/*
 * @(#)StreamInImpl.java   1.11 2000/08/16
 *
 */

package org.w3c.tidy;

/**
 *
 * Input Stream Implementation
 *
 * (c) 1998-2000 (W3C) MIT, INRIA, Keio University
 * Derived from <a href="http://www.w3.org/People/Raggett/tidy">
 * HTML Tidy Release 4 Aug 2000</a>
 *
 * @author  Dave Raggett <dsr@w3.org>
 * @author  Andy Quick <ac.quick@sympatico.ca> (translation to Java)
 * @version 1.0, 1999/05/22
 * @version 1.0.1, 1999/05/29
 * @version 1.1, 1999/06/18 Java Bean
 * @version 1.2, 1999/07/10 Tidy Release 7 Jul 1999
 * @version 1.3, 1999/07/30 Tidy Release 26 Jul 1999
 * @version 1.4, 1999/09/04 DOM support
 * @version 1.5, 1999/10/23 Tidy Release 27 Sep 1999
 * @version 1.6, 1999/11/01 Tidy Release 22 Oct 1999
 * @version 1.7, 1999/12/06 Tidy Release 30 Nov 1999
 * @version 1.8, 2000/01/22 Tidy Release 13 Jan 2000
 * @version 1.9, 2000/06/03 Tidy Release 30 Apr 2000
 * @version 1.10, 2000/07/22 Tidy Release 8 Jul 2000
 * @version 1.11, 2000/08/16 Tidy Release 4 Aug 2000
 */

import java.io.InputStream;
import java.io.IOException;

public class StreamInImpl extends StreamIn {

    /* Mapping for Windows Western character set (128-159) to Unicode */
    private static int[] Win2Unicode =
    {
    0x20AC, 0x0000, 0x201A, 0x0192, 0x201E, 0x2026, 0x2020, 0x2021,
    0x02C6, 0x2030, 0x0160, 0x2039, 0x0152, 0x0000, 0x017D, 0x0000,
    0x0000, 0x2018, 0x2019, 0x201C, 0x201D, 0x2022, 0x2013, 0x2014,
    0x02DC, 0x2122, 0x0161, 0x203A, 0x0153, 0x0000, 0x017E, 0x0178
    };

    /*
    John Love-Jensen contributed this table for mapping MacRoman
    character set to Unicode
    */

    private static int[] Mac2Unicode = 
    {

    0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007,
    0x0008, 0x0009, 0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F,

    0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017,
    0x0018, 0x0019, 0x001A, 0x001B, 0x001C, 0x001D, 0x001E, 0x001F,

    0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
    0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F,

    0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
    0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F,

    0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
    0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F,

    0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
    0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F,

    0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067,
    0x0068, 0x0069, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F,

    0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077,
    0x0078, 0x0079, 0x007A, 0x007B, 0x007C, 0x007D, 0x007E, 0x007F,
    /* x7F = DEL */
    0x00C4, 0x00C5, 0x00C7, 0x00C9, 0x00D1, 0x00D6, 0x00DC, 0x00E1,
    0x00E0, 0x00E2, 0x00E4, 0x00E3, 0x00E5, 0x00E7, 0x00E9, 0x00E8,

    0x00EA, 0x00EB, 0x00ED, 0x00EC, 0x00EE, 0x00EF, 0x00F1, 0x00F3,
    0x00F2, 0x00F4, 0x00F6, 0x00F5, 0x00FA, 0x00F9, 0x00FB, 0x00FC,

    0x2020, 0x00B0, 0x00A2, 0x00A3, 0x00A7, 0x2022, 0x00B6, 0x00DF,
    0x00AE, 0x00A9, 0x2122, 0x00B4, 0x00A8, 0x2260, 0x00C6, 0x00D8,

    0x221E, 0x00B1, 0x2264, 0x2265, 0x00A5, 0x00B5, 0x2202, 0x2211,
    0x220F, 0x03C0, 0x222B, 0x00AA, 0x00BA, 0x03A9, 0x00E6, 0x00F8,

    0x00BF, 0x00A1, 0x00AC, 0x221A, 0x0192, 0x2248, 0x2206, 0x00AB,
    0x00BB, 0x2026, 0x00A0, 0x00C0, 0x00C3, 0x00D5, 0x0152, 0x0153,

    0x2013, 0x2014, 0x201C, 0x201D, 0x2018, 0x2019, 0x00F7, 0x25CA,
    0x00FF, 0x0178, 0x2044, 0x20AC, 0x2039, 0x203A, 0xFB01, 0xFB02,

    0x2021, 0x00B7, 0x201A, 0x201E, 0x2030, 0x00C2, 0x00CA, 0x00C1,
    0x00CB, 0x00C8, 0x00CD, 0x00CE, 0x00CF, 0x00CC, 0x00D3, 0x00D4,
    /* xF0 = Apple Logo */
    0xF8FF, 0x00D2, 0x00DA, 0x00DB, 0x00D9, 0x0131, 0x02C6, 0x02DC,
    0x00AF, 0x02D8, 0x02D9, 0x02DA, 0x00B8, 0x02DD, 0x02DB, 0x02C7
    };

    public StreamInImpl(InputStream stream, int encoding, int tabsize)
    {
        this.stream = stream;
        this.pushed = false;
        this.c = (int)'\0';
        this.tabs = 0;
        this.tabsize = tabsize;
        this.curline = 1;
        this.curcol = 1;
        this.encoding = encoding;
        this.state = FSM_ASCII;
        this.endOfStream = false;
    }

    /* read char from stream */
    public int readCharFromStream()
    {
        int n, c, i, count;

        try {
            c = this.stream.read();

            if (c == EndOfStream) {
                this.endOfStream = true;
                return c;
            }

            /*
               A document in ISO-2022 based encoding uses some ESC sequences
               called "designator" to switch character sets. The designators
               defined and used in ISO-2022-JP are:

                "ESC" + "(" + ?     for ISO646 variants

                "ESC" + "$" + ?     and
                "ESC" + "$" + "(" + ?   for multibyte character sets

               Where ? stands for a single character used to indicate the
               character set for multibyte characters.

               Tidy handles this by preserving the escape sequence and
               setting the top bit of each byte for non-ascii chars. This
               bit is then cleared on output. The input stream keeps track
               of the state to determine when to set/clear the bit.
            */

            if (this.encoding == Configuration.ISO2022)
            {
                if (c == 0x1b)  /* ESC */
                {
                    this.state = FSM_ESC;
                    return c;
                }

                switch (this.state)
                {
                case FSM_ESC:
                    if (c == '$')
                        this.state = FSM_ESCD;
                    else if (c == '(')
                        this.state = FSM_ESCP;
                    else
                        this.state = FSM_ASCII;
                    break;

                case FSM_ESCD:
                    if (c == '(')
                        this.state = FSM_ESCDP;
                    else
                        this.state = FSM_NONASCII;
                    break;

                case FSM_ESCDP:
                    this.state = FSM_NONASCII;
                    break;

                case FSM_ESCP:
                    this.state = FSM_ASCII;
                    break;

                case FSM_NONASCII:
                    c |= 0x80;
                    break;
                }

                return c;
            }

            if (this.encoding != Configuration.UTF8)
                return c;

            /* deal with UTF-8 encoded char */

            if ((c & 0xE0) == 0xC0)  /* 110X XXXX  two bytes */
            {
                n = c & 31;
                count = 1;
            }
            else if ((c & 0xF0) == 0xE0)  /* 1110 XXXX  three bytes */
            {
                n = c & 15;
                count = 2;
            }
            else if ((c & 0xF8) == 0xF0)  /* 1111 0XXX  four bytes */
            {
                n = c & 7;
                count = 3;
            }
            else if ((c & 0xFC) == 0xF8)  /* 1111 10XX  five bytes */
            {
                n = c & 3;
                count = 4;
            }
            else if ((c & 0xFE) == 0xFC)       /* 1111 110X  six bytes */
            {
                n = c & 1;
                count = 5;
            }
            else  /* 0XXX XXXX one byte */
                return c;

            /* successor bytes should have the form 10XX XXXX */
            for (i = 1; i <= count; ++i)
            {
                c = this.stream.read();

                if (c == EndOfStream) {
                    this.endOfStream = true;
                    return c;
                }

                n = (n << 6) | (c & 0x3F);
            }
        }
        catch (IOException e) {
            System.err.println("StreamInImpl.readCharFromStream: " + e.toString());
            n = EndOfStream;
        }

        return n;
    }

    public int readChar()
    {
        int c;

        if (this.pushed)
        {
            this.pushed = false;
            c =  this.c;

            if (c == '\n')
            {
                this.curcol = 1;
                this.curline++;
                return c;
            }

            this.curcol++;
            return c;
        }

        this.lastcol = this.curcol;

        if (this.tabs > 0)
        {
            this.curcol++;
            this.tabs--;
            return ' ';
        }
    
        for (;;)
        {
            c = readCharFromStream();

            if (c < 0)
                return EndOfStream;

            if (c == '\n')
            {
                this.curcol = 1;
                this.curline++;
                break;
            }

            if (c == '\r')
            {
                c = readCharFromStream();
                if (c != '\n')
                {
                    ungetChar(c);
                    c = '\n';
                }
                this.curcol = 1;
                this.curline++;
                break;
            }

            if (c == '\t')
            {
                this.tabs = this.tabsize - ((this.curcol - 1) % this.tabsize) - 1;
                this.curcol++;
                c = ' ';
                break;
            }

            /* strip control characters, except for Esc */

            if (c == '\033')
                break;

            if (0 < c && c < 32)
                continue;

            /* watch out for IS02022 */

            if (this.encoding == Configuration.RAW ||
                this.encoding == Configuration.ISO2022)
            {
                this.curcol++;
                break;
            }

            if (this.encoding == Configuration.MACROMAN)
                c = Mac2Unicode[c];

            /* produced e.g. as a side-effect of smart quotes in Word */

            if (127 < c && c < 160)
            {
                Report.encodingError((Lexer)this.lexer, Report.WINDOWS_CHARS, c);

                c = Win2Unicode[c - 128];

                if (c == 0)
                    continue;
            }

            this.curcol++;
            break;
        }

        return c;
    }

    public void ungetChar(int c)
    {
        this.pushed = true;
        this.c = c;

        if (c == '\n')
        {
            --this.curline;
        }

        this.curcol = this.lastcol;
    }

    public boolean isEndOfStream()
    {
        return this.endOfStream;
    }

}