stdlib: add Base64 encoder

dora/stdlib/base64.dora

@@ -0,0 +1,18 @@
+use std.string.StringBuffer;
+
+let CHARS: String = "-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz";
+
+@pub
+fun encode(src: Array[UInt8]): String {
+  let buffer = StringBuffer::new();
+  var i = 0;
+  while (i < src.size()) {
+    let bits = src(i).toInt32().shiftLeft(16i32) | src(i+1).toInt32().shiftLeft(8i32) | src(i+2).toInt32();
+    i = i + 3;
+    buffer.appendChar(CHARS.getByte(bits.shiftRight(18i32).asInt64() & 0b111111).toChar());
+    buffer.appendChar(CHARS.getByte(bits.shiftRight(12i32).asInt64() & 0b111111).toChar());
+    buffer.appendChar(CHARS.getByte(bits.shiftRight( 6i32).asInt64() & 0b111111).toChar());
+    buffer.appendChar(CHARS.getByte(bits                  .asInt64() & 0b111111).toChar());
+  }
+  return buffer.toString();
+}

dora/stdlib/stdlib.dora

@@ -6,6 +6,7 @@
 @pub use thread.{AtomicInt32, AtomicInt64, Condition, Mutex, Thread};
 
 @pub mod annotations;
+@pub mod base64;
 @pub mod collections;
 @pub mod primitives;
 @pub mod rand;

tests/base64/base64.dora

@@ -0,0 +1,16 @@
+fun main(): Unit {
+  bytes3();
+  bytes15();
+}
+
+fun bytes3(): Unit {
+  let bytes = Array[UInt8]::new(0u8, 12u8, 23u8);
+  let string = std::base64::encode(bytes);
+  println(string);
+}
+
+fun bytes15(): Unit {
+  let bytes = Array[UInt8]::new(0u8, 12u8, 23u8, 45u8, 67u8, 78u8, 89u8, 91u8, 12u8, 23u8, 45u8, 67u8, 78u8, 89u8, 91u8);
+  let string = std::base64::encode(bytes);
+  println(string);
+}

tests/fatal1.dora

@@ -1,5 +1,5 @@
 //= error code 1
-//= stderr "fatal error: bla\n    std::fatalError (stdlib/stdlib.dora:16)\n    main (tests/fatal1.dora:5)\n"
+//= stderr "fatal error: bla\n    std::fatalError (stdlib/stdlib.dora:17)\n    main (tests/fatal1.dora:5)\n"
 
 fun main(): Unit {
     std::fatalError("bla");