115 lines
4.2 KiB
C
115 lines
4.2 KiB
C
/*
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* CDE - Common Desktop Environment
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*
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* Copyright (c) 1993-2012, The Open Group. All rights reserved.
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*
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* These libraries and programs are free software; you can
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* redistribute them and/or modify them under the terms of the GNU
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* Lesser General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* These libraries and programs are distributed in the hope that
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* they will be useful, but WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU Lesser General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with these libraries and programs; if not, write
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* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
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* Floor, Boston, MA 02110-1301 USA
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*/
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/* $XConsortium: sffilbuf.c /main/3 1995/11/01 18:29:01 rswiston $ */
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/***************************************************************
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* *
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* AT&T - PROPRIETARY *
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* *
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* THIS IS PROPRIETARY SOURCE CODE LICENSED BY *
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* AT&T CORP. *
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* *
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* Copyright (c) 1995 AT&T Corp. *
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* All Rights Reserved *
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* *
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* This software is licensed by AT&T Corp. *
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* under the terms and conditions of the license in *
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* http://www.research.att.com/orgs/ssr/book/reuse *
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* *
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* This software was created by the *
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* Software Engineering Research Department *
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* AT&T Bell Laboratories *
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* *
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* For further information contact *
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* gsf@research.att.com *
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* *
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***************************************************************/
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#include "sfhdr.h"
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/* Fill the buffer of a stream with data.
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** If n < 0, sffilbuf() attempts to fill the buffer if it's empty.
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** If n == 0, if the buffer is not empty, just return the first byte;
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** otherwise fill the buffer and return the first byte.
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** If n > 0, even if the buffer is not empty, try a read to get as
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** close to n as possible. n is reset to -1 if stack pops.
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**
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** Written by Kiem-Phong Vo (06/27/90)
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*/
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#if __STD_C
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int _sffilbuf(reg Sfio_t* f, reg int n)
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#else
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_sffilbuf(f,n)
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reg Sfio_t *f; /* fill the read buffer of this stream */
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reg int n; /* see above */
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#endif
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{
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reg int r, local, rcrv, rc;
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GETLOCAL(f,local);
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/* any peek data must be preserved across stacked streams */
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rcrv = f->mode&(SF_RC|SF_RV|SF_LOCK);
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rc = f->getr;
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for(;; f->mode &= ~SF_LOCK)
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{ /* check mode */
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if(SFMODE(f,local) != SF_READ && _sfmode(f,SF_READ,local) < 0)
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return -1;
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SFLOCK(f,local);
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/* current extent of available data */
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if((r = f->endb-f->next) > 0)
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{ if(n <= 0 || (f->flags&SF_STRING))
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break;
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/* shift left to make room for new data */
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if(!(f->flags&SF_MMAP) && n > (f->size - (f->endb-f->data)) )
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{ memcpy((char*)f->data,(char*)f->next,r);
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f->endb = (f->next = f->data)+r;
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}
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}
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else if(!(f->flags&(SF_STRING|SF_MMAP)) )
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f->next = f->endb = f->endr = f->data;
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if(f->flags&SF_MMAP)
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r = n > 0 ? n : f->size;
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else if(!(f->flags&SF_STRING) )
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{ /* make sure we read no more than required */
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r = f->size - (f->endb - f->data);
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if(n > 0 && r > n && f->extent < 0 && (f->flags&SF_SHARE))
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r = n;
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}
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/* SFRD takes care of discipline read and stack popping */
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f->mode |= rcrv;
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f->getr = rc;
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if((r = SFRD(f,f->endb,r,f->disc)) >= 0)
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{ r = f->endb - f->next;
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break;
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}
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}
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SFOPEN(f,local);
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return (n == 0) ? (r > 0 ? (int)(*f->next++) : EOF) : r;
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}
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