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91 lines
2 KiB
C
91 lines
2 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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/* Returns >=64 for invalid chars */
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int FAST_FUNC a2i64(char c)
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{
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unsigned char ch = c;
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if (ch >= 'a')
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/* "a..z" to 38..63 */
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/* anything after "z": positive int >= 64 */
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return (ch - 'a' + 38);
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if (ch > 'Z')
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/* after "Z" but before "a": positive byte >= 64 */
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return ch;
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if (ch >= 'A')
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/* "A..Z" to 12..37 */
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return (ch - 'A' + 12);
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if (ch > '9')
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return 64;
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/* "./0123456789" to 0,1,2..11 */
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/* anything before "." becomes positive byte >= 64 */
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return (unsigned char)(ch - '.');
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}
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/* 0..63 ->
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* "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
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*/
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int FAST_FUNC i2a64(int i)
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{
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i &= 0x3f;
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i += '.';
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/* the above maps 0..11 to "./0123456789":
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* ACSII codes of "./" are ('0'-2) and ('0'-1) */
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if (i > '9')
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i += ('A' - '9' - 1);
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if (i > 'Z')
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i += ('a' - 'Z' - 1);
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return i;
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}
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char* FAST_FUNC
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num2str64_lsb_first(char *s, unsigned v, int n)
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{
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while (--n >= 0) {
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*s++ = i2a64(v);
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v >>= 6;
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}
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return s;
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}
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static void
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num2str64_4chars_msb_first(char *s, unsigned v)
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{
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*s++ = i2a64(v >> 18); /* bits 23..18 */
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*s++ = i2a64(v >> 12); /* bits 17..12 */
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*s++ = i2a64(v >> 6); /* bits 11..6 */
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*s = i2a64(v); /* bits 5..0 */
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}
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int FAST_FUNC crypt_make_rand64encoded(char *p, int cnt /*, int x */)
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{
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/* was: x += ... */
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unsigned x = getpid() + monotonic_us();
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do {
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/* x = (x*1664525 + 1013904223) % 2^32 generator is lame
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* (low-order bit is not "random", etc...),
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* but for our purposes it is good enough */
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x = x*1664525 + 1013904223;
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/* BTW, Park and Miller's "minimal standard generator" is
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* x = x*16807 % ((2^31)-1)
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* It has no problem with visibly alternating lowest bit
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* but is also weak in cryptographic sense + needs div,
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* which needs more code (and slower) on many CPUs */
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*p++ = i2a64(x >> 16);
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*p++ = i2a64(x >> 22);
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} while (--cnt);
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*p = '\0';
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return x;
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}
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