PngDef.hpp

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#ifndef PNGDEF_HPP_
#define PNGDEF_HPP_

extern "C"{
#include <png.h>
#include <stdio.h>
}

#define PNG_BYTES_TO_CHECK 4
/*
 * \brief check if the file
 */
int check_if_png(char *file_name, FILE **fp)
{
                unsigned char buf[PNG_BYTES_TO_CHECK];

                /* Open the prospective PNG file. */
                if ((*fp = fopen(file_name, "rb")) == NULL)
                                return 0;

                /* Read in some of the signature bytes */
                if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
                                return 0;

                /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
      Return nonzero (true) if they match */

                return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
}

#endif /* PNGDEF_HPP_ */