Console/TerminalDxe/Vtutf8.c

	Vtutf8.c revision 4fd606d1f5abe38e1f42c38de1d2e895166bd0f4
/** @file
  Implementation of translation upon VT-UTF8.

Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include "Terminal.h"

/**
  Translate all VT-UTF8 characters in the Raw FIFI into unicode characters,
  and insert them into Unicode FIFO.

  @param TerminalDevice          The terminal device.

**/
VOID
VTUTF8RawDataToUnicode (
  IN  TERMINAL_DEV    *TerminalDevice
  )
{
  UTF8_CHAR Utf8Char;
  UINT8     ValidBytes;
  UINT16    UnicodeChar;

  ValidBytes = 0;
  //
  // pop the raw data out from the raw fifo,
  // and translate it into unicode, then push
  // the unicode into unicode fifo, until the raw fifo is empty.
  //
  while (!IsRawFiFoEmpty (TerminalDevice) && !IsUnicodeFiFoFull (TerminalDevice)) {

    GetOneValidUtf8Char (TerminalDevice, &Utf8Char, &ValidBytes);

    if (ValidBytes < 1 || ValidBytes > 3) {
      continue;
    }

    Utf8ToUnicode (Utf8Char, ValidBytes, (CHAR16 *) &UnicodeChar);

    UnicodeFiFoInsertOneKey (TerminalDevice, UnicodeChar);
  }
}

/**
  Get one valid VT-UTF8 characters set from Raw Data FIFO.

  @param  Utf8Device          The terminal device.
  @param  Utf8Char            Returned valid VT-UTF8 characters set.
  @param  ValidBytes          The count of returned VT-VTF8 characters.
                              If ValidBytes is zero, no valid VT-UTF8 returned.

**/
VOID
GetOneValidUtf8Char (
  IN  TERMINAL_DEV      *Utf8Device,
  OUT UTF8_CHAR         *Utf8Char,
  OUT UINT8             *ValidBytes
  )
{
  UINT8   Temp;
  UINT8   Index;
  BOOLEAN FetchFlag;

  Temp      = 0;
  Index     = 0;
  FetchFlag = TRUE;

  //
  // if no valid Utf8 char is found in the RawFiFo,
  // then *ValidBytes will be zero.
  //
  *ValidBytes = 0;

  while (!IsRawFiFoEmpty (Utf8Device)) {

    RawFiFoRemoveOneKey (Utf8Device, &Temp);

    switch (*ValidBytes) {

    case 0:
      if ((Temp & 0x80) == 0) {
        //
        // one-byte utf8 char
        //
        *ValidBytes       = 1;

        Utf8Char->Utf8_1  = Temp;

        FetchFlag         = FALSE;

      } else if ((Temp & 0xe0) == 0xc0) {
        //
        // two-byte utf8 char
        //
        *ValidBytes         = 2;

        Utf8Char->Utf8_2[1] = Temp;

      } else if ((Temp & 0xf0) == 0xe0) {
        //
        // three-byte utf8 char
        //
        *ValidBytes         = 3;

        Utf8Char->Utf8_3[2] = Temp;

        Index++;

      } else {
        //
        // reset *ValidBytes to zero, let valid utf8 char search restart
        //
        *ValidBytes = 0;
      }

      break;

    case 2:
      //
      // two-byte utf8 char go on
      //
      if ((Temp & 0xc0) == 0x80) {

        Utf8Char->Utf8_2[0] = Temp;

        FetchFlag           = FALSE;

      } else {

        *ValidBytes = 0;
      }
      break;

    case 3:
      //
      // three-byte utf8 char go on
      //
      if ((Temp & 0xc0) == 0x80) {
        if (Index == 1) {
          Utf8Char->Utf8_3[1] = Temp;
          Index++;
        } else {
          Utf8Char->Utf8_3[0] = Temp;
          FetchFlag = FALSE;
        }
      } else {
        //
        // reset *ValidBytes and Index to zero, let valid utf8 char search restart
        //
        *ValidBytes = 0;
        Index       = 0;
      }
      break;

    default:
      break;
    }

    if (!FetchFlag) {
      break;
    }
  }

  return ;
}

/**
  Translate VT-UTF8 characters into one Unicode character.

  UTF8 Encoding Table
  Bits per Character | Unicode Character Range | Unicode Binary  Encoding | UTF8 Binary Encoding
        0-7          |     0x0000 - 0x007F     |     00000000 0xxxxxxx    |   0xxxxxxx
        8-11           |     0x0080 - 0x07FF       |     00000xxx xxxxxxxx    |   110xxxxx 10xxxxxx
       12-16           |     0x0800 - 0xFFFF       |     xxxxxxxx xxxxxxxx    |   1110xxxx 10xxxxxx 10xxxxxx


  @param  Utf8Char         VT-UTF8 character set needs translating.
  @param  ValidBytes       The count of valid VT-UTF8 characters.
  @param  UnicodeChar      Returned unicode character.

**/
VOID
Utf8ToUnicode (
  IN  UTF8_CHAR       Utf8Char,
  IN  UINT8           ValidBytes,
  OUT CHAR16          *UnicodeChar
  )
{
  UINT8 UnicodeByte0;
  UINT8 UnicodeByte1;
  UINT8 Byte0;
  UINT8 Byte1;
  UINT8 Byte2;

  *UnicodeChar = 0;

  //
  // translate utf8 code to unicode, in terminal standard,
  // up to 3 bytes utf8 code is supported.
  //
  switch (ValidBytes) {
  case 1:
    //
    // one-byte utf8 code
    //
    *UnicodeChar = (UINT16) Utf8Char.Utf8_1;
    break;

  case 2:
    //
    // two-byte utf8 code
    //
    Byte0         = Utf8Char.Utf8_2[0];
    Byte1         = Utf8Char.Utf8_2[1];

    UnicodeByte0  = (UINT8) ((Byte1 << 6) | (Byte0 & 0x3f));
    UnicodeByte1  = (UINT8) ((Byte1 >> 2) & 0x07);
    *UnicodeChar  = (UINT16) (UnicodeByte0 | (UnicodeByte1 << 8));
    break;

  case 3:
    //
    // three-byte utf8 code
    //
    Byte0         = Utf8Char.Utf8_3[0];
    Byte1         = Utf8Char.Utf8_3[1];
    Byte2         = Utf8Char.Utf8_3[2];

    UnicodeByte0  = (UINT8) ((Byte1 << 6) | (Byte0 & 0x3f));
    UnicodeByte1  = (UINT8) ((Byte2 << 4) | ((Byte1 >> 2) & 0x0f));
    *UnicodeChar  = (UINT16) (UnicodeByte0 | (UnicodeByte1 << 8));

  default:
    break;
  }

  return ;
}

/**
  Translate one Unicode character into VT-UTF8 characters.

  UTF8 Encoding Table
  Bits per Character | Unicode Character Range | Unicode Binary  Encoding | UTF8 Binary Encoding
        0-7          |     0x0000 - 0x007F     |     00000000 0xxxxxxx    |   0xxxxxxx
        8-11           |     0x0080 - 0x07FF       |     00000xxx xxxxxxxx    |   110xxxxx 10xxxxxx
       12-16           |     0x0800 - 0xFFFF       |     xxxxxxxx xxxxxxxx    |   1110xxxx 10xxxxxx 10xxxxxx


  @param  Unicode          Unicode character need translating.
  @param  Utf8Char         Return VT-UTF8 character set.
  @param  ValidBytes       The count of valid VT-UTF8 characters. If
                           ValidBytes is zero, no valid VT-UTF8 returned.

**/
VOID
UnicodeToUtf8 (
  IN  CHAR16      Unicode,
  OUT UTF8_CHAR   *Utf8Char,
  OUT UINT8       *ValidBytes
  )
{
  UINT8 UnicodeByte0;
  UINT8 UnicodeByte1;
  //
  // translate unicode to utf8 code
  //
  UnicodeByte0  = (UINT8) Unicode;
  UnicodeByte1  = (UINT8) (Unicode >> 8);

  if (Unicode < 0x0080) {

    Utf8Char->Utf8_1  = (UINT8) (UnicodeByte0 & 0x7f);
    *ValidBytes       = 1;

  } else if (Unicode < 0x0800) {
    //
    // byte sequence: high -> low
    //                Utf8_2[0], Utf8_2[1]
    //
    Utf8Char->Utf8_2[1] = (UINT8) ((UnicodeByte0 & 0x3f) + 0x80);
    Utf8Char->Utf8_2[0] = (UINT8) ((((UnicodeByte1 << 2) + (UnicodeByte0 >> 6)) & 0x1f) + 0xc0);

    *ValidBytes         = 2;

  } else {
    //
    // byte sequence: high -> low
    //                Utf8_3[0], Utf8_3[1], Utf8_3[2]
    //
    Utf8Char->Utf8_3[2] = (UINT8) ((UnicodeByte0 & 0x3f) + 0x80);
    Utf8Char->Utf8_3[1] = (UINT8) ((((UnicodeByte1 << 2) + (UnicodeByte0 >> 6)) & 0x3f) + 0x80);
    Utf8Char->Utf8_3[0] = (UINT8) (((UnicodeByte1 >> 4) & 0x0f) + 0xe0);

    *ValidBytes         = 3;
  }
}


/**
  Check if input string is valid VT-UTF8 string.

  @param  TerminalDevice          The terminal device.
  @param  WString                 The input string.

  @retval EFI_SUCCESS             If all input characters are valid.

**/
EFI_STATUS
VTUTF8TestString (
  IN  TERMINAL_DEV    *TerminalDevice,
  IN  CHAR16          *WString
  )
{
  //
  // to utf8, all kind of characters are supported.
  //
  return EFI_SUCCESS;
}