/*
 * Microsoft JDBC Driver for SQL Server Copyright(c) Microsoft Corporation All rights reserved. This program is made
 * available under the terms of the MIT License. See the LICENSE file in the project root for more information.
 */

package com.microsoft.sqlserver.jdbc;

XMLTDSHeader is helper class used to read and write the XML TDS header from a TDS stream.
Typical XML headers ->
XML with schema.
F1 01 <- SCHEMA_PRESENT=1 03|54 00 44 00 53 00 <- DBNAME (1 byte length in UNICODE chars) 03|64 00 62 00 6F 00 <-
OWNING_SCHEMA (1 byte length in UNICODE chars) 09 00|53 00 68 00 69 00 70 00 4F 00 72 00 64 00 65 00 72 00 <-
XML_SCHEMA_COLLECTION (2 byte length in UNICODE chars)
XML without any schema (this is common as well).
F1 00 <- SCHEMA_PRESENT=0
/**
 * XMLTDSHeader is helper class used to read and write the XML TDS header from a TDS stream.
 * 
 * Typical XML headers ->
 * 
 * XML with schema.
 *
 * F1 01 <- SCHEMA_PRESENT=1 03|54 00 44 00 53 00 <- DBNAME (1 byte length in UNICODE chars) 03|64 00 62 00 6F 00 <-
 * OWNING_SCHEMA (1 byte length in UNICODE chars) 09 00|53 00 68 00 69 00 70 00 4F 00 72 00 64 00 65 00 72 00 <-
 * XML_SCHEMA_COLLECTION (2 byte length in UNICODE chars)
 * 
 * XML without any schema (this is common as well).
 *
 * F1 00 <- SCHEMA_PRESENT=0
 * 
 */

final class XMLTDSHeader {
    @SuppressWarnings("unused")
    private final String databaseName; // Database name where XML schema resides.
    @SuppressWarnings("unused")
    private final String owningSchema; // Owner of XML schema (like dbo for example).
    @SuppressWarnings("unused")
    private final String xmlSchemaCollection; // Name of XML schema collection.

    XMLTDSHeader(TDSReader tdsReader) throws SQLServerException {
        // Check schema present byte.
        if (0 != tdsReader.readUnsignedByte()) {
            // Ok, we have a schema present, process it.
            databaseName = tdsReader.readUnicodeString(tdsReader.readUnsignedByte());
            owningSchema = tdsReader.readUnicodeString(tdsReader.readUnsignedByte());
            xmlSchemaCollection = tdsReader.readUnicodeString(tdsReader.readUnsignedShort());
        } else {
            xmlSchemaCollection = null;
            owningSchema = null;
            databaseName = null;
        }
    }
}