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ffmpeg/libavcodec/ansi.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs 
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

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/*
* 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_ITALICS 0x04 /**< Italics (mode 3) */
#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;
/* 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);
}
s->frame = av_frame_alloc();
if (!s->frame)
return AVERROR(ENOMEM);
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 == 3 || 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)) < 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 ';':
if (s->nb_args < MAX_NB_ARGS)
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;
}
static const AVCodecDefault ansi_defaults[] = {
{ "max_pixels", "640*480" },
{ NULL },
};
const 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,
.defaults = ansi_defaults,
};
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