128 lines
2.7 KiB
C
128 lines
2.7 KiB
C
/* buffer.c
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Manipulate buffers used to hold strings.
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Copyright (C) 1992, 1993 Ian Lance Taylor
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This file is part of Taylor UUCP.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License
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as published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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The author of the program may be contacted at ian@airs.com or
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c/o Cygnus Support, Building 200, 1 Kendall Square, Cambridge, MA 02139.
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*/
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#include "uucp.h"
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#include "uudefs.h"
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/* We keep a linked list of buffers. The union is a hack because the
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default definition of offsetof, in uucp.h, takes the address of the
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field, and some C compilers will not let you take the address of an
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array. */
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struct sbuf
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{
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struct sbuf *qnext;
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size_t c;
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union
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{
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char ab[4];
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char bdummy;
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}
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u;
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};
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static struct sbuf *qBlist;
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/* Get a buffer of a given size. The buffer is returned with the
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ubuffree function. */
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char *
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zbufalc (c)
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size_t c;
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{
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register struct sbuf *q;
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if (qBlist == NULL)
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{
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q = (struct sbuf *) xmalloc (sizeof (struct sbuf) + c - 4);
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q->c = c;
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}
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else
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{
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q = qBlist;
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qBlist = q->qnext;
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if (q->c < c)
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{
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q = (struct sbuf *) xrealloc ((pointer) q,
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sizeof (struct sbuf) + c - 4);
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q->c = c;
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}
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}
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return q->u.ab;
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}
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/* Get a buffer holding a given string. */
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char *
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zbufcpy (z)
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const char *z;
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{
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size_t csize;
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char *zret;
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if (z == NULL)
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return NULL;
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csize = strlen (z) + 1;
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zret = zbufalc (csize);
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memcpy (zret, z, csize);
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return zret;
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}
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/* Free up a buffer back onto the linked list. */
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void
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ubuffree (z)
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char *z;
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{
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struct sbuf *q;
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/* The type of ioff should be size_t, but making it int avoids a bug
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in some versions of the HP/UX compiler, and will always work. */
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int ioff;
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if (z == NULL)
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return;
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ioff = offsetof (struct sbuf, u);
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q = (struct sbuf *) (pointer) (z - ioff);
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#ifdef DEBUG_BUFFER
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{
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struct sbuf *qlook;
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for (qlook = qBlist; qlook != NULL; qlook = qlook->qnext)
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{
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if (qlook == q)
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{
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ulog (LOG_ERROR, "ubuffree: Attempt to free buffer twice");
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abort ();
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}
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}
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}
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#endif
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q->qnext = qBlist;
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qBlist = q;
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}
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