package org.litesoft.core.util;

public class CharSource
{
    private String mSource;
    private int mFrom, mTo;

    public CharSource( String pSource, int pFrom )
    {
        mSource = UtilsCommon.deNull( pSource );
        if ( (mFrom = pFrom) < 0 )
        {
            throw new IllegalArgumentException( "'From' not allowed to be negative" );
        }
        mTo = mSource.length();
    }

    public CharSource( String pSource )
    {
        this( pSource, 0 );
    }

    public CharSource( String pSource, int pFrom, int pTo )
    {
        this( pSource, pFrom );
        if ( pTo > mTo )
        {
            throw new IllegalArgumentException( "'To' not allowed to be greater than the length of the 'Source' string" );
        }
        if ( pTo < 0 )
        {
            mTo += pTo;
        }
        else
        {
            mTo = pTo;
        }
    }

    public boolean anyRemaining()
    {
        return (mFrom < mTo);
    }

    public int peek()
    {
        return anyRemaining() ? mSource.charAt( mFrom ) : -1;
    }

    public int get()
    {
        return anyRemaining() ? mSource.charAt( mFrom++ ) : -1;
    }

    public String getUpTo( char c )
    {
        int at = mSource.indexOf( c, mFrom );
        if ( at == -1 )
        {
            return "";
        }
        String rv = mSource.substring( mFrom, at );
        mFrom = at;
        return rv;
    }

    public boolean consumeSpaces()
    {
        while ( peek() == ' ' )
        {
            mFrom++;
        }
        return anyRemaining();
    }

    public String getUpToNonVisible7bitAscii()
    {
        if ( !anyRemaining() )
        {
            return "";
        }
        int zFrom = mFrom;
        for ( int c = peek(); (c != -1) && ((' ' < c) && (c <= 126)); c = peek() )
        {
            mFrom++;
        }
        return mSource.substring( zFrom, mFrom );
    }

    public boolean consumeNonVisible7bitAscii()
    {
        for ( int c = peek(); (c != -1) && ((c <= ' ') || (126 < c)); c = peek() )
        {
            mFrom++;
        }
        return anyRemaining();
    }

    public int getFrom()
    {
        return mFrom;
    }

    public int getLastFrom()
    {
        return mFrom - 1;
    }

    public String toString()
    {
        return mSource.substring( mFrom, mTo );
    }
}