port BitSourceBuilder

src/common/mod.rs

@@ -1999,3 +1999,71 @@ impl DecoderRXingResult {
         self.symbologyModifier
     }
 }
+
+/*
+ * Copyright 2008 ZXing authors
+ *
+ * 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.
+ */
+
+// package com.google.zxing.common;
+
+// import java.io.ByteArrayOutputStream;
+
+/**
+ * Class that lets one easily build an array of bytes by appending bits at a time.
+ *
+ * @author Sean Owen
+ */
+pub struct BitSourceBuilder {
+    output: Vec<u8>,
+    nextByte: u32,
+    bitsLeftInNextByte: u32,
+}
+
+impl BitSourceBuilder {
+    pub fn new() -> Self {
+        Self {
+            output: Vec::new(),
+            nextByte: 0,
+            bitsLeftInNextByte: 8,
+        }
+    }
+
+    pub fn write(&mut self, value: u32, numBits: u32) {
+        if numBits <= self.bitsLeftInNextByte {
+            self.nextByte <<= numBits;
+            self.nextByte |= value;
+            self.bitsLeftInNextByte -= numBits;
+            if self.bitsLeftInNextByte == 0 {
+                self.output.push(self.nextByte as u8);
+                self.nextByte = 0;
+                self.bitsLeftInNextByte = 8;
+            }
+        } else {
+            let bitsToWriteNow = self.bitsLeftInNextByte;
+            let numRestOfBits = numBits - bitsToWriteNow;
+            let mask = 0xFF >> (8 - bitsToWriteNow);
+            let valueToWriteNow = (value >> numRestOfBits) & mask;
+            self.write(valueToWriteNow, bitsToWriteNow);
+            self.write(value, numRestOfBits);
+        }
+    }
+
+    pub fn toByteArray(&mut self) -> &Vec<u8> {
+        if self.bitsLeftInNextByte < 8 {
+            self.write(0, self.bitsLeftInNextByte);
+        }
+        &self.output
+    }
+}