#include <stdlib.h>

 #include "_whelk.h"

 char *whelk_string_prealloc(struct whelk_string *string,size_t len)

 {

     char *new;

     if (string->alloc<string->len+len)

     {

 	new=realloc(string->buffer,string->len+len);

 	if (!new)

 	    return NULL;

 	string->buffer=new;

 	string->alloc=string->len+len;

     }

     return string->buffer+string->len;

 }

 void whelk_string_seek(struct whelk_string *string,ssize_t offset)

 {

     if (offset>=0 || string->len>=(size_t)-offset)

 	string->len+=offset;

     else

 	string->len=0;

 }

 char *whelk_string_finalize(struct whelk_string *string)

 {

     whelk_string_prealloc(string,1);

     string->buffer[string->len]='\0';

     return string->buffer;

 }

 void whelk_string_free(struct whelk_string *string)

 {

     free(string->buffer);

     memset(string,0,sizeof(*string));

 }