// Generated by CoffeeScript 1.6.3
/*
# a collection of utility methods for Buffer
#
# 这个工具类的设计以实现两个目地
# 1. 读写方法，匹配 Actionscript 的 ByteArray 读写方法
# 2. ActionScript 的默认采用 big endian，这个工具方法，对此进行封装，以是外部不用关心 endian
#
*/


(function() {
  module.exports = {
    readUTF: function(buf, offset) {
      var len;
      if (!Buffer.isBuffer(buf)) {
        return null;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      if (buf.length <= offset + 2) {
        return null;
      }
      len = buf.readUInt16BE(offset);
      if (buf.length < len + offset) {
        return null;
      }
      offset += 2;
      buf.position = offset + len;
      return buf.toString('utf8', offset, offset + len);
    },
    readUTFBytes: function(buf, length, offset) {
      if (!Buffer.isBuffer(buf)) {
        return null;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      if (buf.length <= offset) {
        return null;
      }
      buf.position = offset + length;
      return buf.toString('utf8', offset, offset + length);
    },
    readFixLengthASCII: function(buf, offset) {
      var len;
      if (!Buffer.isBuffer(buf)) {
        return null;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      if (buf.length <= offset + 2) {
        return null;
      }
      len = buf.readUInt8(offset);
      if (buf.length < len + offset) {
        return null;
      }
      offset += 1;
      buf.position = offset + len;
      return buf.toString('utf8', offset, offset + len);
    },
    readUnsignedShort: function(buf, offset) {
      if (!Buffer.isBuffer(buf)) {
        return 0;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.position = offset + 2;
      return buf.readUInt16BE(offset);
    },
    readShort: function(buf, offset) {
      if (!Buffer.isBuffer(buf)) {
        return 0;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.position = offset + 2;
      return buf.readInt16BE(offset);
    },
    readUnsignedByte: function(buf, offset) {
      if (!Buffer.isBuffer(buf)) {
        return 0;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.position = offset + 1;
      return buf.readUInt8(offset);
    },
    readByte: function(buf, offset) {
      if (!Buffer.isBuffer(buf)) {
        return 0;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.position = offset + 1;
      return buf.readInt8(offset);
    },
    readUnsignedInt: function(buf, offset) {
      if (!Buffer.isBuffer(buf)) {
        return 0;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.position = offset + 4;
      return buf.readUInt32BE(offset);
    },
    readInt: function(buf, offset) {
      if (!Buffer.isBuffer(buf)) {
        return 0;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.position = offset + 4;
      return buf.readInt32BE(offset);
    },
    readFloat: function(buf, offset) {
      if (!Buffer.isBuffer(buf)) {
        return 0;
      }
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.position = offset + 4;
      return buf.readFloatLE(offset);
    },
    readUnsignedIntArray: function(buf, offset) {
      var a, arr, len;
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      len = buf.readUInt16BE(offset) >>> 2;
      offset += 2;
      arr = [];
      if (len === 0 || len > 1024) {
        buf.position = offset;
        return arr;
      }
      while (len > 0) {
        a = buf.readUInt32BE(offset);
        arr.push(a);
        offset += 4;
        len -= 1;
      }
      buf.position = offset;
      return arr;
    },
    writeUnsignedInt: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeUInt32BE(value, offset);
      buf.position = offset + 4;
    },
    writeInt: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeInt32BE(value, offset);
      buf.position = offset + 4;
    },
    writeFloat: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeFloatLE(value, offset);
      buf.position = offset + 4;
    },
    writeUnsignedShort: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeUInt16BE(value, offset);
      buf.position = offset + 2;
    },
    writeShort: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeInt16BE(value, offset);
      buf.position = offset + 2;
    },
    writeUnsignedByte: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeUInt8(value, offset);
      buf.position = offset + 1;
    },
    writeByte: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeInt8(value, offset);
      buf.position = offset + 1;
    },
    writeBoolean: function(buf, value, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      value = value ? 1 : 0;
      buf.writeInt8(value, offset);
      buf.position = offset + 1;
    },
    writeFixLengthASCII: function(buf, str, maxNumOfChar, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.writeUInt8(maxNumOfChar, offset);
      offset += 1;
      buf.fill(0x20, offset, offset + maxNumOfChar);
      buf.write(str, offset, maxNumOfChar, 'ascii');
      buf.position = offset + maxNumOfChar;
    },
    writeFixLengthUTF: function(buf, str, maxNumOfChar, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      maxNumOfChar *= 6;
      buf.writeUInt16BE(maxNumOfChar, offset);
      offset += 2;
      buf.fill(0x20, offset, offset + maxNumOfChar);
      buf.write(str, offset, maxNumOfChar, 'utf8');
      buf.position = offset + maxNumOfChar;
    },
    writeUTF: function(buf, str, offset) {
      var byteLength;
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      byteLength = Buffer.byteLength(str);
      buf.writeUInt16BE(byteLength, offset);
      offset += 2;
      buf.write(str, offset);
      buf.position = offset + byteLength;
    },
    writeUTFBytes: function(buf, str, offset) {
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      buf.write(str, offset);
      buf.position = offset + Buffer.byteLength(str);
    },
    writeUTFArray: function(buf, strArray, offset) {
      var byteLength, str, _i, _len;
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      if (!((strArray != null) && strArray.length > 0)) {
        buf.writeUInt16BE(0, offset);
        buf.position = offset + 2;
        return;
      }
      buf.writeUInt16BE(strArray.length, offset);
      offset += 2;
      for (_i = 0, _len = strArray.length; _i < _len; _i++) {
        str = strArray[_i];
        byteLength = Buffer.byteLength(str);
        buf.writeUInt16BE(byteLength, offset);
        offset += 2;
        buf.write(str, offset);
        offset += byteLength;
      }
      return buf.position = offset;
    },
    getByteLengthOfUTFArray: function(strArray) {
      var len, str, _i, _len;
      len = 2;
      if (!((strArray != null) && strArray.length > 0)) {
        return len;
      }
      for (_i = 0, _len = strArray.length; _i < _len; _i++) {
        str = strArray[_i];
        len = len + 2 + Buffer.byteLength(str);
      }
      return len;
    },
    writeUnsignedIntArray: function(buf, arr, fixedLength, offset) {
      var i, n, _i, _len;
      if (fixedLength == null) {
        fixedLength = -1;
      }
      arr = arr || [];
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      n = arr.length;
      if (fixedLength > 0 && fixedLength !== n) {
        if (fixedLength < n) {
          arr = arr.slice(0, fixedLength);
        } else {
          arr = arr.concat();
          arr.length = fixedLength;
        }
        n = fixedLength;
      }
      n = n << 2;
      buf.writeUInt16BE(n, offset);
      offset += 2;
      for (_i = 0, _len = arr.length; _i < _len; _i++) {
        i = arr[_i];
        buf.writeUInt32BE(parseInt(i, 10) || 0, offset);
        offset += 4;
      }
      buf.position = offset;
    },
    getByteLengthOfIntArray: function(arr) {
      return (arr.length << 2) + 2;
    },
    writeUnsignedShortArray: function(buf, arr, fixedLength, offset) {
      var i, n, _i, _len;
      if (fixedLength == null) {
        fixedLength = -1;
      }
      arr = arr || [];
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      n = arr.length;
      if (fixedLength > 0 && fixedLength !== n) {
        if (fixedLength < n) {
          arr = arr.slice(0, fixedLength);
        } else {
          arr = arr.concat();
          arr.length = fixedLength;
        }
        n = fixedLength;
      }
      n = n << 1;
      buf.writeUInt16BE(n, offset);
      offset += 2;
      for (_i = 0, _len = arr.length; _i < _len; _i++) {
        i = arr[_i];
        buf.writeUInt16BE(parseInt(i, 10) || 0, offset);
        offset += 2;
      }
      buf.position = offset;
    },
    getBytesAvailable: function(buf) {
      if (buf != null) {
        return buf.length - (buf.position || 0);
      } else {
        return 0;
      }
    },
    scrap: function(buf, length) {
      var offset, result;
      if (!((buf != null) && length > 0)) {
        return null;
      }
      offset = buf.position || 0;
      if (length + offset > buf.length) {
        return null;
      }
      result = new Buffer(length);
      buf.copy(result, 0, offset, offset + length);
      buf.position = offset + length;
      return result;
    },
    duplicate: function(buf) {
      var n, result;
      n = buf.length || 0;
      if (n === 0) {
        return null;
      }
      result = new Buffer(n);
      buf.copy(result, 0, 0, n);
      return result;
    },
    utfStringToBuf: function(str) {
      var buf, n;
      str = String(str || '');
      n = Buffer.byteLength(str, 'utf8');
      buf = new Buffer(n + 2);
      buf.writeUInt16BE(n, 0);
      buf.write(str, 2);
      return buf;
    },
    isAvailableBuf: function(buf) {
      return Buffer.isBuffer(buf) && buf.length > 0;
    },
    writeIntArray: function(buf, arr, fixedLength, offset) {
      var i, n, _i, _len;
      if (fixedLength == null) {
        fixedLength = -1;
      }
      arr = arr || [];
      offset = offset < 0 ? buf.length + offset : (offset === 0 ? 0 : offset || buf.position || 0);
      n = arr.length;
      if (fixedLength > 0 && fixedLength !== n) {
        if (fixedLength < n) {
          arr = arr.slice(0, fixedLength);
        } else {
          arr = arr.concat();
          arr.length = fixedLength;
        }
        n = fixedLength;
      }
      n = n << 2;
      buf.writeUInt16BE(n, offset);
      offset += 2;
      for (_i = 0, _len = arr.length; _i < _len; _i++) {
        i = arr[_i];
        buf.writeInt32BE(parseInt(i, 10) || 0, offset);
        offset += 4;
      }
      buf.position = offset;
    }
  };

}).call(this);