busybox/coreutils/sum.c

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/* vi: set sw=4 ts=4: */
/*
* sum -- checksum and count the blocks in a file
* Like BSD sum or SysV sum -r, except like SysV sum if -s option is given.
*
* Copyright (C) 86, 89, 91, 1995-2002, 2004 Free Software Foundation, Inc.
* Copyright (C) 2005 by Erik Andersen <andersen@codepoet.org>
* Copyright (C) 2005 by Mike Frysinger <vapier@gentoo.org>
*
* Written by Kayvan Aghaiepour and David MacKenzie
* Taken from coreutils and turned into a busybox applet by Mike Frysinger
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
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#include "busybox.h"
/* 1 if any of the files read were the standard input */
static int have_read_stdin;
/* make a little more readable and avoid using strcmp for just 2 bytes */
#define IS_STDIN(s) (s[0] == '-' && s[1] == '\0')
/* Calculate and print the rotated checksum and the size in 1K blocks
of file FILE, or of the standard input if FILE is "-".
If PRINT_NAME is >1, print FILE next to the checksum and size.
The checksum varies depending on sizeof (int).
Return 1 if successful. */
static int bsd_sum_file(const char *file, int print_name)
{
FILE *fp;
int checksum = 0; /* The checksum mod 2^16. */
uintmax_t total_bytes = 0; /* The number of bytes. */
int ch; /* Each character read. */
int ret = 0;
if (IS_STDIN(file)) {
fp = stdin;
have_read_stdin++;
} else {
fp = fopen_or_warn(file, "r");
if (fp == NULL)
goto out;
}
while ((ch = getc(fp)) != EOF) {
++total_bytes;
checksum = (checksum >> 1) + ((checksum & 1) << 15);
checksum += ch;
checksum &= 0xffff; /* Keep it within bounds. */
}
if (ferror(fp)) {
bb_perror_msg(file);
fclose_if_not_stdin(fp);
goto out;
}
if (fclose_if_not_stdin(fp) == EOF) {
bb_perror_msg(file);
goto out;
}
ret++;
printf("%05d %5ju ", checksum, (total_bytes+1023)/1024);
if (print_name > 1)
puts(file);
else
puts("");
out:
return ret;
}
/* Calculate and print the checksum and the size in 512-byte blocks
of file FILE, or of the standard input if FILE is "-".
If PRINT_NAME is >0, print FILE next to the checksum and size.
Return 1 if successful. */
#define MY_BUF_SIZE 8192
static int sysv_sum_file(const char *file, int print_name)
{
RESERVE_CONFIG_BUFFER(buf, MY_BUF_SIZE);
int fd;
uintmax_t total_bytes = 0;
/* The sum of all the input bytes, modulo (UINT_MAX + 1). */
unsigned int s = 0;
if (IS_STDIN(file)) {
fd = 0;
have_read_stdin = 1;
} else {
fd = open(file, O_RDONLY);
if (fd == -1)
goto release_and_ret;
}
while (1) {
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size_t bytes_read = safe_read(fd, buf, MY_BUF_SIZE);
if (bytes_read == 0)
break;
if (bytes_read == -1) {
release_and_ret:
bb_perror_msg(file);
RELEASE_CONFIG_BUFFER(buf);
if (!IS_STDIN(file))
close(fd);
return 0;
}
total_bytes += bytes_read;
while (bytes_read--)
s += buf[bytes_read];
}
if (!IS_STDIN(file) && close(fd) == -1)
goto release_and_ret;
else
RELEASE_CONFIG_BUFFER(buf);
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{
int r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
s = (r & 0xffff) + (r >> 16);
printf("%d %ju ", s, (total_bytes+511)/512);
}
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puts(print_name ? file : "");
return 1;
}
int sum_main(int argc, char **argv)
{
int flags;
int ok;
int (*sum_func)(const char *, int) = bsd_sum_file;
/* give the bsd func priority over sysv func */
flags = getopt32(argc, argv, "sr");
if (flags & 1)
sum_func = sysv_sum_file;
if (flags & 2)
sum_func = bsd_sum_file;
have_read_stdin = 0;
if ((argc - optind) == 0)
ok = sum_func("-", 0);
else
for (ok = 1; optind < argc; optind++)
ok &= sum_func(argv[optind], 1);
if (have_read_stdin && fclose(stdin) == EOF)
bb_perror_msg_and_die("-");
exit(ok ? EXIT_SUCCESS : EXIT_FAILURE);
}