source: neercs/trunk/src/term.c @ 2995

/*
 *  neercs        console-based window manager
 *  Copyright (c) 2006 Sam Hocevar <sam@zoy.org>
 *                All Rights Reserved
 *
 *  $Id$
 *
 *  This program is free software. It comes without any warranty, to
 *  the extent permitted by applicable law. You can redistribute it
 *  and/or modify it under the terms of the Do What The Fuck You Want
 *  To Public License, Version 2, as published by Sam Hocevar. See
 *  http://sam.zoy.org/wtfpl/COPYING for more details.
 */

#include "config.h"

#define _XOPEN_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#if defined HAVE_PTY_H
#   include <pty.h>  /* for openpty and forkpty */
#else
#   include <util.h> /* for OS X */
#endif
#include <unistd.h>
#include <fcntl.h>

#include <caca.h>
#include <caca.h>

#include "neercs.h"

/* DEC ACS with common extensions */
static uint32_t dec_acs(uint32_t uc)
{
    switch (uc)
    {
    case '+': return 0x2192; /* RIGHTWARDS ARROW */
    case ',': return 0x2190; /* LEFTWARDS ARROW */
    case '-': return 0x2191; /* UPWARDS ARROW */
    case '.': return 0x2193; /* DOWNWARDS ARROW */
    case '0': return 0x25AE; /* BLACK VERTICAL RECTANGLE */
    case '_': return 0x25AE; /* BLACK VERTICAL RECTANGLE */
    case '`': return 0x25C6; /* BLACK DIAMOND */
    case 'a': return 0x2592; /* MEDIUM SHADE */
    case 'b': return 0x2409; /* SYMBOL FOR HORIZONTAL TABULATION */
    case 'c': return 0x240C; /* SYMBOL FOR FORM FEED */
    case 'd': return 0x240D; /* SYMBOL FOR CARRIAGE RETURN */
    case 'e': return 0x240A; /* SYMBOL FOR LINE FEED */
    case 'f': return 0x00B0; /* DEGREE SIGN */
    case 'g': return 0x00B1; /* PLUS-MINUS SIGN */
    case 'h': return 0x2424; /* SYMBOL FOR NEWLINE */
    case 'i': return 0x240B; /* SYMBOL FOR VERTICAL TABULATION */
    case 'j': return 0x2518; /* BOX DRAWINGS LIGHT UP AND LEFT */
    case 'k': return 0x2510; /* BOX DRAWINGS LIGHT DOWN AND LEFT */
    case 'l': return 0x250C; /* BOX DRAWINGS LIGHT DOWN AND RIGHT */
    case 'm': return 0x2514; /* BOX DRAWINGS LIGHT UP AND RIGHT */
    case 'n': return 0x253C; /* BOX DRAWINGS LIGHT VERTICAL AND HORIZONTAL */
    case 'o': return 0x23BA; /* HORIZONTAL SCAN LINE-1 */
    case 'p': return 0x23BB; /* HORIZONTAL SCAN LINE-3 */
    case 'q': return 0x2500; /* BOX DRAWINGS LIGHT HORIZONTAL */
    case 'r': return 0x23BC; /* HORIZONTAL SCAN LINE-7 */
    case 's': return 0x23BD; /* HORIZONTAL SCAN LINE-9 */
    case 't': return 0x251C; /* BOX DRAWINGS LIGHT VERTICAL AND RIGHT */
    case 'u': return 0x2524; /* BOX DRAWINGS LIGHT VERTICAL AND LEFT */
    case 'v': return 0x2534; /* BOX DRAWINGS LIGHT UP AND HORIZONTAL */
    case 'w': return 0x252C; /* BOX DRAWINGS LIGHT DOWN AND HORIZONTAL */
    case 'x': return 0x2502; /* BOX DRAWINGS LIGHT VERTICAL */
    case 'y': return 0x2264; /* LESS-THAN OR EQUAL TO */
    case 'z': return 0x2265; /* GREATER-THAN OR EQUAL TO */
    case '{': return 0x03C0; /* GREEK SMALL LETTER PI */
    case '|': return 0x2260; /* NOT EQUAL TO */
    case '}': return 0x00A3; /* POUND SIGN */
    case '~': return 0x00B7; /* MIDDLE DOT */
    default:
        return uc;
    }
};

static void reset_conv_state(struct screen *);

#define LITERAL2CHAR(i0,i1) (((i0) << 8) | (i1))

#define LITERAL3CHAR(i0,i1,i2) LITERAL2CHAR(LITERAL2CHAR(i0, i1), i2)

static void ansi_parse_grcm(struct screen *,
                            unsigned int, unsigned int const *);

long int import_term(struct screen_list *screen_list, struct screen *sc, void const *data, unsigned int size)
{
    unsigned char const *buffer = (unsigned char const*)data;
    unsigned int i, j, k,skip, dummy = 0;
    unsigned int width, height;
    uint32_t savedattr, scrolled = 0;
    int x = 0, y = 0, save_x = 0, save_y = 0;

    width = caca_get_canvas_width(sc->cv);
    height = caca_get_canvas_height(sc->cv);
    x = caca_get_cursor_x(sc->cv);
    y = caca_get_cursor_y(sc->cv);

    if(!sc->init)
    {
        sc->dfg = CACA_DEFAULT;
        sc->dbg = CACA_DEFAULT;

        caca_set_color_ansi(sc->cv, sc->dfg, sc->dbg);
        sc->clearattr = caca_get_attr(sc->cv, -1, -1);

        ansi_parse_grcm(sc, 1, &dummy);

        reset_conv_state(sc);

        sc->init = 1;
    }

    for(i = 0; i < size; i += skip)
    {
        uint32_t ch = 0;
        int wch = 0;

        skip = 1;

        if(buffer[i] == '\r')
        {
            x = 0;
        }

        else if(buffer[i] == '\n')
        {
            x = 0;
            y++;
        }
        else if(buffer[i] == '\a')
        {
            screen_list->in_bell = 10;
            sc->bell = 10;
        }

        else if(buffer[i] == '\t')
        {
            x = (x + 7) & ~7;
        }

        else if(buffer[i] == '\x08')
        {
            if(x > 0)
                x--;
        }

        else if(buffer[i] == '\x0e')
        {
            /* Shift Out (Ctrl-N) -> Switch to
             * Alternate Character Set: invokes
             * the G1 character set. */
            sc->conv_state.glr[0] = 1;
        }

        else if(buffer[i] == '\x0f')
        {
            /* Shift In (Ctrl-O) -> Switch to
             * Standard Character Set: invokes
             * the G0 character set. */
            sc->conv_state.glr[0] = 0;
        }

        /* If there are not enough characters to parse the escape sequence,
         * wait until the next try. We require 3. */
        else if(buffer[i] == '\x1b' && i + 2 >= size)
            break;

        /* Single Shift Select of G2 Character Set (SS2: 0x8e):
         * affects next character only */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == 'N')
        {
            sc->conv_state.ss = 2;
            skip += 1;
        }

        /* Single Shift Select of G3 Character Set (SS2: 0x8f):
         * affects next character only */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == 'O')
        {
            sc->conv_state.ss = 3;
            skip += 1;
        }

        /* LOCKING-SHIFT TWO (LS2), ISO 2022, ECMA-48 (1986), ISO 6429 : 1988 */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == 'n')
        {
            sc->conv_state.glr[0] = 2;
            skip += 1;
        }

        /* LOCKING-SHIFT THREE (LS3) ISO 2022, ECMA-48 (1986), ISO 6429 : 1988 */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == 'o')
        {
            sc->conv_state.glr[0] = 3;
            skip += 1;
        }

        /* RESET TO INITIAL STATE (RIS), ECMA-48 (1986), ISO 6429 : 1988 */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == 'c')
        {
            sc->dfg = CACA_DEFAULT;
            sc->dbg = CACA_DEFAULT;

            caca_set_color_ansi(sc->cv, sc->dfg, sc->dbg);
            sc->clearattr = caca_get_attr(sc->cv, -1, -1);
            ansi_parse_grcm(sc, 1, &dummy);

            reset_conv_state(sc);
            skip += 1;
        }

        /* Coding Method Delimiter (CMD), ECMA-48 (1991), ISO/IEC 6429:1992 (ISO IR 189) */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == 'd')
        {
            reset_conv_state(sc);
            skip += 1;
        }

        /* GZDM4, G0-Designators, multi, 94^n chars [grandfathered short form from ISO 2022:1986] */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && (buffer[i + 2] >= '@') && (buffer[i + 2] <= 'C'))
        {
            sc->conv_state.gn[0] = LITERAL2CHAR('$', buffer[i + 2]);
            skip += 2;
        }

        /* GnDMx Gn-Designators, 9x^n chars; need one more char to distinguish these */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && (i + 3 >= size))
            break;

        /* GZD4 G0-Designator, 94 chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '(')
        {
            sc->conv_state.gn[0] = buffer[i + 2];
            skip += 2;
        }

        /* G1D4 G1-Designator, 94 chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == ')')
        {
            sc->conv_state.gn[1] = buffer[i + 2];
            skip += 2;
        }

        /* G2D4 G2-Designator, 94 chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '*')
        {
            sc->conv_state.gn[2] = buffer[i + 2];
            skip += 2;
        }

        /* G3D4 G3-Designator, 94 chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '+')
        {
            sc->conv_state.gn[3] = buffer[i + 2];
            skip += 2;
        }

        /* G2D6 G2-Designator, 96 chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '.')
        {
            sc->conv_state.gn[2] = LITERAL2CHAR('.', buffer[i + 2]);
            skip += 2;
        }

        /* G3D6 G3-Designator, 96 chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '/')
        {
            sc->conv_state.gn[3] = LITERAL2CHAR('.', buffer[i + 2]);
            skip += 2;
        }

        /* GZDM4 G0-Designator, 94^n chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && buffer[i + 2] == '(')
        {
            sc->conv_state.gn[0] = LITERAL2CHAR('$', buffer[i + 3]);
            skip += 3;
        }

        /* G1DM4 G1-Designator, 94^n chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && buffer[i + 2] == ')')
        {
            sc->conv_state.gn[1] = LITERAL2CHAR('$', buffer[i + 3]);
            skip += 3;
        }

        /* G2DM4 G2-Designator, 94^n chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && buffer[i + 2] == '*')
        {
            sc->conv_state.gn[2] = LITERAL2CHAR('$', buffer[i + 3]);
            skip += 3;
        }

        /* G3DM4 G3-Designator, 94^n chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && buffer[i + 2] == '+')
        {
            sc->conv_state.gn[3] = LITERAL2CHAR('$', buffer[i + 3]);
            skip += 3;
        }

        /* G2DM6 G2-Designator, 96^n chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && buffer[i + 2] == '.')
        {
            sc->conv_state.gn[2] = LITERAL3CHAR('$', '.', buffer[i + 3]);
            skip += 3;
        }

        /* G3DM6 G3-Designator, 96^n chars */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '$' && buffer[i + 2] == '/')
        {
            sc->conv_state.gn[3] = LITERAL3CHAR('$', '.', buffer[i + 3]);
            skip += 3;
        }

        /* Interpret escape commands, as per Standard ECMA-48 "Control
         * Functions for Coded Character Sets", 5.4. Control sequences. */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == '[')
        {
            unsigned int argc = 0, argv[101];
            unsigned int param, inter, final;


        /* Compute offsets to parameter bytes, intermediate bytes and
         * to the final byte. Only the final byte is mandatory, there
         * can be zero of the others.
         * 0  param=2             inter                 final           final+1
         * +-----+------------------+---------------------+-----------------+
         * | CSI | parameter bytes  | intermediate bytes  |   final byte    |
         * |     |   0x30 - 0x3f    |    0x20 - 0x2f      |   0x40 - 0x7e   |
         * | ^[[ | 0123456789:;<=>? | SPC !"#$%&'()*+,-./ | azAZ@[\]^_`{|}~ |
         * +-----+------------------+---------------------+-----------------+
         */
            param = 2;

            for(inter = param; i + inter < size; inter++)
                if(buffer[i + inter] < 0x30 || buffer[i + inter] > 0x3f)
                    break;

            for(final = inter; i + final < size; final++)
                if(buffer[i + final] < 0x20 || buffer[i + final] > 0x2f)
                    break;

            if(i + final >= size
                || buffer[i + final] < 0x40 || buffer[i + final] > 0x7e)
                break; /* Invalid Final Byte */

            skip += final;

            /* Sanity checks */
            if(param < inter && buffer[i + param] >= 0x3c)
            {
                /* Private sequence, only parse what we know */
                debug("ansi import: private sequence \"^[[%.*s\"",
                      final - param + 1, buffer + i + param);
                continue; /* Private sequence, skip it entirely */
            }

            if(final - param > 100)
                continue; /* Suspiciously long sequence, skip it */

            /* Parse parameter bytes as per ECMA-48 5.4.2: Parameter string
             * format */
            if(param < inter)
            {
                argv[0] = 0;
                for(j = param; j < inter; j++)
                {
                    if(buffer[i + j] == ';')
                        argv[++argc] = 0;
                    else if(buffer[i + j] >= '0' && buffer[i + j] <= '9')
                        argv[argc] = 10 * argv[argc] + (buffer[i + j] - '0');
                }
                argc++;
            }

            /* Interpret final byte. The code representations are given in
             * ECMA-48 5.4: Control sequences, and the code definitions are
             * given in ECMA-48 8.3: Definition of control functions. */
            debug("ansi import: command '%c'", buffer[i + final]);
            switch(buffer[i + final])
            {
            case 'H': /* CUP (0x48) - Cursor Position */
                x = (argc > 1 && argv[1] > 0) ? argv[1] - 1 : 0;
                y = (argc > 0 && argv[0] > 0) ? argv[0] - 1 : 0;
                break;
            case 'A': /* CUU (0x41) - Cursor Up */
                y -= argc ? argv[0] : 1;
                if(y < 0)
                    y = 0;
                break;
            case 'B': /* CUD (0x42) - Cursor Down */
                y += argc ? argv[0] : 1;
                break;
            case 'C': /* CUF (0x43) - Cursor Right */
                x += argc ? argv[0] : 1;
                break;
            case 'D': /* CUB (0x44) - Cursor Left */
                x -= argc ? argv[0] : 1;
                if(x < 0)
                    x = 0;
                break;
            case 'G': /* CHA (0x47) - Cursor Character Absolute */
                x = (argc && argv[0] > 0) ? argv[0] - 1 : 0;
                break;
            case 'J': /* ED (0x4a) - Erase In Page */
                savedattr = caca_get_attr(sc->cv, -1, -1);
                caca_set_attr(sc->cv, sc->clearattr);
                if(!argc || argv[0] == 0)
                {
                    caca_draw_line(sc->cv, x, y, width, y, ' ');
                    caca_fill_box(sc->cv, 0, y + 1, width - 1, height - 1, ' ');
                }
                else if(argv[0] == 1)
                {
                    caca_fill_box(sc->cv, 0, 0, width - 1, y - 1, ' ');
                    caca_draw_line(sc->cv, 0, y, x, y, ' ');
                }
                else if(argv[0] == 2)
                {
                    //x = y = 0;
                    caca_fill_box(sc->cv, 0, 0, width, height - 1, ' ');
                }
                caca_set_attr(sc->cv, savedattr);
                break;
            case 'K': /* EL (0x4b) - Erase In Line */
                if(!argc || argv[0] == 0)
                    caca_draw_line(sc->cv, x, y, width, y, ' ');
                else if(argv[0] == 1)
                    caca_draw_line(sc->cv, 0, y, x, y, ' ');
                else if(argv[0] == 2)
                    if((unsigned int)x < width)
                        caca_draw_line(sc->cv, x, y, width - 1, y, ' ');
                //x = width;
                break;
            case 'P': /* DCH (0x50) - Delete Character */
                if(!argc || argv[0] == 0)
                    argv[0] = 1; /* echo -ne 'foobar\r\e[0P\n' */
                for(j = 0; (unsigned int)(j + argv[0]) < width; j++)
                {
                    caca_put_char(sc->cv, j, y,
                                   caca_get_char(sc->cv, j + argv[0], y));
                    caca_put_attr(sc->cv, j, y,
                                   caca_get_attr(sc->cv, j + argv[0], y));
                }
#if 0
                savedattr = caca_get_attr(sc->cv, -1, -1);
                caca_set_attr(sc->cv, sc->clearattr);
                for( ; (unsigned int)j < width; j++)
                    caca_put_char(sc->cv, j, y, ' ');
                caca_set_attr(sc->cv, savedattr);
#endif
            case 'X': /* ECH (0x58) - Erase Character */
                if(argc && argv[0])
                {
                    savedattr = caca_get_attr(sc->cv, -1, -1);
                    caca_set_attr(sc->cv, sc->clearattr);
                    caca_draw_line(sc->cv, x, y, x + argv[0] - 1, y, ' ');
                    caca_set_attr(sc->cv, savedattr);
                }
            case 'd': /* VPA (0x64) - Line Position Absolute */
                y = (argc && argv[0] > 0) ? argv[0] - 1 : 0;
                break;
            case 'f': /* HVP (0x66) - Character And Line Position */
                x = (argc > 1 && argv[1] > 0) ? argv[1] - 1 : 0;
                y = (argc > 0 && argv[0] > 0) ? argv[0] - 1 : 0;
                break;
            case 'r': /* SS  (0x72) - Scroll Screen FIXME */
                if(scrolled) break;
                if((argv[0]==0 && argv[1]==0)  || scrolled) break;
                for(j = argv[0]-1; j < argv[1]-1; j++)
                {
                    for(k = 0; k < width; k++)
                    {
                        caca_put_char(sc->cv, k, j, caca_get_char(sc->cv, k, j+1));
                        caca_put_attr(sc->cv, k, j, caca_get_attr(sc->cv, k, j+1));
                    }
                }
                caca_draw_line(sc->cv, 0, argv[1]-1, width, argv[1]-1, ' ');
                scrolled = 1;
                break;
            case 'h': /* SM (0x68) - FIXME */
                debug("ansi import: set mode %i", argc ? (int)argv[0] : -1);
                break;
            case 'l': /* RM (0x6c) - FIXME */
                debug("ansi import: reset mode %i", argc ? (int)argv[0] : -1);
                break;
            case 'm': /* SGR (0x6d) - Select Graphic Rendition */
                if(argc)
                    ansi_parse_grcm(sc, argc, argv);
                else
                    ansi_parse_grcm(sc, 1, &dummy);
                break;
            case 's': /* Private (save cursor position) */
                save_x = x;
                save_y = y;
                break;
            case 'u': /* Private (reload cursor position) */
                x = save_x;
                y = save_y;
                break;
            default:
                debug("ansi import: unknown command \"^[[%.*s\"",
                      final - param + 1, buffer + i + param);
                break;
            }
        }

        /* Parse OSC stuff. */
        else if(buffer[i] == '\x1b' && buffer[i + 1] == ']')
        {
            char *string;
            unsigned int command = 0;
            unsigned int mode = 2, semicolon, final;

            for(semicolon = mode; i + semicolon < size; semicolon++)
            {
                if(buffer[i + semicolon] < '0' || buffer[i + semicolon] > '9')
                    break;
                command = 10 * command + (buffer[i + semicolon] - '0');
            }

            if(i + semicolon >= size || buffer[i + semicolon] != ';')
                break; /* Invalid Mode */

            for(final = semicolon + 1; i + final < size; final++)
                if(buffer[i + final] < 0x20)
                    break;

            if(i + final >= size || buffer[i + final] != '\a')
                break; /* Not enough data or no bell found */
                /* FIXME: XTerm also reacts to <ESC><backslash> and <ST> */
                /* FIXME: differenciate between not enough data (try again)
                 *        and invalid data (print shit) */

            skip += final;

            string = malloc(final - (semicolon + 1) + 1);
            memcpy(string, buffer + i + (semicolon + 1), final - (semicolon + 1));
            string[final - (semicolon + 1)] = '\0';
            debug("ansi import: got OSC command %i string '%s'", command,
                  string);
            if(command == 0 || command == 2)
            {
                if(sc->title)
                    free(sc->title);
                sc->title = string;
            }
            else
                free(string);
        }

        /* Get the character we’re going to paste */
        else
        {
            size_t bytes;

            if(i + 6 < size)
                ch = caca_utf8_to_utf32((char const *)(buffer + i), &bytes);
            else
            {
                /* Add a trailing zero to what we're going to read */
                char tmp[7];
                memcpy(tmp, buffer + i, size - i);
                tmp[size - i] = '\0';
                ch = caca_utf8_to_utf32(tmp, &bytes);
            }

            if(!bytes)
            {
                /* If the Unicode is invalid, assume it was latin1. */
                ch = buffer[i];
                bytes = 1;
            }

            /* very incomplete ISO-2022 implementation tailored to DEC ACS */
            if(sc->conv_state.cs == '@')
            {
                if (((ch > ' ') && (ch <= '~'))
                    &&
                    (sc->conv_state.gn[sc->conv_state.ss ? sc->conv_state.gn[sc->conv_state.ss] : sc->conv_state.glr[0]] == '0'))
                {
                    ch = dec_acs(ch);
                }
                else if (((ch > 0x80) && (ch < 0xff))
                         &&
                         (sc->conv_state.gn[sc->conv_state.glr[1]] == '0'))
                {
                    ch = dec_acs(ch + ' ' - 0x80);
                }
            }
            sc->conv_state.ss = 0; /* no single-shift (GL) */

            wch = caca_utf32_is_fullwidth(ch) ? 2 : 1;
            skip += bytes - 1;
        }

        /* Wrap long lines or grow horizontally */
        while((unsigned int)x + wch > width)
        {
            x -= width;
            y++;
        }

        /* Scroll or grow vertically */
        if((unsigned int)y >= height)
        {
            int lines = (y - height) + 1;

            savedattr = caca_get_attr(sc->cv, -1, -1);

            for(j = 0; j + lines < height; j++)
            {
                for(k = 0; k < width; k++)
                {
                    caca_put_char(sc->cv, k, j, caca_get_char(sc->cv, k, j + lines));
                    caca_put_attr(sc->cv, k, j, caca_get_attr(sc->cv, k, j + lines));
                }
            }
            caca_set_attr(sc->cv, sc->clearattr);
            caca_fill_box(sc->cv, 0, height - lines,
                                   width - 1, height - 1, ' ');
            y -= lines;
            caca_set_attr(sc->cv, savedattr);
        }

        /* Now paste our character, if any */
        if(wch)
        {
            caca_put_char(sc->cv, x, y, ch);
            x += wch;
        }
    }

    caca_gotoxy(sc->cv, x, y);

    return i;
}

/* Coding Method Delimiter (CMD), ECMA-48 (1991), ISO/IEC 6429:1992 (ISO IR 189) */

static void reset_conv_state(struct screen *sc)
{
    sc->conv_state.cs = '@'; /* ISO-2022 coding system */
    sc->conv_state.cn[0] = '@'; /* ISO 646 C0 control charset */
    sc->conv_state.cn[1] = 'C'; /* ISO 6429-1983 C1 control charset */
    sc->conv_state.glr[0] = 0; /* G0 in GL */
    sc->conv_state.glr[1] = 2; /* G2 in GR */
    sc->conv_state.gn[0] = 'B'; /* US-ASCII G0 charset */
    sc->conv_state.gn[1] = '0'; /* DEC ACS G1 charset */
    sc->conv_state.gn[2] = LITERAL2CHAR('.', 'A'); /* ISO 8859-1 G2 charset */
    sc->conv_state.gn[3] = LITERAL2CHAR('.', 'A'); /* ISO 8859-1 G3 charset */
    sc->conv_state.ss = 0; /* no single-shift (GL) */
    sc->conv_state.ctrl8bit = 1;
}

/* XXX : ANSI loader helper */

static void ansi_parse_grcm(struct screen *sc,
                            unsigned int argc, unsigned int const *argv)
{
    static uint8_t const ansi2caca[] =
    {
        CACA_BLACK, CACA_RED, CACA_GREEN, CACA_BROWN,
        CACA_BLUE, CACA_MAGENTA, CACA_CYAN, CACA_LIGHTGRAY
    };

    unsigned int j;
    uint8_t efg, ebg; /* Effective (libcaca) fg/bg */

    for(j = 0; j < argc; j++)
    {
        /* Defined in ECMA-48 8.3.117: SGR - SELECT GRAPHIC RENDITION */
        if(argv[j] >= 30 && argv[j] <= 37)
            sc->fg = ansi2caca[argv[j] - 30];
        else if(argv[j] >= 40 && argv[j] <= 47)
            sc->bg = ansi2caca[argv[j] - 40];
        else if(argv[j] >= 90 && argv[j] <= 97)
            sc->fg = ansi2caca[argv[j] - 90] + 8;
        else if(argv[j] >= 100 && argv[j] <= 107)
            sc->bg = ansi2caca[argv[j] - 100] + 8;
        else switch(argv[j])
        {
        case 0: /* default rendition */
            sc->fg = sc->dfg;
            sc->bg = sc->dbg;
            sc->bold = sc->blink = sc->italics = sc->negative
             = sc->concealed = sc->underline = sc->faint = sc->strike
             = sc->proportional = 0;
            break;
        case 1: /* bold or increased intensity */
            sc->bold = 1;
            break;
        case 2: /* faint, decreased intensity or second colour */
            sc->faint = 1;
            break;
        case 3: /* italicized */
            sc->italics = 1;
            break;
        case 4: /* singly underlined */
            sc->underline = 1;
            break;
        case 5: /* slowly blinking (less then 150 per minute) */
        case 6: /* rapidly blinking (150 per minute or more) */
            sc->blink = 1;
            break;
        case 7: /* negative image */
            sc->negative = 1;
            break;
        case 8: /* concealed characters */
            sc->concealed = 1;
            break;
        case 9: /* crossed-out (characters still legible but marked as to be
                 * deleted */
            sc->strike = 1;
            break;
        case 21: /* doubly underlined */
            sc->underline = 1;
            break;
        case 22: /* normal colour or normal intensity (neither bold nor
                  * faint) */
            sc->bold = sc->faint = 0;
            break;
        case 23: /* not italicized, not fraktur */
            sc->italics = 0;
            break;
        case 24: /* not underlined (neither singly nor doubly) */
            sc->underline = 0;
            break;
        case 25: /* steady (not blinking) */
            sc->blink = 0;
            break;
        case 26: /* (reserved for proportional spacing as specified in CCITT
                  * Recommendation T.61) */
            sc->proportional = 1;
            break;
        case 27: /* positive image */
            sc->negative = 0;
            break;
        case 28: /* revealed characters */
            sc->concealed = 0;
            break;
        case 29: /* not crossed out */
            sc->strike = 0;
            break;
        case 38: /* (reserved for future standardization, intended for setting
                  * character foreground colour as specified in ISO 8613-6
                  * [CCITT Recommendation T.416]) */
            break;
        case 39: /* default display colour (implementation-defined) */
            sc->fg = sc->dfg;
            break;
        case 48: /* (reserved for future standardization, intended for setting
                  * character background colour as specified in ISO 8613-6
                  * [CCITT Recommendation T.416]) */
            break;
        case 49: /* default background colour (implementation-defined) */
            sc->bg = sc->dbg;
            break;
        case 50: /* (reserved for cancelling the effect of the rendering
                  * aspect established by parameter value 26) */
            sc->proportional = 0;
            break;
        default:
            debug("ansi import: unknown sgr %i", argv[j]);
            break;
        }
    }

    if(sc->concealed)
    {
        efg = ebg = CACA_TRANSPARENT;
    }
    else
    {
        efg = sc->negative ? sc->bg : sc->fg;
        ebg = sc->negative ? sc->fg : sc->bg;

        if(sc->bold)
        {
            if(efg < 8)
                efg += 8;
            else if(efg == CACA_DEFAULT)
                efg = CACA_WHITE;
        }
    }

    caca_set_color_ansi(sc->cv, efg, ebg);
}

int create_pty(char *cmd, unsigned int w, unsigned int h, int *cpid)
{
    char **argv;
    int fd;
    pid_t pid;

    pid = forkpty(&fd, NULL, NULL, NULL);
    if(pid < 0)
    {
        fprintf(stderr, "forkpty() error\n");
        return -1;
    }
    else if(pid == 0)
    {
        set_tty_size(0, w, h);
        putenv("CACA_DRIVER=slang");
        putenv("TERM=xterm");
        argv = malloc(2 * sizeof(char *));
        if(!argv)
        {
            fprintf(stderr, "Can't allocate memory at %s:%d\n", __FUNCTION__, __LINE__);
            return -1;
        }
        argv[0] = cmd;
        argv[1] = NULL;
        execvp(cmd, argv);
        fprintf(stderr, "execvp() error\n");
        return -1;
    }

    *cpid = pid;

    fcntl(fd, F_SETFL, O_NDELAY);
    return fd;
}

int create_pty_grab(long pid, unsigned int w, unsigned int h)
{
    int fdm, fds;

    int ret = openpty(&fdm, &fds, NULL, NULL, NULL);

    if(ret < 0)
    {
        fprintf(stderr, "open() error\n");
        return -1;
    }

    set_tty_size(0, w, h);
    grab_process(pid, ptsname(fdm), fds);

    fcntl(fdm, F_SETFL, O_NDELAY);
    return fdm;
}

int set_tty_size(int fd, unsigned int w, unsigned int h)
{
    struct winsize ws;

    memset(&ws, 0, sizeof(ws));
    ws.ws_row = h;
    ws.ws_col = w;
    ioctl(fd, TIOCSWINSZ, (char *)&ws);

    return 0;
}



int update_terms(struct screen_list* screen_list)
{
    int i, refresh = 0;
    for(i = 0; i < screen_list->count; i++)
    {
        if(screen_list->screen[i]->total && !screen_list->dont_update_coords)
        {
            unsigned long int bytes;

            bytes = import_term(screen_list,
                                screen_list->screen[i],
                                screen_list->screen[i]->buf,
                                screen_list->screen[i]->total);

            if(bytes > 0)
            {
                screen_list->screen[i]->total -= bytes;
                memmove(screen_list->screen[i]->buf,
                        screen_list->screen[i]->buf + bytes,
                        screen_list->screen[i]->total);
                refresh = 1;
            }
        }
    }
    return refresh;
}