1 files changed, 48 insertions, 0 deletions
diff --git a/AWK/b91dec.awk b/AWK/b91dec.awk
new file mode 100755
index 0000000..8a15fc3
--- /dev/null
+++ b/AWK/b91dec.awk
@@ -0,0 +1,48 @@
+#!/usr/bin/awk -f
+
+# basE91 decoder
+# Copyright (c) 2000-2006 Joachim Henke
+# http://base91.sourceforge.net/
+
+BEGIN {
+	b = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,./:;<=>?@[]^_`{|}~\""
+	for (i = 0; i < 256; ++i) {
+		--d[sprintf("%c", i)]
+	}
+	for (i = 0; i < 91; ++i) {
+		d[substr(b, i + 1, 1)] = i
+	}
+	b = 0
+	n = 0
+	v = -1
+}
+
+{
+	l = length($0)
+	for (i = 1; i <= l; ++i) {
+		c = d[substr($0, i, 1)]
+		if (c < 0) {
+			continue
+		}
+		if (v < 0) {
+			v = c
+		} else {
+			v += c * 91
+			b += v * 2 ^ n
+			n += v % 8192 > 88 ? 13 : 14
+			do {
+				b -= c = b % 256
+				printf "%c", c
+				b /= 256
+				n -= 8
+			} while (n > 7)
+			v = -1
+		}
+	}
+}
+
+END {
+	if (v + 1) {
+		printf "%c", b + v * 2 ^ n
+	}
+}