nuttx/libc/lzf/lzf_d.c
2018-03-15 10:47:00 -06:00

305 lines
7.4 KiB
C

/****************************************************************************
* libc/lzf/lzf_c.c
*
* Copyright (c) 2000-2010 Marc Alexander Lehmann <schmorp@schmorp.de>
*
* Redistribution and use in source and binary forms, with or without modifica-
* tion, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include "lzf/lzf.h"
#ifdef CONFIG_LIBC_LZF
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lzf_decompress
*
* Description:
* Decompress data compressed with some version of the lzf_compress
* function and stored at location in_data and length in_len. The result
* will be stored at out_data up to a maximum of out_len characters.
*
* If the output buffer is not large enough to hold the decompressed
* data, a 0 is returned and errno is set to E2BIG. Otherwise the number
* of decompressed bytes (i.e. the original length of the data) is
* returned.
*
* If an error in the compressed data is detected, a zero is returned and
* errno is set to EINVAL.
*
* This function is very fast, about as fast as a copying loop.
*
****************************************************************************/
unsigned int lzf_decompress (FAR const void *const in_data,
unsigned int in_len, FAR void *out_data,
unsigned int out_len)
{
FAR uint8_t const *ip = (const uint8_t *)in_data;
FAR uint8_t *op = (uint8_t *)out_data;
FAR uint8_t const *const in_end = ip + in_len;
FAR uint8_t *const out_end = op + out_len;
do
{
unsigned int ctrl = *ip++;
if (ctrl < (1 << 5)) /* literal run */
{
ctrl++;
if (op + ctrl > out_end)
{
set_errno(E2BIG);
return 0;
}
#if CHECK_INPUT
if (ip + ctrl > in_end)
{
set_errno(EINVAL);
return 0;
}
#endif
#ifdef lzf_movsb
lzf_movsb(op, ip, ctrl);
#else
switch (ctrl)
{
case 32:
*op++ = *ip++;
case 31:
*op++ = *ip++;
case 30:
*op++ = *ip++;
case 29:
*op++ = *ip++;
case 28:
*op++ = *ip++;
case 27:
*op++ = *ip++;
case 26:
*op++ = *ip++;
case 25:
*op++ = *ip++;
case 24:
*op++ = *ip++;
case 23:
*op++ = *ip++;
case 22:
*op++ = *ip++;
case 21:
*op++ = *ip++;
case 20:
*op++ = *ip++;
case 19:
*op++ = *ip++;
case 18:
*op++ = *ip++;
case 17:
*op++ = *ip++;
case 16:
*op++ = *ip++;
case 15:
*op++ = *ip++;
case 14:
*op++ = *ip++;
case 13:
*op++ = *ip++;
case 12:
*op++ = *ip++;
case 11:
*op++ = *ip++;
case 10:
*op++ = *ip++;
case 9:
*op++ = *ip++;
case 8:
*op++ = *ip++;
case 7:
*op++ = *ip++;
case 6:
*op++ = *ip++;
case 5:
*op++ = *ip++;
case 4:
*op++ = *ip++;
case 3:
*op++ = *ip++;
case 2:
*op++ = *ip++;
case 1:
*op++ = *ip++;
}
#endif
}
else /* back reference */
{
unsigned int len = ctrl >> 5;
FAR uint8_t *ref = op - ((ctrl & 0x1f) << 8) - 1;
#if CHECK_INPUT
if (ip >= in_end)
{
set_errno(EINVAL);
return 0;
}
#endif
if (len == 7)
{
len += *ip++;
#if CHECK_INPUT
if (ip >= in_end)
{
set_errno(EINVAL);
return 0;
}
#endif
}
ref -= *ip++;
if (op + len + 2 > out_end)
{
set_errno(E2BIG);
return 0;
}
if (ref < (uint8_t *)out_data)
{
set_errno(EINVAL);
return 0;
}
#ifdef lzf_movsb
len += 2;
lzf_movsb (op, ref, len);
#else
switch (len)
{
default:
len += 2;
if (op >= ref + len)
{
/* Disjunct areas */
memcpy (op, ref, len);
op += len;
}
else
{
/* Overlapping, use octet by octet copying */
do
{
*op++ = *ref++;
}
while (--len);
}
break;
case 9:
*op++ = *ref++;
case 8:
*op++ = *ref++;
case 7:
*op++ = *ref++;
case 6:
*op++ = *ref++;
case 5:
*op++ = *ref++;
case 4:
*op++ = *ref++;
case 3:
*op++ = *ref++;
case 2:
*op++ = *ref++;
case 1:
*op++ = *ref++;
case 0:
/* Two octets more */
*op++ = *ref++;
*op++ = *ref++;
}
#endif
}
}
while (ip < in_end);
return op - (uint8_t *)out_data;
}
#endif /* CONFIG_LIBC_LZF */