diff options
Diffstat (limited to 'toys/cksum.c')
| -rw-r--r-- | toys/cksum.c | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/toys/cksum.c b/toys/cksum.c index a54738cc..9b616671 100644 --- a/toys/cksum.c +++ b/toys/cksum.c @@ -6,18 +6,21 @@ * * See http://www.opengroup.org/onlinepubs/009695399/utilities/cksum.html -USE_CKSUM(NEWTOY(cksum, "F", TOYFLAG_BIN)) +USE_CKSUM(NEWTOY(cksum, "IPLN", TOYFLAG_BIN)) config CKSUM bool "cksum" default y help - usage: cksum [-F] [file...] + usage: cksum [-FL] [file...] For each file, output crc32 checksum value, length and name of file. If no files listed, copy from stdin. Filename "-" is a synonym for stdin. - -F Start with 0xffffffff instead of 0. + -L Little endian (defaults to big endian) + -P Skip pre-inversion + -I Skip post-inversion + -N No length */ #include "toys.h" @@ -28,16 +31,24 @@ DEFINE_GLOBALS( #define TT this.cksum -static unsigned cksum(unsigned crc, unsigned char c) +static unsigned cksum_be(unsigned crc, unsigned char c) { return (crc<<8)^TT.crc_table[(crc>>24)^c]; } +static unsigned cksum_le(unsigned crc, unsigned char c) +{ + return TT.crc_table[(crc^c)&0xff] ^ (crc>>8); +} + static void do_cksum(int fd, char *name) { - unsigned crc = toys.optflags ? 0xffffffff : 0; + unsigned crc = (toys.optflags&4) ? 0 : 0xffffffff; uint64_t llen = 0, llen2; + unsigned (*cksum)(unsigned crc, unsigned char c); + + cksum = (toys.optflags&2) ? cksum_le : cksum_be; // CRC the data for (;;) { @@ -57,18 +68,20 @@ static void do_cksum(int fd, char *name) // CRC the length llen2 = llen; - while (llen) { - crc = cksum(crc, llen); - llen >>= 8; + if (!(toys.optflags&1)) { + while (llen) { + crc = cksum(crc, llen); + llen >>= 8; + } } - printf("%u %"PRIu64, ~crc, llen2); + printf("%u %"PRIu64, (toys.optflags&8) ? crc : ~crc, llen2); if (strcmp("-", name)) printf(" %s", name); xputc('\n'); } void cksum_main(void) { - crc_init(TT.crc_table); + crc_init(TT.crc_table, toys.optflags&2); loopfiles(toys.optargs, do_cksum); } |