contents of zip

scripts/bit_writer.js

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+// Use strict
+"use strict";
+
+
+// Classes
+
+// Bit writer class
+class BitWriter {
+
+	// Public
+
+		// Constructor
+		constructor() {
+		
+			// Set data
+			this.data = new Uint8Array([]);
+			
+			// Initialize byte index
+			this.byteIndex = 0;
+			
+			// Initialize bit index
+			this.bitIndex = 0;
+		}
+		
+		// Set bits
+		setBits(value, numberOfBits) {
+		
+			// Go through all bytes past one byte
+			while(numberOfBits > Common.BITS_IN_A_BYTE) {
+			
+				// Set byte
+				this.setBits(value >>> (Common.BITS_IN_A_BYTE * (Math.floor(numberOfBits / Common.BITS_IN_A_BYTE) - 1) + numberOfBits % Common.BITS_IN_A_BYTE), Math.min(numberOfBits, Common.BITS_IN_A_BYTE));
+				
+				// Update number of bits
+				numberOfBits -= Common.BITS_IN_A_BYTE;
+			}
+			
+			// Check if no bits requested
+			if(numberOfBits === 0) {
+			
+				// Return
+				return;
+			}
+			
+			// Check if more data is needed
+			if(this.bitIndex === 0 || this.bitIndex + numberOfBits > Common.BITS_IN_A_BYTE) {
+			
+				// Increase data's size by one
+				var temp = new Uint8Array(this.data["length"] + 1);
+				
+				temp.set(this.data);
+				
+				this.data = temp;
+			}
+			
+			// Check if value will overflow into the next byte
+			if(this.bitIndex + numberOfBits > Common.BITS_IN_A_BYTE) {
+			
+				// Include data in value at byte index
+				this.data[this.byteIndex] |= value >>> ((this.bitIndex + numberOfBits) - Common.BITS_IN_A_BYTE);
+				
+				// Include data in value at next byte index
+				this.data[this.byteIndex + 1] |= value << (Common.BITS_IN_A_BYTE * 2 - (this.bitIndex + numberOfBits));
+			}
+			
+			// Otherwise
+			else {
+			
+				// Include data in value at byte index
+				this.data[this.byteIndex] |= value << (Common.BITS_IN_A_BYTE - (this.bitIndex + numberOfBits));
+			}
+			
+			// Update bit index
+			this.bitIndex += numberOfBits;
+			
+			// Check if bit index overflowed into the next byte
+			if(this.bitIndex >= Common.BITS_IN_A_BYTE) {
+			
+				// Increment byte index
+				++this.byteIndex;
+			
+				// Correct bit index
+				this.bitIndex %= Common.BITS_IN_A_BYTE;
+			}
+		}
+		
+		// Set bytes
+		setBytes(bytes) {
+		
+			// Go through all bytes
+			for(var i = 0; i < bytes["length"]; ++i) {
+			
+				// Set byte in the data
+				this.setBits(bytes[i], Common.BITS_IN_A_BYTE);
+			}
+		}
+		
+		// Get bytes
+		getBytes() {
+		
+			// Return data
+			return this.data;
+		}
+}
+
+
+// Main function
+
+// Set global object's bit writer
+globalThis["BitWriter"] = BitWriter;