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#define BUFFER_SIZE (1024 * 1024 / 2)
#include <fstream>
#include <iostream>
#include <string>
namespace pgnp {
using namespace std;
class LargeFileStream {
/// @brief File to load
ifstream file;
/// @brief In memory buffer
char buffer[BUFFER_SIZE];
/// @brief Number of chuck read minus 1
long chuck_count;
/// @brief Number of byte read during the last file access
long last_read_size;
/// @brief Keep track of the file offset (to prevent backward read)
long last_loc;
/// @brief Use a string as file content
std::string content;
/// @brief Use to shortcut some methods
bool use_string;
/// @brief End Of File ?
bool eof;
/// @brief Load the next chuck of data from disk to memory
void ReadNextChunk();
public:
LargeFileStream();
void FromFile(std::string filepath);
/// @brief Emulate file access with a string
void FromString(std::string content);
/// @brief Allow array like access to the file
char operator[](long loc);
/// @brief Check if we reach the EOF
bool IsEOF(long loc);
// Various Exceptions
struct BackwardRead : public std::exception {
const char *what() const throw() {
return "LargeFileStream cannot read backward";
}
};
struct ReadToFar : public std::exception {
const char *what() const throw() { return "You reach the end of the file"; }
};
};
} // namespace pgnp
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