added readme and license

LICENSE

@@ -0,0 +1,17 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+Copyright 2024 Aztec Labs
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

README.md

@@ -0,0 +1,55 @@
+# noir_base64
+
+A library to encode ASCII into Base64 and decode Base64 into ASCII
+
+# Usage
+
+### `fn base64_encode`
+Takees an input byte array of ASCII characters and produces an output byte array of base64-encoded characters. The 6-bit base64 characters are packed into a concatenated byte array (e.g. 4 bytes of ASCII produce 3 bytes of encoded Base64)
+
+### `fn base64_decode`
+Takes an input byte array of packed base64 characters and produces an output byte array of ASCII characters (e.g. 3 input bytes of base64 produces 4 output bytes of ASCII)
+
+### `fn base64_encode_elements`
+Takes an input byte array of ASCII characters and produces an output byte array of base64-encoded characters. Data is not packed i.e. each output array element maps to a 6-bit base64 character
+
+### `fn base64_decode_elements`
+Takes an input byte array of base64 characters and produces an output byte array of ASCII characters. Input data is not packed i.e. each input element maps to a 6-bit base64 character
+
+### Example usage
+(see tests in `lib.nr` for more examples)
+
+```
+use dep::noir_base64;
+fn encode() {
+    // Raw bh: GxMlgwLiypnVrE2C0Sf4yzhcWTkAhSZ5+WERhKhXtlU=
+    // Translated directly to ASCII
+    let input: [u8; 44] = [
+        71, 120, 77, 108, 103,
+        119, 76, 105, 121, 112,
+        110, 86, 114, 69, 50,
+        67, 48, 83, 102, 52,
+        121, 122, 104, 99, 87,
+        84, 107, 65, 104, 83,
+        90, 53, 43, 87, 69,
+        82, 104, 75, 104, 88,
+        116, 108, 85, 61
+    ];
+
+    // will produce packed byte array of base64 chars:
+    /*
+    [
+        27, 19, 37, 131, 2, 226, 202, 153, 213, 172,
+        77, 130, 209, 39, 248, 203, 56, 92, 89, 57,
+        0, 133, 38, 121, 249, 97, 17, 132, 168, 87,
+        182, 85
+    ]
+    */
+    let result: [u8; 32] = noir_base64::base64_encode(input);
+}
+```
+
+# Costs
+
+`base64_encode_elements` will encode an array of 44 ASCII bytes in ~470 gates, plus a ~256 gate cost to initialize an encoding lookup table (the initialization cost is incurred once regardless of the number of decodings)
+

src/lib.nr

@@ -175,13 +175,6 @@ pub fn base64_decode<let InputBytes: u64, let OutputElements: u64>(input: [u8; I
     base64_decode_elements(result)
 }
 
-// // to measure, run `info.sh`
-// fn main(x: [u8; 44]) {
-//     for i in 0..1 {
-//         let r: [u8; 32] = base64_encode(x);
-//         println(f"{r}");
-//     }
-// }
 
 // ooook so we take ascii and encode as base64, we get an undefined character
 #[test]