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hello, i am attemping to write a basic swf header reader using the format specification from : http://www.the-labs.com/MacromediaFlash/SWF-Spec/SWFfileformat.html

So far i am able to read the first 3 bytes : FWS, no problem
The problem i am having is reading the version number after, it is displayed as a question mark in the command prompt.
I have tried casting the version number to an unsigned int from char but it still does not display correctly, it becomes avery large number:
FWS?
Converted ? is : 429467177, and 137 as a signed char.

#include <iostream>
#include <fstream>
#include <string.h>
using namespace std;
typedef unsigned char byte;


int main () {

  int length;
  char * buffer;

  ifstream is;
  is.open ("test.swf", ios::binary );

  // get length of file:
  is.seekg (0, ios::end);
  //is.tellg() length = istellg() for whole file
  length = 8; //one for single bit
  is.seekg (0, ios::beg);

  // allocate memory:
  buffer = new char [length];



  // read data as a block and assig it to buffer:
  is.read (buffer,length);
  char newchar = buffer[4]+buffer[5]+buffer[6]+buffer[7];
  unsigned int Int32 = (char)newchar; //casting to integer
  //version = buffer.copy(version,1,2);


  is.close();

  cout.write (buffer,length); //full byte read in
  cout << "\n"<<Int32; //the type cast part

  delete[] buffer;
  return 0;

}

Im sure this is a casting problem, as it it stored according to the specification as an unsigned 8 bit integer. (Version UI8 Single byte file version) but i am unsure about how to cast it to its real value. Any help would be ace :)

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Last Post by WaltP
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I should ellaborate on the file im opening,
The swf file contains the following byte i am trying to read in, in the code above :

FWS||‚ p 4 ƒ@ ^CÂrfxC (^ ÿØÿÛ C

The first part are able to be read directly, as FWS.
The second part is meant to be an unsigned 8 bit integer, however when read from file only display a ? mark or an incorrectly typecasted integer as stated above.

1

Try printing it out as hex first:

for (int i = 0; i < length; i++)
{
    if (i > 0) cout << " ";
    cout << hex << (int)buffer[i];
}
1

Why do people always need to seek to get the length of a file? In this case, you want to read the header, right? How big is the header? Just create an unsigned char or byte array to read in a chunk of the file -- 512, 1024, 2048 bytes...

The line char newchar = buffer[4]+buffer[5]+buffer[6]+buffer[7]; simply adds the bytes together. What are you trying to do here?

it is displayed as a question mark in the command prompt.

Of what use is displaying a binary file at the command prompt. As rubberman suggests start by displaying the data as a series of HEX bytes. But use be sure to use them as unsigned values because bytes are neither positive nor negative.

Votes + Comments
your suggestion is helpful, and the adding the bits together was to try and collect only the bits after FWS, as that already worked i only wanted the version number located from bit 4-8 to be converted to unsigned int, but im still a rookie at following t
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