142 lines
4.6 KiB
C
142 lines
4.6 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <stdint.h>
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/* Tables indexed by a wide character are compressed through the use
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of a multi-level lookup. The compression effect comes from blocks
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that don't need particular data and from blocks that can share their
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data. */
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/* Bit tables are accessed by cutting wc in four 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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- the next 5 bits.
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+------------------+-----+-----+-----+
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wc = + 32-q-p-5 | q | p | 5 |
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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+5 <= 16.
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The table contains the following uint32_t words:
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- q+p+5,
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- s = upper exclusive bound for wc >> (q+p+5),
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- p+5,
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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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static __inline int
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wctype_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 >> 5) & mask3;
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uint32_t lookup3 = ((const uint32_t *)(table + lookup2))[index3];
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return (lookup3 >> (wc & 0x1f)) & 1;
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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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/* Byte tables are similar to bit tables, except that the addressing
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unit is a single byte, and no 5 bits are used as a word index. */
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static __inline int
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wcwidth_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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uint8_t lookup3 = ((const uint8_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 0xff;
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}
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/* Mapping tables are similar to bit tables, except that the
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addressing unit is a single signed 32-bit word, containing the
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difference between the desired result and the argument, and no 5
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bits are used as a word index. */
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static __inline uint32_t
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wctrans_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 wc + lookup3;
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}
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}
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}
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return wc;
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}
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