/* * ASCII/ANSI art decoder * Copyright (c) 2010 Peter Ross <pross@xvid.org> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * ASCII/ANSI art decoder */ #include "libavutil/common.h"#include "libavutil/frame.h"#include "libavutil/lfg.h"#include "libavutil/xga_font_data.h"#include "avcodec.h"#include "cga_data.h"#include "internal.h" #define ATTR_BOLD         0x01  /**< Bold/Bright-foreground (mode 1) */#define ATTR_FAINT        0x02  /**< Faint (mode 2) */#define ATTR_UNDERLINE    0x08  /**< Underline (mode 4) */#define ATTR_BLINK        0x10  /**< Blink/Bright-background (mode 5) */#define ATTR_REVERSE      0x40  /**< Reverse (mode 7) */#define ATTR_CONCEALED    0x80  /**< Concealed (mode 8) */ #define DEFAULT_FG_COLOR     7  /**< CGA color index */#define DEFAULT_BG_COLOR     0#define DEFAULT_SCREEN_MODE  3  /**< 80x25 */ #define FONT_WIDTH           8  /**< Font width */ /** map ansi color index to cga palette index */static const uint8_t ansi_to_cga[16] = {    0,  4,  2,  6,  1,  5,  3, 7, 8, 12, 10, 14,  9, 13, 11, 15}; typedef struct AnsiContext {    AVFrame *frame;    int x;                /**< x cursor position (pixels) */    int y;                /**< y cursor position (pixels) */    int sx;               /**< saved x cursor position (pixels) */    int sy;               /**< saved y cursor position (pixels) */    const uint8_t* font;  /**< font */    int font_height;      /**< font height */    int attributes;       /**< attribute flags */    int fg;               /**< foreground color */    int bg;               /**< background color */    int first_frame;     /* ansi parser state machine */    enum {        STATE_NORMAL = 0,        STATE_ESCAPE,        STATE_CODE,        STATE_MUSIC_PREAMBLE    } state;#define MAX_NB_ARGS 4    int args[MAX_NB_ARGS];    int nb_args;          /**< number of arguments (may exceed MAX_NB_ARGS) */} AnsiContext; static av_cold int decode_init(AVCodecContext *avctx){    AnsiContext *s = avctx->priv_data;    avctx->pix_fmt = AV_PIX_FMT_PAL8;     s->frame = av_frame_alloc();    if (!s->frame)        return AVERROR(ENOMEM);     /* defaults */    s->font        = avpriv_vga16_font;    s->font_height = 16;    s->fg          = DEFAULT_FG_COLOR;    s->bg          = DEFAULT_BG_COLOR;     if (!avctx->width || !avctx->height) {        int ret = ff_set_dimensions(avctx, 80 << 3, 25 << 4);        if (ret < 0)            return ret;    } else if (avctx->width % FONT_WIDTH || avctx->height % s->font_height) {        av_log(avctx, AV_LOG_ERROR, "Invalid dimensions %d %d\n", avctx->width, avctx->height);        return AVERROR(EINVAL);    }    return 0;} static void set_palette(uint32_t *pal){    int r, g, b;    memcpy(pal, ff_cga_palette, 16 * 4);    pal += 16;#define COLOR(x) ((x) * 40 + 55)    for (r = 0; r < 6; r++)        for (g = 0; g < 6; g++)            for (b = 0; b < 6; b++)                *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);#define GRAY(x) ((x) * 10 + 8)    for (g = 0; g < 24; g++)        *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);} static void hscroll(AVCodecContext *avctx){    AnsiContext *s = avctx->priv_data;    int i;     if (s->y <= avctx->height - 2*s->font_height) {        s->y += s->font_height;        return;    }     i = 0;    for (; i < avctx->height - s->font_height; i++)        memcpy(s->frame->data[0] + i * s->frame->linesize[0],               s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],               avctx->width);    for (; i < avctx->height; i++)        memset(s->frame->data[0] + i * s->frame->linesize[0],            DEFAULT_BG_COLOR, avctx->width);} static void erase_line(AVCodecContext * avctx, int xoffset, int xlength){    AnsiContext *s = avctx->priv_data;    int i;    for (i = 0; i < s->font_height; i++)        memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,            DEFAULT_BG_COLOR, xlength);} static void erase_screen(AVCodecContext *avctx){    AnsiContext *s = avctx->priv_data;    int i;    for (i = 0; i < avctx->height; i++)        memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);    s->x = s->y = 0;} /** * Draw character to screen */static void draw_char(AVCodecContext *avctx, int c){    AnsiContext *s = avctx->priv_data;    int fg = s->fg;    int bg = s->bg;     if ((s->attributes & ATTR_BOLD))        fg += 8;    if ((s->attributes & ATTR_BLINK))        bg += 8;    if ((s->attributes & ATTR_REVERSE))        FFSWAP(int, fg, bg);    if ((s->attributes & ATTR_CONCEALED))        fg = bg;    ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,                    s->frame->linesize[0], s->font, s->font_height, c, fg, bg);    s->x += FONT_WIDTH;    if (s->x > avctx->width - FONT_WIDTH) {        s->x = 0;        hscroll(avctx);    }} /** * Execute ANSI escape code * @return 0 on success, negative on error */static int execute_code(AVCodecContext * avctx, int c){    AnsiContext *s = avctx->priv_data;    int ret, i;    int width  = avctx->width;    int height = avctx->height;     switch(c) {    case 'A': //Cursor Up        s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);        break;    case 'B': //Cursor Down        s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);        break;    case 'C': //Cursor Right        s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width  - FONT_WIDTH);        break;    case 'D': //Cursor Left        s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);        break;    case 'H': //Cursor Position    case 'f': //Horizontal and Vertical Position        s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;        s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH,     0, avctx->width  - FONT_WIDTH) : 0;        break;    case 'h': //set screen mode    case 'l': //reset screen mode        if (s->nb_args < 2)            s->args[0] = DEFAULT_SCREEN_MODE;        switch(s->args[0]) {        case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)            s->font = avpriv_cga_font;            s->font_height = 8;            width  = 40<<3;            height = 25<<3;            break;        case 2: case 3: //640x400 (25 rows)            s->font = avpriv_vga16_font;            s->font_height = 16;            width  = 80<<3;            height = 25<<4;            break;        case 6: case 14: //640x200 (25 rows)            s->font = avpriv_cga_font;            s->font_height = 8;            width  = 80<<3;            height = 25<<3;            break;        case 7: //set line wrapping            break;        case 15: case 16: //640x350 (43 rows)            s->font = avpriv_cga_font;            s->font_height = 8;            width  = 80<<3;            height = 43<<3;            break;        case 17: case 18: //640x480 (60 rows)            s->font = avpriv_cga_font;            s->font_height = 8;            width  = 80<<3;            height = 60<<4;            break;        default:            avpriv_request_sample(avctx, "Unsupported screen mode");        }        s->x = av_clip(s->x, 0, width  - FONT_WIDTH);        s->y = av_clip(s->y, 0, height - s->font_height);        if (width != avctx->width || height != avctx->height) {            av_frame_unref(s->frame);            ret = ff_set_dimensions(avctx, width, height);            if (ret < 0)                return ret;            if ((ret = ff_get_buffer(avctx, s->frame,                                     AV_GET_BUFFER_FLAG_REF)) < 0)                return ret;            s->frame->pict_type           = AV_PICTURE_TYPE_I;            s->frame->palette_has_changed = 1;            set_palette((uint32_t *)s->frame->data[1]);            erase_screen(avctx);        } else if (c == 'l') {            erase_screen(avctx);        }        break;    case 'J': //Erase in Page        switch (s->args[0]) {        case 0:            erase_line(avctx, s->x, avctx->width - s->x);            if (s->y < avctx->height - s->font_height)                memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],                    DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);            break;        case 1:            erase_line(avctx, 0, s->x);            if (s->y > 0)                memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);            break;        case 2:            erase_screen(avctx);        }        break;    case 'K': //Erase in Line        switch(s->args[0]) {        case 0:            erase_line(avctx, s->x, avctx->width - s->x);            break;        case 1:            erase_line(avctx, 0, s->x);            break;        case 2:            erase_line(avctx, 0, avctx->width);        }        break;    case 'm': //Select Graphics Rendition        if (s->nb_args == 0) {            s->nb_args = 1;            s->args[0] = 0;        }        for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {            int m = s->args[i];            if (m == 0) {                s->attributes = 0;                s->fg = DEFAULT_FG_COLOR;                s->bg = DEFAULT_BG_COLOR;            } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {                s->attributes |= 1 << (m - 1);            } else if (m >= 30 && m <= 37) {                s->fg = ansi_to_cga[m - 30];            } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {                int index = s->args[i + 2];                s->fg = index < 16 ? ansi_to_cga[index] : index;                i += 2;            } else if (m == 39) {                s->fg = ansi_to_cga[DEFAULT_FG_COLOR];            } else if (m >= 40 && m <= 47) {                s->bg = ansi_to_cga[m - 40];            } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {                int index = s->args[i + 2];                s->bg = index < 16 ? ansi_to_cga[index] : index;                i += 2;            } else if (m == 49) {                s->fg = ansi_to_cga[DEFAULT_BG_COLOR];            } else {                avpriv_request_sample(avctx, "Unsupported rendition parameter");            }        }        break;    case 'n': //Device Status Report    case 'R': //report current line and column        /* ignore */        break;    case 's': //Save Cursor Position        s->sx = s->x;        s->sy = s->y;        break;    case 'u': //Restore Cursor Position        s->x = av_clip(s->sx, 0, avctx->width  - FONT_WIDTH);        s->y = av_clip(s->sy, 0, avctx->height - s->font_height);        break;    default:        avpriv_request_sample(avctx, "Unknown escape code");        break;    }    s->x = av_clip(s->x, 0, avctx->width  - FONT_WIDTH);    s->y = av_clip(s->y, 0, avctx->height - s->font_height);    return 0;} static int decode_frame(AVCodecContext *avctx,                            void *data, int *got_frame,                            AVPacket *avpkt){    AnsiContext *s = avctx->priv_data;    uint8_t *buf = avpkt->data;    int buf_size = avpkt->size;    const uint8_t *buf_end   = buf+buf_size;    int ret, i, count;     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)        return ret;    if (!avctx->frame_number) {        for (i=0; i<avctx->height; i++)            memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width);        memset(s->frame->data[1], 0, AVPALETTE_SIZE);    }     s->frame->pict_type           = AV_PICTURE_TYPE_I;    s->frame->palette_has_changed = 1;    set_palette((uint32_t *)s->frame->data[1]);    if (!s->first_frame) {        erase_screen(avctx);        s->first_frame = 1;    }     while(buf < buf_end) {        switch(s->state) {        case STATE_NORMAL:            switch (buf[0]) {            case 0x00: //NUL            case 0x07: //BEL            case 0x1A: //SUB                /* ignore */                break;            case 0x08: //BS                s->x = FFMAX(s->x - 1, 0);                break;            case 0x09: //HT                i = s->x / FONT_WIDTH;                count = ((i + 8) & ~7) - i;                for (i = 0; i < count; i++)                    draw_char(avctx, ' ');                break;            case 0x0A: //LF                hscroll(avctx);            case 0x0D: //CR                s->x = 0;                break;            case 0x0C: //FF                erase_screen(avctx);                break;            case 0x1B: //ESC                s->state = STATE_ESCAPE;                break;            default:                draw_char(avctx, buf[0]);            }            break;        case STATE_ESCAPE:            if (buf[0] == '[') {                s->state   = STATE_CODE;                s->nb_args = 0;                s->args[0] = -1;            } else {                s->state = STATE_NORMAL;                draw_char(avctx, 0x1B);                continue;            }            break;        case STATE_CODE:            switch(buf[0]) {            case '0': case '1': case '2': case '3': case '4':            case '5': case '6': case '7': case '8': case '9':                if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553)                    s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';                break;            case ';':                s->nb_args++;                if (s->nb_args < MAX_NB_ARGS)                    s->args[s->nb_args] = 0;                break;            case 'M':                s->state = STATE_MUSIC_PREAMBLE;                break;            case '=': case '?':                /* ignore */                break;            default:                if (s->nb_args > MAX_NB_ARGS)                    av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);                if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)                    s->nb_args++;                if ((ret = execute_code(avctx, buf[0])) < 0)                    return ret;                s->state = STATE_NORMAL;            }            break;        case STATE_MUSIC_PREAMBLE:            if (buf[0] == 0x0E || buf[0] == 0x1B)                s->state = STATE_NORMAL;            /* ignore music data */            break;        }        buf++;    }     *got_frame = 1;    if ((ret = av_frame_ref(data, s->frame)) < 0)        return ret;    return buf_size;} static av_cold int decode_close(AVCodecContext *avctx){    AnsiContext *s = avctx->priv_data;     av_frame_free(&s->frame);    return 0;} AVCodec ff_ansi_decoder = {    .name           = "ansi",    .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),    .type           = AVMEDIA_TYPE_VIDEO,    .id             = AV_CODEC_ID_ANSI,    .priv_data_size = sizeof(AnsiContext),    .init           = decode_init,    .close          = decode_close,    .decode         = decode_frame,    .capabilities   = AV_CODEC_CAP_DR1,    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,};