cksum: code shrink

function                                             old     new   delta
cksum_main                                           281     262     -19

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 24 insertions, 23 deletions

diff --git a/coreutils/cksum.c b/coreutils/cksum.c
index 059a33310..e46e249f2 100644
--- a/coreutils/cksum.c
+++ b/coreutils/cksum.c
@@ -31,9 +31,6 @@ 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 crc;
-        off_t length, filesize;
-        int bytes_read;
         int exit_code = EXIT_SUCCESS;
 
 #if ENABLE_DESKTOP
@@ -45,38 +42,42 @@ int cksum_main(int argc UNUSED_PARAM, char **argv)
 
         setup_common_bufsiz();
         do {
+                uint32_t crc;
+                off_t filesize;
                 int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
 
                 if (fd < 0) {
                         exit_code = EXIT_FAILURE;
                         continue;
                 }
-                crc = 0;
-                length = 0;
 
+                crc = 0;
+                filesize = 0;
 #define read_buf bb_common_bufsiz1
-                while ((bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE)) > 0) {
-                        length += bytes_read;
+                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;
+                                }
+                        }
                         crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
+                        if (fd < 0)
+                                break;
                 }
-                close(fd);
-
-                filesize = length;
 
-                while (length) {
-                        crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length];
-                        /* must ensure that shift is unsigned! */
-                        if (sizeof(length) <= sizeof(unsigned))
-                                length = (unsigned)length >> 8;
-                        else if (sizeof(length) <= sizeof(unsigned long))
-                                length = (unsigned long)length >> 8;
-                        else
-                                length = (unsigned long long)length >> 8;
-                }
                 crc = ~crc;
-
-                printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"),
-                                crc, filesize, *argv);
+                printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
+                                (unsigned)crc, filesize, *argv);
         } while (*argv && *++argv);
 
         fflush_stdout_and_exit(exit_code);