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133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
/* Copyright (C) 1996,1997,1998,1999,2000,2003,2004,2011 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Written by Ulrich Drepper, <drepper@cygnus.com>.
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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, see
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<http://www.gnu.org/licenses/>. */
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/* Find index of weight. */
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auto inline int32_t
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__attribute ((always_inline))
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findidx (const unsigned char **cpp, size_t len)
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{
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int_fast32_t i = table[*(*cpp)++];
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const unsigned char *cp;
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const unsigned char *usrc;
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if (i >= 0)
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/* This is an index into the weight table. Cool. */
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return i;
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/* Oh well, more than one sequence starting with this byte.
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Search for the correct one. */
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cp = &extra[-i];
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usrc = *cpp;
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--len;
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while (1)
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{
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size_t nhere;
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/* The first thing is the index. */
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i = *((const int32_t *) cp);
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cp += sizeof (int32_t);
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/* Next is the length of the byte sequence. These are always
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short byte sequences so there is no reason to call any
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function (even if they are inlined). */
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nhere = *cp++;
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if (i >= 0)
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{
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/* It is a single character. If it matches we found our
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index. Note that at the end of each list there is an
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entry of length zero which represents the single byte
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sequence. The first (and here only) byte was tested
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already. */
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size_t cnt;
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for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
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if (cp[cnt] != usrc[cnt])
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break;
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if (cnt == nhere)
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{
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/* Found it. */
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*cpp += nhere;
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return i;
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}
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/* Up to the next entry. */
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cp += nhere;
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if ((1 + nhere) % __alignof__ (int32_t) != 0)
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cp += __alignof__ (int32_t) - (1 + nhere) % __alignof__ (int32_t);
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}
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else
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{
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/* This is a range of characters. First decide whether the
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current byte sequence lies in the range. */
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size_t cnt;
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size_t offset = 0;
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for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
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if (cp[cnt] != usrc[cnt])
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break;
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if (cnt != nhere)
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{
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if (cnt == len || cp[cnt] > usrc[cnt])
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{
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/* Cannot be in this range. */
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cp += 2 * nhere;
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if ((1 + 2 * nhere) % __alignof__ (int32_t) != 0)
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cp += (__alignof__ (int32_t)
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- (1 + 2 * nhere) % __alignof__ (int32_t));
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continue;
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}
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/* Test against the end of the range. */
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for (cnt = 0; cnt < nhere; ++cnt)
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if (cp[nhere + cnt] != usrc[cnt])
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break;
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if (cnt != nhere && cp[nhere + cnt] < usrc[cnt])
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{
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/* Cannot be in this range. */
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cp += 2 * nhere;
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if ((1 + 2 * nhere) % __alignof__ (int32_t) != 0)
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cp += (__alignof__ (int32_t)
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- (1 + 2 * nhere) % __alignof__ (int32_t));
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continue;
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}
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/* This range matches the next characters. Now find
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the offset in the indirect table. */
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for (cnt = 0; cp[cnt] == usrc[cnt]; ++cnt);
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do
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{
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offset <<= 8;
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offset += usrc[cnt] - cp[cnt];
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}
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while (++cnt < nhere);
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}
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*cpp += nhere;
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return indirect[-i + offset];
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}
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}
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/* NOTREACHED */
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return 0x43219876;
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}
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