diff --git a/src/rvprof_stats.c b/src/rvprof_stats.c
new file mode 100644
index 0000000..9126f40
--- /dev/null
+++ b/src/rvprof_stats.c
@@ -0,0 +1,73 @@
+#include "rvprof_internal.h"
+
+// get function id for given name / caller combination or create new one
+int rvprof_stats_find_or_create_function( const char* name, const char* caller){
+    if(g_rvprof.config.merge_regions){
+        // ignore caller when merging stacks
+        for (int i=0; i<g_rvprof.functions.size; i++){
+            if (strcmp(g_rvprof.functions.data[i].name, name) == 0){
+                return i;
+            }
+        }
+    } else {
+        for (int i = 0; i<g_rvprof.functions.size; i++) {
+            if (strcmp(g_rvprof.functions.data[i].name, name) == 0 && strcmp(g_rvprof.functions.data[i].caller, caller) == 0) {
+                return i;
+            }
+        }
+    }
+
+    // ensure capacity
+    int err = function_stats_array_ensure_capacity(&g_rvprof.functions, g_rvprof.functions.size);
+    if (err < 0) return -1;
+
+    // add entry
+    int idx = g_rvprof.functions.size++;
+    function_stats_t* stats = &g_rvprof.functions.data[idx];
+    memset(stats, 0, sizeof(function_stats_t));
+    strncpy(stats->name, name, MAX_NAME_LEN-1);
+    stats->name[MAX_NAME_LEN-1] = '\0';
+    if(!g_rvprof.config.merge_regions){
+        strncpy(stats->caller, caller, MAX_NAME_LEN-1);
+        stats->caller[MAX_NAME_LEN-1] = '\0';
+    }
+
+    return idx;
+}
+
+// get call stack or create it
+int rvprof_stats_get_or_create_stack_id(void) {
+    static char call_stack[4096];
+    call_stack [0] = '\0';
+
+    for (int i=0; i<=g_rvprof.stack_ptr; i++){
+        if (i>0){
+            strcat(call_stack, "<");
+        }
+        strcat(call_stack, g_rvprof.regions.data[i].name);
+    }
+
+    // check if this stack exists already
+    for (int i=0; i<g_rvprof.stacks.size; i++){
+        if (g_rvprof.stacks.data[i].stack_path && strcmp(g_rvprof.stacks.data[i].stack_path, call_stack) == 0){
+            return g_rvprof.stacks.data[i].stid;
+        }
+    }
+
+    // create new stack
+    int err = stack_info_array_ensure_capacity(&g_rvprof.stacks, g_rvprof.stacks.size);
+    if (err < 0) return -1;
+
+    int stack_id = g_rvprof.stacks.size + 1; // start at 1
+
+    // add stack
+    g_rvprof.stacks.data[g_rvprof.stacks.size].stack_path = rvprof_malloc(strlen(call_stack)+1);
+    if (!g_rvprof.stacks.data[g_rvprof.stacks.size].stack_path){
+        return -1;
+    }
+    strcpy(g_rvprof.stacks.data[g_rvprof.stacks.size].stack_path, call_stack);
+    g_rvprof.stacks.data[g_rvprof.stacks.size].stid = stack_id;
+    g_rvprof.stacks.size++;
+
+    return stack_id;
+}
\ No newline at end of file