#define _GNU_SOURCE 1
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>

#include <ctype.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "timer-map.h"

#define START_CT 1000
#define FULL_CT  (1000 * 1000 * 1000)

typedef struct {
    struct timeval start, middle, end;
} race_times_t;

volatile char extern_ch;
char const * text = NULL;

void
print_timings(race_times_t * pb, race_times_t * mac);

void
use_strpbrk(int ct)
{
    while (ct-- > 0) {
        char * p = strpbrk(text, "#~");
        extern_ch = *p;
    }
}

void
use_macros(int ct)
{
    while (ct-- > 0) {
        char * p = SPN_HASH_CHARS(text);
        extern_ch = *p;
    }
}

void
map_file(char const * fname)
{
    struct stat sb;
    int sres = stat(fname, &sb);
    int fd   = open(fname, O_RDONLY);
    void * map = mmap(NULL, sb.st_size+1, PROT_READ, MAP_SHARED, fd, 0);
    if ((sres < 0) || (fd < 0) || (map == MAP_FAILED))
        exit(1);
    text = map;
}

int
main(int argc, char ** argv)
{
    race_times_t for_strpbrk;
    race_times_t for_macros;

    {
        char const * fn = argv[1] ? argv[1] : __FILE__;
        map_file(fn);
    }

    gettimeofday(&for_strpbrk.start, NULL);
    use_strpbrk(START_CT);
    gettimeofday(&for_strpbrk.middle, NULL);
    use_strpbrk(FULL_CT);
    gettimeofday(&for_strpbrk.end, NULL);

    for_macros.start = for_strpbrk.end;
    use_macros(START_CT);
    gettimeofday(&for_macros.middle, NULL);
    use_macros(FULL_CT);
    gettimeofday(&for_macros.end, NULL);

    print_timings(&for_strpbrk, &for_macros);
    return 0;
}

int
delta(struct timeval * s, struct timeval * e)
{
    if (s->tv_sec == e->tv_sec)
        return (500 + e->tv_usec - s->tv_usec) / 1000;
    int msec = (500 + (1000000 - s->tv_usec) + e->tv_usec) / 1000;
    return msec + ((e->tv_sec - s->tv_sec) - 1) * 1000;
}

void
fmtnum(char * buf, int msec)
{
    int len = sprintf(buf, "%04u", msec);
    char * p = buf + len - 3;
    memmove(p+1, p, 4);
    *p = '.';
}

void
print_timings(race_times_t * pb, race_times_t * mac)
{
    static char const fmt[] =
        "%-10s startup time: %9s run time: %12s\n";

    int delta1 = delta(&pb->start,  &pb->middle);
    int delta2 = delta(&pb->middle, &pb->end);
    char buf1[32], buf2[32];
    fmtnum(buf1, delta1);
    fmtnum(buf2, delta2);
    printf(fmt, "strpbrk", buf1, buf2);

    delta1 = delta(&mac->start,  &mac->middle);
    delta2 = delta(&mac->middle, &mac->end);
    fmtnum(buf1, delta1);
    fmtnum(buf2, delta2);
    printf(fmt, "macros", buf1, buf2);
}