lib/trim.c

   1 /* Removes leading and/or trailing whitespaces
   2    Copyright (C) 2006-2020 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Davide Angelocola <davide.angelocola@gmail.com> */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include "trim.h"
  23
  24 #include <ctype.h>
  25 #include <string.h>
  26 #include <stddef.h>
  27 #include <stdlib.h>
  28
  29 #include "mbchar.h"
  30 #include "mbiter.h"
  31 #include "xalloc.h"
  32
  33 /* Use this to suppress gcc's "...may be used before initialized" warnings. */
  34 #if defined GCC_LINT || defined lint
  35 # define IF_LINT(Code) Code
  36 #else
  37 # define IF_LINT(Code) /* empty */
  38 #endif
  39
  40 char *
  41 trim2 (const char *s, int how)
  42 {
  43   char *d;
  44
  45   d = strdup (s);
  46
  47   if (!d)
  48     xalloc_die ();
  49
  50   if (MB_CUR_MAX > 1)
  51     {
  52       mbi_iterator_t i;
  53
  54       /* Trim leading whitespaces. */
  55       if (how != TRIM_TRAILING)
  56         {
  57           mbi_init (i, d, strlen (d));
  58
  59           for (; mbi_avail (i) && mb_isspace (mbi_cur (i)); mbi_advance (i))
  60             ;
  61
  62           memmove (d, mbi_cur_ptr (i), strlen (mbi_cur_ptr (i)) + 1);
  63         }
  64
  65       /* Trim trailing whitespaces. */
  66       if (how != TRIM_LEADING)
  67         {
  68           unsigned int state = 0;
  69           char *r IF_LINT (= NULL); /* used only while state = 2 */
  70
  71           mbi_init (i, d, strlen (d));
  72
  73           for (; mbi_avail (i); mbi_advance (i))
  74             {
  75               if (state == 0 && mb_isspace (mbi_cur (i)))
  76                 continue;
  77
  78               if (state == 0 && !mb_isspace (mbi_cur (i)))
  79                 {
  80                   state = 1;
  81                   continue;
  82                 }
  83
  84               if (state == 1 && !mb_isspace (mbi_cur (i)))
  85                 continue;
  86
  87               if (state == 1 && mb_isspace (mbi_cur (i)))
  88                 {
  89                   state = 2;
  90                   r = (char *) mbi_cur_ptr (i);
  91                 }
  92               else if (state == 2 && mb_isspace (mbi_cur (i)))
  93                 {
  94                   /* empty */
  95                 }
  96               else
  97                 {
  98                   state = 1;
  99                 }
 100             }
 101
 102           if (state == 2)
 103             *r = '\0';
 104         }
 105     }
 106   else
 107     {
 108       char *p;
 109
 110       /* Trim leading whitespaces. */
 111       if (how != TRIM_TRAILING)
 112         {
 113           for (p = d; *p && isspace ((unsigned char) *p); p++)
 114             ;
 115
 116           memmove (d, p, strlen (p) + 1);
 117         }
 118
 119       /* Trim trailing whitespaces. */
 120       if (how != TRIM_LEADING)
 121         {
 122           for (p = d + strlen (d) - 1;
 123                p >= d && isspace ((unsigned char) *p); p--)
 124             *p = '\0';
 125         }
 126     }
 127
 128   return d;
 129 }