[FIXED] How do you determine the size of a file in C?

Issue

How can I figure out the size of a file, in bytes?

#include <stdio.h>

unsigned int fsize(char* file){
  //what goes here?
}

Solution

On Unix-like systems, you can use POSIX system calls: stat on a path, or fstat on an already-open file descriptor (POSIX man page, Linux man page).
(Get a file descriptor from open(2), or fileno(FILE*) on a stdio stream).

Based on NilObject's code:

#include <sys/stat.h>
#include <sys/types.h>

off_t fsize(const char *filename) {
    struct stat st; 

    if (stat(filename, &st) == 0)
        return st.st_size;

    return -1; 
}

Changes:

• Made the filename argument a const char.
• Corrected the struct stat definition, which was missing the variable name.
• Returns -1 on error instead of 0, which would be ambiguous for an empty file. off_t is a signed type so this is possible.

If you want fsize() to print a message on error, you can use this:

#include <sys/stat.h>
#include <sys/types.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>

off_t fsize(const char *filename) {
    struct stat st;

    if (stat(filename, &st) == 0)
        return st.st_size;

    fprintf(stderr, "Cannot determine size of %s: %s\n",
            filename, strerror(errno));

    return -1;
}

On 32-bit systems you should compile this with the option -D_FILE_OFFSET_BITS=64, otherwise off_t will only hold values up to 2 GB. See the "Using LFS" section of Large File Support in Linux for details.

Answered By - T Percival

Answer Checked By - Terry (PHPFixing Volunteer)

Read More

[FIXED] How to display the image file size taken from Flutter image_picker plugin?

Issue

I am creating a Flutter app and I want to show the image file size (in kb/mb) when the user gets an image from either the gallery or camera.

1

Right now, when the user gets an image, it displays a thumbnail and text "Image Selected" on the screen, as shown in the picture. I want it to also display the image file size under "Image Selected".

File _image;
final picker = ImagePicker();

Future getImageFromCamera() async {
  final pickedImage = await picker.getImage(source: ImageSource.camera);

  setState(() {
    if (pickedImage != null) {
      _image = File(pickedImage.path);
    } else {
      print('No image selected.');
    }
  });
}

Future getImageFromGallery() async {
  final pickedImage = await picker.getImage(source: ImageSource.gallery);

  setState(() {
    if (pickedImage != null) {
      _image = File(pickedImage.path);
    } else {
      print('No image selected.');
    }
  });
}

Solution

Here is a solution using a function that will provide you with the file size as a neat formatted string.

Imports:

import 'dart:io';
import 'dart:math';

Output:

//if(await _image.exists())
print(getFilesizeString(bytes: _image.lengthSync()));
// Output Example: 17 Bytes, 30MB, 7GB

Function:

// Format File Size
static String getFileSizeString({@required int bytes, int decimals = 0}) {
  if (bytes <= 0) return "0 Bytes";
  const suffixes = [" Bytes", "KB", "MB", "GB", "TB"];
  var i = (log(bytes) / log(1024)).floor();
  return ((bytes / pow(1024, i)).toStringAsFixed(decimals)) + suffixes[i];
}

Answered By - Webkraft Studios

Answer Checked By - Clifford M. (PHPFixing Volunteer)

Read More