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108 lines
3.0 KiB
C
108 lines
3.0 KiB
C
/* Compare strings while treating digits characters numerically.
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Copyright (C) 1997-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Jean-François Bignolles <bignolle@ecoledoc.ibp.fr>, 1997.
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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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<https://www.gnu.org/licenses/>. */
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#include <stdint.h>
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#include <string.h>
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#include <ctype.h>
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/* states: S_N: normal, S_I: comparing integral part, S_F: comparing
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fractionnal parts, S_Z: idem but with leading Zeroes only */
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#define S_N 0x0
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#define S_I 0x3
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#define S_F 0x6
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#define S_Z 0x9
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/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
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#define CMP 2
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#define LEN 3
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/* Compare S1 and S2 as strings holding indices/version numbers,
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returning less than, equal to or greater than zero if S1 is less than,
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equal to or greater than S2 (for more info, see the texinfo doc).
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*/
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int
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__strverscmp (const char *s1, const char *s2)
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{
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const unsigned char *p1 = (const unsigned char *) s1;
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const unsigned char *p2 = (const unsigned char *) s2;
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/* Symbol(s) 0 [1-9] others
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Transition (10) 0 (01) d (00) x */
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static const uint8_t next_state[] =
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{
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/* state x d 0 */
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/* S_N */ S_N, S_I, S_Z,
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/* S_I */ S_N, S_I, S_I,
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/* S_F */ S_N, S_F, S_F,
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/* S_Z */ S_N, S_F, S_Z
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};
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static const int8_t result_type[] =
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{
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/* state x/x x/d x/0 d/x d/d d/0 0/x 0/d 0/0 */
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/* S_N */ CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
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/* S_I */ CMP, -1, -1, +1, LEN, LEN, +1, LEN, LEN,
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/* S_F */ CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
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/* S_Z */ CMP, +1, +1, -1, CMP, CMP, -1, CMP, CMP
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};
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if (p1 == p2)
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return 0;
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unsigned char c1 = *p1++;
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unsigned char c2 = *p2++;
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/* Hint: '0' is a digit too. */
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int state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
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int diff;
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while ((diff = c1 - c2) == 0)
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{
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if (c1 == '\0')
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return diff;
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state = next_state[state];
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c1 = *p1++;
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c2 = *p2++;
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state += (c1 == '0') + (isdigit (c1) != 0);
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}
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state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
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switch (state)
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{
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case CMP:
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return diff;
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case LEN:
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while (isdigit (*p1++))
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if (!isdigit (*p2++))
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return 1;
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return isdigit (*p2) ? -1 : diff;
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default:
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return state;
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}
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}
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libc_hidden_def (__strverscmp)
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weak_alias (__strverscmp, strverscmp)
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