libbb/pw_ascii64.c: add forgotten source file

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

1 files changed, 91 insertions, 0 deletions

diff --git a/libbb/pw_ascii64.c b/libbb/pw_ascii64.c
new file mode 100644
index 000000000..3993932ca
--- /dev/null
+++ b/libbb/pw_ascii64.c
@@ -0,0 +1,91 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+/* Returns >=64 for invalid chars */
+int FAST_FUNC a2i64(char c)
+{
+        unsigned char ch = c;
+        if (ch >= 'a')
+                /* "a..z" to 38..63 */
+                /* anything after "z": positive int >= 64 */
+                return (ch - 'a' + 38);
+
+        if (ch > 'Z')
+                /* after "Z" but before "a": positive byte >= 64 */
+                return ch;
+
+        if (ch >= 'A')
+                /* "A..Z" to 12..37 */
+                return (ch - 'A' + 12);
+
+        if (ch > '9')
+                return 64;
+
+        /* "./0123456789" to 0,1,2..11 */
+        /* anything before "." becomes positive byte >= 64 */
+        return (unsigned char)(ch - '.');
+}
+
+/* 0..63 ->
+ * "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+ */
+int FAST_FUNC i2a64(int i)
+{
+        i &= 0x3f;
+
+        i += '.';
+        /* the above maps 0..11 to "./0123456789":
+         * ACSII codes of "./" are ('0'-2) and ('0'-1) */
+
+        if (i > '9')
+                i += ('A' - '9' - 1);
+        if (i > 'Z')
+                i += ('a' - 'Z' - 1);
+        return i;
+}
+
+char* FAST_FUNC
+num2str64_lsb_first(char *s, unsigned v, int n)
+{
+        while (--n >= 0) {
+                *s++ = i2a64(v);
+                v >>= 6;
+        }
+        return s;
+}
+
+static void
+num2str64_4chars_msb_first(char *s, unsigned v)
+{
+        *s++ = i2a64(v >> 18); /* bits 23..18 */
+        *s++ = i2a64(v >> 12); /* bits 17..12 */
+        *s++ = i2a64(v >> 6); /* bits 11..6 */
+        *s   = i2a64(v); /* bits 5..0 */
+}
+
+int FAST_FUNC crypt_make_rand64encoded(char *p, int cnt /*, int x */)
+{
+        /* was: x += ... */
+        unsigned x = getpid() + monotonic_us();
+        do {
+                /* x = (x*1664525 + 1013904223) % 2^32 generator is lame
+                 * (low-order bit is not "random", etc...),
+                 * but for our purposes it is good enough */
+                x = x*1664525 + 1013904223;
+                /* BTW, Park and Miller's "minimal standard generator" is
+                 * x = x*16807 % ((2^31)-1)
+                 * It has no problem with visibly alternating lowest bit
+                 * but is also weak in cryptographic sense + needs div,
+                 * which needs more code (and slower) on many CPUs */
+                *p++ = i2a64(x >> 16);
+                *p++ = i2a64(x >> 22);
+        } while (--cnt);
+        *p = '\0';
+        return x;
+}