Board index » C Language

All times are UTC



 Case Insensitive strstr !! 
Author Message
Ravi Ud
#1 / 22
 Case Insensitive strstr !!

Hi..

The function strstr -
[ char *strstr( const char *string, const char *subString ); ]
is used to find a substring, in a given string.

Well this function is CASE SENSITIVE ( subString ).
Can anybody in here help me with a similar function which  returns a
pointer to the first occurrence of substring where in it does in a
CASE INSENSITIVE Manner.
( i.e. it should ignore the case of the input SubString and do its
job. )

Thanks for the support

- Ravi



Wed, 09 Feb 2005 03:52:36 GMT  
Ryan Henness
#2 / 22
 Case Insensitive strstr !!

Quote:

> Hi..

> The function strstr -
> [ char *strstr( const char *string, const char *subString ); ]
> is used to find a substring, in a given string.

> Well this function is CASE SENSITIVE ( subString ).
> Can anybody in here help me with a similar function which  returns a
> pointer to the first occurrence of substring where in it does in a
> CASE INSENSITIVE Manner.
> ( i.e. it should ignore the case of the input SubString and do its
> job. )

> Thanks for the support

> - Ravi

Someone asked a question in here a week or so back about a
case-insensitive strcmp().  The answer here is the same as there:  code
strstr() as normal, except pump each character to tolower() [or
toupper()] first.

Oh, and don't forget to cast each character to unsigned before passing
it to to*().  And don't lie to your compiler, or Eric Sosman will notice
;P

Hope that helps,
Ryan.



Wed, 09 Feb 2005 03:52:40 GMT  
nrk
#3 / 22
 Case Insensitive strstr !!

Quote:

> Hi..

> The function strstr -
> [ char *strstr( const char *string, const char *subString ); ]
> is used to find a substring, in a given string.

> Well this function is CASE SENSITIVE ( subString ).
> Can anybody in here help me with a similar function which  returns a
> pointer to the first occurrence of substring where in it does in a
> CASE INSENSITIVE Manner.
> ( i.e. it should ignore the case of the input SubString and do its
> job. )

> Thanks for the support

> - Ravi

You could re-use the strstr function by creating entirely
lowercase/uppercase copies of the two strings and then calling strstr on
these copies instead of the original string.  If you feel the urge to
optimize, remember the words of the great master: "Pre-mature
optimisation is the root of all evil". ;-)

-nrk.



Wed, 09 Feb 2005 04:41:03 GMT  
jose..
#4 / 22
 Case Insensitive strstr !!

Quote:

> Hi..

> The function strstr -
> [ char *strstr( const char *string, const char *subString ); ]
> is used to find a substring, in a given string.

> Well this function is CASE SENSITIVE ( subString ).
> Can anybody in here help me with a similar function which  returns a
> pointer to the first occurrence of substring where in it does in a
> CASE INSENSITIVE Manner.
> ( i.e. it should ignore the case of the input SubString and do its
> job. )

man strstr(3) has:

     char *
     strcasestr(const char *big, const char *little);

I don't have a copy of the standard handy but FreeBSD claims it's
part of the 'Standard C Library'.

Joe



Wed, 09 Feb 2005 04:46:29 GMT  
jose..
#5 / 22
 Case Insensitive strstr !!

Quote:

> man strstr(3) has:

>     char *
>     strcasestr(const char *big, const char *little);

> I don't have a copy of the standard handy but FreeBSD claims it's
> part of the 'Standard C Library'.

Ok.  I'm on crack.  This isn't on my SunOS box or a RedHat box.  I was wrong.

Joe



Wed, 09 Feb 2005 04:52:38 GMT  
Default Use
#6 / 22
 Case Insensitive strstr !!

Quote:

> Hi..

> The function strstr -
> [ char *strstr( const char *string, const char *subString ); ]
> is used to find a substring, in a given string.

> Well this function is CASE SENSITIVE ( subString ).
> Can anybody in here help me with a similar function which  returns a
> pointer to the first occurrence of substring where in it does in a
> CASE INSENSITIVE Manner.
> ( i.e. it should ignore the case of the input SubString and do its
> job. )

There is no standard function to do that. You must either use a
platform-specific solution (stricmp() is a typical name, check your
documenation) or write your own. It's not too difficult. You could
probably find an implementation via google.

Brian Rodenborn



Wed, 09 Feb 2005 04:54:30 GMT  
Malcol
#7 / 22
 Case Insensitive strstr !!

Quote:

> Hi..

> The function strstr -
> [ char *strstr( const char *string, const char *subString ); ]
> is used to find a substring, in a given string.

> Can anybody in here help me with a similar function which  returns a
> pointer to the first occurrence of substring where in it does in a
> CASE INSENSITIVE Manner.
> ( i.e. it should ignore the case of the input SubString and do its
> job. )

Try this (untested).

char *mystristr(const char *str, const char *substr)
{
   int len;

   len = strlen(substr);

   while(*str)
   {
      if(!mystrincmp(str, substr, len))
        return str;
    }

    return 0;

Quote:
}

int mystrincmp(const char *s1, const char *s2, int len)
{
  int i;

  for(i=0;i<len;i++)
     if(s1[i] != s2[i])
        return s1[i] - s2[i];

  return 0;

Quote:
}



Wed, 09 Feb 2005 05:25:18 GMT  
Malcol
#8 / 22
 Case Insensitive strstr !!

Quote:


> > Hi..

> > The function strstr -
> > [ char *strstr( const char *string, const char *subString ); ]
> > is used to find a substring, in a given string.

> > Can anybody in here help me with a similar function which  returns a
> > pointer to the first occurrence of substring where in it does in a
> > CASE INSENSITIVE Manner.
> > ( i.e. it should ignore the case of the input SubString and do its
> > job. )

> Try this (untested).

> char *mystristr(const char *str, const char *substr)
> {
>    int len;

>    len = strlen(substr);

>    while(*str)
>    {
>       if(!mystrincmp(str, substr, len))
>         return str;
>     }

>     return 0;
> }

> int mystrincmp(const char *s1, const char *s2, int len)
> {
>   int i;

>   for(i=0;i<len;i++)

duh
>      if(tolower(s1[i]) != tolower(s2[i]))
>         return s1[i] - s2[i];

>   return 0;
> }



Wed, 09 Feb 2005 05:29:39 GMT  
nrk
#9 / 22
 Case Insensitive strstr !!
Quote:



>>>Hi..

>>>The function strstr -
>>>[ char *strstr( const char *string, const char *subString ); ]
>>>is used to find a substring, in a given string.

>>>Can anybody in here help me with a similar function which  returns a
>>>pointer to the first occurrence of substring where in it does in a
>>>CASE INSENSITIVE Manner.
>>>( i.e. it should ignore the case of the input SubString and do its
>>>job. )

>>Try this (untested).

>>char *mystristr(const char *str, const char *substr)
>>{
>>   int len;

>>   len = strlen(substr);

>>   while(*str)
>>   {
>>      if(!mystrincmp(str, substr, len))
>>        return str;
>>    }

Huh??

- Show quoted text -

Quote:
>>    return 0;
>>}

>>int mystrincmp(const char *s1, const char *s2, int len)
>>{
>>  int i;

>>  for(i=0;i<len;i++)

> duh

>>     if(tolower(s1[i]) != tolower(s2[i]))
>>        return s1[i] - s2[i];

>>  return 0;
>>}

Can you explain how the above code does what strstr is supposed to do?
(Looks like you missed an increment inside your while loop).

-nrk.



Wed, 09 Feb 2005 05:51:20 GMT  
Default Use
#10 / 22
 Case Insensitive strstr !!

Quote:

> There is no standard function to do that. You must either use a
> platform-specific solution (stricmp() is a typical name

Every get half-way through your answer and forget the original question?
That's what I did. He wanted strstr() not strcmp().

Brian Rodenborn



Wed, 09 Feb 2005 05:43:12 GMT  
bjarke..
#11 / 22
 Case Insensitive strstr !!

Quote:


> > man strstr(3) has:

> >     char *
> >     strcasestr(const char *big, const char *little);

> > I don't have a copy of the standard handy but FreeBSD claims it's
> > part of the 'Standard C Library'.

> Ok.  I'm on crack.  This isn't on my SunOS box or a RedHat box.  I
> was wrong.

From string.h on RedHat 7.3:

#ifdef __USE_GNU
/* Similar to `strstr' but this function ignores the case of both strings.  */
extern char *strcasestr (__const char *__haystack, __const char *__needle)
     __THROW __attribute_pure__;
#endif

From string.h on Irix:

 #if _SGIAPI && _NO_ANSIMODE
extern int ffs(int);
/* Case-insensitive comparision routines from 4.3BSD. */
extern int strcasecmp(const char *, const char *);
extern int strncasecmp(const char *, const char *, size_t);
#endif  /* _SGIAPI */

From string.h on SunOs:

#if defined(__EXTENSIONS__) || (__STDC__ == 0 && \
                !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE))
extern char *strsignal(int);
extern int ffs(int);
extern int strcasecmp(const char *, const char *);
extern int strncasecmp(const char *, const char *, size_t);
#endif /* defined(__EXTENSIONS__)... */

So I think it exists on most platforms.

Bjarke
--
"Always go to other people's funerals, otherwise they won't come to
yours."    - Yogi Berra



Wed, 09 Feb 2005 15:41:16 GMT  
Micah Cowa
#12 / 22
 Case Insensitive strstr !!

Quote:



> > > man strstr(3) has:

> > >     char *
> > >     strcasestr(const char *big, const char *little);

> > > I don't have a copy of the standard handy but FreeBSD claims it's
> > > part of the 'Standard C Library'.

> > Ok.  I'm on crack.  This isn't on my SunOS box or a RedHat box.  I
> > was wrong.

> From string.h on RedHat 7.3:

> #ifdef __USE_GNU
> /* Similar to `strstr' but this function ignores the case of both strings.  */
> extern char *strcasestr (__const char *__haystack, __const char *__needle)
>      __THROW __attribute_pure__;
> #endif

> From string.h on Irix:

>  #if _SGIAPI && _NO_ANSIMODE
> extern int ffs(int);
> /* Case-insensitive comparision routines from 4.3BSD. */
> extern int strcasecmp(const char *, const char *);
> extern int strncasecmp(const char *, const char *, size_t);
> #endif  /* _SGIAPI */

> From string.h on SunOs:

> #if defined(__EXTENSIONS__) || (__STDC__ == 0 && \
>                 !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE))
> extern char *strsignal(int);
> extern int ffs(int);
> extern int strcasecmp(const char *, const char *);
> extern int strncasecmp(const char *, const char *, size_t);
> #endif /* defined(__EXTENSIONS__)... */

> So I think it exists on most platforms.

Why? Neither the Irix nor SunOs citations above have it.

In any case, it is neither part of the C standard, nor part of the
POSIX standard. It shouldn't be relied upon. Right your own, if you
really need it.

-Micah



Wed, 09 Feb 2005 17:00:30 GMT  
Glynn
#13 / 22
 Case Insensitive strstr !!
Ravi......try this:

/*****************************/
#include <stdio.h>
#include <string.h>
#include <ctype.h>

char *strcasestr( char *szSrc, char *szFind )
{
  int i, k, nFind, nSrc;

  if( !szSrc || !szSrc[0] || !szFind || !szFind[0] )  { return(0); }

  nSrc= strlen(szSrc);
  nFind= strlen(szFind);

  for( i=k=0 ; k<nFind && i<nSrc ; i++, k++ ) {
    if( toupper(szSrc[i]) != toupper(szFind[k]) ) {
         i -= k;
         k = -1;
    }
  }

  if( k==nFind ) {
     return(szSrc + i-nFind);
  }
  return(0);

Quote:
}

/*****************************/

~Glynne


Quote:
> Hi..

> The function strstr -
> [ char *strstr( const char *string, const char *subString ); ]
> is used to find a substring, in a given string.

> Well this function is CASE SENSITIVE ( subString ).
> Can anybody in here help me with a similar function which  returns a
> pointer to the first occurrence of substring where in it does in a
> CASE INSENSITIVE Manner.
> ( i.e. it should ignore the case of the input SubString and do its
> job. )

> Thanks for the support

> - Ravi



Thu, 10 Feb 2005 12:49:26 GMT  
Ravi Ud
#14 / 22
 Case Insensitive strstr !!

Quote:




> > > > man strstr(3) has:

> > > >     char *
> > > >     strcasestr(const char *big, const char *little);

> > > > I don't have a copy of the standard handy but FreeBSD claims it's
> > > > part of the 'Standard C Library'.

> > > Ok.  I'm on crack.  This isn't on my SunOS box or a RedHat box.  I
> > > was wrong.

> > From string.h on RedHat 7.3:

> > #ifdef __USE_GNU
> > /* Similar to `strstr' but this function ignores the case of both strings.  */
> > extern char *strcasestr (__const char *__haystack, __const char *__needle)
> >      __THROW __attribute_pure__;
> > #endif

> > From string.h on Irix:

> >  #if _SGIAPI && _NO_ANSIMODE
> > extern int ffs(int);
> > /* Case-insensitive comparision routines from 4.3BSD. */
> > extern int strcasecmp(const char *, const char *);
> > extern int strncasecmp(const char *, const char *, size_t);
> > #endif  /* _SGIAPI */

> > From string.h on SunOs:

> > #if defined(__EXTENSIONS__) || (__STDC__ == 0 && \
> >                 !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE))
> > extern char *strsignal(int);
> > extern int ffs(int);
> > extern int strcasecmp(const char *, const char *);
> > extern int strncasecmp(const char *, const char *, size_t);
> > #endif /* defined(__EXTENSIONS__)... */

> > So I think it exists on most platforms.

> Why? Neither the Irix nor SunOs citations above have it.

> In any case, it is neither part of the C standard, nor part of the
> POSIX standard. It shouldn't be relied upon. Right your own, if you
> really need it.

> -Micah

well just trying..but want to find the best optimum solution. Standard
'C' ofcourse !!


Thu, 10 Feb 2005 19:20:50 GMT  
Micah Cowa
#15 / 22
 Case Insensitive strstr !!

Quote:

> In any case, it is neither part of the C standard, nor part of the
> POSIX standard. It shouldn't be relied upon. Right your own, if you

                                               ^^^^^

Quote:
> really need it.

Doh! So embarassing...

-Micah



Thu, 10 Feb 2005 22:01:01 GMT  
 
 Page 1 of 2
  [ 22 post ]  Go to page: [1] [2]

 Relevant Pages 

1. case-insensitive strstr - my code, need help

2. case insensitive strstr

3. case insensitive strstr()

4. case-insensitive strstr?

5. Looking for a case-insensitive version of strstr()

6. Looking for a case-insensitive version of strstr()

7. search substring case insensitive

8. case insensitive string compare

9. case insensitive in dbx?

10. Case insensitive

11. C/370 is case insensitive

12. Case insensitive compare in STL basic_string

  

 
Powered by phpBB® Forum Software