io.h

Go to the documentation of this file.

/*
  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/>.
*/
#pragma once
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#ifdef __cplusplus
#define __STDC_FORMAT_MACROS 1
#endif
#include <inttypes.h>
#include "endian.h"
#include "ethash.h"

#ifdef __cplusplus
extern "C" {
#endif
// Maximum size for mutable part of DAG file name
// 6 is for "full-R", the suffix of the filename
// 10 is for maximum number of digits of a uint32_t (for REVISION)
// 1 is for - and 16 is for the first 16 hex digits for first 8 bytes of
// the seedhash and last 1 is for the null terminating character
// Reference: https://github.com/ethereum/wiki/wiki/Ethash-DAG
#define DAG_MUTABLE_NAME_MAX_SIZE (6 + 10 + 1 + 16 + 1)
enum ethash_io_rc {
        ETHASH_IO_FAIL = 0,           
        ETHASH_IO_MEMO_SIZE_MISMATCH, 
        ETHASH_IO_MEMO_MISMATCH,      
        ETHASH_IO_MEMO_MATCH,         
};

// small hack for windows. I don't feel I should use va_args and forward just
// to have this one function properly cross-platform abstracted
#if defined(_WIN32) && !defined(__GNUC__)
#define snprintf(...) sprintf_s(__VA_ARGS__)
#endif

#ifdef ETHASH_PRINT_CRITICAL_OUTPUT
#define ETHASH_CRITICAL(...)                                                    \
        do                                                                                                      \
        {                                                                                                       \
                printf("ETHASH CRITICAL ERROR: "__VA_ARGS__);   \
                printf("\n");                                                                   \
                fflush(stdout);                                                                 \
        } while (0)
#else
#define ETHASH_CRITICAL(...)          
#endif

enum ethash_io_rc ethash_io_prepare(
        char const* dirname,
        ethash_h256_t const seedhash,
        FILE** output_file,
        uint64_t file_size,
        bool force_create
);

FILE* ethash_fopen(char const* file_name, char const* mode);

char* ethash_strncat(char* dest, size_t dest_size, char const* src, size_t count);

bool ethash_mkdir(char const* dirname);

bool ethash_file_size(FILE* f, size_t* ret_size);

int ethash_fileno(FILE* f);

char* ethash_io_create_filename(
        char const* dirname,
        char const* filename,
        size_t filename_length
);

bool ethash_get_default_dirname(char* strbuf, size_t buffsize);

static inline bool ethash_io_mutable_name(
        uint32_t revision,
        ethash_h256_t const* seed_hash,
        char* output
)
{
    uint64_t hash = *((uint64_t*)seed_hash);
#if LITTLE_ENDIAN == BYTE_ORDER
    hash = ethash_swap_u64(hash);
#endif
    return snprintf(output, DAG_MUTABLE_NAME_MAX_SIZE, "full-R%u-%016" PRIx64, revision, hash) >= 0;
}

#ifdef __cplusplus
}
#endif