| /* |
| * Copyright (c) 2020, Alliance for Open Media. All rights reserved |
| * |
| * This source code is subject to the terms of the BSD 2 Clause License and |
| * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License |
| * was not distributed with this source code in the LICENSE file, you can |
| * obtain it at www.aomedia.org/license/software. If the Alliance for Open |
| * Media Patent License 1.0 was not distributed with this source code in the |
| * PATENTS file, you can obtain it at www.aomedia.org/license/patent. |
| */ |
| #ifndef AOM_COMMON_STREAM_ITER_H_ |
| #define AOM_COMMON_STREAM_ITER_H_ |
| |
| #include "aom/aom_image.h" |
| #include "common/tools_common.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| struct StreamIter; |
| |
| // The input to each stream iterator can either be an AvxInputContext (when |
| // reading from a file or a pipe like STDIN) or another stream iterator. |
| union StreamInput { |
| struct AvxInputContext *avx; |
| struct StreamIter *stream; |
| }; |
| |
| typedef struct StreamIter { |
| union StreamInput input; |
| // For simplicity, all streams have two additional numbers associated |
| // with them, e.g., for counting the number of frames returned and the |
| // number of frames that should be skipped. Some iterators, like the copy |
| // iterator, do not use either field. |
| int current; |
| int n; |
| // Pointer to the function that performs the read. Returns whether a frame |
| // is available. If a frame is returned, it is written into *raw. |
| int (*reader)(struct StreamIter *iter, aom_image_t *raw); |
| } StreamIter; |
| |
| // Iterator that simply copies the data from the AvxInputContext. |
| void copy_stream_iter_init(StreamIter *iter, struct AvxInputContext *input); |
| |
| // Iterator that skips the first N frames. Takes another stream as input. |
| void skip_stream_iter_init(StreamIter *iter, StreamIter *input, int num_skip); |
| |
| // Iterator that only returns every N-th frame. Takes another stream as input. |
| void step_stream_iter_init(StreamIter *iter, StreamIter *input, int step_size); |
| |
| // Iterator that stops returning frames after the N-th. Takes another stream |
| // as input. |
| void limit_stream_iter_init(StreamIter *iter, StreamIter *input, int limit); |
| |
| // Invokes the iterator's specialized read function to read data from the |
| // stream. Returns if a frame was read. If so, writes the data into *raw. |
| int read_stream_iter(StreamIter *iter, aom_image_t *raw); |
| |
| #ifdef __cplusplus |
| } // extern "C" |
| #endif |
| |
| #endif // AOM_COMMON_STREAM_ITER_H_ |