pcompress/utils.c

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/*
* This file is a part of Pcompress, a chunked parallel multi-
* algorithm lossless compression and decompression program.
*
* Copyright (C) 2012 Moinak Ghosh. All rights reserved.
* Use is subject to license terms.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
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* version 3 of the License, or (at your option) any later version.
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*
* 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
* Lesser General Public License for more details.
*
* moinakg@belenix.org, http://moinakg.wordpress.com/
*
* This program includes partly-modified public domain source
* code from the LZMA SDK: http://www.7-zip.org/sdk.html
*/
#include <sys/types.h>
#include <sys/param.h>
#include <libgen.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <errno.h>
#include <link.h>
#include <rabin_polynomial.h>
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#include "utils.h"
void
err_exit(int show_errno, const char *format, ...)
{
int err = errno;
va_list args;
va_start(args, format);
vfprintf(stderr, format, args);
va_end(args);
if (show_errno)
fprintf(stderr, "\nError: %s\n", strerror(err));
exit(1);
}
/*
* Fetch the command name that started the current process.
* The returned string must be freed by the caller.
*/
const char *
get_execname(const char *argv0)
{
char path[MAXPATHLEN];
char apath[128];
char *tmp1, *tmp2;
pid_t pid;
/* The easiest case: we are in linux */
if (readlink("/proc/self/exe", path, MAXPATHLEN) != -1) {
return (strdup(basename(path)));
}
/* Next easy case: Solaris/Illumos */
pid = getpid();
sprintf(apath, "/proc/%d/path/a.out", pid);
if (readlink(apath, path, MAXPATHLEN) != -1) {
return (strdup(basename(path)));
}
/* Oops... not in linux, not in Solaris no guarantee */
/* check if we have something like execve("foobar", NULL, NULL) */
if (argv0 == NULL) {
/* Give up */
return (strdup("Unknown"));
}
tmp1 = strdup(argv0);
tmp2 = strdup(basename(tmp1));
free(tmp1);
return (tmp2);
}
/*
* Routines to parse a numeric string which can have the following suffixes:
* k - Kilobyte
* m - Megabyte
* g - Gigabyte
*
* The number should fit in an ssize_t data type.
* Numeric overflow is also checked. The routine parse_numeric() returns
* 1 if there was a numeric overflow.
*/
static int
raise_by_multiplier(ssize_t *val, int mult, int power) {
ssize_t result;
while (power-- > 0) {
result = *val * mult;
if (result/mult != *val)
return (1);
*val = result;
}
return (0);
}
int
parse_numeric(ssize_t *val, const char *str)
{
int i, ovr;
char *mult;
*val = strtoll(str, &mult, 0);
if (*mult != '\0') {
switch (*mult) {
case 'k':
case 'K':
ovr = raise_by_multiplier(val, 1024, 1);
break;
case 'm':
case 'M':
ovr = raise_by_multiplier(val, 1024, 2);
break;
case 'g':
case 'G':
ovr = raise_by_multiplier(val, 1024, 3);
break;
default:
ovr = 2;
}
}
return (ovr);
}
/*
* Convert number of bytes into human readable format
*/
char *
bytes_to_size(uint64_t bytes)
{
static char num[20];
uint64_t kilobyte = 1024;
uint64_t megabyte = kilobyte * 1024;
uint64_t gigabyte = megabyte * 1024;
uint64_t terabyte = gigabyte * 1024;
if (bytes < kilobyte) {
sprintf(num, "%llu B", bytes);
} else if (bytes < megabyte) {
sprintf(num, "%llu KB", bytes / kilobyte);
} else if (bytes < gigabyte) {
sprintf(num, "%llu MB", bytes / megabyte);
} else if (bytes < terabyte) {
sprintf(num, "%llu GB", bytes / gigabyte);
} else {
sprintf(num, "%llu B", bytes);
}
return (num);
}
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/*
* Read/Write helpers to ensure a full chunk is read or written
* unless there is an error.
* Additionally can be given an offset in the buf where the data
* should be inserted.
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*/
ssize_t
Read(int fd, void *buf, size_t count)
{
ssize_t rcount, rem;
uchar_t *cbuf;
va_list args;
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rem = count;
cbuf = (uchar_t *)buf;
do {
rcount = read(fd, cbuf, rem);
if (rcount < 0) return (rcount);
if (rcount == 0) break;
rem = rem - rcount;
cbuf += rcount;
} while (rem);
return (count - rem);
}
/*
* Read the requested chunk and return the last rabin boundary in the chunk.
* This helps in splitting chunks at rabin boundaries rather than fixed points.
* The request buffer may have some data at the beginning carried over from
* after the previous rabin boundary.
*/
ssize_t
Read_Adjusted(int fd, uchar_t *buf, size_t count, ssize_t *rabin_count, void *ctx)
{
char *buf2;
ssize_t rcount;
rabin_context_t *rctx = (rabin_context_t *)ctx;
if (!ctx) return (Read(fd, buf, count));
buf2 = buf;
if (*rabin_count) {
buf2 = (char *)buf + *rabin_count;
count -= *rabin_count;
}
rcount = Read(fd, buf2, count);
if (rcount > 0) {
rcount += *rabin_count;
if (rcount == count)
rabin_dedup(rctx, buf, &rcount, *rabin_count, rabin_count);
else
*rabin_count = 0;
} else {
if (rcount == 0) rcount = *rabin_count;
*rabin_count = 0;
}
return (rcount);
}
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ssize_t
Write(int fd, const void *buf, size_t count)
{
ssize_t wcount, rem;
uchar_t *cbuf;
rem = count;
cbuf = (uchar_t *)buf;
do {
wcount = write(fd, cbuf, rem);
if (wcount < 0) return (wcount);
rem = rem - wcount;
cbuf += wcount;
} while (rem);
return (count - rem);
}