use base64 crate for encoding

Cargo.toml

@@ -40,6 +40,7 @@ deflate = { version = "0.9.1", optional = true }
 sha1 = { version = "0.6.0", features = ["std"] }
 tempfile = "3.2.0"
 futures = "0.3.17"
+base64 = "=0.20.0-alpha.1"
 
 [dev-dependencies]
 pretty_assertions = "1.0.0"

src/base64_plantuml.rs

@@ -1,68 +1,19 @@
 use std::vec::Vec;
 
-/// PlantUML has its own base64 dialect, this struct provides the implementation for that
-pub struct Base64PlantUML {}
-
-impl Base64PlantUML {
-    pub fn encode(data: &Vec<u8>) -> String {
-        let mut encoded = String::from("");
-
-        let len = data.len();
-        for i in (0..len).step_by(3) {
-            if i + 2 == len {
-                encoded.push_str(&encode3bytes(data[i], data[i + 1], 0));
-            } else if i + 1 == len {
-                encoded.push_str(&encode3bytes(data[i], 0, 0));
-            } else {
-                encoded.push_str(&encode3bytes(data[i], data[i + 1], data[i + 2]));
-            }
-        }
-
-        encoded
-    }
-}
-
-fn encode3bytes(b1: u8, b2: u8, b3: u8) -> String {
-    let c1 = b1 >> 2;
-    let c2 = ((b1 & 0x3) << 4) | (b2 >> 4);
-    let c3 = ((b2 & 0xF) << 2) | (b3 >> 6);
-    let c4 = b3 & 0x3F;
-
-    let mut res = String::from("");
-    res.push(encode6bit(c1 & 0x3F));
-    res.push(encode6bit(c2 & 0x3F));
-    res.push(encode6bit(c3 & 0x3F));
-    res.push(encode6bit(c4 & 0x3F));
-
-    res
-}
-
-fn encode6bit(c: u8) -> char {
-    let mut b = c;
-    if b < 10 {
-        return (48 + b) as char;
-    }
-
-    b -= 10;
-    if b < 26 {
-        return (65 + b) as char;
-    }
-
-    b -= 26;
-    if b < 26 {
-        return (97 + b) as char;
-    }
-
-    b -= 26;
-    if b == 0 {
-        return '-';
-    }
-
-    if b == 1 {
-        return '_';
-    }
-
-    '?'
+use base64::{
+    alphabet::Alphabet,
+    engine::fast_portable::{self, FastPortable},
+};
+
+const ENGINE: FastPortable =
+    match Alphabet::from_str("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_") {
+        Ok(alphabet) => FastPortable::from(&alphabet, fast_portable::PAD),
+        Err(_e) => unreachable!(),
+    };
+
+/// PlantUML has its own base64 dialect
+pub fn encode(data: &Vec<u8>) -> String {
+    base64::encode_engine(data, &ENGINE)
 }
 
 #[cfg(test)]
@@ -73,13 +24,10 @@ mod tests {
     #[test]
     fn encodes_bytes() {
         let data: Vec<u8> = b"froboz".iter().cloned().collect();
-        assert_eq!(String::from("Pd9lOczw"), Base64PlantUML::encode(&data));
+        assert_eq!(String::from("Pd9lOczw"), encode(&data));
 
         let data: Vec<u8> = b"1234ABCDabcd\x12\x08\x01".iter().cloned().collect();
-        assert_eq!(
-            String::from("CJ8pD452GqHXOcDa4WW1"),
-            Base64PlantUML::encode(&data)
-        );
+        assert_eq!(String::from("CJ8pD452GqHXOcDa4WW1"), encode(&data));
 
         //How would one pass 256 here?
         let data: Vec<u8> = (0 as u8..255 as u8).collect();
@@ -92,7 +40,7 @@ mod tests {
                  YvkhkylRw_mC72myJ5niV8oShBpCtEpz3HqjFKrTRNsDdQszpTtj_WuUBZvENcv-\
                  ZfwklixUxlyF7oy_JrzlVu-Vhx_Ft-"
             ),
-            Base64PlantUML::encode(&data)
+            encode(&data)
         );
     }
 }

src/plantuml_server_backend.rs

@@ -1,4 +1,4 @@
-use crate::base64_plantuml::Base64PlantUML;
+use crate::base64_plantuml;
 use crate::plantuml_backend::PlantUMLBackend;
 use deflate::deflate_bytes;
 use failure::Error;
@@ -94,10 +94,8 @@ impl PlantUMLServer {
 
 /// Compress and encode the image source, return the encoed Base64-ish string
 fn encode_diagram_source(plantuml_code: &String) -> String {
-    let compressed = deflate_bytes(&plantuml_code.as_bytes());
-    let base64_compressed = Base64PlantUML::encode(&compressed);
-
-    base64_compressed
+    let compressed = deflate_bytes(plantuml_code.as_bytes());
+    base64_plantuml::encode(&compressed)
 }
 
 impl PlantUMLBackend for PlantUMLServer {