102 lines
3.3 KiB
C
102 lines
3.3 KiB
C
/* Copyright (C) 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Bruno Haible <haible@clisp.cons.org>, 2000.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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/* Word tables are accessed by cutting wc in three blocks of bits:
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- the high 32-q-p bits,
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- the next q bits,
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- the next p bits.
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+------------------+-----+-----+
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wc = + 32-q-p | q | p |
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+------------------+-----+-----+
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p and q are variable. For 16-bit Unicode it is sufficient to
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choose p and q such that q+p <= 16.
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The table contains the following uint32_t words:
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- q+p,
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- s = upper exclusive bound for wc >> (q+p),
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- p,
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- 2^q-1,
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- 2^p-1,
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- 1st-level table: s offsets, pointing into the 2nd-level table,
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- 2nd-level table: k*2^q offsets, pointing into the 3rd-level table,
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- 3rd-level table: j*2^p words, each containing 32 bits of data.
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*/
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#include <stdint.h>
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/* Lookup in a table of int32_t, with default value 0. */
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static inline int32_t
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collidx_table_lookup (const char *table, uint32_t wc)
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{
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uint32_t shift1 = ((const uint32_t *) table)[0];
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uint32_t index1 = wc >> shift1;
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uint32_t bound = ((const uint32_t *) table)[1];
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if (index1 < bound)
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{
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uint32_t lookup1 = ((const uint32_t *) table)[5 + index1];
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if (lookup1 != 0)
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{
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uint32_t shift2 = ((const uint32_t *) table)[2];
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uint32_t mask2 = ((const uint32_t *) table)[3];
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uint32_t index2 = (wc >> shift2) & mask2;
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uint32_t lookup2 = ((const uint32_t *)(table + lookup1))[index2];
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if (lookup2 != 0)
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{
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uint32_t mask3 = ((const uint32_t *) table)[4];
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uint32_t index3 = wc & mask3;
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int32_t lookup3 = ((const int32_t *)(table + lookup2))[index3];
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return lookup3;
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}
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}
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}
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return 0;
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}
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/* Lookup in a table of uint32_t, with default value 0xffffffff. */
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static inline uint32_t
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collseq_table_lookup (const char *table, uint32_t wc)
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{
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uint32_t shift1 = ((const uint32_t *) table)[0];
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uint32_t index1 = wc >> shift1;
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uint32_t bound = ((const uint32_t *) table)[1];
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if (index1 < bound)
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{
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uint32_t lookup1 = ((const uint32_t *) table)[5 + index1];
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if (lookup1 != 0)
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{
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uint32_t shift2 = ((const uint32_t *) table)[2];
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uint32_t mask2 = ((const uint32_t *) table)[3];
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uint32_t index2 = (wc >> shift2) & mask2;
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uint32_t lookup2 = ((const uint32_t *)(table + lookup1))[index2];
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if (lookup2 != 0)
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{
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uint32_t mask3 = ((const uint32_t *) table)[4];
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uint32_t index3 = wc & mask3;
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uint32_t lookup3 = ((const uint32_t *)(table + lookup2))[index3];
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return lookup3;
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}
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}
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}
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return ~((uint32_t) 0);
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}
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