misc_string.c

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/*
 * Copyright 2008 Search Solution Corporation
 * Copyright 2016 CUBRID Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

/*
 * misc_string.c : case insensitive string comparison routines for 8-bit
 *                 character sets
 */

#ident "$Id$"

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "misc_string.h"

/*
 * ustr_casestr() - find a substring, case ignored
 *   return: char*
 *   s1(in)
 *   s2(in)
 */
char *
ustr_casestr (const char *s1, const char *s2)
{
  size_t len1, len2;
  const char *p1, *p2;
  int c;

  if (!s1 || !s2)
    return NULL;
  if (s1 == s2)
    return (char *) s1;
  if (!*s2)
    return (char *) s1;
  if (!*s1)
    return NULL;

  len1 = strlen (s1);
  len2 = strlen (s2);
  c = tolower (*s2);
  while (len1 >= len2)
    {
      while (tolower (*s1) != c)
    {
      if (--len1 < len2)
        return NULL;
      s1++;
    }

      p1 = s1;
      p2 = s2;
      while (tolower (*p1) == tolower (*p2))
    {
      p1++;
      p2++;
      if (!*p2)
        return (char *) s1;
    }

      if (p1 == s1)
    {
      len1--;
      s1--;
    }
      else
    {
      len1 -= (p1 - s1) + 1;
      s1 += (p1 - s1) + 1;
    }
    }
  return NULL;
}

/*
 * ustr_upper() - replace all lower case characters with upper case characters
 *   return: char *
 *   s(in/out)
 */
char *
ustr_upper (char *s)
{
  char *t;

  if (!s)
    return NULL;

  for (t = s; *t; t++)
    *t = toupper (*t);
  return s;
}

/*
 * ustr_lower() - replace all upper case characters with lower case characters
 *   return: char *
 *   s(in/out)
 */
char *
ustr_lower (char *s)
{
  char *t;

  if (!s)
    return NULL;

  for (t = s; *t; t++)
    *t = tolower (*t);
  return s;
}