str_replace c语言,str_replace的c语言实现

//./str_replace_all "(uid=%u/%u)" "%u" chantra

char *str_replace(const char *string, const char *substr, const char *replacement )

{

char *tok = NULL;

char *newstr = NULL;

char *oldstr = NULL;

/* if either substr or replacement is NULL, duplicate string a let caller handle it */

if ( substr == NULL || replacement == NULL )

return strdup (string);

newstr = strdup (string);

while ( (tok = strstr( newstr, substr)))

{

oldstr = newstr;

newstr = malloc (strlen ( oldstr ) - strlen ( substr ) + strlen ( replacement ) + 1 );

/*failed to alloc mem, free old string and return NULL */

if (newstr == NULL)

{

free (oldstr);

return NULL;

}

memcpy ( newstr, oldstr, tok - oldstr );

memcpy ( newstr + (tok - oldstr), replacement, strlen ( replacement ) );

memcpy ( newstr + (tok - oldstr) + strlen( replacement ), tok + strlen ( substr ), strlen ( oldstr ) - strlen ( substr ) - ( tok - oldstr ) );

memset ( newstr + strlen ( oldstr ) - strlen ( substr ) + strlen ( replacement ) , 0, 1 );

free(oldstr);

}

return newstr;

}