mirror of
https://github.com/claunia/SabreTools.git
synced 2025-12-16 19:14:27 +00:00
351 lines
10 KiB
C#
351 lines
10 KiB
C#
using System;
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using SabreTools.Library.Data;
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using SabreTools.Library.Items;
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using SabreTools.Library.Tools;
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#if MONO
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using System.IO;
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#else
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using BinaryReader = System.IO.BinaryReader;
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using FileStream = System.IO.FileStream;
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using SeekOrigin = System.IO.SeekOrigin;
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#endif
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namespace SabreTools.Library.External
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{
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/// <summary>
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/// This is code adapted from chd.h and chd.cpp in MAME
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/// </summary>
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public class CHDFile
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{
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// core parameters from the header
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private uint m_version; // version of the header
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private ulong m_logicalbytes; // logical size of the raw CHD data in bytes
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private ulong m_mapoffset; // offset of map
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private ulong m_metaoffset; // offset to first metadata bit
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private uint m_hunkbytes; // size of each raw hunk in bytes
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private ulong m_hunkcount; // number of hunks represented
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private uint m_unitbytes; // size of each unit in bytes
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private ulong m_unitcount; // number of units represented
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private CHDCodecType[] m_compression = new CHDCodecType[4]; // array of compression types used
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// key offsets within the header
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private long m_mapoffset_offset; // offset of map offset field
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private long m_metaoffset_offset;// offset of metaoffset field
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private long m_sha1_offset; // offset of SHA1 field
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private long m_rawsha1_offset; // offset of raw SHA1 field
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private long m_parentsha1_offset;// offset of paren SHA1 field
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// map information
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uint m_mapentrybytes; // length of each entry in a map
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/// <summary>
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/// Get internal metadata from a CHD
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/// </summary>
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/// <param name="filename">Filename of possible CHD</param>
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/// <returns>A Disk object with internal SHA-1 on success, null on error, empty Disk otherwise</returns>
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/// <remarks>
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/// Original code had a "writable" param. This is not required for metadata checking
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/// </remarks>
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public DatItem GetCHDInfo(string filename)
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{
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FileStream fs = FileTools.TryOpenRead(filename);
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DatItem datItem = GetCHDInfo(fs);
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fs.Dispose();
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return datItem;
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}
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/// <summary>
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/// Get internal metadata from a CHD
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/// </summary>
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/// <param name="fs">FileStreams of possible CHD</param>
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/// <returns>A Disk object with internal SHA-1 on success, null on error, empty Disk otherwise</returns>
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/// <remarks>
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/// Original code had a "writable" param. This is not required for metadata checking
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/// </remarks>
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public DatItem GetCHDInfo(FileStream fs)
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{
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// Create a blank Disk to populate and return
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Disk datItem = new Disk();
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// Get a binary reader to make life easier
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BinaryReader br = new BinaryReader(fs);
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// Read and verify the CHD signature
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// read the raw header
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byte[] signature = br.ReadBytes(8);
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// verify the signature
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bool correct = true;
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for (int i = 0; i < signature.Length; i++)
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{
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correct &= (signature[i] == Constants.CHDSignature[i]);
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}
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if (!correct)
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{
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// throw CHDERR_INVALID_FILE;
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return null;
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}
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// only allow writes to the most recent version
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br.BaseStream.Seek(12, SeekOrigin.Begin);
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m_version = br.ReadUInt32();
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// read the header if we support it
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byte[] sha1 = new byte[20];
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switch (m_version)
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{
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case 3:
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ParseV3Header(br, out sha1);
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break;
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case 4:
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ParseV4Header(br, out sha1);
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break;
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case 5:
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ParseV5Header(br, out sha1);
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break;
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default:
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// throw CHDERR_UNSUPPORTED_VERSION;
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return null;
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}
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datItem.SHA1 = BitConverter.ToString(sha1).Replace("-", string.Empty).ToLowerInvariant();
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return datItem;
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}
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/// <summary>
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/// Parse a CHD v3 header, populate the fields, and return the SHA-1
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/// </summary>
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/// <param name="br">BinaryReader representing the file to read</param>
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/// <param name="sha1">Out parameter representing the SHA-1</param>
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/// <returns>True if the header was parsed properly, false otherwise</returns>
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/// <remarks>
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/// CHD v3 header layout:
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/// 0x00-0x07 - CHD signature
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/// 0x08-0x0B - Header size
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/// 0x0C-0x0F - [UNUSED]
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/// 0x10-0x13 - Flags (1: Has parent SHA-1, 2: Disallow writes)
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/// 0x14-0x17 - Compression
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/// 0x18-0x1B - Hunk count
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/// 0x1C-0x23 - Logical Bytes
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/// 0x24-0x2C - Metadata Offset
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/// ...
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/// 0x4C-0x4F - Hunk Bytes
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/// 0x50-0x63 - SHA-1
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/// 0x64-0x77 - Parent SHA-1
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/// 0x78-0x87 - Map
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/// </remarks>
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private bool ParseV3Header(BinaryReader br, out byte[] sha1)
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{
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// Set the blank SHA-1 hash
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sha1 = null;
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// Set offsets and defaults
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m_mapoffset_offset = 0;
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m_rawsha1_offset = 0;
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m_mapoffset = 120;
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m_metaoffset_offset = 36;
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m_sha1_offset = 80;
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m_parentsha1_offset = 100;
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m_mapentrybytes = 16;
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// Ensure the proper starting position
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br.BaseStream.Seek(8, SeekOrigin.Begin);
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// Verify header length
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if (br.ReadInt32() != Constants.CHD_V3_HEADER_SIZE)
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{
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// throw CHDERR_INVALID_FILE;
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return false;
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}
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// Skip over the 0x0C-0x0F block
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br.ReadUInt32();
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// Read the CHD flags
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uint flags = br.ReadUInt32();
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// Determine compression
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switch (br.ReadUInt32())
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{
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case 0: m_compression[0] = CHDCodecType.CHD_CODEC_NONE; break;
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case 1: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break;
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case 2: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break;
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case 3: m_compression[0] = CHDCodecType.CHD_CODEC_AVHUFF; break;
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default: /* throw CHDERR_UNKNOWN_COMPRESSION; */ return false;
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}
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m_compression[1] = m_compression[2] = m_compression[3] = CHDCodecType.CHD_CODEC_NONE;
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m_hunkcount = br.ReadUInt32();
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m_logicalbytes = br.ReadUInt64();
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m_metaoffset = br.ReadUInt64();
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br.BaseStream.Seek(76, SeekOrigin.Begin);
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m_hunkbytes = br.ReadUInt32();
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br.BaseStream.Seek(m_sha1_offset, SeekOrigin.Begin);
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sha1 = br.ReadBytes(20);
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// guess at the units based on snooping the metadata
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// m_unitbytes = guess_unitbytes();
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m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes;
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return true;
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}
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/// <summary>
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/// Parse a CHD v4 header, populate the fields, and return the SHA-1
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/// </summary>
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/// <param name="br">BinaryReader representing the file to read</param>
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/// <param name="sha1">Out parameter representing the SHA-1</param>
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/// <returns>True if the header was parsed properly, false otherwise</returns>
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/// <remarks>
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/// CHD v4 header layout:
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/// 0x00-0x07 - CHD signature
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/// 0x08-0x0B - Header size
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/// 0x0C-0x0F - [UNUSED]
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/// 0x10-0x13 - Flags (1: Has parent SHA-1, 2: Disallow writes)
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/// 0x14-0x17 - Compression
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/// 0x18-0x1B - Hunk count
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/// 0x1C-0x23 - Logical Bytes
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/// 0x24-0x2C - Metadata Offset
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/// ...
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/// 0x2C-0x2F - Hunk Bytes
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/// 0x30-0x43 - SHA-1
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/// 0x44-0x57 - Parent SHA-1
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/// 0x58-0x6b - Raw SHA-1
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/// 0x6c-0x7b - Map
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/// </remarks>
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private bool ParseV4Header(BinaryReader br, out byte[] sha1)
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{
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// Set the blank SHA-1 hash
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sha1 = null;
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// Set offsets and defaults
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m_mapoffset_offset = 0;
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m_metaoffset_offset = 36;
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m_sha1_offset = 48;
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m_parentsha1_offset = 68;
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m_rawsha1_offset = 88;
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m_mapoffset = 108;
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m_mapentrybytes = 16;
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// Ensure the proper starting position
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br.BaseStream.Seek(8, SeekOrigin.Begin);
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// Verify header length
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if (br.ReadUInt32() != Constants.CHD_V4_HEADER_SIZE)
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{
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// throw CHDERR_INVALID_FILE;
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return false;
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}
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// Read the CHD flags
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uint flags = br.ReadUInt32();
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// Determine compression
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switch (br.ReadUInt32())
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{
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case 0: m_compression[0] = CHDCodecType.CHD_CODEC_NONE; break;
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case 1: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break;
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case 2: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break;
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case 3: m_compression[0] = CHDCodecType.CHD_CODEC_AVHUFF; break;
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default: /* throw CHDERR_UNKNOWN_COMPRESSION; */ return false;
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}
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m_compression[1] = m_compression[2] = m_compression[3] = CHDCodecType.CHD_CODEC_NONE;
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m_hunkcount = br.ReadUInt32();
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m_logicalbytes = br.ReadUInt64();
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m_metaoffset = br.ReadUInt64();
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br.BaseStream.Seek(44, SeekOrigin.Begin);
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m_hunkbytes = br.ReadUInt32();
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br.BaseStream.Seek(m_sha1_offset, SeekOrigin.Begin);
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sha1 = br.ReadBytes(20);
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// guess at the units based on snooping the metadata
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// m_unitbytes = guess_unitbytes();
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m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes;
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return true;
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}
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/// <summary>
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/// Parse a CHD v5 header, populate the fields, and return the SHA-1
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/// </summary>
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/// <param name="br">BinaryReader representing the file to read</param>
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/// <param name="sha1">Out parameter representing the SHA-1</param>
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/// <returns>True if the header was parsed properly, false otherwise</returns>
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/// <remarks>
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/// CHD v5 header layout:
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/// 0x00-0x07 - CHD signature
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/// 0x08-0x0B - Header size
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/// 0x0C-0x0F - [UNUSED]
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/// 0x10-0x13 - Compression format 1
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/// 0x14-0x17 - Compression format 2
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/// 0x18-0x1B - Compression format 3
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/// 0x1C-0x1F - Compression format 4
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/// 0x18-0x1B - Hunk count
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/// 0x20-0x27 - Logical Bytes
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/// 0x28-0x2F - Map Offset
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/// 0x30-0x37 - Metadata Offset
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/// 0x38-0x3B - Hunk Bytes
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/// 0x3C-0x3F - Unit Bytes
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/// 0x40-0x53 - Raw SHA-1
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/// 0x54-0x67 - SHA-1
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/// 0x68-0x7b - Parent SHA-1
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/// </remarks>
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private bool ParseV5Header(BinaryReader br, out byte[] sha1)
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{
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// Set the blank SHA-1 hash
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sha1 = null;
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// Set offsets and defaults
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m_mapoffset_offset = 40;
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m_metaoffset_offset = 48;
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m_rawsha1_offset = 64;
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m_sha1_offset = 84;
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m_parentsha1_offset = 104;
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// Ensure the proper starting position
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br.BaseStream.Seek(8, SeekOrigin.Begin);
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// Verify header length
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if (br.ReadUInt32() != Constants.CHD_V5_HEADER_SIZE)
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{
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// throw CHDERR_INVALID_FILE
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return false;
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}
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// Determine compression
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m_compression[0] = (CHDCodecType)br.ReadUInt32();
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m_compression[1] = (CHDCodecType)br.ReadUInt32();
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m_compression[2] = (CHDCodecType)br.ReadUInt32();
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m_compression[3] = (CHDCodecType)br.ReadUInt32();
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m_logicalbytes = br.ReadUInt64();
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m_mapoffset = br.ReadUInt64();
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m_metaoffset = br.ReadUInt64();
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m_hunkbytes = br.ReadUInt32();
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m_hunkcount = (m_logicalbytes + m_hunkbytes - 1) / m_hunkbytes;
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m_unitbytes = br.ReadUInt32();
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m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes;
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// m_allow_writes = !compressed();
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// determine properties of map entries
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// m_mapentrybytes = compressed() ? 12 : 4;
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br.BaseStream.Seek(m_sha1_offset, SeekOrigin.Begin);
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sha1 = br.ReadBytes(20);
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return true;
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}
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}
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}
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