io.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
#include "config.h"
 
#include <stddef.h>
#include <stdio.h>
#include <cgraph/cghdr.h>
#include <cgraph/rdr.h>
 
static int iofread(void *chan, char *buf, int bufsize)
{
    if (fgets(buf, bufsize, chan))
        return (int)strlen(buf);
    else
        return 0;
}
 
/* default IO methods */
static int ioputstr(void *chan, const char *str)
{
    return fputs(str, chan);
}
 
static int ioflush(void *chan)
{
    return fflush(chan);
}
 
Agiodisc_t AgIoDisc = { iofread, ioputstr, ioflush };
 
static int
memiofread(void *chan, char *buf, int bufsize)
{
    const char *ptr;
    char *optr;
    char c;
    int l;
    rdr_t *s;
 
    if (bufsize == 0) return 0;
    s = chan;
    if (s->cur >= s->len)
        return 0;
    l = 0;
    ptr = s->data + s->cur;
    optr = buf;
    /* We know we have at least one character */
    c = *ptr++;
    do {
        *optr++ = c;
        l++;
        /* continue if c is not newline, we have space in buffer,
         * and next character is non-null (we are working with
         * null-terminated strings.
         */
    } while (c != '\n' && l < bufsize && (c = *ptr++));
    s->cur += (size_t)l;
    return l;
}
 
static Agiodisc_t memIoDisc = {memiofread, 0, 0};
 
static Agraph_t *agmemread0(Agraph_t *arg_g, const char *cp)
{
    rdr_t rdr;
    Agdisc_t disc;
 
    memIoDisc.putstr = AgIoDisc.putstr;
    memIoDisc.flush = AgIoDisc.flush;
    rdr.data = cp;
    rdr.len = strlen(cp);
    rdr.cur = 0;
 
    disc.id = &AgIdDisc;
    disc.io = &memIoDisc;  
    if (arg_g) return agconcat(arg_g, NULL, &rdr, &disc);
    return agread(&rdr, &disc);
}
 
Agraph_t *agmemread(const char *cp)
{
    return agmemread0(0, cp);
}
 
Agraph_t *agmemconcat(Agraph_t *g, const char *cp)
{
    return agmemread0(g, cp);
}