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/* $Id: agxbuf.c,v 1.3 2004/12/11 19:26:09 ellson Exp $ $Revision: 1.3 $ */
/* vim:set shiftwidth=4 ts=8: */
/**********************************************************
* This software is part of the graphviz package *
* http://www.graphviz.org/ *
* *
* Copyright (c) 1994-2004 AT&T Corp. *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Corp. *
* *
* Information and Software Systems Research *
* AT&T Research, Florham Park NJ *
**********************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <agxbuf.h>
#define N_GNEW(n,t) (t*)malloc((n)*sizeof(t))
/* agxbinit:
* Assume if init is non-null, hint = sizeof(init[])
*/
void agxbinit(agxbuf * xb, unsigned int hint, unsigned char *init)
{
if (init) {
xb->buf = init;
xb->dyna = 0;
} else {
if (hint == 0)
hint = BUFSIZ;
xb->dyna = 1;
xb->buf = N_GNEW(hint, unsigned char);
}
xb->eptr = xb->buf + hint;
xb->ptr = xb->buf;
*xb->ptr = '\0';
}
/* agxbmore;
* Expand buffer to hold at least ssz more bytes.
*/
int agxbmore(agxbuf * xb, unsigned int ssz)
{
int cnt; /* current no. of characters in buffer */
int size; /* current buffer size */
int nsize; /* new buffer size */
unsigned char *nbuf; /* new buffer */
size = xb->eptr - xb->buf;
nsize = 2 * size;
if (size + ssz > nsize)
nsize = size + ssz;
cnt = xb->ptr - xb->buf;
if (xb->dyna) {
nbuf = realloc(xb->buf, nsize);
} else {
nbuf = N_GNEW(nsize, unsigned char);
memcpy(nbuf, xb->buf, cnt);
xb->dyna = 1;
}
xb->buf = nbuf;
xb->ptr = xb->buf + cnt;
xb->eptr = xb->buf + nsize;
return 0;
}
/* agxbput_n:
* Append string s of length n onto xb
*/
int agxbput_n(agxbuf * xb, char *s, unsigned int ssz)
{
if (xb->ptr + ssz > xb->eptr)
agxbmore(xb, ssz);
memcpy(xb->ptr, s, ssz);
xb->ptr += ssz;
return ssz;
}
/* agxbput:
* Append string s into xb
*/
int agxbput(agxbuf * xb, char *s)
{
unsigned int ssz = strlen(s);
return agxbput_n(xb, s, ssz);
}
/* agxbfree:
* Free any malloced resources.
*/
void agxbfree(agxbuf * xb)
{
if (xb->dyna)
free(xb->buf);
}
/* agxbpop:
* Removes last character added, if any.
*/
int agxbpop(agxbuf * xb)
{
int c;
if (xb->ptr > xb->buf) {
c = *xb->ptr--;
return c;
} else
return -1;
}
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