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/*****************************************************************************
unsort - reorder files semi-randomly
Copyright (C) 2007, 2008 Wessel Dankers <wsl@fruit.je>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*****************************************************************************/
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include "error.h"
#include "filebuf.h"
const filebuf_t filebuf_0 = {0};
#define filebuf_off(buf, off) (((uint8_t *)(buf)) + (size_t)(off))
static int filebuf_tmp(void) {
FILE *fh;
int fd;
fh = tmpfile();
if(!fh)
exit_perror(ERROR_SYSTEM, "Can't create temporary file");
fd = dup(fileno(fh));
if(fd == -1)
exit_perror(ERROR_SYSTEM, "Can't dup(%d)", fileno(fh));
fclose(fh);
return fd;
}
static void write_all(int fd, void *buf, size_t len) {
ssize_t r;
while(len) {
r = write(fd, buf, len);
if(!r)
exit_error(ERROR_SYSTEM, "Can't write to fd %d", fd);
if(r < 0)
exit_perror(ERROR_SYSTEM, "Can't write to fd %d", fd);
buf = filebuf_off(buf, r);
len -= (size_t)r;
}
}
static bool filebuf_mmap(int fd, filebuf_t *fb, size_t len) {
void *buf;
buf = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, (ssize_t)0);
if(buf == MAP_FAILED)
return true;
fb->buf = buf;
fb->len = len;
return false;
}
#define BUFSIZE 1048576
#define MINREAD 4096
static void *streambuf = NULL;
static size_t streamleft = BUFSIZE;
static void filebuf_stream(int fd, filebuf_t *fb) {
void *buf;
size_t len = 0, left, edge, offset = 0;
ssize_t r;
int tmp;
static long pg = -1;
if(!streambuf)
streambuf = xalloc(streamleft);
buf = streambuf;
left = streamleft;
while(left >= MINREAD) {
r = read(fd, filebuf_off(buf, len), left);
if(r < 0)
exit_perror(ERROR_SYSTEM, "Can't read from fd %d", fd);
if(!r) {
if(len) {
streambuf = filebuf_off(streambuf, len);
streamleft -= len;
} else {
buf = NULL;
}
fb->buf = buf;
fb->len = len;
return;
}
len += (size_t)r;
left -= (size_t)r;
}
tmp = filebuf_tmp();
write_all(tmp, buf, len);
buf = NULL;
if(pg == -1)
pg = sysconf(_SC_PAGESIZE);
left = 0;
for(;;) {
if(left < MINREAD) {
if(buf && munmap(buf, (size_t)BUFSIZE) == -1)
exit_perror(ERROR_SYSTEM, "Can't munmap %d bytes", BUFSIZE);
edge = len % (size_t)pg;
offset = len - edge;
left = BUFSIZE - edge;
if(ftruncate(tmp, (off_t)(offset + BUFSIZE)) == -1)
exit_perror(ERROR_SYSTEM, "Can't extend fd %d to %ld bytes", tmp, (long)(offset + BUFSIZE));
buf = mmap(NULL, (size_t)BUFSIZE, PROT_WRITE, MAP_SHARED, tmp, (off_t)offset);
if(buf == MAP_FAILED)
exit_perror(ERROR_SYSTEM, "Can't mmap fd %d for writing", fd);
}
r = read(fd, (char *)buf + len - offset, left);
if(!r)
break;
if(r < 0)
exit_perror(ERROR_SYSTEM, "Can't read from fd %d", tmp);
len += (size_t)r;
left -= (size_t)r;
}
if(buf && munmap(buf, (size_t)BUFSIZE) == -1)
exit_perror(ERROR_SYSTEM, "Can't munmap %d bytes", BUFSIZE);
if(ftruncate(tmp, (off_t)len) == -1)
exit_perror(ERROR_SYSTEM, "Can't truncate fd %d to %ld bytes", tmp, (long)len);
if(filebuf_mmap(tmp, fb, len))
exit_perror(ERROR_SYSTEM, "Can't mmap fd %d", tmp);
close(tmp);
}
void filebuf_init(filebuf_t *fb, int fd) {
struct stat st;
if(fstat(fd, &st) || !st.st_size || filebuf_mmap(fd, fb, (size_t)st.st_size))
filebuf_stream(fd, fb);
}
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