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151 lines
3.3 KiB
151 lines
3.3 KiB
/* aKode: MMapFile
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Copyright (C) 2004 Allan Sandfeld Jensen <kde@carewolf.com>
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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
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License as published by the Free Software Foundation; either
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version 2 of 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,
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but 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 License
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along with this library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
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Boston, MA 02110-1301, USA.
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*/
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#include "akodelib.h"
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extern "C" {
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#ifdef HAVE_FEATURES_H
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// Needed for older glibc versions.
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#include <features.h>
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#ifndef __USE_XOPEN2K
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#define __USE_XOPEN2K
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#endif
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#endif
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#include <unistd.h>
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#ifdef HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <string.h>
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#if defined(HAVE_MADVISE) && defined(NEED_MADVISE_PROTOTYPE)
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extern int madvise(void*,size_t,int);
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#endif
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}
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#include "mmapfile.h"
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namespace aKode {
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MMapFile::MMapFile(const char* filename) : File(filename), fd(-1), handle(0), len(0), pos(0) {}
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MMapFile::~MMapFile() {
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close();
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}
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bool MMapFile::openRO() {
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if(handle) return true;
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struct stat stat;
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fd = ::open(filename, O_RDONLY);
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if (fstat(fd, &stat) < 0) return false;
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len = stat.st_size;
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pos = 0;
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handle = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0);
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if (handle == MAP_FAILED) {
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::close(fd);
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handle = 0;
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return false;
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}
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return true;
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}
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void MMapFile::close() {
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if(handle) {
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munmap((char*)handle,len);
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::close(fd);
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}
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handle = 0;
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}
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long MMapFile::read(char* ptr, long num) {
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if(!handle) return -1;
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if (pos+num > len) num = len-pos;
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memcpy(ptr, (char*)handle+pos, num);
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pos += num;
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return num;
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}
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long MMapFile::write(const char*, long) {
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return false;
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}
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ssize_t MMapFile::lseek(long to, int whence) {
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if(!handle) return false;
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long newpos = 0;
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switch (whence) {
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case SEEK_SET:
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newpos = to;
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break;
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case SEEK_CUR:
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newpos = pos + to;
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break;
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case SEEK_END:
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newpos = len + to;
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break;
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default:
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return length();
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}
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if (newpos > len || newpos < 0)
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return -1;
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pos = newpos;
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return newpos;
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}
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long MMapFile::position() const {
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if(!handle) return -1;
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return pos;
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}
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long MMapFile::length() const {
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if(!handle) return -1;
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return len;
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}
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bool MMapFile::error() const {
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return (!handle);
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}
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bool MMapFile::eof() const {
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if(!handle) return true;
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return pos >= len;
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}
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void MMapFile::fadvise() {
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if(!handle) return;
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#if defined(HAVE_POSIX_MADVISE) && defined(POSIX_MADV_SEQUENTIAL)
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posix_madvise((char*)handle+pos, len-pos, POSIX_MADV_SEQUENTIAL);
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#elif defined(HAVE_MADVISE) && defined(MADV_SEQUENTIAL)
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madvise((char*)handle+pos, len-pos, MADV_SEQUENTIAL);
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#endif
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}
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} //namespace
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