I'm doing stuff related to parsing huge globs of textfiles, and was testing what input method to use.

There is not much of a difference using c++ std::ifstreams vs c FILE,

According to the documentation of zlib, it supports uncompressed files, and will read the file without decompression.

I'm seeing a difference from 12 seconds using non zlib to more than 4 minutes using zlib.h

This I've tested doing multiple runs, so its not a disk cache issue.

Am I using zlib in some wrong way?

thanks

#include <zlib.h>
#include <cstdio>
#include <cstdlib>
#include <fstream>
#define LENS 1000000


size_t fg(const char *fname){
  fprintf(stderr,"\t-> using fgets\n");
  FILE *fp =fopen(fname,"r");
  size_t nLines =0;
  char *buffer = new char[LENS];
  while(NULL!=fgets(buffer,LENS,fp))
    nLines++;

  fprintf(stderr,"%lu\n",nLines);
  return nLines;
}

size_t is(const char *fname){
  fprintf(stderr,"\t-> using ifstream\n");
  std::ifstream is(fname,std::ios::in);
  size_t nLines =0;
  char *buffer = new char[LENS];
  while(is. getline(buffer,LENS))
    nLines++;

  fprintf(stderr,"%lu\n",nLines);
  return nLines;
}

size_t iz(const char *fname){
  fprintf(stderr,"\t-> using zlib\n");
  gzFile fp =gzopen(fname,"r");
  size_t nLines =0;
  char *buffer = new char[LENS];
  while(0!=gzgets(fp,buffer,LENS))
    nLines++;

  fprintf(stderr,"%lu\n",nLines);
  return nLines;
}

int main(int argc,char**argv){
  if(atoi(argv[2])==0)
    fg(argv[1]);
  if(atoi(argv[2])==1)
    is(argv[1]);
  if(atoi(argv[2])==2)
    iz(argv[1]);

}