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[CHDFile] Make CHD code more object-oriented

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This commit is contained in:
Matt Nadareski
2017-10-31 09:53:10 -07:00
parent fcbca10fce
commit fa1284c707
1 changed files with 107 additions and 72 deletions
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179
SabreTools.Library/External/CHDFile.cs vendored
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@@ -64,7 +64,7 @@ namespace SabreTools.Library.External
/// 0x68-0x7b - Parent SHA-1 /// 0x68-0x7b - Parent SHA-1
/// ---------------------------------------------- /// ----------------------------------------------
/// </remrks> /// </remrks>
public class CHDFile public class CHDFile : IDisposable
{ {
#region Private instance variables #region Private instance variables
@@ -82,20 +82,74 @@ namespace SabreTools.Library.External
private CHDCodecType[] m_compression = new CHDCodecType[4]; // array of compression types used private CHDCodecType[] m_compression = new CHDCodecType[4]; // array of compression types used
// map information // map information
private uint m_mapentrybytes; // length of each entry in a map private uint m_mapentrybytes; // length of each entry in a map
// additional required vars
private BinaryReader m_br; // Binary reader representing the CHD stream
#endregion #endregion
#region Instance Methods #region Instance Methods
#region Constructors
/// <summary>
/// Create a new CHDFile from an input stream
/// </summary>
/// <param name="chdstream">Stream representing the CHD file</param>
public CHDFile(Stream chdstream)
{
BinaryReader br = new BinaryReader(chdstream);
}
/// <summary>
/// Dispose of the CHDFile
/// </summary>
public void Dispose()
{
m_br.Dispose();
}
#endregion
#region Header Parsing #region Header Parsing
/// <summary>
/// Validate the initial signature, version, and header size
/// </summary>
/// <returns>Unsigned int containing the version number, null if invalid</returns>
public uint? ValidateHeaderVersion()
{
// Read and verify the CHD signature
m_signature = m_br.ReadUInt64();
if (m_signature != Constants.CHDSignature)
{
// throw CHDERR_INVALID_FILE;
return null;
}
// Get the header size and version
m_headersize = m_br.ReadUInt32();
m_version = m_br.ReadUInt32();
// If we have an invalid combination of size and version
if ((m_version == 3 && m_headersize != Constants.CHD_V3_HEADER_SIZE)
|| (m_version == 4 && m_headersize != Constants.CHD_V4_HEADER_SIZE)
|| (m_version == 5 && m_headersize == Constants.CHD_V5_HEADER_SIZE)
|| (m_version < 3 || m_version > 5))
{
// throw CHDERR_UNSUPPORTED_VERSION;
return null;
}
return m_version;
}
/// <summary> /// <summary>
/// Parse a CHD v3 header /// Parse a CHD v3 header
/// </summary> /// </summary>
/// <param name="br">Binary reader representing the input stream</param>
/// <returns>The extracted SHA-1 on success, null otherwise</returns> /// <returns>The extracted SHA-1 on success, null otherwise</returns>
public byte[] ParseCHDv3Header(BinaryReader br) public byte[] ParseCHDv3Header()
{ {
// Set the blank SHA-1 hash // Set the blank SHA-1 hash
byte[] sha1 = new byte[20]; byte[] sha1 = new byte[20];
@@ -105,10 +159,10 @@ namespace SabreTools.Library.External
m_mapentrybytes = 16; m_mapentrybytes = 16;
// Read the CHD flags // Read the CHD flags
uint flags = br.ReadUInt32(); uint flags = m_br.ReadUInt32();
// Determine compression // Determine compression
switch (br.ReadUInt32()) switch (m_br.ReadUInt32())
{ {
case 0: m_compression[0] = CHDCodecType.CHD_CODEC_NONE; break; case 0: m_compression[0] = CHDCodecType.CHD_CODEC_NONE; break;
case 1: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break; case 1: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break;
@@ -119,15 +173,15 @@ namespace SabreTools.Library.External
m_compression[1] = m_compression[2] = m_compression[3] = CHDCodecType.CHD_CODEC_NONE; m_compression[1] = m_compression[2] = m_compression[3] = CHDCodecType.CHD_CODEC_NONE;
m_hunkcount = br.ReadUInt32(); m_hunkcount = m_br.ReadUInt32();
m_logicalbytes = br.ReadUInt64(); m_logicalbytes = m_br.ReadUInt64();
m_metaoffset = br.ReadUInt64(); m_metaoffset = m_br.ReadUInt64();
br.BaseStream.Seek(76, SeekOrigin.Begin); m_br.BaseStream.Seek(76, SeekOrigin.Begin);
m_hunkbytes = br.ReadUInt32(); m_hunkbytes = m_br.ReadUInt32();
br.BaseStream.Seek(Constants.CHDv3SHA1Offset, SeekOrigin.Begin); m_br.BaseStream.Seek(Constants.CHDv3SHA1Offset, SeekOrigin.Begin);
sha1 = br.ReadBytes(20); sha1 = m_br.ReadBytes(20);
// guess at the units based on snooping the metadata // guess at the units based on snooping the metadata
// m_unitbytes = guess_unitbytes(); // m_unitbytes = guess_unitbytes();
@@ -139,9 +193,8 @@ namespace SabreTools.Library.External
/// <summary> /// <summary>
/// Parse a CHD v4 header /// Parse a CHD v4 header
/// </summary> /// </summary>
/// <param name="br">Binary reader representing the input stream</param>
/// <returns>The extracted SHA-1 on success, null otherwise</returns> /// <returns>The extracted SHA-1 on success, null otherwise</returns>
public byte[] ParseCHDv4Header(BinaryReader br) public byte[] ParseCHDv4Header()
{ {
// Set the blank SHA-1 hash // Set the blank SHA-1 hash
byte[] sha1 = new byte[20]; byte[] sha1 = new byte[20];
@@ -151,10 +204,10 @@ namespace SabreTools.Library.External
m_mapentrybytes = 16; m_mapentrybytes = 16;
// Read the CHD flags // Read the CHD flags
uint flags = br.ReadUInt32(); uint flags = m_br.ReadUInt32();
// Determine compression // Determine compression
switch (br.ReadUInt32()) switch (m_br.ReadUInt32())
{ {
case 0: m_compression[0] = CHDCodecType.CHD_CODEC_NONE; break; case 0: m_compression[0] = CHDCodecType.CHD_CODEC_NONE; break;
case 1: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break; case 1: m_compression[0] = CHDCodecType.CHD_CODEC_ZLIB; break;
@@ -165,15 +218,15 @@ namespace SabreTools.Library.External
m_compression[1] = m_compression[2] = m_compression[3] = CHDCodecType.CHD_CODEC_NONE; m_compression[1] = m_compression[2] = m_compression[3] = CHDCodecType.CHD_CODEC_NONE;
m_hunkcount = br.ReadUInt32(); m_hunkcount = m_br.ReadUInt32();
m_logicalbytes = br.ReadUInt64(); m_logicalbytes = m_br.ReadUInt64();
m_metaoffset = br.ReadUInt64(); m_metaoffset = m_br.ReadUInt64();
br.BaseStream.Seek(44, SeekOrigin.Begin); m_br.BaseStream.Seek(44, SeekOrigin.Begin);
m_hunkbytes = br.ReadUInt32(); m_hunkbytes = m_br.ReadUInt32();
br.BaseStream.Seek(Constants.CHDv4SHA1Offset, SeekOrigin.Begin); m_br.BaseStream.Seek(Constants.CHDv4SHA1Offset, SeekOrigin.Begin);
sha1 = br.ReadBytes(20); sha1 = m_br.ReadBytes(20);
// guess at the units based on snooping the metadata // guess at the units based on snooping the metadata
// m_unitbytes = guess_unitbytes(); // m_unitbytes = guess_unitbytes();
@@ -184,25 +237,24 @@ namespace SabreTools.Library.External
/// <summary> /// <summary>
/// Parse a CHD v5 header /// Parse a CHD v5 header
/// </summary> /// </summary>
/// <param name="br">Binary reader representing the input stream</param>
/// <returns>The extracted SHA-1 on success, null otherwise</returns> /// <returns>The extracted SHA-1 on success, null otherwise</returns>
public byte[] ParseCHDv5Header(BinaryReader br) public byte[] ParseCHDv5Header()
{ {
// Set the blank SHA-1 hash // Set the blank SHA-1 hash
byte[] sha1 = new byte[20]; byte[] sha1 = new byte[20];
// Determine compression // Determine compression
m_compression[0] = (CHDCodecType)br.ReadUInt32(); m_compression[0] = (CHDCodecType)m_br.ReadUInt32();
m_compression[1] = (CHDCodecType)br.ReadUInt32(); m_compression[1] = (CHDCodecType)m_br.ReadUInt32();
m_compression[2] = (CHDCodecType)br.ReadUInt32(); m_compression[2] = (CHDCodecType)m_br.ReadUInt32();
m_compression[3] = (CHDCodecType)br.ReadUInt32(); m_compression[3] = (CHDCodecType)m_br.ReadUInt32();
m_logicalbytes = br.ReadUInt64(); m_logicalbytes = m_br.ReadUInt64();
m_mapoffset = br.ReadUInt64(); m_mapoffset = m_br.ReadUInt64();
m_metaoffset = br.ReadUInt64(); m_metaoffset = m_br.ReadUInt64();
m_hunkbytes = br.ReadUInt32(); m_hunkbytes = m_br.ReadUInt32();
m_hunkcount = (m_logicalbytes + m_hunkbytes - 1) / m_hunkbytes; m_hunkcount = (m_logicalbytes + m_hunkbytes - 1) / m_hunkbytes;
m_unitbytes = br.ReadUInt32(); m_unitbytes = m_br.ReadUInt32();
m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes; m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes;
// m_allow_writes = !compressed(); // m_allow_writes = !compressed();
@@ -210,8 +262,8 @@ namespace SabreTools.Library.External
// determine properties of map entries // determine properties of map entries
// m_mapentrybytes = compressed() ? 12 : 4; // m_mapentrybytes = compressed() ? 12 : 4;
br.BaseStream.Seek(Constants.CHDv5SHA1Offset, SeekOrigin.Begin); m_br.BaseStream.Seek(Constants.CHDv5SHA1Offset, SeekOrigin.Begin);
sha1 = br.ReadBytes(20); sha1 = m_br.ReadBytes(20);
return sha1; return sha1;
} }
@@ -270,47 +322,30 @@ namespace SabreTools.Library.External
Disk datItem = new Disk(); Disk datItem = new Disk();
// Get a CHD object to store the data // Get a CHD object to store the data
CHDFile chd = new CHDFile(); CHDFile chd = new CHDFile(fs);
// Get a binary reader to make life easier // Get and validate the header version
BinaryReader br = new BinaryReader(fs); uint? version = chd.ValidateHeaderVersion();
// Read and verify the CHD signature
chd.m_signature = br.ReadUInt64();
if (chd.m_signature != Constants.CHDSignature)
{
// throw CHDERR_INVALID_FILE;
return null;
}
// Get the header size and version
chd.m_headersize = br.ReadUInt32();
chd.m_version = br.ReadUInt32();
// Create a placeholder for the extracted SHA-1 // Create a placeholder for the extracted SHA-1
byte[] sha1 = new byte[20]; byte[] sha1 = new byte[20];
// If we have a CHD v3 file, parse it accordingly // Now parse the rest of the header according to the version
if (chd.m_headersize == Constants.CHD_V3_HEADER_SIZE && chd.m_version == 3) switch (version)
{ {
sha1 = chd.ParseCHDv3Header(br); case 3:
} sha1 = chd.ParseCHDv3Header();
// If we have a CHD v4 file, parse it accordingly break;
else if (chd.m_headersize == Constants.CHD_V4_HEADER_SIZE && chd.m_version == 4) case 4:
{ sha1 = chd.ParseCHDv4Header();
sha1 = chd.ParseCHDv4Header(br); break;
} case 5:
// If we have a CHD v5 file, parse it accordingly sha1 = chd.ParseCHDv5Header();
else if (chd.m_headersize == Constants.CHD_V5_HEADER_SIZE && chd.m_version == 5) break;
{ case null:
sha1 = chd.ParseCHDv5Header(br); default:
} // throw CHDERR_INVALID_FILE;
// If we don't have a valid combination, return null return null;
else
{
// throw CHDERR_UNSUPPORTED_VERSION;
// throw CHDERR_INVALID_FILE;
return null;
} }
// Set the SHA-1 of the Disk to return // Set the SHA-1 of the Disk to return