Express bitfields more simply. Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
		
			
				
	
	
		
			123 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			123 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * XBM image format
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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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#include "libavutil/avstring.h"
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#include "avcodec.h"
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#include "internal.h"
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#include "mathops.h"
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static int xbm_decode_frame(AVCodecContext *avctx, void *data,
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                            int *got_frame, AVPacket *avpkt)
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{
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    AVFrame *p = data;
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    int ret, linesize, i;
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    int width  = 0;
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    int height = 0;
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    const uint8_t *ptr = avpkt->data;
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    uint8_t *dst;
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    avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
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    while (!width || !height) {
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        ptr += strcspn(ptr, "#");
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        if (ptr >= avpkt->data + avpkt->size) {
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            av_log(avctx, AV_LOG_ERROR, "End of file reached.\n");
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            return AVERROR_INVALIDDATA;
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        }
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        if (strncmp(ptr, "#define", 7) != 0) {
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            av_log(avctx, AV_LOG_ERROR,
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                   "Unexpected preprocessor directive.\n");
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            return AVERROR_INVALIDDATA;
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        }
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        // skip the name
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        ptr += strcspn(ptr, "_") + 1;
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        // get width or height
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        if (strncmp(ptr, "width", 5) == 0) {
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            ptr += strcspn(ptr, " ");
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            width = strtol(ptr, NULL, 10);
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        } else if (strncmp(ptr, "height", 6) == 0) {
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            ptr += strcspn(ptr, " ");
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            height = strtol(ptr, NULL, 10);
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        } else {
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            // skip offset and unknown variables
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            av_log(avctx, AV_LOG_VERBOSE,
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                   "Ignoring preprocessor directive.\n");
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        }
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    }
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    if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
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        return ret;
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    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
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        return ret;
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    // go to start of image data
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    ptr += strcspn(ptr, "{");
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    linesize = (avctx->width + 7) / 8;
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    for (i = 0; i < avctx->height; i++) {
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        int eol = 0, e = 0;
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        dst = p->data[0] + i * p->linesize[0];
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        if (ptr >= avpkt->data + avpkt->size) {
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            av_log(avctx, AV_LOG_ERROR, "End of file reached.\n");
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            return AVERROR_INVALIDDATA;
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        }
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        do {
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            int val;
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            uint8_t *endptr;
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            ptr += strcspn(ptr, "x") - 1; // -1 to get 0x
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            val = strtol(ptr, (char **)&endptr, 16);
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            if (endptr - ptr == 4) {
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                // XBM X11 format
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                *dst++ = ff_reverse[val];
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                eol = linesize;
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            } else if (endptr - ptr == 6) {
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                // XBM X10 format
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                *dst++ = ff_reverse[val >> 8];
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                *dst++ = ff_reverse[val & 0xFF];
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                eol = linesize / 2; // 2 bytes read
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            } else {
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                av_log(avctx, AV_LOG_ERROR,
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                       "Unexpected data at %.8s.\n", ptr);
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                return AVERROR_INVALIDDATA;
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            }
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            ptr = endptr;
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        } while (++e < eol);
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    }
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    p->key_frame = 1;
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    p->pict_type = AV_PICTURE_TYPE_I;
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    *got_frame = 1;
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    return avpkt->size;
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}
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AVCodec ff_xbm_decoder = {
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    .name         = "xbm",
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    .long_name    = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
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    .type         = AVMEDIA_TYPE_VIDEO,
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    .id           = AV_CODEC_ID_XBM,
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    .decode       = xbm_decode_frame,
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    .capabilities = AV_CODEC_CAP_DR1,
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};
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