SabreTools/SabreTools.Serialization
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Fix logical block extension

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Matt Nadareski
2025-11-04 10:25:55 -05:00
parent 4ee4a6e85f
commit b908732f5c
1 changed files with 31 additions and 17 deletions
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48
SabreTools.Serialization/Extensions/ISO9660.cs
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@@ -1,5 +1,6 @@
using System;
using SabreTools.Data.Models.ISO9660;
using SabreTools.Numerics;
namespace SabreTools.Data.Extensions
{
@@ -8,36 +9,49 @@ namespace SabreTools.Data.Extensions
/// <summary>
/// Get the logical block size from a sector length
/// </summary>
/// <param name="bvd">Volume descriptor containing block information</param>
/// <param name="vd">Volume descriptor containing block information</param>
/// <param name="sectorLength">Defined sector length</param>
/// <returns>Size of a logical block</returns>
public static short GetLogicalBlockSize(this BaseVolumeDescriptor bvd, short sectorLength)
public static short GetLogicalBlockSize(this VolumeDescriptor vd, short sectorLength)
{
short blockLength = sectorLength;
if (bvd.LogicalBlockSize.IsValid)
{
// Validate logical block length
if (bvd.LogicalBlockSize >= 512 && bvd.LogicalBlockSize <= sectorLength && (bvd.LogicalBlockSize & (bvd.LogicalBlockSize - 1)) == 0)
blockLength = bvd.LogicalBlockSize;
}
BothInt16 blockLength;
if (vd is PrimaryVolumeDescriptor pvd)
blockLength = pvd.LogicalBlockSize;
else if (vd is SupplementaryVolumeDescriptor svd)
blockLength = svd.LogicalBlockSize;
else
{
// If logical block size is ambiguous check if only one is valid, otherwise default to sector length
short le = bvd.LogicalBlockSize.LittleEndian;
bool leValid = le >= 512 && le <= sectorLength && (le & (le - 1)) == 0;
return sectorLength;
short be = bvd.LogicalBlockSize.LittleEndian;
bool beValid = be >= 512 && be <= sectorLength && (be & (be - 1)) == 0;
// If the block size is inconsistent
if (!blockLength.IsValid)
{
bool leValid = BlockLengthValid(blockLength.LittleEndian, sectorLength);
bool beValid = BlockLengthValid(blockLength.BigEndian, sectorLength);
if (leValid && !beValid)
blockLength = le;
blockLength = blockLength.LittleEndian;
else if (beValid && !leValid)
blockLength = be;
blockLength = blockLength.BigEndian;
else
return sectorLength;
}
// Validate logical block length
if (!BlockLengthValid(blockLength, sectorLength))
blockLength = sectorLength;
return blockLength;
}
/// <summary>
/// Indicates if a block length is valid
/// </summary>
/// <param name="blockLength">Block length to check</param>
/// <param name="sectorLength">Defined sector length</param>
/// <returns>True if the block length is valid, false otherwise</returns>
private static bool BlockLengthValid(short blockLength, short sectorLength)
=> blockLength >= 512 && blockLength <= sectorLength && (blockLength & (blockLength - 1)) == 0;
/// <summary>
/// Indicates if an array contains all ASCII numeric digits
/// </summary>