Why am I reading end of file in this code? - c++

Question

I'm trying to implement some simple function wrappers around OpenAL.
When trying to load a file piece by piece to stream it through several buffers, I'm somehow reading the eof.
#include <iostream>
#include <type_traits>
#include <cstring>
#include <fstream>
int32_t convert_to_int(char* buffer, std::size_t len, const std::endian endianess)
{
int32_t a = 0;
if(endianess == std::endian::little)
std::memcpy(&a, buffer, len);
else
for(std::size_t i = 0; i < len; ++i)
reinterpret_cast<char*>(&a)[3 - i] = buffer[i];
return a;
}
bool load_wav_file_header(std::ifstream& file, uint8_t& channels, int32_t& sampleRate, uint8_t& bitsPerSample, int32_t& size)
{
char buffer[4];
if(!file.is_open())
return false;
// the RIFF
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read RIFF" << std::endl;
return false;
}
if(std::strncmp(buffer, "RIFF", 4) != 0)
{
std::cerr << "ERROR: file is not a valid WAVE file (header doesn't begin with RIFF)" << std::endl;
return false;
}
// the size of the file
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read size of file" << std::endl;
return false;
}
// the WAVE
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read WAVE" << std::endl;
return false;
}
if(std::strncmp(buffer, "WAVE", 4) != 0)
{
std::cerr << "ERROR: file is not a valid WAVE file (header doesn't contain WAVE)" << std::endl;
return false;
}
// "fmt/0"
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read fmt/0" << std::endl;
return false;
}
// this is always 16, the size of the fmt data chunk
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read the 16" << std::endl;
return false;
}
// PCM should be 1?
if(!file.read(buffer, 2))
{
std::cerr << "ERROR: could not read PCM" << std::endl;
return false;
}
// the number of channels
if(!file.read(buffer, 2))
{
std::cerr << "ERROR: could not read number of channels" << std::endl;
return false;
}
channels = convert_to_int(buffer, 2, std::endian::little);
// sample rate
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read sample rate" << std::endl;
return false;
}
sampleRate = convert_to_int(buffer, 4, std::endian::little);
// (sampleRate * bitsPerSample * channels) / 8
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read (sampleRate * bitsPerSample * channels) / 8" << std::endl;
return false;
}
// ?? dafaq
if(!file.read(buffer, 2))
{
std::cerr << "ERROR: could not read dafaq" << std::endl;
return false;
}
// bitsPerSample
if(!file.read(buffer, 2))
{
std::cerr << "ERROR: could not read bits per sample" << std::endl;
return false;
}
bitsPerSample = convert_to_int(buffer, 2, std::endian::little);
// data chunk header "data"
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read data chunk header" << std::endl;
return false;
}
if(std::strncmp(buffer, "data", 4) != 0)
{
std::cerr << "ERROR: file is not a valid WAVE file (doesn't have 'data' tag)" << std::endl;
return false;
}
// size of data
if(!file.read(buffer, 4))
{
std::cerr << "ERROR: could not read data size" << std::endl;
return false;
}
size = convert_to_int(buffer, 4, std::endian::little);
/* cannot be at the end of file */
if(file.eof())
{
std::cerr << "ERROR: reached EOF on the file" << std::endl;
return false;
}
if(file.fail())
{
std::cerr << "ERROR: fail state set on the file" << std::endl;
return false;
}
return true;
}
const int32_t BUFFER_SIZE = 320000;
const int32_t NUM_BUFFERS = 4;
int main()
{
std::string filename = "Assets/session.wav";
std::ifstream file;
file.open(filename);
if(!file.is_open())
{
std::cerr << "ERROR: could not open file \"" << filename << "\"" << std::endl;
return false;
}
uint8_t channels;
int32_t sampleRate;
uint8_t bitsPerSample;
int32_t size;
if(!load_wav_file_header(file,channels,sampleRate,bitsPerSample,size))
{
std::cerr << "ERROR: could not open wav header of \"" << filename << "\"" << std::endl;
return false;
}
char* data = new char[size];
if(!file.read(data, size))
{
if(file.eof())
std::cerr << "ERROR: reached end of file trying to read "
<< size << " bytes. Actually read " << file.gcount() << std::endl;
else if(file.fail())
std::cerr << "ERROR: fail state" << std::endl;
else if(file.bad())
perror(("error while reading file " + filename).c_str());
return 0;
}
return 0;
}
The output of the program is:
ERROR: reached end of file trying to read 7035488 bytes. Actually read 554
According to cppreference this happens with read when you reach the eof, which based on gcount(), it looks like I have. The problem is that this file is a total of 6,871 KB, and the reported size in the .WAV file is otherwise larger than the 554 it's claiming to have left in it.