/*
 * Latin1Encoding.cs - Implementation of the
 *			"System.Text.Latin1Encoding" class.
 *
 * Copyright (c) 2002  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]
internal class Latin1Encoding : Encoding
{
	// Magic number used by Windows for the ISO Latin1 code page.
	internal const int ISOLATIN_CODE_PAGE = 28591;

	// Constructor.
	public Latin1Encoding () : base (ISOLATIN_CODE_PAGE)
	{
		// Nothing to do here.
	}

#if NET_2_0
	public override bool IsSingleByte {
		get { return true; }
	}

	public override bool IsAlwaysNormalized (NormalizationForm form)
	{
		return form == NormalizationForm.FormC;
	}
#endif

	// 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 NET_2_0
// well, yes, I know this #if is ugly, but I think it is the simplest switch.
		EncoderFallbackBuffer buffer = null;
		char [] fallback_chars = null;
		return GetBytes (chars, charIndex, charCount, bytes,
			byteIndex, ref buffer, ref fallback_chars);
	}

	int GetBytes (char[] chars, int charIndex, int charCount,
		      byte[] bytes, int byteIndex,
		      ref EncoderFallbackBuffer buffer,
		      ref char [] fallback_chars)
	{
#endif
		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)0x0100) {
				bytes [byteIndex++] = (byte)ch;
			} else if (ch >= '\uFF01' && ch <= '\uFF5E') {
				bytes [byteIndex++] = (byte)(ch - 0xFEE0);
			} else {
#if NET_2_0
				if (buffer == null)
					buffer = EncoderFallback.CreateFallbackBuffer ();
				if (Char.IsSurrogate (ch) && count > 1 &&
				    Char.IsSurrogate (chars [charIndex]))
					buffer.Fallback (ch, chars [charIndex], charIndex++ - 1);
				else
					buffer.Fallback (ch, charIndex - 1);
				if (fallback_chars == null || fallback_chars.Length < buffer.Remaining)
					fallback_chars = new char [buffer.Remaining];
				for (int i = 0; i < fallback_chars.Length; i++)
					fallback_chars [i] = buffer.GetNextChar ();
				byteIndex += GetBytes (fallback_chars, 0, 
					fallback_chars.Length, bytes, byteIndex,
					ref buffer, ref fallback_chars);
#else
				bytes [byteIndex++] = (byte)'?';
#endif
			}
		}
		return charCount;
	}

	// Convenience wrappers for "GetBytes".
	public override int GetBytes (String s, int charIndex, int charCount,
								 byte[] bytes, int byteIndex)
	{
#if NET_2_0
// I know this #if is ugly, but I think it is the simplest switch.
		EncoderFallbackBuffer buffer = null;
		char [] fallback_chars = null;
		return GetBytes (s, charIndex, charCount, bytes, byteIndex,
			ref buffer, ref fallback_chars);
	}

	int GetBytes (String s, int charIndex, int charCount,
		      byte[] bytes, int byteIndex,
		      ref EncoderFallbackBuffer buffer,
		      ref char [] fallback_chars)
	{
#endif
		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)0x0100) {
				bytes [byteIndex++] = (byte)ch;
			} else if (ch >= '\uFF01' && ch <= '\uFF5E') {
				bytes [byteIndex++] = (byte)(ch - 0xFEE0);
			} else {

#if NET_2_0
				if (buffer == null)
					buffer = EncoderFallback.CreateFallbackBuffer ();
				if (Char.IsSurrogate (ch) && count > 1 &&
				    Char.IsSurrogate (s [charIndex]))
					buffer.Fallback (ch, s [charIndex], charIndex++ - 1);
				else
					buffer.Fallback (ch, charIndex - 1);
				if (fallback_chars == null || fallback_chars.Length < buffer.Remaining)
					fallback_chars = new char [buffer.Remaining];
				for (int i = 0; i < fallback_chars.Length; i++)
					fallback_chars [i] = buffer.GetNextChar ();
				byteIndex += GetBytes (fallback_chars, 0, 
					fallback_chars.Length, bytes, byteIndex,
					ref buffer, ref fallback_chars);
#else
				bytes [byteIndex++] = (byte)'?';
#endif
			}
		}
		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"));
		}
		if (count == 0)
		    return String.Empty;
		unsafe {
			fixed (byte* bytePtr = bytes) {
				string s = string.InternalAllocateStr (count);

				fixed (char* charPtr = s) {
					byte* currByte = bytePtr + index;
					byte* lastByte = currByte + count;
					char* currChar = charPtr;

					while (currByte < lastByte)
						currChar++ [0] = (char) currByte++ [0];
				}

				return s;
			}
		}
	}
	public override String GetString (byte[] bytes)
	{
		if (bytes == null) {
			throw new ArgumentNullException ("bytes");
		}

		return GetString (bytes, 0, bytes.Length);
	}

#if !ECMA_COMPAT

	// Get the mail body name for this encoding.
	public override String BodyName
	{
		get {
			return "iso-8859-1";
		}
	}

	// Get the human-readable name for this encoding.
	public override String EncodingName
	{
		get {
			return "Western European (ISO)";
		}
	}

	// Get the mail agent header name for this encoding.
	public override String HeaderName
	{
		get {
			return "iso-8859-1";
		}
	}

	// Determine if this encoding can be displayed in a Web browser.
	public override bool IsBrowserDisplay
	{
		get {
			return true;
		}
	}

	// Determine if this encoding can be saved from a Web browser.
	public override bool IsBrowserSave
	{
		get {
			return true;
		}
	}

	// 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 "iso-8859-1";
		}
	}

#endif // !ECMA_COMPAT

}; // class Latin1Encoding

}; // namespace System.Text