mirror of
git://git.code.sf.net/p/cdesktopenv/code
synced 2025-03-09 15:50:02 +00:00
e8b3274a65
- fix to buildin.c to prevent compiler from optimizing it out - fix to realpath.c to handle case where 'path' is NULL - fix to emacs.c (I think from dgk) - fix to file.c (I think from gsf) - fix to tail.c (I think from gsf) - fix to code setting the malloc init hook (for vmalloc) - changed memcpy to memmove in several places in sfio because src and dst might overlap - fixes to macros like FILE_defined to fix header file issues - fixes to expr.h to handle macro definition issue
140 lines
4 KiB
C
140 lines
4 KiB
C
/***********************************************************************
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* *
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* This software is part of the ast package *
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* Copyright (c) 1985-2011 AT&T Intellectual Property *
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* and is licensed under the *
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* Eclipse Public License, Version 1.0 *
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* by AT&T Intellectual Property *
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* *
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* A copy of the License is available at *
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* http://www.eclipse.org/org/documents/epl-v10.html *
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* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
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* *
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* Information and Software Systems Research *
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* AT&T Research *
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* Florham Park NJ *
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* *
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* Glenn Fowler <gsf@research.att.com> *
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* David Korn <dgk@research.att.com> *
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* Phong Vo <kpv@research.att.com> *
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* *
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***********************************************************************/
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#include "sfhdr.h"
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/* Read n bytes from a stream into a buffer
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**
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** Written by Kiem-Phong Vo.
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*/
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#if __STD_C
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ssize_t sfread(Sfio_t* f, Void_t* buf, size_t n)
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#else
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ssize_t sfread(f,buf,n)
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Sfio_t* f; /* read from this stream. */
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Void_t* buf; /* buffer to read into */
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size_t n; /* number of bytes to be read. */
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#endif
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{
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reg uchar *s, *begs;
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reg ssize_t r;
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reg int local, justseek;
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SFMTXDECL(f);
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SFMTXENTER(f, (ssize_t)(-1));
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GETLOCAL(f,local);
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justseek = f->bits&SF_JUSTSEEK; f->bits &= ~SF_JUSTSEEK;
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if(!buf)
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SFMTXRETURN(f, (ssize_t)(n == 0 ? 0 : -1) );
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/* release peek lock */
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if(f->mode&SF_PEEK)
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{ if(!(f->mode&SF_READ) )
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SFMTXRETURN(f, (ssize_t)(-1));
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if(f->mode&SF_GETR)
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{ if(((uchar*)buf + f->val) != f->next &&
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(!f->rsrv || f->rsrv->data != (uchar*)buf) )
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SFMTXRETURN(f, (ssize_t)(-1));
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f->mode &= ~SF_PEEK;
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SFMTXRETURN(f, 0);
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}
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else
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{ if((uchar*)buf != f->next)
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SFMTXRETURN(f, (ssize_t)(-1));
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f->mode &= ~SF_PEEK;
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if(f->mode&SF_PKRD)
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{ /* actually read the data now */
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f->mode &= ~SF_PKRD;
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if(n > 0)
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n = (r = sysreadf(f->file,f->data,n)) < 0 ? 0 : r;
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f->endb = f->data+n;
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f->here += n;
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}
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f->next += n;
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f->endr = f->endb;
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SFMTXRETURN(f, n);
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}
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}
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s = begs = (uchar*)buf;
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for(;; f->mode &= ~SF_LOCK)
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{ /* check stream mode */
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if(SFMODE(f,local) != SF_READ && _sfmode(f,SF_READ,local) < 0)
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{ n = s > begs ? s-begs : (size_t)(-1);
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SFMTXRETURN(f, (ssize_t)n);
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}
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SFLOCK(f,local);
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if((r = f->endb - f->next) > 0) /* has buffered data */
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{ if(r > (ssize_t)n)
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r = (ssize_t)n;
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if(s != f->next)
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memmove(s, f->next, r);
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f->next += r;
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s += r;
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n -= r;
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}
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if(n <= 0) /* all done */
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break;
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if(!(f->flags&SF_STRING) && !(f->bits&SF_MMAP) )
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{ f->next = f->endb = f->data;
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/* exact IO is desirable for these cases */
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if(SFDIRECT(f,n) ||
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((f->flags&SF_SHARE) && f->extent < 0) )
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r = (ssize_t)n;
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else if(justseek && n <= f->iosz && f->iosz <= f->size)
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r = f->iosz; /* limit buffering */
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else r = f->size; /* full buffering */
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/* if read almost full size, then just do it direct */
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if(r > (ssize_t)n && (r - r/8) <= (ssize_t)n)
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r = (ssize_t)n;
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/* read directly to user's buffer */
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if(r == (ssize_t)n && (r = SFRD(f,s,r,f->disc)) >= 0)
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{ s += r;
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n -= r;
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if(r == 0 || n == 0) /* eof or eob */
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break;
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}
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else goto do_filbuf;
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}
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else
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{ do_filbuf:
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if(justseek)
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f->bits |= SF_JUSTSEEK;
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if(SFFILBUF(f,-1) <= 0)
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break;
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}
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}
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SFOPEN(f,local);
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r = s-begs;
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SFMTXRETURN(f, r);
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}
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