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/* $OpenBSD: mmfile.c,v 1.11 2006/09/19 05:52:23 otto Exp $ */

/*-
* Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
* 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, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/

#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <err.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

#include "grep.h"

#define MAX_MAP_LEN 1048576

mmf_t *
mmopen(char *fn, char *mode)
{
mmf_t *mmf;
struct stat st;

/* XXX ignore mode for now */
mode = mode;

mmf = grep_malloc(sizeof *mmf);
if ((mmf->fd = open(fn, O_RDONLY)) == -1)
goto ouch1;
if (fstat(mmf->fd, &st) == -1)
goto ouch2;
if (st.st_size > SIZE_T_MAX) /* too big to mmap */
goto ouch2;
if (!S_ISREG(st.st_mode)) /* only mmap regular files */
goto ouch2;
mmf->len = (size_t)st.st_size;
mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
if (mmf->base == MAP_FAILED)
goto ouch2;
mmf->ptr = mmf->base;
mmf->end = mmf->base + mmf->len;
#ifndef __minix
madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
#endif
return mmf;

ouch2:
close(mmf->fd);
ouch1:
free(mmf);
return NULL;
}

void
mmclose(mmf_t *mmf)
{
munmap(mmf->base, mmf->len);
close(mmf->fd);
free(mmf);
}

char *
mmfgetln(mmf_t *mmf, size_t *l)
{
static char *p;
char *start = mmf->ptr; /* Remove speed bump */
char *end = mmf->end; /* Remove speed bump */

if (start >= end)
return NULL;
     for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
         if (*mmf->ptr == '\n')
             break;

*l = mmf->ptr - p;
++mmf->ptr;
return p;
}
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