BufFile.cpp
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上传日期:2013-08-04
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- /*
- * Copyright (c) 2001,2002,2003 Mike Matsnev. All Rights Reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice immediately at the beginning of the file, without modification,
- * this list of conditions, and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. Absolutely no warranty of function or purpose is made by the author
- * Mike Matsnev.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * $Id: BufFile.cpp,v 1.24.2.1 2003/04/12 22:52:32 mike Exp $
- *
- */
- //#include <afx.h>
- #include "stdafx.h"
- #include "ptr.h"
- #include "BufFile.h"
- #ifdef _DEBUG
- #undef THIS_FILE
- static char THIS_FILE[]=__FILE__;
- #define new DEBUG_NEW
- #endif
- CBufFile::CBufFile(kilo::auto_ptr<RFile> file) :
- m_fp(file),
- m_ptr(0)
- {
- m_cur=&m_b1;
- }
- void CBufFile::swapbuf() {
- if (m_cur->len)
- m_cur=m_cur==&m_b1 ? &m_b2 : &m_b1;
- }
- int CBufFile::nextbuf_ch()
- {
- seek(m_cur->off+m_ptr);
- return m_ptr<m_cur->len ? m_cur->buf[m_ptr++] : BEOF;
- }
- int CBufFile::read(void *buf,int count) {
- BYTE *bp=(BYTE*)buf;
- while (count>0) {
- // fill in our buffer
- if (m_ptr>=m_cur->len)
- seek(m_cur->off+m_ptr);
- // if there are no bytes still, then exit
- if (m_ptr>=m_cur->len)
- break;
- // copy whatever is left in our buffer
- int nb=m_cur->len-m_ptr;
- if (nb>count)
- nb=count;
- memcpy(bp,m_cur->buf+m_ptr,nb);
- m_ptr+=nb;
- bp+=nb;
- count-=nb;
- }
- return bp-(BYTE*)buf;
- }
- void CBufFile::seek(DWORD pos) {
- if (pos>=m_cur->off && pos<m_cur->off+m_cur->len) // inside current buffer
- m_ptr=pos-m_cur->off;
- else {
- swapbuf();
- if (pos>=m_cur->off && pos<m_cur->off+m_cur->len) // inside other buffer
- m_ptr=pos-m_cur->off;
- else if (pos>=m_fp->size()) { // don't seek past eof
- m_cur->off=pos;
- m_cur->len=m_ptr=0;
- } else { // do seek on underlying file and fill next buffer
- m_cur->off=pos&RFile::BMASK;
- m_fp->seek(m_cur->off);
- m_cur->len=m_fp->read(m_cur->buf);
- m_ptr=pos-m_cur->off;
- }
- }
- }