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Claunia.Encoding/Claunia.Encoding/ZX81.cs

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C#

//
// ZX81.cs
//
// Author:
// Natalia Portillo <claunia@claunia.com>
//
// Copyright © 2016-2021 Natalia Portillo
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
namespace Claunia.Encoding
{
/// <summary>Represents a ZX81 character encoding of Unicode characters.</summary>
public class Zx81 : Encoding
{
const string BODY_NAME = "zx81";
const int CODEPAGE = 0;
const string ENCODING_NAME = "Sinclair ZX81 character set";
const string HEADER_NAME = "zx81";
const string WEB_NAME = "";
const int WINDOWS_CODEPAGE = 0;
const bool BROWSER_DISPLAY = false;
const bool BROWSER_SAVE = false;
const bool MAIL_NEWS_DISPLAY = false;
const bool MAIL_NEWS_SAVE = false;
const bool READ_ONLY = false;
const bool SINGLE_BYTE = true;
/// <summary>The ZX81 to Unicode character map.</summary>
static readonly char[] _zx81Table =
{
// 0x00
'\u0020', '\u2598', '\u259D', '\u2580', '\u2596', '\u258C', '\u259E', '\u259B',
// 0x08
'\u2592', '\uFFFD', '\uFFFD', '\u0022', '\u00A3', '\u0024', '\u003A', '\u003F',
// 0x10
'\u0028', '\u0029', '\u003E', '\u003C', '\u003D', '\u002B', '\u002D', '\u002A',
// 0x18
'\u002F', '\u003B', '\u002C', '\u002E', '\u0030', '\u0031', '\u0032', '\u0033',
// 0x20
'\u0034', '\u0035', '\u0036', '\u0037', '\u0038', '\u0039', '\u0041', '\u0042',
// 0x28
'\u0043', '\u0044', '\u0045', '\u0046', '\u0047', '\u0048', '\u0049', '\u004A',
// 0x30
'\u004B', '\u004C', '\u004D', '\u004E', '\u004F', '\u0050', '\u0051', '\u0052',
// 0x38
'\u0053', '\u0054', '\u0055', '\u0056', '\u0057', '\u0058', '\u0059', '\u005A',
// 0x40
'\uFFFF', '\uFFFF', '\uFFFF', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000',
// 0x48
'\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000',
// 0x50
'\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000',
// 0x58
'\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000',
// 0x60
'\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000',
// 0x68
'\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000', '\u0000',
// 0x70
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\u000A', '\u0008',
// 0x78
'\uFFFF', '\uFFFF', '\u0000', '\u0000', '\u0000', '\u0000', '\uFFFF', '\uFFFF',
// 0x80
'\u2588', '\u259F', '\u2599', '\u2584', '\u259C', '\u2590', '\u259A', '\u2597',
// 0x88
'\u2592', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD',
// 0x90
'\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD',
// 0x98
'\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD',
// 0xA0
'\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD',
// 0xA8
'\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD',
// 0xB0
'\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD',
// 0xB8
'\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD', '\uFFFD',
// 0xC0
'\uFFFF', '\uFFFF', '\uFFFF', '\u0000', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF',
// 0xC8
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF',
// 0xD0
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF',
// 0xD8
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF',
// 0xE0
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF',
// 0xE8
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF',
// 0xF0
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF',
// 0xF8
'\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF', '\uFFFF'
};
/// <summary>Gets a value indicating whether the current encoding can be used by browser clients for displaying content.</summary>
public override bool IsBrowserDisplay => BROWSER_DISPLAY;
/// <summary>Gets a value indicating whether the current encoding can be used by browser clients for saving content.</summary>
public override bool IsBrowserSave => BROWSER_SAVE;
/// <summary>
/// Gets a value indicating whether the current encoding can be used by mail and news clients for displaying
/// content.
/// </summary>
public override bool IsMailNewsDisplay => MAIL_NEWS_DISPLAY;
/// <summary>Gets a value indicating whether the current encoding can be used by mail and news clients for saving content.</summary>
public override bool IsMailNewsSave => MAIL_NEWS_SAVE;
/// <summary>Gets a value indicating whether the current encoding is read-only.</summary>
/// <value>The is single byte.</value>
public override bool IsReadOnly => READ_ONLY;
/// <summary>Gets a value indicating whether the current encoding uses single-byte code points.</summary>
public override bool IsSingleByte => SINGLE_BYTE;
/// <summary>Gets the code page identifier of the current Encoding.</summary>
public override int CodePage => CODEPAGE;
/// <summary>Gets a name for the current encoding that can be used with mail agent body tags</summary>
public override string BodyName => BODY_NAME;
/// <summary>Gets a name for the current encoding that can be used with mail agent header tags</summary>
public override string HeaderName => HEADER_NAME;
/// <summary>Gets the name registered with the Internet Assigned Numbers Authority (IANA) for the current encoding.</summary>
public override string WebName => WEB_NAME;
/// <summary>Gets the human-readable description of the current encoding.</summary>
public override string EncodingName => ENCODING_NAME;
/// <summary>Gets the Windows operating system code page that most closely corresponds to the current encoding.</summary>
public override int WindowsCodePage => WINDOWS_CODEPAGE;
/// <summary>Calculates the number of bytes produced by encoding the characters in the specified <see cref="string" />.</summary>
/// <returns>The number of bytes produced by encoding the specified characters.</returns>
/// <param name="s">The <see cref="string" /> containing the set of characters to encode.</param>
public override int GetByteCount(string s)
{
if(s == null)
throw new ArgumentNullException(nameof(s));
return s.Length;
}
/// <summary>Calculates the number of bytes produced by encoding a set of characters from the specified character array.</summary>
/// <returns>The number of bytes produced by encoding the specified characters.</returns>
/// <param name="chars">The character array containing the set of characters to encode.</param>
/// <param name="index">The index of the first character to encode.</param>
/// <param name="count">The number of characters to encode.</param>
public override int GetByteCount(char[] chars, int index, int count)
{
if(chars == null)
throw new ArgumentNullException(nameof(chars));
if(index < 0 ||
index >= chars.Length)
throw new ArgumentOutOfRangeException(nameof(index));
if(count < 0 ||
index + count > chars.Length)
throw new ArgumentOutOfRangeException(nameof(index));
return count;
}
/// <summary>Calculates the number of bytes produced by encoding all the characters in the specified character array.</summary>
/// <returns>The number of bytes produced by encoding all the characters in the specified character array.</returns>
/// <param name="chars">The character array containing the characters to encode.</param>
public override int GetByteCount(char[] chars)
{
if(chars == null)
throw new ArgumentNullException(nameof(chars));
return chars.Length;
}
/// <summary>Encodes a set of characters from the specified <see cref="string" /> into the specified byte array.</summary>
/// <returns>The actual number of bytes written into bytes.</returns>
/// <param name="s">The <see cref="string" /> containing the set of characters to encode.</param>
/// <param name="charIndex">The index of the first character to encode.</param>
/// <param name="charCount">The number of characters to encode.</param>
/// <param name="bytes">The byte array to contain the resulting sequence of bytes.</param>
/// <param name="byteIndex">The index at which to start writing the resulting sequence of bytes.</param>
public override int GetBytes(string s, int charIndex, int charCount, byte[] bytes, int byteIndex) =>
GetBytes(s.ToCharArray(), charIndex, charCount, bytes, byteIndex);
/// <summary>Encodes all the characters in the specified string into a sequence of bytes.</summary>
/// <returns>A byte array containing the results of encoding the specified set of characters.</returns>
/// <param name="s">The string containing the characters to encode.</param>
public override byte[] GetBytes(string s)
{
if(s == null)
throw new ArgumentNullException(nameof(s));
return GetBytes(s.ToCharArray(), 0, s.Length);
}
/// <summary>Encodes a set of characters from the specified character array into the specified byte array.</summary>
/// <returns>The actual number of bytes written into bytes.</returns>
/// <param name="chars">The character array containing the set of characters to encode.</param>
/// <param name="charIndex">The index of the first character to encode.</param>
/// <param name="charCount">The number of characters to encode.</param>
/// <param name="bytes">The byte array to contain the resulting sequence of bytes.</param>
/// <param name="byteIndex">The index at which to start writing the resulting sequence of bytes.</param>
public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex)
{
if(chars == null)
throw new ArgumentNullException(nameof(chars));
if(bytes == null)
throw new ArgumentNullException(nameof(bytes));
if(charIndex < 0)
throw new ArgumentOutOfRangeException(nameof(charIndex));
if(charCount < 0)
throw new ArgumentOutOfRangeException(nameof(charCount));
if(byteIndex < 0)
throw new ArgumentOutOfRangeException(nameof(byteIndex));
if(charIndex >= chars.Length)
throw new ArgumentOutOfRangeException(nameof(charIndex));
if(charCount + charIndex > chars.Length)
throw new ArgumentOutOfRangeException(nameof(charCount));
if(byteIndex >= bytes.Length)
throw new ArgumentOutOfRangeException(nameof(byteIndex));
if(byteIndex + charCount > bytes.Length)
throw new ArgumentException(nameof(bytes));
byte[] temp = GetBytes(chars, charIndex, charCount);
for(int i = 0; i < temp.Length; i++)
bytes[i + byteIndex] = temp[i];
return charCount;
}
/// <summary>Encodes a set of characters from the specified character array into a sequence of bytes.</summary>
/// <returns>A byte array containing the results of encoding the specified set of characters.</returns>
/// <param name="chars">The character array containing the set of characters to encode.</param>
/// <param name="index">The index of the first character to encode.</param>
/// <param name="count">The number of characters to encode.</param>
public override byte[] GetBytes(char[] chars, int index, int count)
{
if(chars == null)
throw new ArgumentNullException(nameof(chars));
if(index < 0)
throw new ArgumentOutOfRangeException(nameof(index));
if(count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if(count + index > chars.Length)
throw new ArgumentOutOfRangeException(nameof(count));
byte[] bytes = new byte[count];
for(int i = 0; i < count; i++)
bytes[i] = GetByte(chars[index + i]);
return bytes;
}
/// <summary>Encodes all the characters in the specified character array into a sequence of bytes.</summary>
/// <returns>A byte array containing the results of encoding the specified set of characters.</returns>
/// <param name="chars">The character array containing the characters to encode.</param>
public override byte[] GetBytes(char[] chars) => GetBytes(chars, 0, chars.Length);
/// <summary>Calculates the number of characters produced by decoding all the bytes in the specified byte array.</summary>
/// <returns>The number of characters produced by decoding the specified sequence of bytes.</returns>
/// <param name="bytes">The byte array containing the sequence of bytes to decode.</param>
public override int GetCharCount(byte[] bytes) => GetCharCount(bytes, 0, bytes.Length);
/// <summary>Calculates the number of characters produced by decoding a sequence of bytes from the specified byte array.</summary>
/// <returns>The number of characters produced by decoding the specified sequence of bytes.</returns>
/// <param name="bytes">The byte array containing the sequence of bytes to decode.</param>
/// <param name="index">The index of the first byte to decode.</param>
/// <param name="count">The number of bytes to decode.</param>
public override int GetCharCount(byte[] bytes, int index, int count)
{
if(bytes == null)
throw new ArgumentNullException(nameof(bytes));
if(index < 0)
throw new ArgumentOutOfRangeException(nameof(index));
if(count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if(count + index > bytes.Length)
throw new ArgumentOutOfRangeException(nameof(count));
return count;
}
/// <summary>Decodes a sequence of bytes from the specified byte array into the specified character array.</summary>
/// <returns>The actual number of characters written into chars.</returns>
/// <param name="bytes">The byte array containing the sequence of bytes to decode.</param>
/// <param name="byteIndex">The index of the first byte to decode.</param>
/// <param name="byteCount">The number of bytes to decode.</param>
/// <param name="chars">The character array to contain the resulting set of characters.</param>
/// <param name="charIndex">The index at which to start writing the resulting set of characters.</param>
public override int GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex)
{
if(bytes == null)
throw new ArgumentNullException(nameof(bytes));
if(chars == null)
throw new ArgumentNullException(nameof(chars));
if(byteIndex < 0)
throw new ArgumentOutOfRangeException(nameof(byteIndex));
if(byteCount < 0)
throw new ArgumentOutOfRangeException(nameof(byteCount));
if(charIndex < 0)
throw new ArgumentOutOfRangeException(nameof(charIndex));
if(byteIndex >= bytes.Length)
throw new ArgumentOutOfRangeException(nameof(byteIndex));
if(byteCount + byteIndex > bytes.Length)
throw new ArgumentOutOfRangeException(nameof(byteCount));
if(charIndex >= chars.Length)
throw new ArgumentOutOfRangeException(nameof(charIndex));
if(charIndex + byteCount > chars.Length)
throw new ArgumentException(nameof(chars));
char[] temp = GetChars(bytes, byteIndex, byteCount);
for(int i = 0; i < temp.Length; i++)
chars[i + charIndex] = temp[i];
return byteCount;
}
/// <summary>Decodes all the bytes in the specified byte array into a set of characters.</summary>
/// <returns>A character array containing the results of decoding the specified sequence of bytes.</returns>
/// <param name="bytes">The byte array containing the sequence of bytes to decode.</param>
public override char[] GetChars(byte[] bytes) => GetChars(bytes, 0, bytes.Length);
/// <summary>Decodes a sequence of bytes from the specified byte array into a set of characters.</summary>
/// <returns>The chars.</returns>
/// <param name="bytes">The byte array containing the sequence of bytes to decode.</param>
/// <param name="index">The index of the first byte to decode.</param>
/// <param name="count">The number of bytes to decode.</param>
public override char[] GetChars(byte[] bytes, int index, int count)
{
if(bytes == null)
throw new ArgumentNullException(nameof(bytes));
if(index < 0)
throw new ArgumentOutOfRangeException(nameof(index));
if(count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if(count + index > bytes.Length)
throw new ArgumentOutOfRangeException(nameof(count));
char[] chars = new char[count];
for(int i = 0; i < count; i++)
chars[i] = GetChar(bytes[index + i]);
return chars;
}
/// <summary>Calculates the maximum number of bytes produced by encoding the specified number of characters.</summary>
/// <returns>The maximum number of bytes produced by encoding the specified number of characters.</returns>
/// <param name="charCount">The number of characters to encode.</param>
public override int GetMaxByteCount(int charCount)
{
if(charCount < 0)
throw new ArgumentOutOfRangeException(nameof(charCount));
return charCount;
}
/// <summary>Calculates the maximum number of characters produced by decoding the specified number of bytes.</summary>
/// <returns>The maximum number of characters produced by decoding the specified number of bytes.</returns>
/// <param name="byteCount">The number of bytes to decode.</param>
public override int GetMaxCharCount(int byteCount)
{
if(byteCount < 0)
throw new ArgumentOutOfRangeException(nameof(byteCount));
return byteCount;
}
/// <summary>Returns a sequence of bytes that specifies the encoding used.</summary>
/// <returns>A byte array of length zero, as a preamble is not required.</returns>
public override byte[] GetPreamble() => new byte[0];
/// <summary>Decodes all the bytes in the specified byte array into a string.</summary>
/// <returns>A string that contains the results of decoding the specified sequence of bytes.</returns>
/// <param name="bytes">The byte array containing the sequence of bytes to decode.</param>
public override string GetString(byte[] bytes) => GetString(bytes, 0, bytes.Length);
/// <summary>Decodes a sequence of bytes from the specified byte array into a string.</summary>
/// <returns>A string that contains the results of decoding the specified sequence of bytes.</returns>
/// <param name="bytes">The byte array containing the sequence of bytes to decode.</param>
/// <param name="index">The index of the first byte to decode.</param>
/// <param name="count">The number of bytes to decode.</param>
public override string GetString(byte[] bytes, int index, int count) => new(GetChars(bytes, index, count));
/// <summary>Converts a ZX81 character to an Unicode character</summary>
/// <returns>Unicode character.</returns>
/// <param name="character">ZX81 character.</param>
static char GetChar(byte character) => _zx81Table[character];
/// <summary>Converts a Unicode character to an ZX81 character</summary>
/// <returns>ZX81 character.</returns>
/// <param name="character">Unicode character.</param>
static byte GetByte(char character)
{
switch(character)
{
case '\u0020': return 0x00;
case '\u2598': return 0x01;
case '\u259D': return 0x02;
case '\u2580': return 0x03;
case '\u2596': return 0x04;
case '\u258C': return 0x05;
case '\u259E': return 0x06;
case '\u259B': return 0x07;
case '\u2592': return 0x08;
case '\u0022': return 0x0B;
case '\u00A3': return 0x0C;
case '\u0024': return 0x0D;
case '\u003A': return 0x0E;
case '\u003F': return 0x0F;
case '\u0028': return 0x10;
case '\u0029': return 0x11;
case '\u003E': return 0x12;
case '\u003C': return 0x13;
case '\u003D': return 0x14;
case '\u002B': return 0x15;
case '\u002D': return 0x16;
case '\u002A': return 0x17;
case '\u002F': return 0x18;
case '\u003B': return 0x19;
case '\u002C': return 0x1A;
case '\u002E': return 0x1B;
case '\u0030': return 0x1C;
case '\u0031': return 0x1D;
case '\u0032': return 0x1E;
case '\u0033': return 0x1F;
case '\u0034': return 0x20;
case '\u0035': return 0x21;
case '\u0036': return 0x22;
case '\u0037': return 0x23;
case '\u0038': return 0x24;
case '\u0039': return 0x25;
case '\u0041': return 0x26;
case '\u0042': return 0x27;
case '\u0043': return 0x28;
case '\u0044': return 0x29;
case '\u0045': return 0x2A;
case '\u0046': return 0x2B;
case '\u0047': return 0x2C;
case '\u0048': return 0x2D;
case '\u0049': return 0x2E;
case '\u004A': return 0x2F;
case '\u004B': return 0x30;
case '\u004C': return 0x31;
case '\u004D': return 0x32;
case '\u004E': return 0x33;
case '\u004F': return 0x34;
case '\u0050': return 0x35;
case '\u0051': return 0x36;
case '\u0052': return 0x37;
case '\u0053': return 0x38;
case '\u0054': return 0x39;
case '\u0055': return 0x3A;
case '\u0056': return 0x3B;
case '\u0057': return 0x3C;
case '\u0058': return 0x3D;
case '\u0059': return 0x3E;
case '\u005A': return 0x3F;
case '\u000D': return 0x74;
case '\u000A': return 0x76;
case '\u0008': return 0x77;
case '\u2588': return 0x80;
case '\u259F': return 0x81;
case '\u2599': return 0x82;
case '\u2584': return 0x83;
case '\u259C': return 0x84;
case '\u2590': return 0x85;
case '\u259A': return 0x86;
case '\u2597': return 0x87;
default:
// Fallback to '?'
return 0x0F;
}
}
}
}