check_png.cpp File Reference

#include <stdio.h>
#include "check_png.h"

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Macros
#define	PNG_BYTES_TO_CHECK   4

Functions
bool	check_is_png (const PPath &fileName)
	Check if the given filename is a png file.

Macro Definition Documentation

PNG_BYTES_TO_CHECK

#define PNG_BYTES_TO_CHECK   4

Definition at line 10 of file check_png.cpp.

Referenced by check_is_png().

Function Documentation

check_is_png()

bool check_is_png

(

const PPath &

fileName

)

Check if the given filename is a png file.

Parameters

fileName

: name of the file to be checked

Returns

true if the given file is a png, false if not

Definition at line 16 of file check_png.cpp.

                                         {
        unsigned char buf[PNG_BYTES_TO_CHECK];
 
        FILE * fp = fopen(fileName.c_str(), "rb");
        /* Open the prospective PNG file. */
        if(fp == NULL){return false;}
 
        /* Read in some of the signature bytes. */
        if(fread(buf, 1, PNG_BYTES_TO_CHECK, fp) != PNG_BYTES_TO_CHECK){
                fclose(fp);
                return false;
        }
        /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
        * Return nonzero (true) if they match.
        */
        bool b(!png_sig_cmp(buf, 0, PNG_BYTES_TO_CHECK));
        fclose(fp);
        return b;
}

References PNG_BYTES_TO_CHECK.

Referenced by PImagePng::read().

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