Re: [GLib] How to get substrings?

[Iago Rubio <iago rubio hispalinux es>]

On Mon, 2004-11-08 at 12:31, Daniel Miralles GarcÃa wrote:
> Hi, dudes!
>
> I'm porting my old-style char* to gchar* (due to some SF's that appear 
> when I dont't printf("")).
>
> I've been looking a few here and there, but found no function to get a 
> substring (I mean, from a string, get a substring between two characters 
> or even two positions). For instance:
>
>   Origin = "ABCDEFGH"
>   my_str = g_get_substring_beteen (origin, "D", "G");
>
> and then my_str=="EF"

> From memory:

/* all strings should be NULL terminated. 
   returns a newly allocated string or NULL */

gchar*
substring_between( gchar* haystack, gchar* needle1, gchar* needle2)
{
        gchar* pos1;
        gchar* pos2;
        gchar* strcopy;
        gchar* retval;

        if( haystack == NULL || needle1 == NULL || needle2 == NULL )
                return NULL;
        strcopy = g_strdup(haystack);
        pos1 = g_strrstr( (const gchar*) strcopy,
                           (const gchar*) needle1 );
        if( pos1 == NULL) {
                g_free(strcopy);
                return NULL;
        }
        pos2 =  g_strrstr( (const gchar*) pos1,
                           (const gchar*) needle2);
        if( pos2 == NULL ) { 
                g_free(strcopy); 
                return NULL;
        }
        if( (pos1 += strlen(needle1)) >= pos2) {
                g_free(strcopy);
                return NULL;
        }
        *pos2 = '\0';
        retval =  g_strdup(pos1);
        g_free(strcopy);
        return retval;
}

> I though making it, but I need some "look a character" function:
>
>   char mychar = g_get_char (origin, position);
> or something like this...
> ...and then maybe appending a character to a string? 
>   origin = g_strdup("hell");
>   g_string_append_char (origin, "o");

It should be g_string_append_string or 
g_string_append_char(oring, 'o');

>   just to have origin -> "hello"...

gchar* string = g_strconcat( origin, "o", NULL );
// use string
g_free(string); // we no needed anymore

or,

gchar* // returns a newly allocated string or NULL
string_append_char( gchar* string, gchar character, gboolean free_old )
{
        gchar* new_string;
        
        g_return_val_if_fail(string != NULL, NULL);

        new_string = g_strdup_printf("%s%c", string, character);
        if( free_old ) g_free( string );
        return new_string;
}

> Any function in GLIB to do that?

Nope, but lots of helpers to implement it.
-- 
Iago Rubio