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/*
This file is part of ethash.
ethash is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
ethash 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with ethash. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file io.h
* @author Lefteris Karapetsas <lefteris@ethdev.com>
* @date 2015
*/
#pragma once
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include "ethash.h"
#ifdef __cplusplus
extern "C" {
#endif
typedef struct ethash_blockhash { uint8_t b[32]; } ethash_blockhash_t;
static const char DAG_FILE_NAME[] = "full";
static const char DAG_MEMO_NAME[] = "full.info";
// MSVC thinks that "static const unsigned int" is not a compile time variable. Sorry for the #define :(
#define DAG_MEMO_BYTESIZE 36
/// Possible return values of @see ethash_io_prepare
enum ethash_io_rc {
ETHASH_IO_FAIL = 0, ///< There has been an IO failure
ETHASH_IO_MEMO_MISMATCH, ///< Memo file either did not exist or there was content mismatch
ETHASH_IO_MEMO_MATCH, ///< Memo file existed and contents matched. No need to do anything
};
/**
* Prepares io for ethash
*
* Create the DAG directory if it does not exist, and check if the memo file matches.
* If it does not match then it's deleted to pave the way for @ref ethash_io_write()
*
* @param dirname A null terminated c-string of the path of the ethash
* data directory. If it does not exist it's created.
* @param seedhash The seedhash of the current block number
* @return For possible return values @see enum ethash_io_rc
*/
enum ethash_io_rc ethash_io_prepare(char const *dirname, ethash_blockhash_t seedhash);
/**
* Fully computes data and writes it to the file on disk.
*
* This function should be called after @see ethash_io_prepare() and only if
* its return value is @c ETHASH_IO_MEMO_MISMATCH. Will write both the full data
* and the memo file.
*
* @param[in] dirname A null terminated c-string of the path of the ethash
* data directory. Has to exist.
* @param[in] params An ethash_params object containing the full size
* and the cache size
* @param[in] seedhash The seedhash of the current block number
* @param[in] cache The cache data. Would have usually been calulated by
* @see ethash_prep_light().
* @param[out] data Pass a pointer to uint8_t by reference here. If the
* function is succesfull then this point to the allocated
* data calculated by @see ethash_prep_full(). Memory
* ownership is transfered to the callee. Remember that
* you eventually need to free this with a call to free().
* @param[out] data_size Pass a size_t by value. If the function is succesfull
* then this will contain the number of bytes allocated
* for @a data.
* @return True for success and false in case of failure.
*/
bool ethash_io_write(char const *dirname,
ethash_params const* params,
ethash_blockhash_t seedhash,
void const* cache,
uint8_t **data,
size_t *data_size);
static inline void ethash_io_serialize_info(uint32_t revision,
ethash_blockhash_t seed_hash,
char *output)
{
// if .info is only consumed locally we don't really care about endianess
memcpy(output, &revision, 4);
memcpy(output + 4, &seed_hash, 32);
}
static inline char *ethash_io_create_filename(char const *dirname,
char const* filename,
size_t filename_length)
{
// in C the cast is not needed, but a C++ compiler will complain for invalid conversion
char *name = (char*)malloc(strlen(dirname) + filename_length);
if (!name) {
return NULL;
}
name[0] = '\0';
strcat(name, dirname);
strcat(name, filename);
return name;
}
#ifdef __cplusplus
}
#endif