function CmsParser() {
    this.CMS_FLAG_FORMAT_FOUND = 0x01;
    this.CMS_FLAG_TRACK_FOUND = 0x02;
    this.CMS_FLAG_STOP_WHEN_ERROR = 0x04;

    this.CMS_PART_UNKNOWN = 'na';
    this.CMS_PART_H264_i_FRAME = 'i';
    this.CMS_PART_H264_p_FRAME = 'p';
    this.CMS_PART_AUDIO = 'a';
    this.CMS_PART_JPG = 'j';


    this.CMS_E_HEADER_FIELD = 0;
    this.CMS_E_HEADER_END = 1;
    this.CMS_E_PART_HEADER = 2;
    this.CMS_E_PART_HEADER_FIELD = 3;
    this.CMS_E_PART_HEADER_END = 4;
    this.CMS_E_PART_END = 5;
    this.CMS_E_CHUNK = 6;
    this.CMS_E_PARSE_FAIL = 7;



    this.CMS_HEADER = 0;
    this.CMS_DETECT_BOUNDARY = 1;
    this.CMS_PART_HEADER = 2;
    this.CMS_FINISHED = 3;
    this.CMS_FAIL = 4;

    this.flag = 0;
    this.shift = 0;

    this.line_buf = new Uint8Array(2000);
    this.line_buf_ptr = 0;
    this.state = this.CMS_HEADER;

    this.cache = new Uint8Array(100); // for boundary
    this.cached_len = 0;

    this.is_first_part = true;
    this.callback_context = null;
    this.callback = null;

    this.boundary = null;
    this.boundary_size = 0;
    this.boundary_ptr = 0;

    // boundary = strdup("\r\n----asdfasdf\r\n");
    // boundary.length = strlen(boundary);
    this._header = {
        hasAudio: false,
        hasVideo: false
    };
    this.parts = [];
    this.part = {
        header: {},
        shift: 0,
        chunks: []
    };
};

CmsParser.prototype.fail = function (error) {
    this.emit(this.CMS_E_PARSE_FAIL, error);
    if (this.flag & this.CMS_FLAG_STOP_WHEN_ERROR) {
        this.state = this.CMS_FAIL;
        return true;
    } else {
        this.state = this.CMS_DETECT_BOUNDARY;
        return false;
    }
}

CmsParser.prototype.parse = function (data) {
    var chunk = 0;
    for (var i = 0; i < data.length; i++) {
        var ch = data[i];
        ch = String.fromCharCode(ch);
        this.shift++;
        switch (this.state) {
            case this.CMS_FAIL: {
                if (this.fail("CmsParser parse stoped.")) {
                    return;
                }
                break;
            };
            case this.CMS_HEADER: {
                if (ch === '\r') {
                } else if (ch === '\n') {
                    if (this.line_buf_ptr === 0) {
                        this.emit(this.CMS_E_HEADER_END);
                        if (!this.boundary) {
                            if (this.fail("Boundary not found.")) {
                                return;
                            }
                        } else if (!(this.flag & this.CMS_FLAG_FORMAT_FOUND)) {
                            if (this.fail("Format not found.")) {
                                return;
                            }
                        } else if (!(this.flag & this.CMS_FLAG_TRACK_FOUND)) {
                            if (this.fail("Track not found.")) {
                                return;
                            }
                        } else {
                            this.state = this.CMS_DETECT_BOUNDARY;
                            this.boundary_ptr = 2;
                            chunk = i + 1;
                        }
                    } else {
                        var s = String.fromCharCode.apply(null, this.line_buf.slice(0, this.line_buf_ptr));
                        s = s.split(":");
                        var key = s.shift().trim();
                        var value = s.join(":").trim();
                        // console.log("cms header:", key, '=', value);
                        if (key && value) {
                            if (key === "boundary") {
                                this.boundary = "\r\n--" + value + "\r\n";
                            } else if (key === "format" && value === "cms") {
                                this.flag = this.flag | this.CMS_FLAG_FORMAT_FOUND;
                            } else if (key === "track") {
                                this.flag = this.flag | this.CMS_FLAG_TRACK_FOUND;
                            }
                            var kv = {
                                key: key,
                                value: value
                            };
                            this.emit(this.CMS_E_HEADER_FIELD, kv);
                        } else {
                            if (this.fail("Invalid key value.")) {
                                return;
                            }
                        }
                    }
                    this.line_buf_ptr = 0;
                    this.line_buf.fill(0);
                } else {
                    this.line_buf[this.line_buf_ptr] = ch.charCodeAt(0);
                    this.line_buf_ptr++;
                }
                break;
            };
            case this.CMS_DETECT_BOUNDARY: {
                if (!this.boundary) {
                    break;
                }
                if (ch == this.boundary[this.boundary_ptr]) {
                    this.boundary_ptr++;
                } else if (this.boundary_ptr == 1 && ch == this.boundary[this.boundary_ptr - 1]) {

                } else {
                    if (this.cached_len > 0) {
                        this.emit(this.CMS_E_CHUNK, this.cache.slice(0, this.cached_len));
                        this.cached_len = 0;
                    }
                    this.boundary_ptr = 0;
                }
                if (this.boundary_ptr === this.boundary.length) {
                    if (i - chunk >= (this.boundary.length - this.cached_len)) {
                        var chunk_len = i - chunk - (this.boundary.length - this.cached_len) + 1;
                        this.emit(this.CMS_E_CHUNK, data.slice(chunk, chunk + chunk_len));
                    }
                    this.cached_len = 0;
                    if (this.is_first_part) {
                        this.is_first_part = false;
                    } else {
                        this.emit(this.CMS_E_PART_END);
                    }
                    this.emit(this.CMS_E_PART_HEADER);

                    this.state = this.CMS_PART_HEADER;
                    this.part = {
                        header: {
                            type: this.CMS_PART_UNKNOWN,
                            track: -1,
                            length: 0,
                            ts: -1
                        },
                        shift: this.shift,
                        chunks: []
                    }
                    chunk = i + 1;
                    this.boundary_ptr = 0;
                    this.line_buf_ptr = 0;
                    this.line_buf[0] = 0;
                }
                break;
            };
            case this.CMS_PART_HEADER: {
                if (ch == '\r') {
                } else if (ch == '\n') {
                    if (this.line_buf_ptr == 0) {
                        this.emit(this.CMS_E_PART_HEADER_END);
                        this.state = this.CMS_DETECT_BOUNDARY;
                        chunk = i + 1;
                    } else {
                        var s = String.fromCharCode.apply(null, this.line_buf.slice(0, this.line_buf_ptr)).split(":");
                        var key = s.shift().trim();
                        var value = s.join(":").trim();
                        // console.log("part header:", key, '=', value);
                        if (key && value) {
                            if (key === "f") {
                                if (value === "i") {
                                    this.part.header.type = this.CMS_PART_H264_i_FRAME;
                                } else if (value === "p") {
                                    this.part.header.type = this.CMS_PART_H264_p_FRAME;
                                } else if (value === "a") {
                                    this.part.header.type = this.CMS_PART_AUDIO;
                                } else if (value === "j") {
                                    this.part.header.type = this.CMS_PART_JPG;
                                } else {
                                    console.error("Unknown frame type:", value);
                                }
                            } else if (key === "ts") {
                                this.part.header.ts = parseInt(value, 10);
                            } else if (key === "l") {
                                this.part.header.length = parseInt(value, 10);
                            } else if (key === "t") {
                                this.part.header.track = parseInt(value, 10);
                            }
                            var kv = {
                                key: key,
                                value: value
                            };
                            this.emit(this.CMS_E_PART_HEADER_FIELD, kv);
                        } else {
                            if (this.fail("Part header Invalid key value.")) {
                                return;
                            }
                        }
                    }
                    this.line_buf_ptr = 0;
                    this.line_buf.fill(0);
                } else {
                    if (this.line_buf_ptr < this.line_buf.length - 1) {
                        this.line_buf[this.line_buf_ptr] = ch.charCodeAt(0);
                        this.line_buf_ptr++;
                    } else {
                        if (this.fail("Part header line too long.")) {
                            return;
                        }
                    }
                }

                break;
            };
        }
    }
    if (this.state == this.CMS_DETECT_BOUNDARY) {
        if (chunk < data.length) {
            if (this.boundary_ptr > 0) {
                this.cached_len = this.boundary_ptr;
                var pos = data.length - this.boundary_ptr;
                if (pos >= 0) {
                    this.cache = data.slice(pos, this.cached_len);
                }
            }
            this.emit(this.CMS_E_CHUNK, data.slice(chunk, chunk + data.length - chunk - this.boundary_ptr));
        }
    }
};
CmsParser.prototype.set_callback = function (cb, context) {
    this.callback = cb;
    this.callback_context = context;
};
CmsParser.prototype.emit = function (e, data, size) {
    if (this.callback) {
        return this.callback(this, e, data, size, this.callback_context);
    } else {
        this.cache_data(e, data);
    }
};

CmsParser.prototype.cache_data = function (e, data) {
    switch (e) {
        case this.CMS_E_HEADER_FIELD: {
            var key = data.key;
            var value = data.value;
            this._header[key] = value;
            if (key === 'track') {
                var tracks = value.split(';');
                this._header.tracks = [];
                for (var t = 0; t < tracks.length; t++) {
                    var fields = tracks[t].split(',');
                    var track = {};
                    for (var j = 0; j < fields.length; j++) {
                        var f = fields[j].split('=');
                        var key = f.shift();
                        var value = f.join('=');
                        track[key] = value;
                        if (key === 'codec') {
                            if (value === 'alaw') {
                                this._header.hasAudio = true;
                                this._header.audioTrack = track;
                            } else if (value === 'h264') {
                                this._header.hasVideo = true;
                                this._header.videoTrack = track;
                            }
                        }
                    }
                    this._header.tracks.push(track);
                }
            } else if (key === "duration") {
                this._header.duration = parseInt(value, 10);
            }
            break;
        };
        case this.CMS_E_HEADER_END: {
            this.header = this._header;
            break;
        };
        case this.CMS_E_PART_HEADER: {
            break;
        };
        case this.CMS_E_PART_HEADER_FIELD: {
            break;
        };
        case this.CMS_E_PART_HEADER_END: {
            break;
        };
        case this.CMS_E_PART_END: {
            var chunks = this.part.chunks;
            var size = 0;
            for (var i = 0; i < chunks.length; i++) {
                size = size + chunks[i].length;
            }
            this.part.data = new ArrayBuffer(size);
            var data = new Uint8Array(this.part.data);
            var shift = 0;
            for (var i = 0; i < chunks.length; i++) {
                data.set(chunks[i], shift);
                shift = shift + chunks[i].length;
            }
            this.parts.push(this.part);
            break;
        };
        case this.CMS_E_CHUNK: {
            this.part.chunks.push(data);
            break;
        };
        case this.CMS_E_PARSE_FAIL: {
            break;
        };

    }
};

module.exports = CmsParser;
// var cms = new CmsParser();

// var fs = require('fs');
// var f = fs.createReadStream("/home/gxy/work/cms/cms/tmp/ttt.cms");
// f.on('end', function (err) {
//     console.log("end");
// });
// f.on('error', function (err) {
//     console.error(err);
// });
// f.on('data', function (chunk) {
//     cms.parse(chunk);
//     if (cms.header) {
//         console.log(cms.header);
//         cms.header = null;
//     }
//     var parts = cms.parts;
//     while (parts.length > 0) {
//         var part = parts.shift();
//         console.log(part.header);
//         var chunks = part.chunks;
//         var len = 0;
//         for (var i = 0; i < chunks.length; i++) {
//             len = len + chunks[i].length;
//         }
//         if (len !== part.header.length) {
//             console.log("mismatch: len=%d part.len=%d", len, part.header.length);
//         }
//     }
// });