AWK solution for week 2, part 2

1 files changed, 80 insertions, 0 deletions

diff --git a/challenge-002/abigail/awk/ch-2.awk b/challenge-002/abigail/awk/ch-2.awk
new file mode 100644
index 0000000000..b171fcd08f
--- /dev/null
+++ b/challenge-002/abigail/awk/ch-2.awk
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+#!/usr/bin/awk
+#
+# See ../README.md
+#
+
+#
+# Run as: awk -f ch-2.awk {-f | -t} < input-file
+#
+# -f: Translate from base 35 to base 10
+# -t: Translate to base 35 from base 10
+#
+
+BEGIN {
+    #
+    # Parse command line
+    #
+    from_base = 0;
+    to_base   = 0;
+    for (i = 0; i < ARGC; i ++) {
+        if (ARGV [i] == "-f") {
+            from_base = 1
+        }
+        if (ARGV [i] == "-t") {
+            to_base = 1
+        }
+    }
+    ARGC = 0  # Prevent AWK to process the parameters.
+
+    #
+    # Map base-35 digits to base-10 numbers, and back
+    #
+    BASE   = 35
+    for (i = 0; i < 10; i ++) {
+        digits  [i] = i
+    }
+    for (i = 10; i < BASE; i ++) {
+        char = sprintf("%c", 65 + i - 10)
+        digits [i] = char
+        digits [char] = i
+    }
+}
+
+#
+# This is only executed if the -t option is used
+#
+to_base {
+    #
+    # Translate the input number from base 10 to base BASE,
+    # using a standard mod and divide approach.
+    #
+    number = $0
+    out = ""
+    while (number > 0) {
+        digit  = number % BASE
+        out    = digits [digit] out
+        number = int(number / BASE)
+    }
+}
+
+#
+# This is only executed if the -f option is used
+#
+from_base {
+    #
+    # Translate the input number from base BASE to base 10,
+    # using a standard multiply and add approach.
+    #
+    out = 0
+    n = split ($0, d, "")
+    for (i = 1; i <= n; i ++) {
+        out = BASE * out + digits [d [i]]
+    }
+}
+
+#
+# Always executed
+#
+{
+    print out
+}