Add base64 lib

3 files changed, 100 insertions, 0 deletions

diff --git a/examples/README.md b/examples/README.md
index 4cf3562c..157ac7a3 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -1,5 +1,6 @@
 # Example Programs
 
+- [base64](base64/): A base64 encoding/decoding library.
 - [game](game/): An example game using raylib.
 - [http](http/http.tm): An HTTP library to make basic synchronous HTTP requests.
 - [ini](ini/ini.tm): An INI configuration file reader tool.
diff --git a/examples/base64/README.md b/examples/base64/README.md
new file mode 100644
index 00000000..8db0f8ec
--- /dev/null
+++ b/examples/base64/README.md
@@ -0,0 +1,3 @@
+# Base64
+
+This is a library for encoding/decoding Base64 values.
diff --git a/examples/base64/base64.tm b/examples/base64/base64.tm
new file mode 100644
index 00000000..e765d86a
--- /dev/null
+++ b/examples/base64/base64.tm
@@ -0,0 +1,96 @@
+# Base 64 encoding and decoding
+
+_enc := "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/":utf8_bytes()
+
+_EQUAL_BYTE := 0x3D[B]
+
+_dec := [
+    255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
+    255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
+    255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
+    255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
+    255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
+    255[B], 255[B], 255[B], 62[B],  255[B], 255[B], 255[B], 63[B],
+    52[B],  53[B],  54[B],  55[B],  56[B],  57[B],  58[B],  59[B],
+    60[B],  61[B],  255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
+    255[B], 0[B],   1[B],   2[B],   3[B],   4[B],   5[B],   6[B],
+    7[B],   8[B],   9[B],   10[B],  11[B],  12[B],  13[B],  14[B],
+    15[B],  16[B],  17[B],  18[B],  19[B],  20[B],  21[B],  22[B],
+    23[B],  24[B],  25[B],  255[B], 255[B], 255[B], 255[B], 255[B],
+    255[B], 26[B],  27[B],  28[B],  29[B],  30[B],  31[B],  32[B],
+    33[B],  34[B],  35[B],  36[B],  37[B],  38[B],  39[B],  40[B],
+    41[B],  42[B],  43[B],  44[B],  45[B],  46[B],  47[B],  48[B],
+    49[B],  50[B],  51[B],  255[B], 255[B], 255[B], 255[B], 255[B],
+]
+
+lang Base64:
+    func from_text(text:Text -> Base64?):
+        return Base64.from_bytes(text:utf8_bytes())
+
+    func from_bytes(bytes:[Byte] -> Base64?):
+        output := [0[B] for _ in bytes.length * 4 / 3 + 4]
+        src := 1[64]
+        dest := 1[64]
+        while src + 2[64] <= bytes.length:
+            chunk24 := (
+                (Int32(bytes[src]) <<< 16) or (Int32(bytes[src+1[64]]) <<< 8) or Int32(bytes[src+2[64]])
+            )
+            src += 3
+
+            output[dest]       = _enc[1[32] + ((chunk24 >>> 18) and 0b111111[32])]
+            output[dest+1[64]] = _enc[1[32] + ((chunk24 >>> 12) and 0b111111[32])]
+            output[dest+2[64]] = _enc[1[32] + ((chunk24 >>> 6) and 0b111111[32])]
+            output[dest+3[64]] = _enc[1[32] + (chunk24 and 0b111111[32])]
+            dest += 4
+
+        if src + 1[64] == bytes.length:
+            chunk16 := (
+                (Int32(bytes[src]) <<< 8) or Int32(bytes[src+1[64]])
+            )
+            output[dest]       = _enc[1[32] + ((chunk16 >>> 10) and 0b111111[32])]
+            output[dest+1[64]] = _enc[1[32] + ((chunk16 >>> 4) and 0b111111[32])]
+            output[dest+2[64]] = _enc[1[32] + ((chunk16 <<< 2)and 0b111111[32])]
+            output[dest+3[64]] = _EQUAL_BYTE
+        else if src == bytes.length:
+            chunk8 := Int32(bytes[src])
+            output[dest]       = _enc[1[32] + ((chunk8 >>> 2) and 0b111111[32])]
+            output[dest+1[64]] = _enc[1[32] + ((chunk8 <<< 4) and 0b111111[32])]
+            output[dest+2[64]] = _EQUAL_BYTE
+            output[dest+3[64]] = _EQUAL_BYTE
+
+        return Base64.without_escaping(Text.from_bytes(output) or return !Base64)
+
+    func decode_text(b64:Base64 -> Text?):
+        return Text.from_bytes(b64:decode_bytes() or return !Text)
+
+    func decode_bytes(b64:Base64 -> [Byte]?):
+        bytes := b64.text_content:utf8_bytes()
+        output := [0[B] for _ in bytes.length/4 * 3]
+        src := 1[64]
+        dest := 1[64]
+        while src + 3[64] <= bytes.length:
+            chunk24 := (
+                (Int32(_dec[1[B]+bytes[src]]) <<< 18) or
+                (Int32(_dec[1[B]+bytes[src+1[64]]]) <<< 12) or
+                (Int32(_dec[1[B]+bytes[src+2[64]]]) <<< 6) or
+                Int32(_dec[1[B]+bytes[src+3[64]]])
+            )
+            src += 4
+
+            output[dest]       = Byte((chunk24 >>> 16) and 0xFF[32])
+            output[dest+1[64]] = Byte((chunk24 >>> 8) and 0xFF[32])
+            output[dest+2[64]] = Byte(chunk24 and 0xFF[32])
+            dest += 3
+
+        while output[-1] == 0xFF[B]:
+            output = output:to(-2)
+
+        return output
+
+func main(input=(/dev/stdin), decode=no):
+    if decode:
+        b := Base64.without_escaping(input:read()!)
+        say(b:decode_text()!)
+    else:
+        text := input:read()!
+        say(Base64.from_text(text)!.text_content)