utils: Make string utils const where possible

This will help prevent unnecessary allocations

diff --git a/src/libs/utils.cpp b/src/libs/utils.cpp
index 883652e..bd6dd51 100644 (file)
--- a/src/libs/utils.cpp
+++ b/src/libs/utils.cpp
@@ -15,7 +15,7 @@ using std::string;
 
 volatile bool _isr_context = false;
 
-uint16_t get_checksum(string to_check){
+uint16_t get_checksum(const string to_check){
    // From: http://en.wikipedia.org/wiki/Fletcher%27s_checksum
    uint16_t sum1 = 0;
    uint16_t sum2 = 0;
@@ -26,16 +26,16 @@ uint16_t get_checksum(string to_check){
    return (sum2 << 8) | sum1;
 }
 
-void get_checksums(uint16_t check_sums[],string key){
-    key = key.append(" ");
+void get_checksums(uint16_t check_sums[], const string key){
+    const string k = key+" ";
     check_sums[0] = 0x0000;
     check_sums[1] = 0x0000;
     check_sums[2] = 0x0000;
     size_t begin_key = 0;
     unsigned int counter = 0;
     while( begin_key < key.size()-1 ){
-        size_t end_key =  key.find_first_of(" .", begin_key);
-        string key_node = key.substr(begin_key, end_key - begin_key);
+        const size_t end_key =  k.find_first_of(" .", begin_key);
+        const string key_node = k.substr(begin_key, end_key - begin_key);
         check_sums[counter] = get_checksum(key_node);
         begin_key = end_key + 1;
         counter++;
@@ -79,7 +79,7 @@ string get_arguments( string possible_command ){
 }
 
 // Returns true if the file exists
-bool file_exists( string file_name ){
+bool file_exists( const string file_name ){
     bool exists = false;
     FILE *lp = fopen(file_name.c_str(), "r");
     if(lp){ exists = true; }

diff --git a/src/libs/utils.h b/src/libs/utils.h
index 5c17893..e54d61c 100644 (file)
--- a/src/libs/utils.h
+++ b/src/libs/utils.h
@@ -13,15 +13,15 @@ string lc(string str);
 
 string remove_non_number( string str );
 
-uint16_t get_checksum(string to_check);
+uint16_t get_checksum(const string to_check);
 
-void get_checksums(uint16_t check_sums[], string key);
+void get_checksums(uint16_t check_sums[], const string key);
 
 string shift_parameter( string &parameters );
 
 string get_arguments( string possible_command );
 
-bool file_exists( string file_name );
+bool file_exists( const string file_name );
 
 void system_reset( void );