lab 5 TDDE45

debugging/Makefile

+all: workitems dividearrays fileutil
+
+workitems: workitems.c
+	$(CC) -g -O0 -o $@ $< -lpthread
+dividearrays: dividearrays.cpp
+	$(CXX) -g -O0 -o $@ $<
+fileutil: fileutil.cpp
+	$(CXX) -g -O0 -o $@ $<
+run: fileutil
+	./fileutil
+	diff -u bible.txt copy.txt

debugging/dividearrays.cpp

+#include <random>
+
+int main(int argc, char **argv)
+{
+  std::random_device generator;
+  std::uniform_int_distribution<int> intdist(0,50);
+  double res[1024];
+
+  for (int i=0; i<1024; i++) {
+    int nom = intdist(generator);
+    int denom = intdist(generator);
+    while(denom == 0){
+      denom = intdist(generator);
+    }
+    res[i] = nom / denom;
+  }
+  return 0;
+}

debugging/fileutil.cpp

+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+namespace std {
+
+static void getline(char *line, FILE *fin)
+{
+  int c = '\0', cur = 0;
+  while (c != '\n' && (c = fgetc(fin)) != EOF) {
+    line[cur++] = c;
+  }
+  line[cur] = '\0';
+}
+
+}
+
+using namespace std;
+
+int main(int argc, char **argv)
+{
+  int cur = 0;
+  char *lines[16536];
+  char line[80];
+  // Fix num lines, num columns, strdup-1
+  FILE *fin = fopen("bible.txt", "r");
+  if(fin!=NULL){
+    while (!feof(fin)) {
+    getline(line, fin);
+    lines[cur] = (char*) malloc(strlen(line));
+    strcpy(lines[cur], line);
+    cur++;
+    }
+    fclose(fin);
+  }
+
+  FILE *fout = fopen("copy.txt", "w");
+  for (int i=0; i<cur; i++) {
+    fputs(lines[i], fout);
+  }
+  fclose(fout);
+  return 0;
+}
+
+

debugging/gdb.txt

+Starting program: /home/wakakkakaaa/Documents/lab5-metaprogramming-and-debugging-lab-master/debugging/fileutil 
+
+Program received signal SIGSEGV, Segmentation fault.
+0x00007ffff7e51323 in _IO_feof (fp=0x0) at feof.c:35
+35	feof.c: No such file or directory.
+Quit
+Starting program: /home/wakakkakaaa/Documents/lab5-metaprogramming-and-debugging-lab-master/debugging/fileutil 
+
+Program received signal SIGSEGV, Segmentation fault.
+0x00007ffff7e51323 in _IO_feof (fp=0x0) at feof.c:35
+35	feof.c: No such file or directory.
+Starting program: /home/wakakkakaaa/Documents/lab5-metaprogramming-and-debugging-lab-master/debugging/fileutil 
+
+Program received signal SIGSEGV, Segmentation fault.
+0x00005555555552bd in main (argc=1, argv=0x7fffffffdfb8) at fileutil.cpp:30
+30	            lines[cur] = (char*) malloc(strlen(line));

debugging/workitems.c

+#include <assert.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+
+typedef struct workitem {
+  void (*fn)(double *);
+  int current;
+  int len;
+  double *data;
+  int started;
+} workitem;
+
+static void* launchThread(void *in)
+{
+  //pthread_mutex_lock(&mutex);
+  int n;
+  workitem *data = (workitem*) in;
+  //pthread_mutex_lock(&mutex);
+  volatile int started = 0;
+  while (!(started = data->started));
+  while (1) {
+    pthread_mutex_lock(&mutex);
+    n = data->current++;
+    if (n >= data->len) {
+        pthread_mutex_unlock(&mutex);
+        break;
+    }
+    data->fn(&data->data[n]);
+    pthread_mutex_unlock(&mutex);
+  }
+  pthread_mutex_unlock(&mutex);
+  return NULL;
+}
+
+void launchParallel(int numThreads, double *values, int len, void (*fn)(double *))
+{
+  //pthread_mutex_lock(&mutex);
+  workitem *data = calloc(1, sizeof(workitem));
+  pthread_t th[numThreads];
+
+  memset(th, 0, numThreads*sizeof(pthread_t));
+
+  data->fn = fn;
+  data->current = 0;
+  data->len = len;
+  data->data = values;
+  data->started = 0;
+  //thread_mutex_lock(&mutex);
+  for (int i=0; i<numThreads; i++) {
+    //pthread_mutex_lock(&mutex);
+    assert(0 == pthread_create(&th[i], NULL, launchThread, data));
+    //pthread_mutex_unlock(&mutex);
+  }
+  pthread_mutex_lock(&mutex);
+  data->started = 1;
+  pthread_mutex_unlock(&mutex);
+  //pthread_mutex_lock(&mutex);
+  for (int i=0; i<numThreads; i++) {
+
+    assert(th[i] && 0==pthread_join(th[i], NULL));
+
+  }
+  //pthread_mutex_lock(&mutex);
+  assert(data->current >= len);
+  //pthread_mutex_unlock(&mutex);
+  free(data);
+  //pthread_mutex_unlock(&mutex);
+}
+
+void mul2(double *d)
+{
+  *d = *d * 2;
+}
+
+int main(int argc, char **argv)
+{
+
+  double vals[100];
+  for (int i=0; i<100; i++) {
+    vals[i] = i*1.5;
+  }
+  launchParallel(4 /* Increase this if no error occurs */, vals, 100, mul2);
+  for (int i=0; i<100; i++) {
+    if (vals[i] != 1.5*2*i) {
+      fprintf(stderr, "Expected vals[%d] to have value %.1f, got value %.1f\n", i, (double)1.5*2*i, (double)vals[i]);
+    }
+  }
+  return 0;
+}