Some improvements

3 files changed, 95 insertions, 91 deletions

diff --git a/NesContainers.csproj b/NesContainers.csproj
index 5104559..94c63be 100644
--- a/NesContainers.csproj
+++ b/NesContainers.csproj
@@ -16,12 +16,12 @@
     <PackageProjectUrl>https://github.com/ClusterM/nes-containers</PackageProjectUrl>

     <Copyright>Alexey 'Cluster' Avdyukhin, 2022</Copyright>

     <Description>A simple .NET Standard 2.0 library for reading and modifying NES/Famicom ROM containers: .nes (iNES, NES 2.0), .unf (UNIF), and .fds (Famicom Disk System images).</Description>

-    <Version>1.0.0</Version>

+    <Version>1.0.1</Version>

     <RepositoryUrl>https://github.com/ClusterM/nes-containers</RepositoryUrl>

     <RepositoryType>git</RepositoryType>

     <PackageTags>nes,famicom,famicom disk system</PackageTags>

-    <AssemblyVersion>1.0.0</AssemblyVersion>

-    <FileVersion>1.0.0</FileVersion>

+    <AssemblyVersion>1.0.1</AssemblyVersion>

+    <FileVersion>1.0.1</FileVersion>

     <Authors>Alexey 'Cluster' Avdyukhin</Authors>

   </PropertyGroup>

 

diff --git a/NesFile.cs b/NesFile.cs
index 3877027..de87ced 100644
--- a/NesFile.cs
+++ b/NesFile.cs
@@ -14,39 +14,39 @@ namespace com.clusterrr.Famicom.Containers
         /// <summary>

         /// PRG data

         /// </summary>

-        public IEnumerable<byte> PRG

+        public byte[] PRG

         {

-            get => Array.AsReadOnly(prg);

+            get => prg;

             set => prg = (value ?? new byte[0]).ToArray();

         }

         /// <summary>

-        /// CHR data (can be null if none)

+        /// CHR data

         /// </summary>

-        public IEnumerable<byte>? CHR

+        public byte[] CHR

         {

-            get => chr.Length == 0 ? null : Array.AsReadOnly(chr);

+            get => chr;

             set => chr = (value ?? new byte[0]).ToArray();

         }

         /// <summary>

-        /// Trainer (can be null if none)

+        /// Trainer

         /// </summary>

-        public IEnumerable<byte>? Trainer

+        public byte[] Trainer

         {

-            get => trainer.Length == 0 ? null : Array.AsReadOnly(trainer);

+            get => trainer;

             set

             {

-                if (value != null && value.Count() != 0 && value.Count() != 512)

-                    throw new ArgumentOutOfRangeException("Trainer size must be 512 bytes");

-                chr = (value ?? new byte[0]).ToArray();

+                if (value != null && value.Count() != 0 && value.Count() > 512)

+                    throw new ArgumentOutOfRangeException("Trainer size must be 512 bytes or less");

+                chr = value ?? new byte[0];

             }

         }

         /// <summary>

-        /// Miscellaneous ROM (NES 2.0 only, can be null if none)

+        /// Miscellaneous ROM (NES 2.0 only)

         /// </summary>

-        public IEnumerable<byte>? MiscellaneousROM

+        public byte[] MiscellaneousROM

         {

-            get => miscellaneousROM.Length == 0 ? null : Array.AsReadOnly(miscellaneousROM);

-            set => miscellaneousROM = (value ?? new byte[0]).ToArray();

+            get => miscellaneousROM;

+            set => miscellaneousROM = value ?? new byte[0];

         }

         /// <summary>

         /// Mapper number

@@ -635,7 +635,7 @@ namespace com.clusterrr.Famicom.Containers
             }

 

             uint offset = (uint)header.Length;

-            if (trainer != null && trainer.Length > 0)

+            if (trainer.Length > 0)

             {

                 if (offset < data.Length)

                     Array.Copy(data, offset, trainer, 0, Math.Max(0, Math.Min(trainer.Length, data.Length - offset)));

@@ -698,9 +698,6 @@ namespace com.clusterrr.Famicom.Containers
             header[1] = (byte)'E';

             header[2] = (byte)'S';

             header[3] = 0x1A;

-            if (prg == null) prg = new byte[0];

-            if (chr == null) chr = new byte[0];

-            if (trainer == null) trainer = new byte[0];

             ulong prgSizePadded, chrSizePadded;

             if (Version == iNesVersion.iNES)

             {

@@ -750,7 +747,10 @@ namespace com.clusterrr.Famicom.Containers
 

                 data.AddRange(header);

                 if (trainer.Length > 0)

+                {

                     data.AddRange(trainer);

+                    if (trainer.Length < 512) data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)512 - trainer.Length));

+                }

                 data.AddRange(prg);

                 data.AddRange(chr);

             }

@@ -843,19 +843,22 @@ namespace com.clusterrr.Famicom.Containers
                 header[15] |= (byte)((byte)DefaultExpansionDevice & 0x3F);

 

                 data.AddRange(header);

-                if (Trainer != null)

-                    data.AddRange(Trainer);

+                if (trainer.Length > 0)

+                {

+                    data.AddRange(trainer);

+                    if (trainer.Length < 512) data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)512 - trainer.Length));

+                }

                 data.AddRange(prg);

                 data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)prgSizePadded - prg.Length));

                 data.AddRange(chr);

                 data.AddRange(Enumerable.Repeat<byte>(0xFF, (int)chrSizePadded - chr.Length));

-                if (MiscellaneousROMsCount > 0 || (MiscellaneousROM != null && MiscellaneousROM.Count() > 0))

+                if (MiscellaneousROMsCount > 0 || miscellaneousROM.Length > 0)

                 {

                     if (MiscellaneousROMsCount == 0)

                         throw new InvalidDataException("MiscellaneousROMsCount is zero while MiscellaneousROM is not empty");

-                    if (MiscellaneousROM == null)

+                    if (MiscellaneousROM.Length == 0)

                         throw new InvalidDataException("MiscellaneousROM is empty while MiscellaneousROMsCount is not zero");

-                    data.AddRange(MiscellaneousROM);

+                    data.AddRange(miscellaneousROM);

                 }

             }

             return data.ToArray();

@@ -923,28 +926,18 @@ namespace com.clusterrr.Famicom.Containers
         /// <summary>

         /// Calculate MD5 checksum of ROM (CHR+PRG without header)

         /// </summary>

+        /// <returns>MD5 checksum for all PRG and CHR data</returns>

         public byte[] CalculateMD5()

         {

             var md5 = MD5.Create();

-            if (prg == null) prg = new byte[0];

-            if (chr == null) chr = new byte[0];

-            var alldata = new byte[prg.Length + chr.Length];

-            Array.Copy(prg, 0, alldata, 0, prg.Length);

-            Array.Copy(chr, 0, alldata, prg.Length, chr.Count());

+            var alldata = Enumerable.Concat(prg ?? new byte[0], chr ?? new byte[0]).ToArray();

             return md5.ComputeHash(alldata);

         }

 

         /// <summary>

         /// Calculate CRC32 checksum of ROM (CHR+PRG without header)

         /// </summary>

-        public uint CalculateCRC32()

-        {

-            if (prg == null) prg = new byte[0];

-            if (chr == null) chr = new byte[0];

-            var alldata = new byte[prg.Length + chr.Length];

-            Array.Copy(prg, 0, alldata, 0, prg.Length);

-            Array.Copy(chr, 0, alldata, prg.Length, chr.Length);

-            return Crc32Calculator.CalculateCRC32(alldata);

-        }

+        /// <returns>CRC32 checksum for all PRG and CHR data</returns>

+        public uint CalculateCRC32() => Crc32Calculator.CalculateCRC32(Enumerable.Concat(prg ?? new byte[0], chr ?? new byte[0]).ToArray());

     }

 }

diff --git a/UnifFile.cs b/UnifFile.cs
index 6872372..7caf4ed 100644
--- a/UnifFile.cs
+++ b/UnifFile.cs
@@ -4,6 +4,8 @@ using System.Collections.Generic;
 using System.Drawing;

 using System.IO;

 using System.Linq;

+using System.Runtime.ConstrainedExecution;

+using System.Security.Cryptography;

 using System.Text;

 using System.Xml.Linq;

 

@@ -12,7 +14,7 @@ namespace com.clusterrr.Famicom.Containers
     /// <summary>

     /// UNIF file container for NES/Famicom games

     /// </summary>

-    public class UnifFile : IEnumerable<KeyValuePair<string, IEnumerable<byte>>>

+    public class UnifFile : IEnumerable<KeyValuePair<string, byte[]>>

     {

         /// <summary>

         /// UNIF fields

@@ -29,13 +31,13 @@ namespace com.clusterrr.Famicom.Containers
         /// </summary>

         /// <param name="key">UNIF data block key</param>

         /// <returns></returns>

-        public IEnumerable<byte> this[string key]

+        public byte[] this[string key]

         {

             get

             {

                 if (key.Length != 4) throw new ArgumentException("UNIF data block key must be 4 characters long");

                 if (!ContainsField(key)) throw new IndexOutOfRangeException($"There is no {key} field");

-                return Array.AsReadOnly(fields[key]);

+                return fields[key];

             }

             set

             {

@@ -43,7 +45,7 @@ namespace com.clusterrr.Famicom.Containers
                 if (value == null)

                     this.RemoveField(key);

                 else

-                    fields[key] = (value ?? new byte[0]).ToArray();

+                    fields[key] = value;

             }

         }

 

@@ -64,8 +66,8 @@ namespace com.clusterrr.Famicom.Containers
         /// Returns enumerator that iterates throught fields

         /// </summary>

         /// <returns>IEnumerable object</returns>

-        public IEnumerator<KeyValuePair<string, IEnumerable<byte>>> GetEnumerator()

-            => fields.Select(kv => new KeyValuePair<string, IEnumerable<byte>>(kv.Key, Array.AsReadOnly(kv.Value))).GetEnumerator();

+        public IEnumerator<KeyValuePair<string, byte[]>> GetEnumerator()

+            => fields.Select(kv => new KeyValuePair<string, byte[]>(kv.Key, kv.Value)).GetEnumerator();

 

         IEnumerator IEnumerable.GetEnumerator() => this.GetEnumerator();

 

@@ -145,10 +147,10 @@ namespace com.clusterrr.Famicom.Containers
             foreach (var kv in this)

             {

                 data.AddRange(Encoding.UTF8.GetBytes(kv.Key));

-                var v = kv.Value.ToArray();

-                int len = v.Length;

+                var value = kv.Value;

+                int len = value.Length;

                 data.AddRange(BitConverter.GetBytes(len));

-                data.AddRange(v);

+                data.AddRange(value);

             }

             return data.ToArray();

         }

@@ -188,11 +190,11 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// Mapper name

+        /// Mapper name (null if none)

         /// </summary>

         public string? Mapper

         {

-            get => ContainsField("MAPR") ? UTF8NToString(this["MAPR"].ToArray()) : null;

+            get => ContainsField("MAPR") ? UTF8NToString(this["MAPR"]) : null;

             set

             {

                 if (value == null)

@@ -203,7 +205,7 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// The dumper name

+        /// The dumper name (null if none)

         /// </summary>

         /// 

         public string? DumperName

@@ -212,7 +214,7 @@ namespace com.clusterrr.Famicom.Containers
             {

                 if (!ContainsField("DINF"))

                     return null;

-                var data = this["DINF"].ToArray();

+                var data = this["DINF"];

                 if (data.Length >= 204 && data[0] != 0)

                     return UTF8NToString(data, 100);

                 else

@@ -224,7 +226,7 @@ namespace com.clusterrr.Famicom.Containers
                 {

                     if (!ContainsField("DINF"))

                         this["DINF"] = new byte[204];

-                    var data = this["DINF"].ToArray();

+                    var data = this["DINF"];

                     for (int i = 0; i < 100; i++)

                         data[i] = 0;

                     if (value != null)

@@ -239,7 +241,7 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// The name of the dumping software or mechanism

+        /// The name of the dumping software or mechanism (null if none)

         /// </summary>

         public string? DumpingSoftware

         {

@@ -247,7 +249,7 @@ namespace com.clusterrr.Famicom.Containers
             {

                 if (!ContainsField("DINF"))

                     return null;

-                var data = this["DINF"].ToArray();

+                var data = this["DINF"];

                 if (data.Length >= 204 && data[0] != 0)

                     return UTF8NToString(data, 100, 104);

                 else

@@ -259,7 +261,7 @@ namespace com.clusterrr.Famicom.Containers
                 {

                     if (!ContainsField("DINF"))

                         this["DINF"] = new byte[204];

-                    var data = this["DINF"].ToArray();

+                    var data = this["DINF"];

                     for (int i = 104; i < 104 + 100; i++)

                         data[i] = 0;

                     if (value != null)

@@ -274,14 +276,14 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// Date of the dump

+        /// Date of the dump (null if none)

         /// </summary>

         public DateTime? DumpDate

         {

             get

             {

                 if (!ContainsField("DINF")) return null;

-                var data = this["DINF"].ToArray();

+                var data = this["DINF"];

                 if (data[0] == 0 && data[1] == 0 && data[2] == 0 && data[3] == 0)

                     return null;

                 return new DateTime(

@@ -296,7 +298,7 @@ namespace com.clusterrr.Famicom.Containers
                 {

                     if (!ContainsField("DINF"))

                         this["DINF"] = new byte[204];

-                    var data = this["DINF"].ToArray();

+                    var data = this["DINF"];

                     if (value != null)

                     {

                         data[100] = (byte)value.Value.Day;

@@ -307,10 +309,7 @@ namespace com.clusterrr.Famicom.Containers
                     else

                     {

                         // Is it valid?

-                        data[100] = 0;

-                        data[101] = 0;

-                        data[102] = 0;

-                        data[103] = 0;

+                        data[100] = data[101] = data[102] = data[103] = 0;

                     }

                     this["DINF"] = data;

                 }

@@ -319,11 +318,11 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// Name of the game

+        /// Name of the game (null if none)

         /// </summary>

         public string? GameName

         {

-            get => ContainsField("NAME") ? UTF8NToString(this["NAME"].ToArray()) : null;

+            get => ContainsField("NAME") ? UTF8NToString(this["NAME"]) : null;

             set

             {

                 if (value == null)

@@ -334,7 +333,7 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// For non-homebrew NES/Famicom games, this field's value is always a function of the region in which a game was released

+        /// For non-homebrew NES/Famicom games, this field's value is always a function of the region in which a game was released (null if none)

         /// </summary>

         public Timing? Region

         {

@@ -355,7 +354,7 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// Controllers usable by this game (bitmask)

+        /// Controllers usable by this game, bitmask (null if none)

         /// </summary>

         public Controller? Controllers

         {

@@ -376,7 +375,7 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// Battery-backed (or other non-volatile memory) memory is present

+        /// Battery-backed (or other non-volatile memory) memory is present (null if none)

         /// </summary>

         public bool? Battery

         {

@@ -397,7 +396,7 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// Mirroring type

+        /// Mirroring type (null if none)

         /// </summary>

         public MirroringType? Mirroring

         {

@@ -418,9 +417,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// PRG0 field

+        /// PRG0 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? PRG0

+        public byte[]? PRG0

         {

             get

             {

@@ -439,9 +438,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// PRG1 field

+        /// PRG1 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? PRG1

+        public byte[]? PRG1

         {

             get

             {

@@ -460,9 +459,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// PRG2 field

+        /// PRG2 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? PRG2

+        public byte[]? PRG2

         {

             get

             {

@@ -481,9 +480,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// PRG3 field

+        /// PRG3 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? PRG3

+        public byte[]? PRG3

         {

             get

             {

@@ -502,9 +501,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// CHR0 field

+        /// CHR0 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? CHR0

+        public byte[]? CHR0

         {

             get

             {

@@ -523,9 +522,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// CHR1 field

+        /// CHR1 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? CHR1

+        public byte[]? CHR1

         {

             get

             {

@@ -544,9 +543,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// CHR2 field

+        /// CHR2 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? CHR2

+        public byte[]? CHR2

         {

             get

             {

@@ -565,9 +564,9 @@ namespace com.clusterrr.Famicom.Containers
         }

 

         /// <summary>

-        /// CHR3 field

+        /// CHR3 field (null if none)

         /// </summary>

-        public IEnumerable<byte>? CHR3

+        public byte[]? CHR3

         {

             get

             {

@@ -593,21 +592,33 @@ namespace com.clusterrr.Famicom.Containers
             foreach (var kv in this.Where(kv => kv.Key.StartsWith("PRG")))

             {

                 var num = kv.Key[3];

-                var crc32 = Crc32Calculator.CalculateCRC32(kv.Value.ToArray());

+                var crc32 = Crc32Calculator.CalculateCRC32(kv.Value);

                 this[$"PCK{num}"] = BitConverter.GetBytes(crc32);

             }

             foreach (var kv in this.Where(kv => kv.Key.StartsWith("CHR")))

             {

                 var num = kv.Key[3];

-                var crc32 = Crc32Calculator.CalculateCRC32(kv.Value.ToArray());

+                var crc32 = Crc32Calculator.CalculateCRC32(kv.Value);

                 this[$"CCK{num}"] = BitConverter.GetBytes(crc32);

             }

         }

 

         /// <summary>

-        /// Calculate overall CRC32

+        /// Calculate MD5 checksum of ROM (all PRG fields + all CHR fields)

         /// </summary>

-        /// <returns></returns>

+        /// <returns>MD5 checksum for all PRG and CHR data</returns>

+        public byte[] CalculateMD5()

+        {

+            var md5 = MD5.Create();

+            var alldata = Enumerable.Concat(fields.Where(k => k.Key.StartsWith("PRG")).OrderBy(k => k.Key).SelectMany(i => i.Value),

+                                  fields.Where(k => k.Key.StartsWith("CHR")).OrderBy(k => k.Key).SelectMany(i => i.Value)).ToArray();

+            return md5.ComputeHash(alldata);

+        }

+

+        /// <summary>

+        /// Calculate CRC32 checksum of ROM (all PRG fields + all CHR fields)

+        /// </summary>

+        /// <returns>CRC32 checksum for all PRG and CHR data</returns>

         public uint CalculateCRC32()

             => Crc32Calculator.CalculateCRC32(

                 Enumerable.Concat(fields.Where(k => k.Key.StartsWith("PRG")).OrderBy(k => k.Key).SelectMany(i => i.Value),