mirror of https://code.videolan.org/videolan/vlc
150 lines
4.5 KiB
C
150 lines
4.5 KiB
C
/*****************************************************************************
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* vlc_hash.h: Hash functions
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*****************************************************************************
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* Copyright © 2004-2020 VLC authors and VideoLAN
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*
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* Authors: Rémi Denis-Courmont
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* Rafaël Carré
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* Marvin Scholz
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU 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 License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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#ifndef VLC_HASH_H
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# define VLC_HASH_H
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/**
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* \defgroup vlc_hash Hash functions
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* APIs for simple and frequently used hash algorithms in VLC
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*
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* Each hash algorithm has a context object which stores all data needed for the
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* hash calculation, this context is not supposed to be modified directly by the
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* called but only with the functions listed here.
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*
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* Supported hash algorithms:
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* - \ref vlc_hash_md5 "MD5"
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*
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* @{
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*/
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/**
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* \defgroup vlc_hash_utils Helper functions
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* Functions commonly used together with hashing functions
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* @{
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*/
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/**
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* Finish hash computation and return hex representation
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*
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* Finishes the hash computation and provides the hash for the
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* concatenation of all provided data in hex encoded format.
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* The result is written to the buffer pointed to by output, which
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* must be larger than twice the size of the hash output.
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*
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* \param[in,out] ctx Hash context to finish
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* \param[out] output Output buffer to write the string to
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*/
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#ifndef __cplusplus
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#define vlc_hash_FinishHex(ctx, output) \
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do { \
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char out_tmp[_Generic((ctx), \
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vlc_hash_md5_t *: VLC_HASH_MD5_DIGEST_SIZE)]; \
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_Generic((ctx), \
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vlc_hash_md5_t *: vlc_hash_md5_Finish) \
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(ctx, out_tmp, sizeof(out_tmp)); \
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vlc_hex_encode_binary(out_tmp, sizeof(out_tmp), output); \
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} while (0)
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#endif
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/**
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* @}
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*/
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/**
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* \defgroup vlc_hash_md5 MD5 hashing
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* APIs to hash data using the Message-Digest Algorithm 5 (MD5)
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* @{
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*/
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/**
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* MD5 hash context
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*/
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typedef struct vlc_hash_md5_ctx
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{
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struct md5_s {
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uint32_t A, B, C, D; /* chaining variables */
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uint32_t nblocks;
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uint8_t buf[64];
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int count;
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} priv; /**< \internal Private */
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} vlc_hash_md5_t;
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/**
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* MD5 digest output size
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*/
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#define VLC_HASH_MD5_DIGEST_SIZE 16
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/**
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* MD5 digest hex representation size
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*/
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#define VLC_HASH_MD5_DIGEST_HEX_SIZE 33 // 2 chars per byte + null
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/**
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* Initialize MD5 context
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*
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* Initializes the given MD5 hash function context, if the context is
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* already initialized, it is reset.
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*
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* \param[out] ctx MD5 hash context to init
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*/
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VLC_API void vlc_hash_md5_Init(vlc_hash_md5_t *ctx);
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/**
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* Update MD5 hash computation with new data
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*
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* Updates the context with provided data which is used for the hash
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* calculation. Can be called repeatedly with new data. The final
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* hash represents the hash for the concatenation of all data.
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*
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* \param[in,out] ctx MD5 hash context to update
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* \param data Data to add
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* \param size Size of the data to add
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*/
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VLC_API void vlc_hash_md5_Update(vlc_hash_md5_t *ctx, const void *data, size_t size);
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/**
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* Finish MD5 hash computation
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*
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* Finishes the MD5 hash computation and provides the hash for the
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* concatenation of all provided data by previous calls to \ref vlc_hash_md5_Update.
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* The result is written to the buffer pointed to by output, which must be at
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* least \ref VLC_HASH_MD5_DIGEST_SIZE big.
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*
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* \param[in,out] ctx MD5 hash context to finish
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* \param[out] output Output buffer to write to
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* \param size Output buffer size
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*/
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VLC_API void vlc_hash_md5_Finish(vlc_hash_md5_t *ctx, void *output, size_t size);
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/**
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* @}
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*/
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/**
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* @}
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*/
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#endif
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