From: ian <ian>
Date: Sun, 16 Jan 2005 00:09:04 +0000 (+0000)
Subject: usleep_gettod to replace usleep (which is very coarse and tends to sleep for 20ms... 
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=e6bc056b9f817471e3b43980f6fb913d86ce8065;p=trains.git

usleep_gettod to replace usleep (which is very coarse and tends to sleep for 20ms every time!  also, siggen supports limiting total number of iterations
---

diff --git a/parport/lib.c b/parport/lib.c
index f36eef4..096fc7c 100644
--- a/parport/lib.c
+++ b/parport/lib.c
@@ -3,6 +3,8 @@
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
+#include <sys/time.h>
+#include <time.h>
 #include <stdlib.h>
 
 #include <sys/ioctl.h>
@@ -33,3 +35,24 @@ unsigned long number(const char *a) {
   }
   return v;
 }
+
+static void gettod(struct timeval *now_r) {
+  int r;
+  r= gettimeofday(now_r,0);
+  if (r) { perror("gettimeofday failed"); exit(127); }
+}  
+
+void usleep_gettod(unsigned long us) {
+  struct timeval start, end, now;
+  ldiv_t ld;
+
+  gettod(&start);
+
+  ld= ldiv(start.tv_usec + us, 1000000);
+  end.tv_sec= start.tv_sec + ld.quot;
+  end.tv_usec= ld.rem;
+
+  do {
+    gettod(&now);
+  } while (timercmp(&now,&end,<));
+}
diff --git a/parport/lib.h b/parport/lib.h
index 8372ec8..77f4583 100644
--- a/parport/lib.h
+++ b/parport/lib.h
@@ -4,6 +4,7 @@
 #define LIB_H
 
 void doioctl(int ioctlnum, void *vp, unsigned long vpv);
+void usleep_gettod(unsigned long us);
 unsigned long number(const char *a);
 extern int fd;
 
diff --git a/parport/siggen.c b/parport/siggen.c
index c5bc73a..c04004e 100644
--- a/parport/siggen.c
+++ b/parport/siggen.c
@@ -18,23 +18,40 @@ static void badusage(void) {
 	  "  t<value>   PPWDATA    value\n"
 	  "  w<value>   usleep(value)\n"
 	  "options:\n"
+	  "  n<value>   do whole list n times\n"
 	  "  m<value>   do every item m times\n");
 }	  
 
 int main(int argc, const char *const *argv) {
-  int ii, io=0, m=1;
+  int ii, io=0, m=1, n=-1, loops_count, loops_n, loops_incr;
+  unsigned long ul;
   unsigned char v;
   const char *a;
 
   argc--;
   argv++;
-  if (argc>=1 && (a=argv[0]) && a[0]=='m') {
-    m= number(a+1);
+  while (argc>=1 && (a=argv[0])) {
+    switch (a[0]) {
+    case 'm': m= number(a+1); break;
+    case 'n': n= number(a+1); break;
+    default: goto loop_break_options;
+    }
     argc--;
     argv++;
   }
+loop_break_options:
   if (argc<1) badusage();
-  for (ii=0; ; ii++, ii%=(argc*m)) {
+
+  if (n==-1) {
+    loops_n= 1;
+    loops_incr= 0;
+  } else {
+    loops_n= n * argc * m;
+    loops_incr= 1;
+  }
+  for (ii=0, loops_count=0;
+       loops_count < loops_n;
+       ii++, ii%=(argc*m), loops_count += loops_incr) {
     a= argv[ii/m];
     switch (a[0]) {
     case 'k': io= PPWCONTROL; break;
@@ -42,11 +59,13 @@ int main(int argc, const char *const *argv) {
     case 'w': io= -1;         break;
     default: badusage();
     }
-    v= number(a+1);
+    ul= number(a+1);
     if (io==-1) {
-      usleep(v);
+      usleep_gettod(ul);
     } else {
+      v= ul;
       doioctl(io, &v, v);
     }
   }
+  return 0;
 }