/*
* FileAndMemoryReader - a tiny helper to utify file reading from a disk and memory block
*
* Copyright (c) 2015-2018 Vitaly Novichkov <admin@wohlnet.ru>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#pragma once
#ifndef FILE_AND_MEM_READER_HHHH
#define FILE_AND_MEM_READER_HHHH
#include <string> // std::string
#include <cstdio> // std::fopen, std::fread, std::fseek, std::ftell, std::fclose, std::feof
#include <stdint.h> // uint*_t
#include <stddef.h> // size_t and friends
#ifdef _WIN32
#define NOMINMAX 1
#include <cstring> // std::strlen
#include <windows.h> // MultiByteToWideChar
#endif
/**
* @brief A little class gives able to read filedata from disk and also from a memory segment
*/
class FileAndMemReader
{
//! Currently loaded filename (empty for a memory blocks)
std::string m_file_name;
//! File reader descriptor
std::FILE *m_fp;
//! Memory pointer descriptor
const void *m_mp;
//! Size of memory block
size_t m_mp_size;
//! Cursor position in the memory block
size_t m_mp_tell;
public:
/**
* @brief Relation direction
*/
enum relTo
{
//! At begin position
SET = SEEK_SET,
//! At current position
CUR = SEEK_CUR,
//! At end position
END = SEEK_END
};
/**
* @brief C.O.: It's a constructor!
*/
FileAndMemReader() :
m_fp(NULL),
m_mp(NULL),
m_mp_size(0),
m_mp_tell(0)
{}
/**
* @brief C.O.: It's a destructor!
*/
~FileAndMemReader()
{
close();
}
/**
* @brief Open file from a disk
* @param path Path to the file in UTF-8 (even on Windows!)
*/
void openFile(const char *path)
{
if(m_fp)
this->close();//Close previously opened file first!
#if !defined(_WIN32) || defined(__WATCOMC__)
m_fp = std::fopen(path, "rb");
#else
wchar_t widePath[MAX_PATH];
int size = MultiByteToWideChar(CP_UTF8, 0, path, static_cast<int>(std::strlen(path)), widePath, MAX_PATH);
widePath[size] = '\0';
m_fp = _wfopen(widePath, L"rb");
#endif
m_file_name = path;
m_mp = NULL;
m_mp_size = 0;
m_mp_tell = 0;
}
/**
* @brief Open file from memory block
* @param mem Pointer to the memory block
* @param lenght Size of given block
*/
void openData(const void *mem, size_t lenght)
{
if(m_fp)
this->close();//Close previously opened file first!
m_fp = NULL;
m_mp = mem;
m_mp_size = lenght;
m_mp_tell = 0;
}
/**
* @brief Seek to given position
* @param pos Offset or position
* @param rel_to Relation (at begin, at current, or at end)
*/
void seek(long pos, int rel_to)
{
if(!this->isValid())
return;
if(m_fp)//If a file
{
std::fseek(m_fp, pos, rel_to);
}
else//If a memory block
{
switch(rel_to)
{
case SET:
m_mp_tell = static_cast<size_t>(pos);
break;
case END:
m_mp_tell = m_mp_size - static_cast<size_t>(pos);
break;
case CUR:
m_mp_tell = m_mp_tell + static_cast<size_t>(pos);
break;
}
if(m_mp_tell > m_mp_size)
m_mp_tell = m_mp_size;
}
}
/**
* @brief Seek to given position (unsigned integer 64 as relation. Negative values not supported)
* @param pos Offset or position
* @param rel_to Relation (at begin, at current, or at end)
*/
inline void seeku(uint64_t pos, int rel_to)
{
this->seek(static_cast<long>(pos), rel_to);
}
/**
* @brief Read the buffer from a file
* @param buf Pointer to the destination memory block
* @param num Number of elements
* @param size Size of one element
* @return Size
*/
size_t read(void *buf, size_t num, size_t size)
{
if(!this->isValid())
return 0;
if(m_fp)
return std::fread(buf, num, size, m_fp);
else
{
size_t pos = 0;
size_t maxSize = static_cast<size_t>(size * num);
while((pos < maxSize) && (m_mp_tell < m_mp_size))
{
reinterpret_cast<uint8_t *>(buf)[pos] = reinterpret_cast<const uint8_t *>(m_mp)[m_mp_tell];
m_mp_tell++;
pos++;
}
return pos / num;
}
}
/**
* @brief Get one byte and seek forward
* @return Readed byte or EOF (a.k.a. -1)
*/
int getc()
{
if(!this->isValid())
return -1;
if(m_fp)//If a file
{
return std::getc(m_fp);
}
else //If a memory block
{
if(m_mp_tell >= m_mp_size)
return -1;
int x = reinterpret_cast<const uint8_t *>(m_mp)[m_mp_tell];
m_mp_tell++;
return x;
}
}
/**
* @brief Returns current offset of cursor in a file
* @return Offset position
*/
size_t tell()
{
if(!this->isValid())
return 0;
if(m_fp)//If a file
return static_cast<size_t>(std::ftell(m_fp));
else//If a memory block
return m_mp_tell;
}
/**
* @brief Close the file
*/
void close()
{
if(m_fp)
std::fclose(m_fp);
m_fp = NULL;
m_mp = NULL;
m_mp_size = 0;
m_mp_tell = 0;
}
/**
* @brief Is file instance valid
* @return true if vaild
*/
bool isValid()
{
return (m_fp) || (m_mp);
}
/**
* @brief Is End Of File?
* @return true if end of file was reached
*/
bool eof()
{
if(!this->isValid())
return true;
if(m_fp)
return (std::feof(m_fp) != 0);
else
return m_mp_tell >= m_mp_size;
}
/**
* @brief Get a current file name
* @return File name of currently loaded file
*/
const std::string &fileName()
{
return m_file_name;
}
/**
* @brief Retrieve file size
* @return Size of file in bytes
*/
size_t fileSize()
{
if(!this->isValid())
return 0;
if(!m_fp)
return m_mp_size; //Size of memory block is well known
size_t old_pos = this->tell();
seek(0l, FileAndMemReader::END);
size_t file_size = this->tell();
seek(static_cast<long>(old_pos), FileAndMemReader::SET);
return file_size;
}
};
#endif /* FILE_AND_MEM_READER_HHHH */