'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }(); /**
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      * Parser for exponential Golomb codes, a variable-bitwidth number encoding scheme used by h264.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     */

var _logger = require('../utils/logger');

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

var ExpGolomb = function () {
  function ExpGolomb(data) {
    _classCallCheck(this, ExpGolomb);

    this.data = data;
    // the number of bytes left to examine in this.data
    this.bytesAvailable = data.byteLength;
    // the current word being examined
    this.word = 0; // :uint
    // the number of bits left to examine in the current word
    this.bitsAvailable = 0; // :uint
  }

  // ():void


  _createClass(ExpGolomb, [{
    key: 'loadWord',
    value: function loadWord() {
      var data = this.data,
          bytesAvailable = this.bytesAvailable,
          position = data.byteLength - bytesAvailable,
          workingBytes = new Uint8Array(4),
          availableBytes = Math.min(4, bytesAvailable);
      if (availableBytes === 0) {
        throw new Error('no bytes available');
      }
      workingBytes.set(data.subarray(position, position + availableBytes));
      this.word = new DataView(workingBytes.buffer).getUint32(0);
      // track the amount of this.data that has been processed
      this.bitsAvailable = availableBytes * 8;
      this.bytesAvailable -= availableBytes;
    }

    // (count:int):void

  }, {
    key: 'skipBits',
    value: function skipBits(count) {
      var skipBytes; // :int
      if (this.bitsAvailable > count) {
        this.word <<= count;
        this.bitsAvailable -= count;
      } else {
        count -= this.bitsAvailable;
        skipBytes = count >> 3;
        count -= skipBytes >> 3;
        this.bytesAvailable -= skipBytes;
        this.loadWord();
        this.word <<= count;
        this.bitsAvailable -= count;
      }
    }

    // (size:int):uint

  }, {
    key: 'readBits',
    value: function readBits(size) {
      var bits = Math.min(this.bitsAvailable, size),
          // :uint
      valu = this.word >>> 32 - bits; // :uint
      if (size > 32) {
        _logger.logger.error('Cannot read more than 32 bits at a time');
      }
      this.bitsAvailable -= bits;
      if (this.bitsAvailable > 0) {
        this.word <<= bits;
      } else if (this.bytesAvailable > 0) {
        this.loadWord();
      }
      bits = size - bits;
      if (bits > 0 && this.bitsAvailable) {
        return valu << bits | this.readBits(bits);
      } else {
        return valu;
      }
    }

    // ():uint

  }, {
    key: 'skipLZ',
    value: function skipLZ() {
      var leadingZeroCount; // :uint
      for (leadingZeroCount = 0; leadingZeroCount < this.bitsAvailable; ++leadingZeroCount) {
        if (0 !== (this.word & 0x80000000 >>> leadingZeroCount)) {
          // the first bit of working word is 1
          this.word <<= leadingZeroCount;
          this.bitsAvailable -= leadingZeroCount;
          return leadingZeroCount;
        }
      }
      // we exhausted word and still have not found a 1
      this.loadWord();
      return leadingZeroCount + this.skipLZ();
    }

    // ():void

  }, {
    key: 'skipUEG',
    value: function skipUEG() {
      this.skipBits(1 + this.skipLZ());
    }

    // ():void

  }, {
    key: 'skipEG',
    value: function skipEG() {
      this.skipBits(1 + this.skipLZ());
    }

    // ():uint

  }, {
    key: 'readUEG',
    value: function readUEG() {
      var clz = this.skipLZ(); // :uint
      return this.readBits(clz + 1) - 1;
    }

    // ():int

  }, {
    key: 'readEG',
    value: function readEG() {
      var valu = this.readUEG(); // :int
      if (0x01 & valu) {
        // the number is odd if the low order bit is set
        return 1 + valu >>> 1; // add 1 to make it even, and divide by 2
      } else {
        return -1 * (valu >>> 1); // divide by two then make it negative
      }
    }

    // Some convenience functions
    // :Boolean

  }, {
    key: 'readBoolean',
    value: function readBoolean() {
      return 1 === this.readBits(1);
    }

    // ():int

  }, {
    key: 'readUByte',
    value: function readUByte() {
      return this.readBits(8);
    }

    // ():int

  }, {
    key: 'readUShort',
    value: function readUShort() {
      return this.readBits(16);
    }
    // ():int

  }, {
    key: 'readUInt',
    value: function readUInt() {
      return this.readBits(32);
    }

    /**
     * Advance the ExpGolomb decoder past a scaling list. The scaling
     * list is optionally transmitted as part of a sequence parameter
     * set and is not relevant to transmuxing.
     * @param count {number} the number of entries in this scaling list
     * @see Recommendation ITU-T H.264, Section 7.3.2.1.1.1
     */

  }, {
    key: 'skipScalingList',
    value: function skipScalingList(count) {
      var lastScale = 8,
          nextScale = 8,
          j,
          deltaScale;
      for (j = 0; j < count; j++) {
        if (nextScale !== 0) {
          deltaScale = this.readEG();
          nextScale = (lastScale + deltaScale + 256) % 256;
        }
        lastScale = nextScale === 0 ? lastScale : nextScale;
      }
    }

    /**
     * Read a sequence parameter set and return some interesting video
     * properties. A sequence parameter set is the H264 metadata that
     * describes the properties of upcoming video frames.
     * @param data {Uint8Array} the bytes of a sequence parameter set
     * @return {object} an object with configuration parsed from the
     * sequence parameter set, including the dimensions of the
     * associated video frames.
     */

  }, {
    key: 'readSPS',
    value: function readSPS() {
      var frameCropLeftOffset = 0,
          frameCropRightOffset = 0,
          frameCropTopOffset = 0,
          frameCropBottomOffset = 0,
          profileIdc,
          profileCompat,
          levelIdc,
          numRefFramesInPicOrderCntCycle,
          picWidthInMbsMinus1,
          picHeightInMapUnitsMinus1,
          frameMbsOnlyFlag,
          scalingListCount,
          i,
          readUByte = this.readUByte.bind(this),
          readBits = this.readBits.bind(this),
          readUEG = this.readUEG.bind(this),
          readBoolean = this.readBoolean.bind(this),
          skipBits = this.skipBits.bind(this),
          skipEG = this.skipEG.bind(this),
          skipUEG = this.skipUEG.bind(this),
          skipScalingList = this.skipScalingList.bind(this);

      readUByte();
      profileIdc = readUByte(); // profile_idc
      profileCompat = readBits(5); // constraint_set[0-4]_flag, u(5)
      skipBits(3); // reserved_zero_3bits u(3),
      levelIdc = readUByte(); //level_idc u(8)
      skipUEG(); // seq_parameter_set_id
      // some profiles have more optional data we don't need
      if (profileIdc === 100 || profileIdc === 110 || profileIdc === 122 || profileIdc === 244 || profileIdc === 44 || profileIdc === 83 || profileIdc === 86 || profileIdc === 118 || profileIdc === 128) {
        var chromaFormatIdc = readUEG();
        if (chromaFormatIdc === 3) {
          skipBits(1); // separate_colour_plane_flag
        }
        skipUEG(); // bit_depth_luma_minus8
        skipUEG(); // bit_depth_chroma_minus8
        skipBits(1); // qpprime_y_zero_transform_bypass_flag
        if (readBoolean()) {
          // seq_scaling_matrix_present_flag
          scalingListCount = chromaFormatIdc !== 3 ? 8 : 12;
          for (i = 0; i < scalingListCount; i++) {
            if (readBoolean()) {
              // seq_scaling_list_present_flag[ i ]
              if (i < 6) {
                skipScalingList(16);
              } else {
                skipScalingList(64);
              }
            }
          }
        }
      }
      skipUEG(); // log2_max_frame_num_minus4
      var picOrderCntType = readUEG();
      if (picOrderCntType === 0) {
        readUEG(); //log2_max_pic_order_cnt_lsb_minus4
      } else if (picOrderCntType === 1) {
        skipBits(1); // delta_pic_order_always_zero_flag
        skipEG(); // offset_for_non_ref_pic
        skipEG(); // offset_for_top_to_bottom_field
        numRefFramesInPicOrderCntCycle = readUEG();
        for (i = 0; i < numRefFramesInPicOrderCntCycle; i++) {
          skipEG(); // offset_for_ref_frame[ i ]
        }
      }
      skipUEG(); // max_num_ref_frames
      skipBits(1); // gaps_in_frame_num_value_allowed_flag
      picWidthInMbsMinus1 = readUEG();
      picHeightInMapUnitsMinus1 = readUEG();
      frameMbsOnlyFlag = readBits(1);
      if (frameMbsOnlyFlag === 0) {
        skipBits(1); // mb_adaptive_frame_field_flag
      }
      skipBits(1); // direct_8x8_inference_flag
      if (readBoolean()) {
        // frame_cropping_flag
        frameCropLeftOffset = readUEG();
        frameCropRightOffset = readUEG();
        frameCropTopOffset = readUEG();
        frameCropBottomOffset = readUEG();
      }
      var pixelRatio = [1, 1];
      if (readBoolean()) {
        // vui_parameters_present_flag
        if (readBoolean()) {
          // aspect_ratio_info_present_flag
          var aspectRatioIdc = readUByte();
          switch (aspectRatioIdc) {
            case 1:
              pixelRatio = [1, 1];break;
            case 2:
              pixelRatio = [12, 11];break;
            case 3:
              pixelRatio = [10, 11];break;
            case 4:
              pixelRatio = [16, 11];break;
            case 5:
              pixelRatio = [40, 33];break;
            case 6:
              pixelRatio = [24, 11];break;
            case 7:
              pixelRatio = [20, 11];break;
            case 8:
              pixelRatio = [32, 11];break;
            case 9:
              pixelRatio = [80, 33];break;
            case 10:
              pixelRatio = [18, 11];break;
            case 11:
              pixelRatio = [15, 11];break;
            case 12:
              pixelRatio = [64, 33];break;
            case 13:
              pixelRatio = [160, 99];break;
            case 14:
              pixelRatio = [4, 3];break;
            case 15:
              pixelRatio = [3, 2];break;
            case 16:
              pixelRatio = [2, 1];break;
            case 255:
              {
                pixelRatio = [readUByte() << 8 | readUByte(), readUByte() << 8 | readUByte()];
                break;
              }
          }
        }
      }
      return {
        width: Math.ceil((picWidthInMbsMinus1 + 1) * 16 - frameCropLeftOffset * 2 - frameCropRightOffset * 2),
        height: (2 - frameMbsOnlyFlag) * (picHeightInMapUnitsMinus1 + 1) * 16 - (frameMbsOnlyFlag ? 2 : 4) * (frameCropTopOffset + frameCropBottomOffset),
        pixelRatio: pixelRatio
      };
    }
  }, {
    key: 'readSliceType',
    value: function readSliceType() {
      // skip NALu type
      this.readUByte();
      // discard first_mb_in_slice
      this.readUEG();
      // return slice_type
      return this.readUEG();
    }
  }]);

  return ExpGolomb;
}();

exports.default = ExpGolomb;