Library to work with image files
image is a library (or small set of functions) to work with image files. Mostly it can read and write binary data into a file.
The library admits two types of constructors:
image(void);
image(std::string fname);The first one only creates the file. The second, also opens the file. You can check if an image is open with the method:
bool is_open(void);To open and close a file you must use the following methods:
int open(std::string fname);
int close(void);Both functions return zero on correct ending and a non-zero value on error. To perform the write or read of a file, you can use one of the following methods:
int read(char *c);
int read(char *buff, std::streamsize n);
int read(char *buff, std::streamsize n, std::streampos offset);
int write(const char *c);
int write(const char *buff, std::streamsize n);
int write(const char *buff, std::streamsize n, std::streampos offset);The first one reads/writes one character at the actual position, the second reads/writes n bytes at the actual position, and the last one, reads/writes n bytes at the offset position.
/* test-image.cpp - tests the image library
* g++ -o test-image -Iinclude -L. test-image.cpp -limage
*/
#include <iostream>
#include <cstring>
#include <image>
int
main(void) {
image img;
char dot, elf[3];
if (img.open("file.elf") != 0) {
std::cerr << "error openning file 'file.elf'" << std::endl;
return 1;
}
/* Open an ELF file */
if (img.is_open()) {
if (img.read(&dot) != 0 || dot != 0x7f) {
std::cerr << "error reading file" << std::endl;
return 2;
}
if (img.read(elf, 3, 1) != 0 || elf[0] != 0x45 || elf[1] != 0x4c ||
elf[2] != 0x46) {
std::cerr << "error reading file" << std::endl;
return 3;
}
}
/* Read ELF header */
/* img.close();
Closing the file isn't necessary, the destructor will do it for us */
return 0;
}