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/*
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 * ASCII/ANSI art decoder
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 * Copyright (c) 2010 Peter Ross <pross@xvid.org>
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * ASCII/ANSI art decoder
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 */
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#include "libavutil/lfg.h"
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#include "avcodec.h"
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#include "cga_data.h"
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#define ATTR_BOLD         0x01  /**< Bold/Bright-foreground (mode 1) */
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#define ATTR_FAINT        0x02  /**< Faint (mode 2) */
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#define ATTR_UNDERLINE    0x08  /**< Underline (mode 4) */
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#define ATTR_BLINK        0x10  /**< Blink/Bright-background (mode 5) */
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#define ATTR_REVERSE      0x40  /**< Reverse (mode 7) */
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#define ATTR_CONCEALED    0x80  /**< Concealed (mode 8) */
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#define DEFAULT_FG_COLOR     7  /**< CGA color index */
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#define DEFAULT_BG_COLOR     0
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#define DEFAULT_SCREEN_MODE  3  /**< 80x25 */
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#define FONT_WIDTH           8  /**< Font width */
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/** map ansi color index to cga palette index */
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static const uint8_t ansi_to_cga[16] = {
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    0,  4,  2,  6,  1,  5,  3, 7, 8, 12, 10, 14,  9, 13, 11, 15
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};
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typedef struct {
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    AVFrame frame;
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    int x;                /**< x cursor position (pixels) */
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    int y;                /**< y cursor position (pixels) */
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    int sx;               /**< saved x cursor position (pixels) */
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    int sy;               /**< saved y cursor position (pixels) */
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    const uint8_t* font;  /**< font */
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    int font_height;      /**< font height */
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    int attributes;       /**< attribute flags */
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    int fg;               /**< foreground color */
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    int bg;               /**< background color */
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    /* ansi parser state machine */
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    enum {
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        STATE_NORMAL = 0,
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        STATE_ESCAPE,
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        STATE_CODE,
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        STATE_MUSIC_PREAMBLE
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    } state;
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#define MAX_NB_ARGS 4
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    int args[MAX_NB_ARGS];
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    int nb_args;          /**< number of arguments (may exceed MAX_NB_ARGS) */
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} AnsiContext;
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static av_cold int decode_init(AVCodecContext *avctx)
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{
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    AnsiContext *s = avctx->priv_data;
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    /* defaults */
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    s->font        = ff_vga16_font;
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    s->font_height = 16;
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    s->fg          = DEFAULT_FG_COLOR;
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    s->bg          = DEFAULT_BG_COLOR;
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    if (!avctx->width || !avctx->height)
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        avcodec_set_dimensions(avctx, 80<<3, 25<<4);
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    return 0;
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}
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static void hscroll(AVCodecContext *avctx)
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{
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    AnsiContext *s = avctx->priv_data;
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    int i;
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    if (s->y < avctx->height - s->font_height) {
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        s->y += s->font_height;
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        return;
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    }
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    i = 0;
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    for (; i < avctx->height - s->font_height; i++)
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        memcpy(s->frame.data[0] + i * s->frame.linesize[0],
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               s->frame.data[0] + (i + s->font_height) * s->frame.linesize[0],
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               avctx->width);
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    for (; i < avctx->height; i++)
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        memset(s->frame.data[0] + i * s->frame.linesize[0],
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            DEFAULT_BG_COLOR, avctx->width);
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}
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static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
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{
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    AnsiContext *s = avctx->priv_data;
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    int i;
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    for (i = 0; i < s->font_height; i++)
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        memset(s->frame.data[0] + (s->y + i)*s->frame.linesize[0] + xoffset,
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            DEFAULT_BG_COLOR, xlength);
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}
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static void erase_screen(AVCodecContext *avctx)
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{
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    AnsiContext *s = avctx->priv_data;
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    int i;
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    for (i = 0; i < avctx->height; i++)
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        memset(s->frame.data[0] + i * s->frame.linesize[0], DEFAULT_BG_COLOR, avctx->width);
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    s->x = s->y = 0;
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}
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/**
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 * Draw character to screen
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 */
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static void draw_char(AVCodecContext *avctx, int c)
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{
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    AnsiContext *s = avctx->priv_data;
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    int fg = s->fg;
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    int bg = s->bg;
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    if ((s->attributes & ATTR_BOLD))
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        fg += 8;
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    if ((s->attributes & ATTR_BLINK))
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        bg += 8;
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    if ((s->attributes & ATTR_REVERSE))
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        FFSWAP(int, fg, bg);
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    if ((s->attributes & ATTR_CONCEALED))
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        fg = bg;
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    ff_draw_pc_font(s->frame.data[0] + s->y * s->frame.linesize[0] + s->x,
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                    s->frame.linesize[0], s->font, s->font_height, c, fg, bg);
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    s->x += FONT_WIDTH;
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    if (s->x >= avctx->width) {
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        s->x = 0;
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        hscroll(avctx);
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    }
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}
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/**
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 * Execute ANSI escape code
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 * @param <0 error
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 */
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static int execute_code(AVCodecContext * avctx, int c)
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{
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    AnsiContext *s = avctx->priv_data;
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    int ret, i, width, height;
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    switch(c) {
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    case 'A': //Cursor Up
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        s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
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        break;
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    case 'B': //Cursor Down
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        s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
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        break;
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    case 'C': //Cursor Right
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        s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width  - FONT_WIDTH);
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        break;
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    case 'D': //Cursor Left
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        s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
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        break;
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    case 'H': //Cursor Position
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    case 'f': //Horizontal and Vertical Position
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        s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
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        s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH,     0, avctx->width  - FONT_WIDTH) : 0;
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        break;
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    case 'h': //set creen mode
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    case 'l': //reset screen mode
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        if (s->nb_args < 2)
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            s->args[0] = DEFAULT_SCREEN_MODE;
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        switch(s->args[0]) {
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        case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)
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            s->font = ff_cga_font;
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            s->font_height = 8;
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            width  = 40<<3;
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            height = 25<<3;
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            break;
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        case 2: case 3: //640x400 (25 rows)
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            s->font = ff_vga16_font;
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            s->font_height = 16;
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            width  = 80<<3;
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            height = 25<<4;
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            break;
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        case 6: case 14: //640x200 (25 rows)
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            s->font = ff_cga_font;
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            s->font_height = 8;
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            width  = 80<<3;
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            height = 25<<3;
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            break;
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        case 7: //set line wrapping
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            break;
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        case 15: case 16: //640x350 (43 rows)
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            s->font = ff_cga_font;
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            s->font_height = 8;
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            width  = 80<<3;
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            height = 43<<3;
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            break;
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        case 17: case 18: //640x480 (60 rows)
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            s->font = ff_cga_font;
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            s->font_height = 8;
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            width  = 80<<3;
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            height = 60<<4;
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            break;
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        default:
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            av_log_ask_for_sample(avctx, "unsupported screen mode\n");
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        }
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        if (width != avctx->width || height != avctx->height) {
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            if (s->frame.data[0])
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                avctx->release_buffer(avctx, &s->frame);
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            avcodec_set_dimensions(avctx, width, height);
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            ret = avctx->get_buffer(avctx, &s->frame);
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            if (ret < 0) {
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                av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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                return ret;
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            }
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            s->frame.pict_type           = FF_I_TYPE;
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            s->frame.palette_has_changed = 1;
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            memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
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            erase_screen(avctx);
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        } else if (c == 'l') {
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            erase_screen(avctx);
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        }
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        break;
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    case 'J': //Erase in Page
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        switch (s->args[0]) {
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        case 0:
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            erase_line(avctx, s->x, avctx->width - s->x);
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            if (s->y < avctx->height - s->font_height)
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                memset(s->frame.data[0] + (s->y + s->font_height)*s->frame.linesize[0],
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                    DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame.linesize[0]);
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            break;
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        case 1:
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            erase_line(avctx, 0, s->x);
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            if (s->y > 0)
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                memset(s->frame.data[0], DEFAULT_BG_COLOR, s->y * s->frame.linesize[0]);
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            break;
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        case 2:
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            erase_screen(avctx);
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        }
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        break;
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    case 'K': //Erase in Line
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        switch(s->args[0]) {
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        case 0:
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            erase_line(avctx, s->x, avctx->width - s->x);
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            break;
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        case 1:
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            erase_line(avctx, 0, s->x);
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            break;
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        case 2:
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            erase_line(avctx, 0, avctx->width);
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        }
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        break;
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    case 'm': //Select Graphics Rendition
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        if (s->nb_args == 0) {
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            s->nb_args = 1;
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            s->args[0] = 0;
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        }
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        for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
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            int m = s->args[i];
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            if (m == 0) {
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                s->attributes = 0;
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                s->fg = DEFAULT_FG_COLOR;
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                s->bg = DEFAULT_BG_COLOR;
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            } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
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                s->attributes |= 1 << (m - 1);
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            } else if (m >= 30 && m <= 38) {
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                s->fg = ansi_to_cga[m - 30];
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            } else if (m == 39) {
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                s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
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            } else if (m >= 40 && m <= 47) {
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                s->bg = ansi_to_cga[m - 40];
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            } else if (m == 49) {
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                s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
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            } else {
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                av_log_ask_for_sample(avctx, "unsupported rendition parameter\n");
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            }
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        }
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        break;
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    case 'n': //Device Status Report
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    case 'R': //report current line and column
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        /* ignore */
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        break;
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    case 's': //Save Cursor Position
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        s->sx = s->x;
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        s->sy = s->y;
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        break;
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    case 'u': //Restore Cursor Position
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        s->x = av_clip(s->sx, 0, avctx->width  - FONT_WIDTH);
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        s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
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        break;
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    default:
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        av_log_ask_for_sample(avctx, "unsupported escape code\n");
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        break;
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    }
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    return 0;
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}
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static int decode_frame(AVCodecContext *avctx,
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                            void *data, int *data_size,
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                            AVPacket *avpkt)
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{
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    AnsiContext *s = avctx->priv_data;
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    uint8_t *buf = avpkt->data;
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    int buf_size = avpkt->size;
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    const uint8_t *buf_end   = buf+buf_size;
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    int ret, i, count;
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321
    ret = avctx->reget_buffer(avctx, &s->frame);
322
    if (ret < 0){
323
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
324
        return ret;
325
    }
326
    s->frame.pict_type           = FF_I_TYPE;
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    s->frame.palette_has_changed = 1;
328
    memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
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330
    while(buf < buf_end) {
331
        switch(s->state) {
332
        case STATE_NORMAL:
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            switch (buf[0]) {
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            case 0x00: //NUL
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            case 0x07: //BEL
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            case 0x1A: //SUB
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                /* ignore */
338
                break;
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            case 0x08: //BS
340
                s->x = FFMAX(s->x - 1, 0);
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                break;
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            case 0x09: //HT
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                i = s->x / FONT_WIDTH;
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                count = ((i + 8) & ~7) - i;
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                for (i = 0; i < count; i++)
346
                    draw_char(avctx, ' ');
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                break;
348
            case 0x0A: //LF
349
                hscroll(avctx);
350
            case 0x0D: //CR
351
                s->x = 0;
352
                break;
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            case 0x0C: //FF
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                erase_screen(avctx);
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                break;
356
            case 0x1B: //ESC
357
                s->state = STATE_ESCAPE;
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                break;
359
            default:
360
                draw_char(avctx, buf[0]);
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            }
362
            break;
363
        case STATE_ESCAPE:
364
            if (buf[0] == '[') {
365
                s->state   = STATE_CODE;
366
                s->nb_args = 0;
367
                s->args[0] = 0;
368
            } else {
369
                s->state = STATE_NORMAL;
370
                draw_char(avctx, 0x1B);
371
                    return -1;
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                continue;
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            }
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            break;
375
        case STATE_CODE:
376
            switch(buf[0]) {
377
            case '0': case '1': case '2': case '3': case '4':
378
            case '5': case '6': case '7': case '8': case '9':
379
                if (s->nb_args < MAX_NB_ARGS)
380
                    s->args[s->nb_args] = s->args[s->nb_args] * 10 + buf[0] - '0';
381
                break;
382
            case ';':
383
                s->nb_args++;
384
                if (s->nb_args < MAX_NB_ARGS)
385
                    s->args[s->nb_args] = 0;
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                break;
387
            case 'M':
388
                s->state = STATE_MUSIC_PREAMBLE;
389
                break;
390
            case '=': case '?':
391
                /* ignore */
392
                break;
393
            default:
394
                if (s->nb_args > MAX_NB_ARGS)
395
                    av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);
396
                if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args])
397
                    s->nb_args++;
398
                if (execute_code(avctx, buf[0]) < 0)
399
                    return -1;
400
                s->state = STATE_NORMAL;
401
            }
402
            break;
403
        case STATE_MUSIC_PREAMBLE:
404
            if (buf[0] == 0x0E || buf[0] == 0x1B)
405
                s->state = STATE_NORMAL;
406
            /* ignore music data */
407
            break;
408
        }
409
        buf++;
410
    }
411

    
412
    *data_size = sizeof(AVFrame);
413
    *(AVFrame*)data = s->frame;
414
    return buf_size;
415
}
416

    
417
static av_cold int decode_close(AVCodecContext *avctx)
418
{
419
    AnsiContext *s = avctx->priv_data;
420
    if (s->frame.data[0])
421
        avctx->release_buffer(avctx, &s->frame);
422
    return 0;
423
}
424

    
425
AVCodec ff_ansi_decoder = {
426
    .name           = "ansi",
427
    .type           = AVMEDIA_TYPE_VIDEO,
428
    .id             = CODEC_ID_ANSI,
429
    .priv_data_size = sizeof(AnsiContext),
430
    .init           = decode_init,
431
    .close          = decode_close,
432
    .decode         = decode_frame,
433
    .capabilities   = CODEC_CAP_DR1,
434
    .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
435
};