Add ffmpeg externals

Externals/ffmpeg/include/libavutil/aes_ctr.h

@@ -0,0 +1,83 @@
+/*
+ * AES-CTR cipher
+ * Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com>
+ *
+ * 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
+ */
+
+#ifndef AVUTIL_AES_CTR_H
+#define AVUTIL_AES_CTR_H
+
+#include <stdint.h>
+
+#include "attributes.h"
+#include "version.h"
+
+#define AES_CTR_KEY_SIZE (16)
+#define AES_CTR_IV_SIZE (8)
+
+struct AVAESCTR;
+
+/**
+ * Allocate an AVAESCTR context.
+ */
+struct AVAESCTR *av_aes_ctr_alloc(void);
+
+/**
+ * Initialize an AVAESCTR context.
+ * @param key encryption key, must have a length of AES_CTR_KEY_SIZE
+ */
+int av_aes_ctr_init(struct AVAESCTR *a, const uint8_t *key);
+
+/**
+ * Release an AVAESCTR context.
+ */
+void av_aes_ctr_free(struct AVAESCTR *a);
+
+/**
+ * Process a buffer using a previously initialized context.
+ * @param dst destination array, can be equal to src
+ * @param src source array, can be equal to dst
+ * @param size the size of src and dst
+ */
+void av_aes_ctr_crypt(struct AVAESCTR *a, uint8_t *dst, const uint8_t *src, int size);
+
+/**
+ * Get the current iv
+ */
+const uint8_t* av_aes_ctr_get_iv(struct AVAESCTR *a);
+
+/**
+ * Generate a random iv
+ */
+void av_aes_ctr_set_random_iv(struct AVAESCTR *a);
+
+/**
+ * Forcefully change the iv
+ */
+void av_aes_ctr_set_iv(struct AVAESCTR *a, const uint8_t* iv);
+
+/**
+ * Increment the top 64 bit of the iv (performed after each frame)
+ */
+void av_aes_ctr_increment_iv(struct AVAESCTR *a);
+
+/**
+ * @}
+ */
+
+#endif /* AVUTIL_AES_CTR_H */