < 4)
return UCL_E_TRUNCATED;
uint32_t in_len = xread32(src); src += 4, src_len -= 4;
if(in_len > block_size || out_len > block_size ||
in_len == 0 || in_len > out_len)
return UCL_E_CORRUPTED;
if(src_len < in_len)
return UCL_E_TRUNCATED;
if(in_len < out_len) {
uint32_t actual_out_len = dst_ilen;
int rc = ucl_nrv2e_decompress_8(src, in_len, dst, &actual_out_len);
if(rc != UCL_E_OK)
return rc;
if(actual_out_len != out_len)
return UCL_E_CORRUPTED;
} else {
for(size_t i = 0; i < in_len; ++i)
dst[i] = src[i];
}
src += in_len;
src_len -= in_len;
dst += out_len;
dst_ilen -= out_len;
}
/* subtract leftover number of bytes to get size of compressed output */
*dst_len -= dst_ilen;
return UCL_E_OK;
}
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