add the darshan-diff utility back

darshan-util/Makefile.in

-all: libdarshan-util.a darshan-null-logutils.o darshan-analyzer darshan-convert darshan-parser jenkins-hash-gen
+all: libdarshan-util.a darshan-null-logutils.o darshan-analyzer darshan-convert darshan-diff darshan-parser jenkins-hash-gen
 
 DESTDIR =
 srcdir = @srcdir@
@@ -99,10 +99,8 @@ darshan-analyzer: darshan-analyzer.c darshan-logutils.h $(DARSHAN_LOG_FORMAT) $(
 darshan-convert: darshan-convert.c darshan-logutils.h $(DARSHAN_LOG_FORMAT) libdarshan-util.a lookup3.o | uthash-1.9.2
 	$(CC) $(CFLAGS) $(LDFLAGS) $< lookup3.o libdarshan-util.a -o $@ $(LIBS)
 
-#darshan-diff: darshan-diff.o $(DARSHAN_LOG_FORMAT) darshan-logutils.o darshan-logutils.h
-#	$(CC) $(CFLAGS)  $(LDFLAGS) $< darshan-logutils.o -o $@ $(LIBS)
-#darshan-diff.o: darshan-diff.c
-#	$(CC) $(CFLAGS) -c  $< -o $@
+darshan-diff: darshan-diff.c darshan-logutils.h $(DARSHAN_LOG_FORMAT) $(DARSHAN_MOD_LOGUTIL_HEADERS) $(DARSHAN_MOD_LOG_FORMATS) libdarshan-util.a | uthash-1.9.2
+	$(CC) $(CFLAGS) $(LDFLAGS) $< libdarshan-util.a -o $@ $(LIBS) 
 
 darshan-parser: darshan-parser.c darshan-logutils.h $(DARSHAN_LOG_FORMAT) $(DARSHAN_MOD_LOGUTIL_HEADERS) $(DARSHAN_MOD_LOG_FORMATS) libdarshan-util.a | uthash-1.9.2
 	$(CC) $(CFLAGS) $(LDFLAGS) $< libdarshan-util.a -o $@ $(LIBS) 
@@ -120,7 +118,7 @@ install:: all
 	install -d $(pkgconfigdir)
 	install -m 755 darshan-analyzer $(bindir)
 	install -m 755 darshan-convert $(bindir)
-#	install -m 755 darshan-diff $(bindir)
+	install -m 755 darshan-diff $(bindir)
 	install -m 755 darshan-parser $(bindir)
 	install -m 755 $(srcdir)/darshan-summary-per-file.sh $(bindir)
 	install -m 755 libdarshan-util.a $(libdir)

darshan-util/darshan-logutils.h

@@ -91,6 +91,13 @@ struct darshan_mod_logutil_funcs
     );
     /* print module-specific description of I/O characterization data */
     void (*log_print_description)(void);
+    /* print a text diff of 2 module I/O records */
+    void (*log_print_diff)(
+        void *rec1,
+        char *name1,
+        void *rec2,
+        char *name2
+    );
 };
 
 extern struct darshan_mod_logutil_funcs *mod_logutils[];

darshan-util/darshan-posix-logutils.c

@@ -36,13 +36,16 @@ static int darshan_log_put_posix_file(darshan_fd fd, void* posix_buf, int ver);
 static void darshan_log_print_posix_file(void *file_rec,
     char *file_name, char *mnt_pt, char *fs_type, int ver);
 static void darshan_log_print_posix_description(void);
+static void darshan_log_print_posix_file_diff(void *file_rec1, char *file_name1,
+    void *file_rec2, char *file_name2);
 
 struct darshan_mod_logutil_funcs posix_logutils =
 {
     .log_get_record = &darshan_log_get_posix_file,
     .log_put_record = &darshan_log_put_posix_file,
     .log_print_record = &darshan_log_print_posix_file,
-    .log_print_description = &darshan_log_print_posix_description
+    .log_print_description = &darshan_log_print_posix_description,
+    .log_print_diff = &darshan_log_print_posix_file_diff
 };
 
 static int darshan_log_get_posix_file(darshan_fd fd, void* posix_buf, 
@@ -149,6 +152,78 @@ static void darshan_log_print_posix_description()
     return;
 }
 
+static void darshan_log_print_posix_file_diff(void *file_rec1, char *file_name1,
+    void *file_rec2, char *file_name2)
+{
+    struct darshan_posix_file *file1 = (struct darshan_posix_file *)file_rec1;
+    struct darshan_posix_file *file2 = (struct darshan_posix_file *)file_rec2;
+    int i;
+
+    /* NOTE: we assume that both input records are the same module format version */
+
+    for(i=0; i<POSIX_NUM_INDICES; i++)
+    {
+        if(!file2)
+        {
+            printf("- ");
+            DARSHAN_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file1->rank, file1->f_id, posix_counter_names[i],
+                file1->counters[i], file_name1, "", "");
+            
+        }
+        else if(!file1)
+        {
+            printf("+ ");
+            DARSHAN_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file2->rank, file2->f_id, posix_counter_names[i],
+                file2->counters[i], file_name2, "", "");
+        }
+        else if(file1->counters[i] != file2->counters[i])
+        {
+            printf("- ");
+            DARSHAN_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file1->rank, file1->f_id, posix_counter_names[i],
+                file1->counters[i], file_name1, "", "");
+            printf("+ ");
+            DARSHAN_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file2->rank, file2->f_id, posix_counter_names[i],
+                file2->counters[i], file_name2, "", "");
+        }
+    }
+
+    for(i=0; i<POSIX_F_NUM_INDICES; i++)
+    {
+        if(!file2)
+        {
+            printf("- ");
+            DARSHAN_F_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file1->rank, file1->f_id, posix_f_counter_names[i],
+                file1->fcounters[i], file_name1, "", "");
+            
+        }
+        else if(!file1)
+        {
+            printf("+ ");
+            DARSHAN_F_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file2->rank, file2->f_id, posix_f_counter_names[i],
+                file2->fcounters[i], file_name2, "", "");
+        }
+        else if(file1->fcounters[i] != file2->fcounters[i])
+        {
+            printf("- ");
+            DARSHAN_F_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file1->rank, file1->f_id, posix_f_counter_names[i],
+                file1->fcounters[i], file_name1, "", "");
+            printf("+ ");
+            DARSHAN_F_COUNTER_PRINT(darshan_module_names[DARSHAN_POSIX_MOD],
+                file2->rank, file2->f_id, posix_f_counter_names[i],
+                file2->fcounters[i], file_name2, "", "");
+        }
+    }
+
+    return;
+}
+
 /*
  * Local variables:
  *  c-indent-level: 4