src/libk8clock/k8clock.c

   1 /* coded by Ketmar // Vampire Avalon (psyc://ketmar.no-ip.org/~Ketmar)
   2  * Understanding is not required. Only obedience.
   3  *
   4  * This program is free software. It comes without any warranty, to
   5  * the extent permitted by applicable law. You can redistribute it
   6  * and/or modify it under the terms of the Do What The Fuck You Want
   7  * To Public License, Version 2, as published by Sam Hocevar. See
   8  * http://www.wtfpl.net/txt/copying/ for more details.
   9  */
  10 #include <ctype.h>
  11 #include <stdlib.h>
  12 #include <stdio.h>
  13 #include <string.h>
  14
  15 #include "k8clock.h"
  16
  17
  18 k8clock_type k8clock_initialized = K8CLOCK_ERROR;
  19 k8clock_t clk;
  20
  21
  22 #ifndef CLOCK_MONOTONIC_RAW
  23 # define K8CLOCK_CLOCK_TYPE  CLOCK_MONOTONIC_RAW
  24 #else
  25 # define K8CLOCK_CLOCK_TYPE  CLOCK_MONOTONIC
  26 #endif
  27
  28
  29 static k8clock_type k8clock_check_source (void) {
  30   FILE *fl = fopen("/sys/devices/system/clocksource/clocksource0/current_clocksource", "r");
  31   char buf[128];
  32   if (fl == NULL) {
  33     fprintf(stderr, "WARNING: can't determine clock source!\n");
  34     return K8CLOCK_OTHER;
  35   }
  36   memset(buf, 0, sizeof(buf));
  37   if (fgets(buf, sizeof(buf)-1, fl) == NULL) {
  38     fclose(fl);
  39     fprintf(stderr, "WARNING: can't determine clock source!\n");
  40     return K8CLOCK_OTHER;
  41   }
  42   fclose(fl);
  43   while (buf[0] && isspace(buf[strlen(buf)-1])) buf[strlen(buf)-1] = 0;
  44   //fprintf(stderr, "clock source: %s\n", buf);
  45   return (strcasecmp(buf, "hpet") == 0 ? K8CLOCK_HPET : K8CLOCK_OTHER);
  46 }
  47
  48
  49 __attribute__((constructor)) static void k8clock_ctor (void) {
  50   if (k8clock_initialized == K8CLOCK_ERROR) {
  51     struct timespec cres;
  52     k8clock_initialized = k8clock_check_source();
  53     if (clock_getres(K8CLOCK_CLOCK_TYPE, &cres) != 0) {
  54       fprintf(stderr, "ERROR: can't get clock resolution!\n");
  55       k8clock_initialized = K8CLOCK_ERROR;
  56       return;
  57     }
  58     //fprintf(stderr, "CLOCK_MONOTONIC: %ld:%ld\n", cres.tv_sec, cres.tv_nsec);
  59     if (cres.tv_sec > 0 || cres.tv_nsec > (long)1000000*10 /*10 ms*/) {
  60       fprintf(stderr, "ERROR: real-time clock resolution is too low!\n");
  61       k8clock_initialized = K8CLOCK_ERROR;
  62       return;
  63     }
  64     k8clock_init(&clk);
  65   }
  66 }
  67
  68
  69 void k8clock_init (k8clock_t *clk) {
  70   if (clk != NULL && k8clock_initialized != K8CLOCK_ERROR) {
  71     if (clock_gettime(K8CLOCK_CLOCK_TYPE, &clk->stt) != 0) {
  72       fprintf(stderr, "ERROR: can't get real-time clock value!\n");
  73     }
  74   }
  75 }
  76
  77
  78 uint64_t k8clock_ms (k8clock_t *clk) {
  79   if (clk != NULL && k8clock_initialized != K8CLOCK_ERROR) {
  80     struct timespec ts;
  81     if (clock_gettime(K8CLOCK_CLOCK_TYPE, &ts) != 0) {
  82       fprintf(stderr, "ERROR: can't get real-time clock value!\n");
  83       return 0;
  84     }
  85     // ah, ignore nanoseconds in clk->stt here: we need only 'differential' time, and it can start with something weird
  86     return ((int64_t)(ts.tv_sec-clk->stt.tv_sec))*1000+(ts.tv_nsec-clk->stt.tv_nsec)/1000000+1;
  87   }
  88   return 0;
  89 }
  90
  91
  92 uint64_t k8clock_micro (k8clock_t *clk) {
  93   if (clk != NULL && k8clock_initialized != K8CLOCK_ERROR) {
  94     struct timespec ts;
  95     if (clock_gettime(K8CLOCK_CLOCK_TYPE, &ts) != 0) {
  96       fprintf(stderr, "ERROR: can't get real-time clock value!\n");
  97       return 0;
  98     }
  99     // ah, ignore nanoseconds in clk->stt here: we need only 'differential' time, and it can start with something weird
 100     return ((int64_t)(ts.tv_sec-clk->stt.tv_sec))*1000000+(ts.tv_nsec-clk->stt.tv_nsec)/1000+1;
 101   }
 102   return 0;
 103 }
 104
 105
 106 uint64_t k8clock (void) {
 107   return k8clock_ms(&clk);
 108 }
 109
 110
 111 uint64_t k8clockmicro (void) {
 112   return k8clock_micro(&clk);
 113 }