ASCII/ANSI art decoder

Originally committed as revision 24299 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 432 insertions, 0 deletions

diff --git a/libavcodec/ansi.c b/libavcodec/ansi.c
new file mode 100644
index 0000000000..6fa62cc680
--- /dev/null
+++ b/libavcodec/ansi.c
@@ -0,0 +1,432 @@
+/*
+ * 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 "avcodec.h"
+#include "cga_data.h"
+#include <libavutil/lfg.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 {
+    AVFrame frame;
+    int x, y;             /** cursor position (pixels) */
+    int sx, sy;           /** saved cursor position (pixels) */
+    const uint8_t* font;  /** font */
+    int font_height;      /** font height */
+    int attributes;       /** attribute flags */
+    int fg, bg;           /** foreground and background color */
+
+    /* 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 = PIX_FMT_PAL8;
+
+    /* defaults */
+    s->font        = ff_vga16_font;
+    s->font_height = 16;
+    s->fg          = DEFAULT_FG_COLOR;
+    s->bg          = DEFAULT_BG_COLOR;
+
+    if (!avctx->width || !avctx->height)
+        avcodec_set_dimensions(avctx, 80<<3, 25<<4);
+
+    return 0;
+}
+
+static void hscroll(AVCodecContext *avctx)
+{
+    AnsiContext *s = avctx->priv_data;
+    int i;
+
+    if (s->y < avctx->height - 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) {
+        s->x = 0;
+        hscroll(avctx);
+    }
+}
+
+/**
+ * Execute ANSI escape code
+ * @param <0 error
+ */
+static int execute_code(AVCodecContext * avctx, int c)
+{
+    AnsiContext *s = avctx->priv_data;
+    int ret, i, width, 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 creen 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 = ff_cga_font;
+            s->font_height = 8;
+            width  = 40<<3;
+            height = 25<<3;
+            break;
+        case 2: case 3: //640x400 (25 rows)
+            s->font = ff_vga16_font;
+            s->font_height = 16;
+            width  = 80<<3;
+            height = 25<<4;
+            break;
+        case 6: case 14: //640x200 (25 rows)
+            s->font = ff_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 = ff_cga_font;
+            s->font_height = 8;
+            width  = 80<<3;
+            height = 43<<3;
+            break;
+        case 17: case 18: //640x480 (60 rows)
+            s->font = ff_cga_font;
+            s->font_height = 8;
+            width  = 80<<3;
+            height = 60<<4;
+            break;
+        default:
+            av_log_ask_for_sample(avctx, "unsupported screen mode\n");
+        }
+        if (width != avctx->width || height != avctx->height) {
+            if (s->frame.data[0])
+                avctx->release_buffer(avctx, &s->frame);
+            avcodec_set_dimensions(avctx, width, height);
+            ret = avctx->get_buffer(avctx, &s->frame);
+            if (ret < 0) {
+                av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+                return ret;
+            }
+            s->frame.pict_type           = FF_I_TYPE;
+            s->frame.palette_has_changed = 1;
+            memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
+            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 <= 38) {
+                s->fg = ansi_to_cga[m - 30];
+            } 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 == 49) {
+                s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
+            } else {
+                av_log_ask_for_sample(avctx, "unsupported rendition parameter\n");
+            }
+        }
+        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:
+        av_log_ask_for_sample(avctx, "unsupported escape code\n");
+        break;
+    }
+    return 0;
+}
+
+static int decode_frame(AVCodecContext *avctx,
+                            void *data, int *data_size,
+                            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;
+
+    ret = avctx->reget_buffer(avctx, &s->frame);
+    if (ret < 0){
+        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+        return ret;
+    }
+    s->frame.pict_type           = FF_I_TYPE;
+    s->frame.palette_has_changed = 1;
+    memcpy(s->frame.data[1], ff_cga_palette, 16 * 4);
+
+    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] = 0;
+            } else {
+                s->state = STATE_NORMAL;
+                draw_char(avctx, 0x1B);
+                    return -1;
+                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] = s->args[s->nb_args] * 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])
+                    s->nb_args++;
+                if (execute_code(avctx, buf[0]) < 0)
+                    return -1;
+                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++;
+    }
+
+    *data_size = sizeof(AVFrame);
+    *(AVFrame*)data = s->frame;
+    return buf_size;
+}
+
+static av_cold int decode_close(AVCodecContext *avctx)
+{
+    AnsiContext *s = avctx->priv_data;
+    if (s->frame.data[0])
+        avctx->release_buffer(avctx, &s->frame);
+    return 0;
+}
+
+AVCodec ansi_decoder = {
+    .name           = "ansi",
+    .type           = CODEC_TYPE_VIDEO,
+    .id             = CODEC_ID_ANSI,
+    .priv_data_size = sizeof(AnsiContext),
+    .init           = decode_init,
+    .close          = decode_close,
+    .decode         = decode_frame,
+    .capabilities   = CODEC_CAP_DR1,
+    .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),
+};