[git commit] crc32: new applet

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=ea9b96e5aab5a42518041e04b5d2780f6af80c7a
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
cksum_main                                           258     377    +119
.rodata                                           103672  103681      +9
applet_names                                        2745    2751      +6
applet_main                                         1588    1592      +4
packed_usage                                       33734   33698     -36
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 138/-36)           Total: 102 bytes

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 coreutils/cksum.c | 42 +++++++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 15 deletions(-)

diff --git a/coreutils/cksum.c b/coreutils/cksum.c
index 633322bc7..ecc43857d 100644
--- a/coreutils/cksum.c
+++ b/coreutils/cksum.c
@@ -9,32 +9,39 @@
 //config:config CKSUM
 //config:	bool "cksum (4.1 kb)"
 //config:	default y
-//config:	help
-//config:	cksum is used to calculate the CRC32 checksum of a file.
+//config:
+//config:config CRC32
+//config:	bool "crc32 (4.1 kb)"
+//config:	default y
 
 //applet:IF_CKSUM(APPLET_NOEXEC(cksum, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
+//applet:IF_CKSUM(APPLET_NOEXEC(crc32, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
 /* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
 
 //kbuild:lib-$(CONFIG_CKSUM) += cksum.o
+//kbuild:lib-$(CONFIG_CRC32) += cksum.o
 
 //usage:#define cksum_trivial_usage
 //usage:       "FILE..."
 //usage:#define cksum_full_usage "\n\n"
-//usage:       "Calculate the CRC32 checksums of FILEs"
+//usage:       "Calculate CRC32 checksum of FILEs"
 
 #include "libbb.h"
 #include "common_bufsiz.h"
 
 /* This is a NOEXEC applet. Be very careful! */
 
+#define IS_CRC32 (ENABLE_CRC32 && (!ENABLE_CKSUM || applet_name[1] == 'r'))
+#define IS_CKSUM (ENABLE_CKSUM && (!ENABLE_CRC32 || applet_name[1] == 'k'))
+
 int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int cksum_main(int argc UNUSED_PARAM, char **argv)
 {
-	uint32_t *crc32_table = crc32_filltable(NULL, 1);
+	uint32_t *crc32_table = crc32_filltable(NULL, IS_CKSUM);
 	int exit_code = EXIT_SUCCESS;
 
 #if ENABLE_DESKTOP
-	getopt32(argv, ""); /* coreutils 6.9 compat */
+	getopt32(argv, ""); /* cksum coreutils 6.9 compat */
 	argv += optind;
 #else
 	argv++;
@@ -51,33 +58,38 @@ int cksum_main(int argc UNUSED_PARAM, char **argv)
 			continue;
 		}
 
-		crc = 0;
+		crc = IS_CKSUM ? 0 : 0xffffffff;
 		filesize = 0;
 #define read_buf bb_common_bufsiz1
 		for (;;) {
-			uoff_t t;
 			int bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE);
 			if (bytes_read > 0) {
 				filesize += bytes_read;
 			} else {
-				/* Checksum filesize bytes, LSB first, and exit */
 				close(fd);
 				fd = -1; /* break flag */
-				t = filesize;
-				bytes_read = 0;
-				while (t != 0) {
-					read_buf[bytes_read++] = (uint8_t)t;
-					t >>= 8;
+				/* Checksum filesize bytes, LSB first */
+				if (IS_CKSUM) {
+					uoff_t t = filesize;
+					bytes_read = 0;
+					while (t != 0) {
+						read_buf[bytes_read++] = (uint8_t)t;
+						t >>= 8;
+					}
 				}
 			}
-			crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
+			crc = (IS_CKSUM ? crc32_block_endian1 : crc32_block_endian0)(crc, read_buf, bytes_read, crc32_table);
 			if (fd < 0)
 				break;
 		}
 
 		crc = ~crc;
-		printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
+		if (IS_CKSUM)
+			printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
 				(unsigned)crc, filesize, *argv);
+		else
+			printf((*argv ? "%08x %s\n" : "%08x\n"),
+				(unsigned)crc, *argv);
 	} while (*argv && *++argv);
 
 	fflush_stdout_and_exit(exit_code);