/*
* ScanCmd.java
*
* Copyright (c) 1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
* 
* Included in SQLite3 port to C# for use in testharness only;  2008 Noah B Hart
*
* RCS @(#) $Id: ScanCmd.java,v 1.2 1999/05/09 01:22:09 dejong Exp $
*
*/
using System;
namespace tcl.lang
{

  /// <summary> This class implements the built-in "scan" command in Tcl.
  /// 
  /// </summary>

  class ScanCmd : Command
  {
    /// <summary> This procedure is invoked to process the "scan" Tcl command.
    /// See the user documentation for details on what it does.
    /// 
    /// Each iteration of the cmdProc compares the scanArr's current index to 
    /// the frmtArr's index.  If the chars are equal then the indicies are
    /// incremented.  If a '%' is found in the frmtArr, the formatSpecifier 
    /// is parced from the frmtArr, the corresponding value is extracted from 
    /// the scanArr, and that value is set in the Tcl Interp.
    /// 
    /// If the chars are not equal, or the conversion fails, the boolean 
    /// scanArrDone is set to true, indicating the scanArr is not to be 
    /// parced and no new values are to be set.  However the frmtArr is still 
    /// parced because of the priority of error messages.  In the C version 
    /// of Tcl, bad format specifiers throw errors before incorrect argument 
    /// input or other scan errors.  Thus we need to parce the entire frmtArr 
    /// to verify correct formating.  This is dumb and inefficient but it is 
    /// consistent w/ the current C-version of Tcl.
    /// </summary>

    public TCL.CompletionCode cmdProc( Interp interp, TclObject[] argv )
    {

      if ( argv.Length < 3 )
      {
        throw new TclNumArgsException( interp, 1, argv, "string format ?varName varName ...?" );
      }
      ;

      StrtoulResult strul; // Return value for parcing the scanArr when
      // extracting integers/longs
      StrtodResult strd;
      ; // Return value for parcing the scanArr when
      // extracting doubles
      char[] scanArr; // Array containing parce info
      char[] frmtArr; // Array containing info on how to 
      // parse the scanArr
      int scanIndex; // Index into the scan array
      int frmtIndex; // Index into the frmt array
      int tempIndex; // Temporary index holder
      int argIndex; // Index into the current arg
      int width; // Stores the user specified result width 
      int base_; // Base of the integer being converted
      int numUnMatched; // Number of fields actually set.
      int numMatched; // Number of fields actually matched.
      int negateScan; // Mult by result, set to -1 if true
      int i; // Generic variable
      char ch; // Generic variable
      bool cont; // Used in loops to indicate when to stop
      bool scanOK; // Set to false if strtoul/strtod fails
      bool scanArrDone; // Set to false if strtoul/strtod fails
      bool widthFlag; // True is width is specified
      bool discardFlag; // If a "%*" is in the formatString dont 
      // write output to arg


      scanArr = argv[1].ToString().ToCharArray();

      frmtArr = argv[2].ToString().ToCharArray();
      width = base_ = numMatched = numUnMatched = 0;
      scanIndex = frmtIndex = 0;
      scanOK = true;
      scanArrDone = false;
      argIndex = 3;

      // Skip all (if any) of the white space before getting to a char

      frmtIndex = skipWhiteSpace( frmtArr, frmtIndex );

      // Search through the frmtArr.  If the next char is a '%' parse the
      // next chars and determine the type (if any) of the format specifier.
      // If the scanArr has been fully searched, do nothing but incerment
      // "numUnMatched".  The reason to continue the frmtArr search is for 
      // consistency in output.  Previously scan format errors were reported
      // before arg input mismatch, so this maintains the same level of error
      // checking.

      while ( frmtIndex < frmtArr.Length )
      {
        discardFlag = widthFlag = false;
        negateScan = 1;
        cont = true;

        // Parce the format array and read in the correct value from the 
        // scan array.  When the correct value is retrieved, set the 
        // variable (from argv) in the interp.

        if ( frmtArr[frmtIndex] == '%' )
        {

          frmtIndex++;
          checkOverFlow( interp, frmtArr, frmtIndex );

          // Two '%'s in a row, do nothing...

          if ( frmtArr[frmtIndex] == '%' )
          {
            frmtIndex++;
            scanIndex++;
            continue;
          }

          // Check for a discard field flag

          if ( frmtArr[frmtIndex] == '*' )
          {
            discardFlag = true;
            frmtIndex++;
            checkOverFlow( interp, frmtArr, frmtIndex );
          }

          // Check for a width field and accept the 'h', 'l', 'L'
          // characters, but do nothing with them.
          //
          // Note: The order of the width specifier and the other
          // chars is unordered, so we need to iterate until all
          // of the specifiers are identified.

          while ( cont )
          {
            cont = false;

            switch ( frmtArr[frmtIndex] )
            {

              case 'h':
              case 'l':
              case 'L':
                {
                  // Just ignore these values

                  frmtIndex++;
                  cont = true;
                  break;
                }

              default:
                {
                  if ( System.Char.IsDigit( frmtArr[frmtIndex] ) )
                  {
                    strul = Util.strtoul( new string( frmtArr ), frmtIndex, base_ );
                    frmtIndex = strul.index;
                    width = (int)strul.value;
                    widthFlag = true;
                    cont = true;
                  }
                }
                break;

            }
            checkOverFlow( interp, frmtArr, frmtIndex );
          }

          // On all conversion specifiers except 'c', move the
          // scanIndex to the next non-whitespace.

          ch = frmtArr[frmtIndex];
          if ( ( ch != 'c' ) && ( ch != '[' ) && !scanArrDone )
          {
            scanIndex = skipWhiteSpace( scanArr, scanIndex );
          }
          if ( scanIndex >= scanArr.Length )
          {
            scanArrDone = true;
          }

          if ( ( scanIndex < scanArr.Length ) && ( ch != 'c' ) && ( ch != '[' ) )
          {
            // Since strtoul dosent take signed numbers, make the
            // value positive and store the sign.

            if ( scanArr[scanIndex] == '-' )
            {
              negateScan = -1;
              scanIndex++;
              width--;
            }
            else if ( scanArr[scanIndex] == '+' )
            {
              scanIndex++;
              width--;
            }

            // The width+scanIndex might be greater than
            // the scanArr so we need to re-adjust when this
            // happens.

            if ( widthFlag && ( width + scanIndex > scanArr.Length ) )
            {
              width = scanArr.Length - scanIndex;
            }
          }

          if ( scanIndex >= scanArr.Length )
          {
            scanArrDone = true;
          }

          // Foreach iteration we want strul and strd to be
          // null since we error check on this case.

          strul = null;
          strd = null;

          switch ( ch )
          {

            case 'd':
            case 'o':
            case 'x':
              {

                if ( !scanArrDone )
                {

                  if ( ch == 'd' )
                  {
                    base_ = 10;
                  }
                  else if ( ch == 'o' )
                  {
                    base_ = 8;
                  }
                  else
                  {
                    base_ = 16;
                  }

                  // If the widthFlag is set then convert only 
                  // "width" characters to an ascii representation, 
                  // else read in until the end of the integer.  The 
                  // scanIndex is moved to the point where we stop
                  // reading in.

                  if ( widthFlag )
                  {
                    strul = Util.strtoul( new string( scanArr, 0, width + scanIndex ), scanIndex, base_ );
                  }
                  else
                  {
                    strul = Util.strtoul( new string( scanArr ), scanIndex, base_ );
                  }
                  if ( strul.errno != 0 )
                  {
                    scanOK = false;
                    break;
                  }
                  scanIndex = strul.index;

                  if ( !discardFlag )
                  {
                    i = (int)strul.value * negateScan;
                    if ( argIndex == argv.Length )
                      numMatched--;
                    else
                      testAndSetVar( interp, argv, argIndex++, TclInteger.newInstance( i ) );
                  }
                }
                break;
              }

            case 'c':
              {
                if ( widthFlag )
                {
                  errorCharFieldWidth( interp );
                }
                if ( !discardFlag && !scanArrDone )
                {
                  testAndSetVar( interp, argv, argIndex++, TclInteger.newInstance( scanArr[scanIndex++] ) );
                }
                break;
              }

            case 's':
              {
                if ( !scanArrDone )
                {
                  // If the widthFlag is set then read only "width"
                  // characters into the string, else read in until 
                  // the first whitespace or endArr is found.  The 
                  // scanIndex is moved to the point where we stop 
                  // reading in.

                  tempIndex = scanIndex;
                  if ( !widthFlag )
                  {
                    width = scanArr.Length;
                  }
                  for ( i = 0; ( scanIndex < scanArr.Length ) && ( i < width ); i++ )
                  {
                    ch = scanArr[scanIndex];
                    if ( ( ch == ' ' ) || ( ch == '\n' ) || ( ch == '\r' ) || ( ch == '\t' ) || ( ch == '\f' ) )
                    {
                      break;
                    }
                    scanIndex++;
                  }

                  if ( !discardFlag )
                  {
                    string str = new string( scanArr, tempIndex, scanIndex - tempIndex );
                    testAndSetVar( interp, argv, argIndex++, TclString.newInstance( str ) );
                  }
                }
                break;
              }

            case 'e':
            case 'f':
            case 'g':
              {
                if ( !scanArrDone )
                {
                  // If the wisthFlag is set then read only "width"
                  // characters into the string, else read in until 
                  // the first whitespace or endArr is found.  The 
                  // scanIndex is moved to the point where we stop 
                  // reading in.

                  if ( widthFlag )
                  {
                    strd = Util.strtod( new string( scanArr, 0, width + scanIndex ), scanIndex );
                  }
                  else
                  {
                    strd = Util.strtod( new string( scanArr ), scanIndex );
                  }
                  if ( strd.errno != 0 )
                  {
                    scanOK = false;
                    break;
                  }
                  scanIndex = strd.index;

                  if ( !discardFlag )
                  {
                    double d = strd.value * negateScan;
                    testAndSetVar( interp, argv, argIndex++, TclDouble.newInstance( d ) );
                  }
                }
                break;
              }

            case '[':
              {
                bool charMatchFound = false;
                bool charNotMatch = false;
                char[] tempArr;
                int startIndex;
                int endIndex;
                string unmatched = "unmatched [ in format string";

                if ( ( ++frmtIndex ) >= frmtArr.Length )
                {
                  throw new TclException( interp, unmatched );
                }

                if ( frmtArr[frmtIndex] == '^' )
                {
                  charNotMatch = true;
                  frmtIndex += 2;
                }
                else
                {
                  frmtIndex++;
                }
                tempIndex = frmtIndex - 1;

                if ( frmtIndex >= frmtArr.Length )
                {
                  throw new TclException( interp, unmatched );
                }

                // Extract the list of chars for matching.

                while ( frmtArr[frmtIndex] != ']' )
                {
                  if ( ( ++frmtIndex ) >= frmtArr.Length )
                  {
                    throw new TclException( interp, unmatched );
                  }
                }
                tempArr = new string( frmtArr, tempIndex, frmtIndex - tempIndex ).ToCharArray();

                startIndex = scanIndex;
                if ( charNotMatch )
                {
                  // Format specifier contained a '^' so interate
                  // until one of the chars in tempArr is found.

                  while ( scanOK && !charMatchFound )
                  {
                    if ( scanIndex >= scanArr.Length )
                    {
                      scanOK = false;
                      break;
                    }
                    for ( i = 0; i < tempArr.Length; i++ )
                    {
                      if ( tempArr[i] == scanArr[scanIndex] )
                      {
                        charMatchFound = true;
                        break;
                      }
                    }
                    if ( widthFlag && ( ( scanIndex - startIndex ) >= width ) )
                    {
                      break;
                    }
                    if ( !charMatchFound )
                    {
                      scanIndex++;
                    }
                  }
                }
                else
                {
                  // Iterate until the char in the scanArr is not 
                  // in the tempArr.

                  charMatchFound = true;
                  while ( scanOK && charMatchFound )
                  {
                    if ( scanIndex >= scanArr.Length )
                    {
                      scanOK = false;
                      break;
                    }
                    charMatchFound = false;
                    for ( i = 0; i < tempArr.Length; i++ )
                    {
                      if ( tempArr[i] == scanArr[scanIndex] )
                      {
                        charMatchFound = true;
                        break;
                      }
                    }
                    if ( widthFlag && ( scanIndex - startIndex ) >= width )
                    {
                      break;
                    }
                    if ( charMatchFound )
                    {
                      scanIndex++;
                    }
                  }
                }

                // Indicates nothing was found.

                endIndex = scanIndex - startIndex;
                if ( endIndex <= 0 )
                {
                  scanOK = false;
                  break;
                }

                if ( !discardFlag )
                {
                  string str = new string( scanArr, startIndex, endIndex );
                  testAndSetVar( interp, argv, argIndex++, TclString.newInstance( str ) );
                }
                break;
              }

            default:
              {
                errorBadField( interp, ch );
              }
              break;

          }

          // As long as the scan was successful (scanOK), the format
          // specifier did not contain a '*' (discardFlag), and
          // we are not at the end of the scanArr (scanArrDone);
          // increment the num of vars set in the interp.  Otherwise
          // increment the number of valid format specifiers.

          if ( scanOK && !discardFlag && !scanArrDone )
          {
            numMatched++;
          }
          else if ( ( scanArrDone || !scanOK ) && !discardFlag )
          {
            numUnMatched++;
          }
          frmtIndex++;
        }
        else if ( scanIndex < scanArr.Length && scanArr[scanIndex] == frmtArr[frmtIndex] )
        {
          // No '%' was found, but the characters matched

          scanIndex++;
          frmtIndex++;
        }
        else
        {
          // No '%' found and the characters int frmtArr & scanArr
          // did not match.

          frmtIndex++;
        }
      }

      // The numMatched is the return value: a count of the num of vars set.
      // While the numUnMatched is the number of formatSpecifiers that
      // passed the parsing stage, but did not match anything in the scanArr.

      if ( ( numMatched + numUnMatched ) != ( argv.Length - 3 ) )
      {
        errorDiffVars( interp );
      }
      interp.setResult( TclInteger.newInstance( numMatched ) );
      return TCL.CompletionCode.RETURN;
    }


    /// <summary> Given an array and an index into it, move the index forward
    /// until a non-whitespace char is found.
    /// 
    /// </summary>
    /// <param name="arr">  - the array to search
    /// </param>
    /// <param name="index">- where to begin the search
    /// </param>
    /// <returns> The index value where the whitespace ends.
    /// </returns>

    private int skipWhiteSpace( char[] arr, int index )
    {
      bool cont;
      do
      {
        if ( index >= arr.Length )
        {
          return index;
        }
        cont = false;
        switch ( arr[index] )
        {

          case '\t':
          case '\n':
          case '\r':
          case '\f':
          case ' ':
            {
              cont = true;
              index++;
            }
            break;
        }
      }
      while ( cont );

      return index;
    }


    /// <summary> Called whenever the cmdProc wants to set an interp value.  
    /// This method <ol>
    /// <li> verifies that there exisits a varName from the argv array, 
    /// <li> that the variable either dosent exisit or is of type scalar
    /// <li> set the variable in interp if (1) and (2) are OK
    /// </ol>
    /// 
    /// </summary>
    /// <param name="interp">  - the Tcl interpreter
    /// </param>
    /// <param name="argv">    - the argument array
    /// </param>
    /// <param name="argIndex">- the current index into the argv array
    /// </param>
    /// <param name="tobj">    - the TclObject that the varName equals
    /// 
    /// </param>

    private static void testAndSetVar( Interp interp, TclObject[] argv, int argIndex, TclObject tobj )
    {
      if ( argIndex < argv.Length )
      {
        try
        {

          interp.setVar( argv[argIndex].ToString(), tobj, 0 );
        }
        catch ( TclException e )
        {

          throw new TclException( interp, "couldn't set variable \"" + argv[argIndex].ToString() + "\"" );
        }
      }
      else
      {
        errorDiffVars( interp );
      }
    }


    /// <summary> Called whenever the frmtIndex in the cmdProc is changed.  It verifies
    /// the the array index is still within the bounds of the array.  If no
    /// throw error.
    /// </summary>
    /// <param name="interp"> - The TclInterp which called the cmdProc method .
    /// </param>
    /// <param name="arr">    - The array to be checked.
    /// </param>
    /// <param name="index">  - The new value for the array index.
    /// </param>

    private static void checkOverFlow( Interp interp, char[] arr, int index )
    {
      if ( ( index >= arr.Length ) || ( index < 0 ) )
      {
        throw new TclException( interp, "\"%n$\" argument index out of range" );
      }
    }


    /// <summary> Called whenever the number of varName args do not match the number
    /// of found and valid formatSpecifiers (matched and unmatched).
    /// 
    /// </summary>
    /// <param name="interp"> - The TclInterp which called the cmdProc method .
    /// </param>

    private static void errorDiffVars( Interp interp )
    {

      throw new TclException( interp, "different numbers of variable names and field specifiers" );
    }


    /// <summary> Called whenever the current char in the frmtArr is erroneous
    /// 
    /// </summary>
    /// <param name="interp"> - The TclInterp which called the cmdProc method .
    /// </param>
    /// <param name="fieldSpecifier"> - The erroneous character
    /// </param>

    private static void errorBadField( Interp interp, char fieldSpecifier )
    {
      throw new TclException( interp, "bad scan conversion character \"" + fieldSpecifier + "\"" );
    }


    /// <summary> Called whenever the a width field is used in a char ('c') format 
    /// specifier
    /// 
    /// </summary>
    /// <param name="interp"> - The TclInterp which called the cmdProc method .
    /// </param>

    private static void errorCharFieldWidth( Interp interp )
    {
      throw new TclException( interp, "field width may not be specified in %c conversion" );
    }
  }
}