diffusion/src/internal/data/record/recordv2-parser.js

Diffusion JavaScript client

"use strict";
/**
 * @module diffusion.datatypes.RecordV2
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.parse = void 0;
var recordv2_utils_1 = require("./../../data/record/recordv2-utils");
var uint8array_1 = require("./../../util/uint8array");
/**
 * Parse a buffer of Record V2 data and split it into records and fields
 *
 * @param  bytes   the buffer to parse
 * @param  offset  the starting position in the buffer
 * @param  length  the number of bytes to convert
 * @return         an array of records, each containing an array of fields
 */
function parse(bytes, offset, length) {
    if (offset === void 0) { offset = 0; }
    if (length === void 0) { length = bytes.length; }
    // empty bytes returns empty record list
    if (length === 0) {
        return [];
    }
    // record MU returns single empty record
    if (length === 1 && bytes[offset] === recordv2_utils_1.RECORD_MU) {
        return [[]];
    }
    // process all records
    var records = [];
    var fields = [];
    var pos = offset;
    for (var i = offset; i < length; ++i) {
        if (bytes[i] === recordv2_utils_1.RECORD_DELIMITER) {
            processRecordDelimiter(bytes, records, pos, i, fields);
            pos = i + 1;
        }
        else if (bytes[i] === recordv2_utils_1.FIELD_DELIMITER) {
            addField(bytes, records, pos, i, fields);
            pos = i + 1;
        }
    }
    processEnd(bytes, records, pos, length, fields);
    return records;
}
exports.parse = parse;
/**
 * Process a record delimiter
 *
 * @param  bytes     the buffer to parse
 * @param  records   a reference to the records that will be constructed. A
 *                   new record will be added to this array.
 * @param  startPos  the start position in the buffer of the last field
 * @param  endPos    the end position in the buffer of the last field
 * @param  field     a reference to the fields that are being constructed for
 *                   this record. A new field will be added to this array before
 *                   this array will be added to the records.
 */
function processRecordDelimiter(bytes, records, startPos, endPos, fields) {
    var written = false;
    // if we have a field add it to list
    if (startPos < endPos) {
        written = addField(bytes, records, startPos, endPos, fields);
    }
    else {
        // buf if we're not at the start of content && the last delimiter was for a field
        // it implies an empty field
        if (startPos > 0 && bytes[startPos - 1] === recordv2_utils_1.FIELD_DELIMITER) {
            fields.push('');
        }
    }
    if (!written) {
        records.push(Array.from(fields));
    }
    // clear fields array
    fields.length = 0;
}
/**
 * Process the end of the record data
 *
 * @param  bytes     the buffer to parse
 * @param  records   a reference to the records that will be constructed. A
 *                   new record will be added to this array.
 * @param  startPos  the start position in the buffer of the last field
 * @param  endPos    the end position in the buffer of the last field
 * @param  field     a reference to the fields that are being constructed for
 *                   this record. A new field will be added to this array before
 *                   this array will be added to the records.
 */
function processEnd(bytes, records, startPos, endPos, fields) {
    // if we have read something then add to fields
    if (endPos > startPos) {
        addField(bytes, records, startPos, endPos, fields);
    }
    else {
        // nothing at end so process possible final delimiter
        var endByte = bytes[endPos - 1];
        if (endByte === recordv2_utils_1.RECORD_DELIMITER) {
            // a record delimiter at the end implies a final empty record
            records.push([]);
        }
        else if (endByte === recordv2_utils_1.FIELD_DELIMITER) {
            // a field delimiter implies an empty field
            fields.push('');
        }
    }
    // if we have some fields add record. This is not the case if
    // the last thing read was a record delimiter or start of content
    if (fields.length) {
        records.push(Array.from(fields));
    }
}
/**
 * Add a field to the array of fields
 *
 * @param  bytes     the buffer to parse
 * @param  records   a reference to the records that will be constructed.
 * @param  startPos  the start position in the buffer of the last field
 * @param  endPos    the end position in the buffer of the last field
 * @param  field     a reference to the fields that are being constructed for
 *                   this record. A new field will be added to this array.
 * @return           `true` if the fields have been added to the records.
 */
function addField(bytes, records, startPos, endPos, fields) {
    var len = endPos - startPos;
    if (fields.length === 0 && len === 1 && bytes[startPos] === recordv2_utils_1.FIELD_MU) {
        records.push(['']);
        return true;
    }
    else {
        fields.push(uint8array_1.uint8toUtf8(bytes, startPos, endPos));
    }
    return false;
}