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/* $Id: sfwrite.c,v 1.1.1.1 2004/12/23 04:04:16 ellson Exp $ $Revision: 1.1.1.1 $ */
/* 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 "sfhdr.h"
/* Write data out to the file system
**
** Written by Kiem-Phong Vo.
*/
#if __STD_C
ssize_t sfwrite(reg Sfio_t * f, const Void_t * buf, reg size_t n)
#else
ssize_t sfwrite(f, buf, n)
reg Sfio_t *f; /* write to this stream. */
Void_t *buf; /* buffer to be written. */
reg size_t n; /* number of bytes. */
#endif
{
reg uchar *s, *begs, *next;
reg ssize_t w;
reg int local;
SFMTXSTART(f, (ssize_t) (-1));
GETLOCAL(f, local);
if (!buf)
SFMTXRETURN(f, (ssize_t) (-1));
/* release peek lock */
if (f->mode & SF_PEEK) {
if (!(f->mode & SF_WRITE) && (f->flags & SF_RDWR) != SF_RDWR)
SFMTXRETURN(f, (ssize_t) (-1));
if ((uchar *) buf != f->next &&
(!f->rsrv || f->rsrv->data != (uchar *) buf))
SFMTXRETURN(f, (ssize_t) (-1));
f->mode &= ~SF_PEEK;
if (f->mode & SF_PKRD) { /* read past peeked data */
char buf[16];
reg ssize_t r;
for (w = n; w > 0;) {
if ((r = w) > sizeof(buf))
r = sizeof(buf);
if ((r = read(f->file, buf, r)) <= 0) {
n -= w;
break;
} else
w -= r;
}
f->mode &= ~SF_PKRD;
f->endb = f->data + n;
f->here += n;
}
if ((f->mode & SF_READ) && f->proc)
f->next += n;
}
s = begs = (uchar *) buf;
for (;; f->mode &= ~SF_LOCK) { /* check stream mode */
if (SFMODE(f, local) != SF_WRITE
&& _sfmode(f, SF_WRITE, local) < 0) {
w = s > begs ? s - begs : -1;
SFMTXRETURN(f, w);
}
SFLOCK(f, local);
w = f->endb - f->next;
if (s == f->next) { /* after sfreserve */
if (w > (ssize_t) n)
w = (ssize_t) n;
f->next = (s += w);
n -= w;
break;
}
/* attempt to create space in buffer */
if (w == 0 || ((f->flags & SF_WHOLE) && w < (ssize_t) n)) {
if (f->flags & SF_STRING) { /* extend buffer */
(void) SFWR(f, s, n - w, f->disc);
if ((w = f->endb - f->next) < (ssize_t) n)
break;
} else if (f->next > f->data) {
(void) SFFLSBUF(f, -1);
if ((w = f->endb - f->next) < (ssize_t) n &&
(f->flags & SF_WHOLE) && f->next > f->data)
break;
}
}
if (!(f->flags & SF_STRING) && f->next == f->data && SFDIRECT(f, n)) { /* bypass buffering */
if ((w = SFWR(f, s, n, f->disc)) <= 0)
break;
} else {
if (w > (ssize_t) n)
w = (ssize_t) n;
if (w <= 0) /* no forward progress possible */
break;
memcpy(f->next, s, w);
f->next += w;
}
s += w;
if ((n -= w) <= 0)
break;
}
/* always flush buffer for share streams */
if (f->extent < 0 && (f->flags & SF_SHARE) && !(f->flags & SF_PUBLIC))
(void) SFFLSBUF(f, -1);
/* check to see if buffer should be flushed */
else if (n == 0 && (f->flags & SF_LINE) && !(f->flags & SF_STRING)) {
if ((ssize_t) (n = f->next - f->data) > (w = s - begs))
n = w;
if (n > 0 && n < HIFORLINE) {
for (next = f->next - 1; n > 0; --n, --next) {
if (*next == '\n') {
n = HIFORLINE;
break;
}
}
}
if (n >= HIFORLINE)
(void) SFFLSBUF(f, -1);
}
SFOPEN(f, local);
w = s - begs;
SFMTXRETURN(f, w);
}
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