Mercurial > hg > toybox
view toys/posix/cksum.c @ 818:264b9da809df
Simplify license text, as mentioned on the mailing list.
Reasoning: it was never my intent to require anybody to copy license
text into another project if they cut and pasted something out of
toybox. The "permission for any purpose" is as close to public domain
as you can get in our current screwed up legal system without making
people uncomfortable the _other_ way. (Besides, my initial reading of
that was "all copies of the source code" but that's not what it says,
and somebody pointed out that Android has "show license text" options
because paranoid lawyers think that sort of thing applies to the BINARY
version, which is nuts.)
author | Rob Landley <rob@landley.net> |
---|---|
date | Thu, 14 Mar 2013 09:02:37 -0500 |
parents | 6cc69be43c42 |
children | 22739b6d5a0e |
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/* cksum.c - produce crc32 checksum value for each input * * Copyright 2008 Rob Landley <rob@landley.net> * * See http://opengroup.org/onlinepubs/9699919799/utilities/cksum.html USE_CKSUM(NEWTOY(cksum, "IPLN", TOYFLAG_BIN)) config CKSUM bool "cksum" default y help usage: cksum [-IPLN] [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. -L Little endian (defaults to big endian) -P Pre-inversion -I Skip post-inversion -N Do not include length in CRC calculation */ #define FOR_cksum #include "toys.h" GLOBALS( unsigned crc_table[256]; ) 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&4) ? 0xffffffff : 0; uint64_t llen = 0, llen2; unsigned (*cksum)(unsigned crc, unsigned char c); cksum = (toys.optflags&2) ? cksum_le : cksum_be; // CRC the data for (;;) { int len, i; len = read(fd, toybuf, sizeof(toybuf)); if (len<0) perror_msg("%s", name); if (len<1) break; llen += len; for (i=0; i<len; i++) crc=cksum(crc, toybuf[i]); } // CRC the length llen2 = llen; if (!(toys.optflags&1)) { while (llen) { crc = cksum(crc, llen); llen >>= 8; } } 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, toys.optflags&2); loopfiles(toys.optargs, do_cksum); }