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b804eb4323
The helpers use local memory to compute the final hash, making AV_HASH_MAX_SIZE safe to use.
113 lines
3.5 KiB
C
113 lines
3.5 KiB
C
/*
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* Copyright (C) 2013 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
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*
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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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#ifndef AVUTIL_HASH_H
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#define AVUTIL_HASH_H
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#include <stdint.h>
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struct AVHashContext;
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/**
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* Allocate a hash context for the algorithm specified by name.
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*
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* @return >= 0 for success, a negative error code for failure
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* @note The context is not initialized, you must call av_hash_init().
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*/
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int av_hash_alloc(struct AVHashContext **ctx, const char *name);
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/**
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* Get the names of available hash algorithms.
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*
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* This function can be used to enumerate the algorithms.
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*
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* @param i index of the hash algorithm, starting from 0
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* @return a pointer to a static string or NULL if i is out of range
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*/
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const char *av_hash_names(int i);
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/**
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* Get the name of the algorithm corresponding to the given hash context.
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*/
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const char *av_hash_get_name(const struct AVHashContext *ctx);
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/**
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* Maximum value that av_hash_get_size will currently return.
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*
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* You can use this if you absolutely want or need to use static allocation
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* and are fine with not supporting hashes newly added to libavutil without
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* recompilation.
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* Note that you still need to check against av_hash_get_size, adding new hashes
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* with larger sizes will not be considered an ABI change and should not cause
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* your code to overflow a buffer.
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*/
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#define AV_HASH_MAX_SIZE 64
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/**
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* Get the size of the resulting hash value in bytes.
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*
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* The pointer passed to av_hash_final have space for at least this many bytes.
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*/
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int av_hash_get_size(const struct AVHashContext *ctx);
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/**
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* Initialize or reset a hash context.
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*/
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void av_hash_init(struct AVHashContext *ctx);
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/**
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* Update a hash context with additional data.
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*/
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void av_hash_update(struct AVHashContext *ctx, const uint8_t *src, int len);
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/**
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* Finalize a hash context and compute the actual hash value.
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*/
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void av_hash_final(struct AVHashContext *ctx, uint8_t *dst);
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/**
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* Finalize a hash context and compute the actual hash value.
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* If size is smaller than the hash size, the hash is truncated;
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* if size is larger, the buffer is padded with 0.
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*/
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void av_hash_final_bin(struct AVHashContext *ctx, uint8_t *dst, int size);
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/**
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* Finalize a hash context and compute the actual hash value as a hex string.
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* The string is always 0-terminated.
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* If size is smaller than 2 * hash_size + 1, the hex string is truncated.
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*/
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void av_hash_final_hex(struct AVHashContext *ctx, uint8_t *dst, int size);
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/**
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* Finalize a hash context and compute the actual hash value as a base64 string.
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* The string is always 0-terminated.
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* If size is smaller than AV_BASE64_SIZE(hash_size), the base64 string is
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* truncated.
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*/
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void av_hash_final_b64(struct AVHashContext *ctx, uint8_t *dst, int size);
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/**
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* Free hash context.
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*/
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void av_hash_freep(struct AVHashContext **ctx);
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#endif /* AVUTIL_HASH_H */
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