From 47fb5e9f3d4a00a51d385b858454d7e7850fc9c0 Mon Sep 17 00:00:00 2001
From: Luca <deri@ntop.org>
Date: Thu, 7 Sep 2023 11:12:37 +0200
Subject: Cleanup

---
 src/include/ndpi_api.h  | 42 ++++++++++++++++++++++++++----------------
 src/lib/ndpi_bitmap64.c | 32 +++++++++++++++++++++-----------
 2 files changed, 47 insertions(+), 27 deletions(-)

diff --git a/src/include/ndpi_api.h b/src/include/ndpi_api.h
index 612847da4..f3580e59a 100644
--- a/src/include/ndpi_api.h
+++ b/src/include/ndpi_api.h
@@ -98,10 +98,10 @@ extern "C" {
    *
    * @par    flow    = the flow to analyze
    * @return the error code or 0 otherwise
-   *                        
+   *
    */
   u_int32_t ndpi_get_flow_error_code(struct ndpi_flow_struct *flow);
-  
+
   /**
    * nDPI personal allocation and free functions
    **/
@@ -818,7 +818,7 @@ extern "C" {
    */
   int ndpi_load_category_file(struct ndpi_detection_module_struct *ndpi_str,
 			      char* path, ndpi_protocol_category_t category_id);
-  
+
   /**
    * Load files (whose name is <categoryid>_<label>.<extension>) stored
    * in a directory and bind each domain to the specified category.
@@ -1784,14 +1784,14 @@ extern "C" {
   void ndpi_hw_free(struct ndpi_hw_struct *hw);
   int  ndpi_hw_add_value(struct ndpi_hw_struct *hw, const u_int64_t value, double *forecast,  double *confidence_band);
   void ndpi_hw_reset(struct ndpi_hw_struct *hw);
-  
+
   /* ******************************* */
 
   int ndpi_ses_init(struct ndpi_ses_struct *ses, double alpha, float significance);
   int ndpi_ses_add_value(struct ndpi_ses_struct *ses, const double _value, double *forecast, double *confidence_band);
   void ndpi_ses_fitting(double *values, u_int32_t num_values, float *ret_alpha);
   void ndpi_ses_reset(struct ndpi_ses_struct *ses);
-  
+
   /* ******************************* */
 
   void ndpi_md5(const u_char *data, size_t data_len, u_char hash[16]);
@@ -1799,21 +1799,21 @@ extern "C" {
   u_int32_t ndpi_nearest_power_of_two(u_int32_t x);
 
   /* ******************************* */
-  
+
   u_int32_t ndpi_quick_hash(unsigned char *str, u_int str_len);
   u_int64_t ndpi_quick_hash64(char *str, u_int str_len);
   u_int32_t ndpi_hash_string(char *str);
   u_int32_t ndpi_rev_hash_string(char *str);
   u_int32_t ndpi_hash_string_len(char *str, u_int len);
   u_int32_t ndpi_murmur_hash(char *str, u_int str_len);
-    
+
   /* ******************************* */
 
   int ndpi_des_init(struct ndpi_des_struct *des, double alpha, double beta, float significance);
   int ndpi_des_add_value(struct ndpi_des_struct *des, const double _value, double *forecast, double *confidence_band);
   void ndpi_des_fitting(double *values, u_int32_t num_values, float *ret_alpha, float *ret_beta);
   void ndpi_des_reset(struct ndpi_des_struct *des);
-  
+
   /* ******************************* */
 
   int   ndpi_jitter_init(struct ndpi_jitter_struct *hw, u_int16_t num_periods);
@@ -1845,11 +1845,11 @@ extern "C" {
 			    u_int16_t *client_score, u_int16_t *server_score);
 
   u_int8_t ndpi_check_issuerdn_risk_exception(struct ndpi_detection_module_struct *ndpi_str,
-					      char *issuerDN);    
+					      char *issuerDN);
   u_int8_t ndpi_check_flow_risk_exceptions(struct ndpi_detection_module_struct *ndpi_str,
 					   u_int num_params,
 					   ndpi_risk_params params[]);
-  
+
   /* ******************************* */
 
   /* HyperLogLog cardinality estimator [count unique items] */
@@ -1874,7 +1874,7 @@ extern "C" {
   void ndpi_cm_sketch_add(struct ndpi_cm_sketch *sketch, u_int32_t element);
   u_int32_t ndpi_cm_sketch_count(struct ndpi_cm_sketch *sketch, u_int32_t element);
   void ndpi_cm_sketch_destroy(struct ndpi_cm_sketch *sketch);
-  
+
   /* ******************************* */
 
   /* PopCount [count how many bits are set to 1] */
@@ -2002,8 +2002,12 @@ extern "C" {
   /*
     Bitmap based on compressed bitmaps
     implemented by https://roaringbitmap.org
+
+    This is
+    - NOT a probabilistic datastructure (i.e. no false positives)
+    - mutable (i.e. you can add values at any time)
   */
-  
+
   ndpi_bitmap* ndpi_bitmap_alloc(void);
   ndpi_bitmap* ndpi_bitmap_alloc_size(u_int32_t size);
   void ndpi_bitmap_free(ndpi_bitmap* b);
@@ -2025,7 +2029,7 @@ extern "C" {
   ndpi_bitmap* ndpi_bitmap_ot_alloc(ndpi_bitmap* a, ndpi_bitmap* b_and);
   void ndpi_bitmap_xor(ndpi_bitmap* a, ndpi_bitmap* b_xor);
   void ndpi_bitmap_optimize(ndpi_bitmap* a);
-  
+
   ndpi_bitmap_iterator* ndpi_bitmap_iterator_alloc(ndpi_bitmap* b);
   void ndpi_bitmap_iterator_free(ndpi_bitmap* b);
   bool ndpi_bitmap_iterator_next(ndpi_bitmap_iterator* i, u_int32_t *value);
@@ -2035,6 +2039,11 @@ extern "C" {
   /*
     Bitmap with 64 bit values based
     on https://github.com/FastFilter/xor_singleheader/tree/master
+
+    This is
+    - a probabilistic datastructure !!! (i.e. be prepared to false positives)
+    - immutable (i.e. adding keys after a search (i.e. ndpi_bitmap64_isset)
+      is not allowed
    */
 
   ndpi_bitmap64* ndpi_bitmap64_alloc();
@@ -2045,6 +2054,7 @@ extern "C" {
   u_int32_t ndpi_bitmap64_size(ndpi_bitmap64 *b);
 
   /* ******************************* */
+
   /*
     Bloom-filter on steroids based on ndpi_bitmap
 
@@ -2078,7 +2088,7 @@ extern "C" {
   void         ndpi_filter_free(ndpi_filter *f);
   size_t       ndpi_filter_size(ndpi_filter *f);
   u_int32_t    ndpi_filter_cardinality(ndpi_filter *f);
-  
+
   /* ******************************* */
 
   /*
@@ -2097,7 +2107,7 @@ extern "C" {
   bool                  ndpi_domain_classify_contains(ndpi_domain_classify *s,
 						      u_int8_t *class_id /* out */,
 						      char *domain);
-  
+
   /* ******************************* */
 
   /*
@@ -2114,7 +2124,7 @@ extern "C" {
 
   /* ******************************* */
 
-  
+
   /* ******************************* */
 
   char* ndpi_get_flow_risk_info(struct ndpi_flow_struct *flow,
diff --git a/src/lib/ndpi_bitmap64.c b/src/lib/ndpi_bitmap64.c
index ae34a2704..1c8368b29 100644
--- a/src/lib/ndpi_bitmap64.c
+++ b/src/lib/ndpi_bitmap64.c
@@ -84,12 +84,12 @@ bool ndpi_bitmap64_compress(ndpi_bitmap64 *_b) {
 
     /* Now remove duplicates */
     u_int64_t old_value = b->entries[0], new_len = 1;
-    
+
     for(i=1; i<b->num_used_entries; i++) {
       if(b->entries[i] != old_value) {
 	if(new_len != i)
 	  memcpy(&b->entries[new_len], &b->entries[i], sizeof(u_int64_t));
-	
+
 	old_value = b->entries[i];
 	new_len++;
       } else {
@@ -97,21 +97,21 @@ bool ndpi_bitmap64_compress(ndpi_bitmap64 *_b) {
 	printf("Skipping duplicate hash %lluu [id: %u/%u]\n",
 	       b->entries[i].value, i, b->num_used_entries);
 #endif
-      }    
+      }
     }
-    
+
     b->num_used_entries = b->num_allocated_entries = new_len;
   }
 
   if(binary_fuse16_allocate(b->num_used_entries, &b->bitmap)) {
-    if(binary_fuse16_populate(b->entries, b->num_used_entries, &b->bitmap)) {    
+    if(binary_fuse16_populate(b->entries, b->num_used_entries, &b->bitmap)) {
       ndpi_free(b->entries), b->num_used_entries = b->num_allocated_entries = 0;
       b->entries = NULL;
     } else
       return(false);
   } else
     return(false);
-      
+
   b->is_compressed = true;
 
   return(true);
@@ -121,7 +121,17 @@ bool ndpi_bitmap64_compress(ndpi_bitmap64 *_b) {
 
 bool ndpi_bitmap64_set(ndpi_bitmap64 *_b, u_int64_t value) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
-  
+
+  if(b->is_compressed) {
+    /*
+      We need to discard the filter and start over as this
+      datastructure is immutable
+    */
+
+    binary_fuse16_free(&b->bitmap);
+    /* No need to call b->is_compressed = false; as it will be set below */
+  }
+
   if(b->num_used_entries >= b->num_allocated_entries) {
     u_int64_t *rc;
     u_int32_t new_len = b->num_allocated_entries + NDPI_BITMAP64_REALLOC_SIZE;
@@ -144,7 +154,7 @@ bool ndpi_bitmap64_set(ndpi_bitmap64 *_b, u_int64_t value) {
 
 bool ndpi_bitmap64_isset(ndpi_bitmap64 *_b, u_int64_t value) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
-  
+
   if(!b->is_compressed) ndpi_bitmap64_compress(b);
 
   return(binary_fuse16_contain(value, &b->bitmap));
@@ -154,12 +164,12 @@ bool ndpi_bitmap64_isset(ndpi_bitmap64 *_b, u_int64_t value) {
 
 void ndpi_bitmap64_free(ndpi_bitmap64 *_b) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
-  
+
   if(b->entries)        ndpi_free(b->entries);
 
   if(b->is_compressed)
     binary_fuse16_free(&b->bitmap);
-  
+
   ndpi_free(b);
 }
 
@@ -167,6 +177,6 @@ void ndpi_bitmap64_free(ndpi_bitmap64 *_b) {
 
 u_int32_t ndpi_bitmap64_size(ndpi_bitmap64 *_b) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
-  
+
   return(sizeof(ndpi_bitmap64) + binary_fuse16_size_in_bytes(&b->bitmap));
 }
-- 
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