filebuf_sgetn_unbuf.cc [plain text]
#include <cstdio>
#include <fstream>
#include <testsuite_performance.h>
int main()
{
using namespace std;
using namespace __gnu_test;
time_counter time;
resource_counter resource;
const int iterations = 500000;
const int chunksize = 100;
char* chunk = new char[chunksize];
const char* name1 = "/usr/share/dict/words";
const char* name2 = "/usr/share/dict/linux.words";
const char* name = name1;
FILE* file;
if (!(file = fopen(name, "r")))
{
name = name2;
if (!(file = fopen(name, "r")))
exit(1);
}
setvbuf(file, 0, _IONBF, 0);
start_counters(time, resource);
for (int i = 0; i < iterations; ++i)
if (fread(chunk, 1, chunksize, file) < chunksize)
fseek(file, 0, SEEK_SET);
stop_counters(time, resource);
fclose(file);
report_performance(__FILE__, "C", time, resource);
clear_counters(time, resource);
file = fopen(name, "r");
setvbuf(file, 0, _IONBF, 0);
start_counters(time, resource);
for (int i = 0; i < iterations; ++i)
if (fread_unlocked(chunk, 1, chunksize, file) < chunksize)
fseek(file, 0, SEEK_SET);
stop_counters(time, resource);
fclose(file);
report_performance(__FILE__, "C unlocked", time, resource);
clear_counters(time, resource);
filebuf buf;
buf.pubsetbuf(0, 0);
buf.open(name, ios_base::in);
start_counters(time, resource);
for (int i = 0; i < iterations; ++i)
if (buf.sgetn(chunk, chunksize) < chunksize)
buf.pubseekoff(0, ios::beg);
stop_counters(time, resource);
report_performance(__FILE__, "C++", time, resource);
delete [] chunk;
return 0;
}