Refactor @uri and @urid and fix multi-byte UTF-8 corruption (#3495)

This commit improves performance by refactoring `@uri` and `@urid`
to pre-alloacte buffers and build the `jv` string at the end.
Also, this fixes `@urid` to prevent multi-byte UTF-8 corruption,
and to preserve embedded null bytes.

tests/uri.test

@@ -1,38 +1,92 @@
 # Tests are groups of three lines: program, input, expected output
 # Blank lines and lines starting with # are ignored
 
+# @uri
+
 @uri
-"<>&'\"\t"
-"%3C%3E%26%27%22%09"
+""
+""
 
-# decoding encoded output results in same text
-(@uri|@urid)
-"<>&'\"\t"
-"<>&'\"\t"
+@uri
+"\b\t\n\f\r\"\\"
+"%08%09%0A%0C%0D%22%5C"
+
+@uri
+",-./09:;<=>?@AZ[\\]^_`az{|}~\u007f"
+"%2C-.%2F09%3A%3B%3C%3D%3E%3F%40AZ%5B%5C%5D%5E_%60az%7B%7C%7D~%7F"
 
-# testing variable length unicode characters
 @uri
 "a \u03bc \u2230 \ud83d\ude0e"
 "a%20%CE%BC%20%E2%88%B0%20%F0%9F%98%8E"
 
+@uri
+"a\u0000b\u0000c"
+"a%00b%00c"
+
+# @urid
+
+@urid
+""
+""
+
+@urid
+"%08%09%0A%0C%0D%22%5C"
+"\b\t\n\f\r\"\\"
+
+@urid
+"%2C-.%2F09%3A%3B%3C%3D%3E%3F%40AZ%5B%5C%5D%5E_%60az%7B%7C%7D~%7F"
+",-./09:;<=>?@AZ[\\]^_`az{|}~\u007f"
+
 @urid
 "a%20%CE%BC%20%E2%88%B0%20%F0%9F%98%8E"
 "a \u03bc \u2230 \ud83d\ude0e"
 
-### invalid uri strings
+@urid
+"a%00b%00c"
+"a\u0000b\u0000c"
 
-# unicode character should be length 4 (not 3)
+@urid
+"hello world"
+"hello world"
+
+@urid
+"Knäckebröd"
+"Knäckebröd"
+
+@urid
+"%c3%a4b%c3%a7d%c3%ab"
+"äbçdë"
+
+@urid
+"a\u0000b\u0000c"
+"a\u0000b\u0000c"
+
+# '%' at end of string
 . | try @urid catch .
-"%F0%93%81"
-"string (\"%F0%93%81\") is not a valid uri encoding"
+"abc%"
+"string (\"abc%\") is not a valid uri encoding"
+
+# '%' followed by only one hex digit
+. | try @urid catch .
+"abc%f"
+"string (\"abc%f\") is not a valid uri encoding"
+
+# '%' followed by non-hex character
+. | try @urid catch .
+"abc%g"
+"string (\"abc%g\") is not a valid uri encoding"
 
 # invalid hex value ('FX')
 . | try @urid catch .
 "%FX%9F%98%8E"
 "string (\"%FX%9F%98%8E\") is not a valid uri encoding"
 
-# trailing utf-8 octets must be formatted like 10xxxxxx
-# 'C0' = 11000000 invalid
+# incomplete 4-byte UTF-8 sequence (only 3 bytes)
+. | try @urid catch .
+"%F0%93%81"
+"string (\"%F0%93%81\") is not a valid uri encoding"
+
+# invalid continuation byte (0xC0 is not 10xxxxxx)
 . | try @urid catch .
 "%F0%C0%81%8E"
 "string (\"%F0%C0%81%8E\") is not a valid uri encoding"