61 lines
2.0 KiB
C
61 lines
2.0 KiB
C
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/****************************************************************
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* *
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* Copyright 2001, 2009 Fidelity Information Services, Inc *
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* *
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* This source code contains the intellectual property *
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* of its copyright holder(s), and is made available *
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* under a license. If you do not know the terms of *
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* the license, please stop and do not read further. *
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* *
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****************************************************************/
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#include "mdef.h"
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#include "gtm_string.h"
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#include "copy.h"
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#include "patcode.h"
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#include "min_max.h"
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/* If a pattern contains consecutive atoms that could be combined, this procedure will attempt to do so.
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* For instance both .E.N and .N.E could be simplified to .E
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*/
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int pat_compress(uint4 pattern_mask,
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pat_strlit *strlit_buff,
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boolean_t infinite,
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boolean_t last_infinite,
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uint4 *lastpatptr)
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{
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uint4 y_max;
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uint4 lastpat_mask;
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assert(pattern_mask);
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if ((infinite == last_infinite) && !(pattern_mask & PATM_ALT))
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{
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lastpat_mask = *lastpatptr & (PATM_STRLIT | PATM_LONGFLAGS);
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if (lastpat_mask == pattern_mask)
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{
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if (pattern_mask & PATM_STRLIT)
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{ /* PATM_STRLIT pattern consists of PAT_STRLIT_PADDING int4s that contain padding information */
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if (!memcmp(lastpatptr + 1, strlit_buff, strlit_buff->bytelen + PAT_STRLIT_PADDING * SIZEOF(int4)))
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return TRUE;
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} else
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return TRUE;
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} else if (infinite && lastpat_mask && !(lastpat_mask & PATM_STRLIT) && !(pattern_mask & PATM_STRLIT))
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{ /* lastpat_mask can be 0 if the previous pattern mask was PATM_ALT which is outside of PATM_LONGFLAGS range.
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* Do not compress in that case. Hence the && lastpat_mask in the else if above.
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*/
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y_max = MAX(lastpat_mask, pattern_mask);
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/* Check if one pattern subsumes the other. The check is a simple bit-wise OR condition.
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* This is because lastpat_mask and pattern_mask are non-zero here.
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*/
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if ((lastpat_mask | pattern_mask) == y_max)
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{
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*lastpatptr = y_max;
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return TRUE;
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}
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}
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}
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return FALSE;
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}
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