174 lines
4.6 KiB
C
174 lines
4.6 KiB
C
/*
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* This source code may contain confidential information of QNX Software
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* Systems Ltd. (QSSL) and its licensors. Any use, reproduction,
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* modification, disclosure, distribution or transfer of this software,
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* or any software which includes or is based upon any of this code, is
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* prohibited unless expressly authorized by QSSL by written agreement. For
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* more information (including whether this source code file has been
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* published) please email licensing@qnx.com.
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*/
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/* n2b_d.c -- implementation of the NRV2B decompression algorithm
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This file is part of the UCL real-time data compression library.
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Copyright (C) 1996-2000 Markus Franz Xaver Johannes Oberhumer
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Markus F.X.J. Oberhumer
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<markus.oberhumer@jk.uni-linz.ac.at>
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http://wildsau.idv.uni-linz.ac.at/mfx/ucl.html
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*/
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/***********************************************************************
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// actual implementation used by a recursive #include
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************************************************************************/
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#ifdef getbit
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#ifdef SAFE
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#define fail(x,r) if (x) { *dst_len = olen; return r; }
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#else
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#define fail(x,r)
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#endif
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{
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ucl_uint32 bb = 0;
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#ifdef TEST_OVERLAP
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ucl_uint ilen = src_off, olen = 0, last_m_off = 1;
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#else
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ucl_uint ilen = 0, olen = 0, last_m_off = 1;
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#endif
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#ifdef SAFE
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const ucl_uint oend = *dst_len;
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#endif
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UCL_UNUSED(wrkmem);
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#ifdef TEST_OVERLAP
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src_len += src_off;
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fail(oend >= src_len, UCL_E_OVERLAP_OVERRUN);
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#endif
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for (;;)
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{
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ucl_uint m_off, m_len;
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if (getbit(bb))
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{
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fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
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fail(olen >= oend, UCL_E_OUTPUT_OVERRUN);
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#ifdef TEST_OVERLAP
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fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
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olen++; ilen++;
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#else
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dst[olen++] = src[ilen++];
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#endif
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continue;
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}
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m_off = 1;
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do {
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m_off = m_off*2 + getbit(bb);
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fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
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fail(m_off > 0xffffff + 3, UCL_E_LOOKBEHIND_OVERRUN);
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} while (!getbit(bb));
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if (m_off == 2)
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{
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m_off = last_m_off;
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}
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else
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{
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fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
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m_off = (m_off-3)*256 + src[ilen++];
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if (m_off == 0xffffffff)
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break;
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last_m_off = ++m_off;
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}
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m_len = getbit(bb);
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m_len = m_len*2 + getbit(bb);
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if (m_len == 0)
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{
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m_len++;
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do {
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m_len = m_len*2 + getbit(bb);
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fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
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fail(m_len >= oend, UCL_E_OUTPUT_OVERRUN);
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} while (!getbit(bb));
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m_len += 2;
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}
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m_len += (m_off > 0xd00);
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fail(olen + m_len > oend, UCL_E_OUTPUT_OVERRUN);
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fail(m_off > olen, UCL_E_LOOKBEHIND_OVERRUN);
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#ifdef TEST_OVERLAP
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olen += m_len + 1;
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fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
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#else
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{
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const ucl_byte *m_pos;
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m_pos = dst + olen - m_off;
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dst[olen++] = *m_pos++;
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do dst[olen++] = *m_pos++; while (--m_len > 0);
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}
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#endif
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}
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*dst_len = olen;
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return ilen == src_len ? UCL_E_OK : (ilen < src_len ? UCL_E_INPUT_NOT_CONSUMED : UCL_E_INPUT_OVERRUN);
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}
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#undef fail
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#endif /* getbit */
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/***********************************************************************
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// decompressor entries for the different bit-buffer sizes
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************************************************************************/
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#ifndef getbit
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#include <ucl/ucl.h>
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#include "ucl_conf.h"
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#include "getbit.h"
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UCL_PUBLIC(int)
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ucl_nrv2b_decompress_8 ( const ucl_byte *src, ucl_uint src_len,
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ucl_byte *dst, ucl_uint *dst_len,
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ucl_voidp wrkmem )
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{
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#define getbit(bb) getbit_8(bb,src,ilen)
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#include "n2b_d.c"
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#undef getbit
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}
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UCL_PUBLIC(int)
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ucl_nrv2b_decompress_le16 ( const ucl_byte *src, ucl_uint src_len,
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ucl_byte *dst, ucl_uint *dst_len,
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ucl_voidp wrkmem )
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{
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#define getbit(bb) getbit_le16(bb,src,ilen)
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#include "n2b_d.c"
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#undef getbit
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}
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UCL_PUBLIC(int)
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ucl_nrv2b_decompress_le32 ( const ucl_byte *src, ucl_uint src_len,
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ucl_byte *dst, ucl_uint *dst_len,
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ucl_voidp wrkmem )
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{
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unsigned bc = 0;
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#define getbit(bb) getbit_le32(bb,bc,src,ilen)
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#include "n2b_d.c"
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#undef getbit
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}
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#endif /* !getbit */
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/*
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vi:ts=4:et
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*/
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