Move src files

src/js/huffman.js

@@ -0,0 +1,60 @@
+'use strict';
+
+var HUFFMAN_EOF = -1;
+
+function huffmanDecodeBuf(inBuf, inBufCharacterCount, huffmanTree, huffmanLenIndex)
+{
+    var code = 0;
+    var codeLen = 0;
+    var testBit = 0x80;
+    var eof = false;
+    var outBuf = [];
+
+    while (!eof && inBuf.byteLength != 0) {
+        if (outBuf.length == inBufCharacterCount) {
+            // we've exhausted the input stream, discard any odd bits on the end
+            break;
+        }
+
+        if (inBuf.byteLength == 0) {
+            throw new Error('unexpected');
+        }
+
+        // get the next bit from the input buffer
+        code <<= 1;
+        ++codeLen;
+        if (inBuf[0] & testBit) {
+            code |= 0x01;
+        }
+        testBit >>= 1;
+        if (testBit == 0) {
+            testBit = 0x80;
+            inBuf = inBuf.subarray(1);
+        }
+
+        // check if the code is a leaf node or an interior node
+        if (huffmanLenIndex[codeLen] != -1) {
+            // look for the code in the tree, only leaf nodes are stored in the tree
+            for (var i = huffmanLenIndex[codeLen]; (i < huffmanTree.length) && (huffmanTree[i].codeLen == codeLen); ++i) {
+                if (huffmanTree[i].code == code) {
+                    // we've found the code, so it is a leaf node
+                    var value = huffmanTree[i].value;
+
+                    if (value == HUFFMAN_EOF) {
+                        eof = true;
+                    } else {
+                        // output the value
+                        outBuf.push(value);
+                    }
+
+                    // reset the code to continue decompressing the input buffer
+                    code = 0;
+                    codeLen = 0;
+                    break;
+                }
+            }
+        }
+    }
+
+    return new Uint8Array(outBuf);
+}