Implementation of common TRestRawToSignalProcesss::FRead

[jgalan]

We could perhaps simplify the code of external to raw signal processes if we introduce a template method inside TRestRawToSignalProcess::FRead.

Each time we read, it is required to increase the variable totalBytesRead. This could also be encapsulated in the base class. And probably totalBytesReaded could be made private.

For example:

    char buffer[CTAG_SZ];
    if (fread(buffer, sizeof(char), CTAG_SZ, fInputBinFile) != CTAG_SZ) {
        printf("Error: could not read first ACQ prefix.\n");
        exit(1);
    }
    totalBytesReaded += CTAG_SZ * sizeof(char);

could be replaced by:

char buffer[CTAG_SZ];
FRead( buffer, sizeof(char), CTAG_SZ);

For example:

    if (fread(&tmp, sizeof(int32_t), 1, fInputBinFile) != 1) {
        printf("Error: could not read timestamp.\n");
        exit(1);
    }
    totalBytesReaded += sizeof(int32_t);

could be replaced by:

int32_t tmp;
FRead( tmp, sizeof(int32_t), 1);

or even

int32_t tmp;
FReadOne( tmp, sizeof(int32_t));

or

tmp = FRead<int32_t>();

[juanangp]

I think that to do a template for fread is overcomplicated, in case that you want to automatically increase totalBytesReaded I would suggest something like this:

void FRead( void* buffer, std::size_t size, std::size_t count ){
  if ( fread(buffer, size, count, fInputBinFile) != count){
    printf("Error: could not read %d bytes.\n", size*count);
    exit(1);
  }
totalBytesReaded += size*count;
}

Then in the example above you just do:

char buffer[CTAG_SZ];
FRead( buffer, sizeof(char), CTAG_SZ);

[nkx111]

There is already an FRead() implemented in this PR: #33, which shall be working in normal cases. However it was a little problematic to reach the original goal of online analysis. I don't know why... So the PR has not been merged yet.