grab sum from coreutils, clean it up, and make it busybox happy

coreutils/Config.in

@@ -428,6 +428,12 @@ config CONFIG_STTY
 	help
 	  stty is used to change and print terminal line settings.
 
+config CONFIG_SUM
+	bool "sum"
+	default n
+	help
+	  checksum and count the blocks in a file
+
 config CONFIG_SYNC
 	bool "sync"
 	default n

coreutils/Makefile.in

@@ -71,6 +71,7 @@ COREUTILS-$(CONFIG_SHA1SUM) 	+= md5_sha1_sum.o
 COREUTILS-$(CONFIG_SLEEP)   	+= sleep.o
 COREUTILS-$(CONFIG_SORT)    	+= sort.o
 COREUTILS-$(CONFIG_STTY)    	+= stty.o
+COREUTILS-$(CONFIG_SUM)     	+= sum.o
 COREUTILS-$(CONFIG_SYNC)    	+= sync.o
 COREUTILS-$(CONFIG_TAIL)    	+= tail.o
 COREUTILS-$(CONFIG_TEE)     	+= tee.o

coreutils/sum.c

@@ -0,0 +1,182 @@
+/*
+ * 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
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <getopt.h>
+
+#include "libbb.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)
+{
+	register FILE *fp;
+	register int checksum = 0;          /* The checksum mod 2^16. */
+	register uintmax_t total_bytes = 0; /* The number of bytes. */
+	register int ch;                    /* Each character read. */
+
+	if (IS_STDIN(file)) {
+		fp = stdin;
+		have_read_stdin = 1;
+	} else {
+		fp = fopen(file, "r");
+		if (fp == NULL) {
+			bb_perror_msg("%s", file);
+			return 0;
+		}
+	}
+
+	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("%s", file);
+		if (!IS_STDIN(file))
+			fclose(fp);
+		return 0;
+	}
+
+	if (!IS_STDIN(file) && fclose(fp) == EOF) {
+		bb_perror_msg("%s", file);
+		return 0;
+	}
+
+	printf("%05d %5s", checksum,
+	       make_human_readable_str(total_bytes, 1, 1024));
+	if (print_name > 1)
+		printf(" %s", file);
+	putchar('\n');
+
+	return 1;
+}
+
+/* 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.  */
+static int sysv_sum_file(const char *file, int print_name)
+{
+	int fd;
+	unsigned char buf[8192];
+	uintmax_t total_bytes = 0;
+	int r;
+	int checksum;
+
+	/* 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) {
+			bb_perror_msg("%s", file);
+			return 0;
+		}
+	}
+
+	while (1) {
+		size_t i;
+		size_t bytes_read = safe_read(fd, buf, sizeof(buf));
+
+		if (bytes_read == 0)
+			break;
+
+		if (bytes_read == -1) {
+			bb_perror_msg("%s", file);
+			if (!IS_STDIN(file))
+				close(fd);
+			return 0;
+		}
+
+		for (i = 0; i < bytes_read; i++)
+			s += buf[i];
+		total_bytes += bytes_read;
+	}
+
+	if (!IS_STDIN(file) && close(fd) == -1) {
+		bb_perror_msg("%s", file);
+		return 0;
+	}
+
+	r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
+	checksum = (r & 0xffff) + (r >> 16);
+
+	printf("%d %s", checksum,
+	       make_human_readable_str(total_bytes, 1, 512));
+	if (print_name)
+		printf(" %s", file);
+	putchar('\n');
+
+	return 1;
+}
+
+int sum_main(int argc, char **argv)
+{
+	int flags;
+	int ok;
+	int files_given;
+	int (*sum_func)(const char *, int) = bsd_sum_file;
+
+	/* give the bsd func priority over sysv func */
+	flags = bb_getopt_ulflags(argc, argv, "sr");
+	if (flags & 1)
+		sum_func = sysv_sum_file;
+	if (flags & 2)
+		sum_func = bsd_sum_file;
+
+	have_read_stdin = 0;
+	files_given = argc - optind;
+	if (files_given <= 0)
+		ok = sum_func("-", files_given);
+	else
+		for (ok = 1; optind < argc; optind++)
+			ok &= sum_func(argv[optind], files_given);
+
+	if (have_read_stdin && fclose(stdin) == EOF)
+		bb_perror_msg_and_die("-");
+
+	exit(ok ? EXIT_SUCCESS : EXIT_FAILURE);
+}