The construct of using offsetof on a (potentially anonymous) struct defined within the offsetof expression, while supported by all current compilers, has been declared explicitly undefined by the C standards committee [1]. Clang recently got a change to identify this as an issue [2]; initially it was treated as a hard error, but it was soon after softened into a warning under the -Wgnu-offsetof-extensions option (not enabled automatically as part of -Wall though). Nevertheless - in this particular case, it's trivial to fix the code not to rely on the construct that the standards committee has explicitly called out as undefined. [1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm [2] https://reviews.llvm.org/D133574 Signed-off-by: Martin Storsjö <martin@martin.st>
		
			
				
	
	
		
			81 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			81 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * This file is part of FFmpeg.
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|  *
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|  * FFmpeg 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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|  * FFmpeg 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 FFmpeg; 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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| #include <stddef.h>
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| #include <stdint.h>
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| 
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| #include "buffer.h"
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| #include "frame.h"
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| #include "mem.h"
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| #include "video_enc_params.h"
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| 
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| AVVideoEncParams *av_video_enc_params_alloc(enum AVVideoEncParamsType type,
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|                                             unsigned int nb_blocks, size_t *out_size)
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| {
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|     struct TestStruct {
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|         AVVideoEncParams   p;
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|         AVVideoBlockParams b;
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|     };
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|     const size_t blocks_offset = offsetof(struct TestStruct, b);
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|     size_t size = blocks_offset;
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|     AVVideoEncParams *par;
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| 
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|     if (nb_blocks > (SIZE_MAX - size) / sizeof(AVVideoBlockParams))
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|         return NULL;
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|     size += sizeof(AVVideoBlockParams) * nb_blocks;
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| 
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|     par = av_mallocz(size);
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|     if (!par)
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|         return NULL;
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| 
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|     par->type          = type;
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|     par->nb_blocks     = nb_blocks;
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|     par->block_size    = sizeof(AVVideoBlockParams);
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|     par->blocks_offset = blocks_offset;
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| 
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|     if (out_size)
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|         *out_size = size;
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| 
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|     return par;
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| }
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| 
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| AVVideoEncParams*
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| av_video_enc_params_create_side_data(AVFrame *frame, enum AVVideoEncParamsType type,
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|                                      unsigned int nb_blocks)
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| {
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|     AVBufferRef      *buf;
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|     AVVideoEncParams *par;
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|     size_t size;
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| 
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|     par = av_video_enc_params_alloc(type, nb_blocks, &size);
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|     if (!par)
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|         return NULL;
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|     buf = av_buffer_create((uint8_t *)par, size, NULL, NULL, 0);
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|     if (!buf) {
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|         av_freep(&par);
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|         return NULL;
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|     }
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| 
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|     if (!av_frame_new_side_data_from_buf(frame, AV_FRAME_DATA_VIDEO_ENC_PARAMS, buf)) {
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|         av_buffer_unref(&buf);
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|         return NULL;
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|     }
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| 
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|     return par;
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| }
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