mono/mcs/class/corlib/System.Text/ASCIIEncoding.cs

/*
 * ASCIIEncoding.cs - Implementation of the "System.Text.ASCIIEncoding" class.
 *
 * Copyright (c) 2001  Southern Storm Software, Pty Ltd
 *
 * 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.
 */

namespace System.Text
{

using System;

[Serializable]
public class ASCIIEncoding : Encoding
{
	// Magic number used by Windows for "ASCII".
	internal const int ASCII_CODE_PAGE = 20127;

	// Constructor.
	public ASCIIEncoding () : base(ASCII_CODE_PAGE) {}

	// Get the number of bytes needed to encode a character buffer.
	public override int GetByteCount (char[] chars, int index, int count)
	{
		if (chars == null) {
			throw new ArgumentNullException ("chars");
		}
		if (index < 0 || index > chars.Length) {
			throw new ArgumentOutOfRangeException ("index", _("ArgRange_Array"));
		}
		if (count < 0 || count > (chars.Length - index)) {
			throw new ArgumentOutOfRangeException ("count", _("ArgRange_Array"));
		}
		return count;
	}

	// Convenience wrappers for "GetByteCount".
	public override int GetByteCount (String s)
	{
		if (s == null) {
			throw new ArgumentNullException ("s");
		}
		return s.Length;
	}

	// Get the bytes that result from encoding a character buffer.
	public override int GetBytes (char[] chars, int charIndex, int charCount,
								 byte[] bytes, int byteIndex)
	{
		if (chars == null) {
			throw new ArgumentNullException ("chars");
		}
		if (bytes == null) {
			throw new ArgumentNullException ("bytes");
		}
		if (charIndex < 0 || charIndex > chars.Length) {
			throw new ArgumentOutOfRangeException ("charIndex", _("ArgRange_Array"));
		}
		if (charCount < 0 || charCount > (chars.Length - charIndex)) {
			throw new ArgumentOutOfRangeException ("charCount", _("ArgRange_Array"));
		}
		if (byteIndex < 0 || byteIndex > bytes.Length) {
			throw new ArgumentOutOfRangeException ("byteIndex", _("ArgRange_Array"));
		}
		if ((bytes.Length - byteIndex) < charCount) {
			throw new ArgumentException (_("Arg_InsufficientSpace"));
		}
		int count = charCount;
		char ch;
		while (count-- > 0) {
			ch = chars [charIndex++];
			if (ch < (char)0x80) {
				bytes [byteIndex++] = (byte)ch;
			} else {
				bytes [byteIndex++] = (byte)'?';
			}
		}
		return charCount;
	}

	// Convenience wrappers for "GetBytes".
	public override int GetBytes (String s, int charIndex, int charCount,
								 byte[] bytes, int byteIndex)
	{
		if (s == null) {
			throw new ArgumentNullException ("s");
		}
		if (bytes == null) {
			throw new ArgumentNullException ("bytes");
		}
		if (charIndex < 0 || charIndex > s.Length) {
			throw new ArgumentOutOfRangeException ("charIndex", _("ArgRange_StringIndex"));
		}
		if (charCount < 0 || charCount > (s.Length - charIndex)) {
			throw new ArgumentOutOfRangeException ("charCount", _("ArgRange_StringRange"));
		}
		if (byteIndex < 0 || byteIndex > bytes.Length) {
			throw new ArgumentOutOfRangeException ("byteIndex", _("ArgRange_Array"));
		}
		if ((bytes.Length - byteIndex) < charCount) {
			throw new ArgumentException (_("Arg_InsufficientSpace"));
		}
		int count = charCount;
		char ch;
		while (count-- > 0) {
			ch = s [charIndex++];
			if (ch < (char)0x80) {
				bytes [byteIndex++] = (byte)ch;
			} else {
				bytes [byteIndex++] = (byte)'?';
			}
		}
		return charCount;
	}

	// Get the number of characters needed to decode a byte buffer.
	public override int GetCharCount (byte[] bytes, int index, int count)
	{
		if (bytes == null) {
			throw new ArgumentNullException ("bytes");
		}
		if (index < 0 || index > bytes.Length) {
			throw new ArgumentOutOfRangeException ("index", _("ArgRange_Array"));
		}
		if (count < 0 || count > (bytes.Length - index)) {
			throw new ArgumentOutOfRangeException ("count", _("ArgRange_Array"));
		}
		return count;
	}

	// Get the characters that result from decoding a byte buffer.
	public override int GetChars (byte[] bytes, int byteIndex, int byteCount,
								 char[] chars, int charIndex)
	{
		if (bytes == null) {
			throw new ArgumentNullException ("bytes");
		}
		if (chars == null) {
			throw new ArgumentNullException ("chars");
		}
		if (byteIndex < 0 || byteIndex > bytes.Length) {
			throw new ArgumentOutOfRangeException ("byteIndex", _("ArgRange_Array"));
		}
		if (byteCount < 0 || byteCount > (bytes.Length - byteIndex)) {
			throw new ArgumentOutOfRangeException ("byteCount", _("ArgRange_Array"));
		}
		if (charIndex < 0 || charIndex > chars.Length) {
			throw new ArgumentOutOfRangeException ("charIndex", _("ArgRange_Array"));
		}
		if ((chars.Length - charIndex) < byteCount) {
			throw new ArgumentException (_("Arg_InsufficientSpace"));
		}
		int count = byteCount;
		while (count-- > 0) {
			chars [charIndex++] = (char)(bytes [byteIndex++]);
		}
		return byteCount;
	}

	// Get the maximum number of bytes needed to encode a
	// specified number of characters.
	public override int GetMaxByteCount (int charCount)
	{
		if (charCount < 0) {
			throw new ArgumentOutOfRangeException ("charCount", _("ArgRange_NonNegative"));
		}
		return charCount;
	}

	// Get the maximum number of characters needed to decode a
	// specified number of bytes.
	public override int GetMaxCharCount (int byteCount)
	{
		if (byteCount < 0) {
			throw new ArgumentOutOfRangeException ("byteCount", _("ArgRange_NonNegative"));
		}
		return byteCount;
	}

	// Decode a buffer of bytes into a string.
	public override String GetString (byte[] bytes, int index, int count)
	{
		if (bytes == null) {
			throw new ArgumentNullException ("bytes");
		}
		if (index < 0 || index > bytes.Length) {
			throw new ArgumentOutOfRangeException ("index", _("ArgRange_Array"));
		}
		if (count < 0 || count > (bytes.Length - index)) {
			throw new ArgumentOutOfRangeException ("count", _("ArgRange_Array"));
		}
		unsafe {
			fixed (byte *ss = &bytes [0]) {
				return new String ((sbyte*)ss, index, count);
			}
		}
	}
	public override String GetString (byte[] bytes)
	{
		if (bytes == null) {
			throw new ArgumentNullException ("bytes");
		}
		int count = bytes.Length;
		unsafe {
			fixed (byte *ss = &bytes [0]) {
				return new String ((sbyte*)ss, 0, count);
			}
		}
	}

#if !ECMA_COMPAT

	// Get the mail body name for this encoding.
	public override String BodyName
	{
		get {
			return "us-ascii";
		}
	}

	// Get the human-readable name for this encoding.
	public override String EncodingName
	{
		get {
			return "US-ASCII";
		}
	}

	// Get the mail agent header name for this encoding.
	public override String HeaderName
	{
		get {
			return "us-ascii";
		}
	}

	// Determine if this encoding can be displayed in a mail/news agent.
	public override bool IsMailNewsDisplay
	{
		get {
			return true;
		}
	}

	// Determine if this encoding can be saved from a mail/news agent.
	public override bool IsMailNewsSave
	{
		get {
			return true;
		}
	}

	// Get the IANA-preferred Web name for this encoding.
	public override String WebName
	{
		get {
			return "us-ascii";
		}
	}

#endif // !ECMA_COMPAT

}; // class ASCIIEncoding

}; // namespace System.Text