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Task/URL-decoding/AWK/url-decoding.awk

@@ -0,0 +1,18 @@
+# syntax: GAWK -f URL_DECODING.AWK
+BEGIN {
+    str = "http%3A%2F%2Ffoo%20bar%2F" # "http://foo bar/"
+    printf("%s\n",str)
+    while (match(str,/%/)) {
+      L = substr(str,1,RSTART-1) # chars to left of "%"
+      M = substr(str,RSTART+1,2) # 2 chars to right of "%"
+      R = substr(str,RSTART+3)   # chars to right of "%xx"
+      str = sprintf("%s%c%s",L,hex2dec(M),R)
+    }
+    printf("%s\n",str)
+    exit(0)
+}
+function hex2dec(s,  num) {
+    num = index("0123456789ABCDEF",toupper(substr(s,length(s)))) - 1
+    sub(/.$/,"",s)
+    return num + (length(s) ? 16*hex2dec(s) : 0)
+}