AP_Param: Factor load_defaults_file (NFC)

libraries/AP_Param/AP_Param.cpp

@@ -1743,14 +1743,8 @@ bool AP_Param::parse_param_line(char *line, char **vname, float &value)
     return true;
 }
 
-/*
-  load a default set of parameters from a file
- */
-bool AP_Param::load_defaults_file(const char *filename, bool panic_on_error)
+uint16_t AP_Param::count_defaults_in_file(const char *filename, uint16_t &num_defaults, bool panic_on_error)
 {
-    if (filename == nullptr) {
-        return false;
-    }
     FILE *f = fopen(filename, "r");
     if (f == nullptr) {
         return false;
@@ -1760,7 +1754,6 @@ bool AP_Param::load_defaults_file(const char *filename, bool panic_on_error)
     /*
       work out how many parameter default structures to allocate
      */
-    uint16_t num_defaults = 0;
     while (fgets(line, sizeof(line)-1, f)) {
         char *pname;
         float value;
@@ -1782,27 +1775,19 @@ bool AP_Param::load_defaults_file(const char *filename, bool panic_on_error)
     }
     fclose(f);
 
-    if (param_overrides != nullptr) {
-        free(param_overrides);
-    }
-    num_param_overrides = 0;
-
-    param_overrides = new param_override[num_defaults];
-    if (param_overrides == nullptr) {
-        AP_HAL::panic("AP_Param: Failed to allocate overrides");
-        return false;
-    }
+    return true;
+}
 
-    /* 
-       re-open to avoid possible seek issues with NuttX
-     */
-    f = fopen(filename, "r");
+bool AP_Param::read_param_defaults_file(const char *filename)
+{
+    FILE *f = fopen(filename, "r");
     if (f == nullptr) {
         AP_HAL::panic("AP_Param: Failed to re-open defaults file");
         return false;
     }
 
     uint16_t idx = 0;
+    char line[100];
     while (fgets(line, sizeof(line)-1, f)) {
         char *pname;
         float value;
@@ -1822,6 +1807,37 @@ bool AP_Param::load_defaults_file(const char *filename, bool panic_on_error)
         }
     }
     fclose(f);
+    return true;
+}
+
+/*
+  load a default set of parameters from a file
+ */
+bool AP_Param::load_defaults_file(const char *filename, bool panic_on_error)
+{
+    if (filename == nullptr) {
+        return false;
+    }
+
+    uint16_t num_defaults = 0;
+    if (!count_defaults_in_file(filename, num_defaults, panic_on_error)) {
+        return false;
+    }
+
+    if (param_overrides != nullptr) {
+        free(param_overrides);
+    }
+    num_param_overrides = 0;
+
+    param_overrides = new param_override[num_defaults];
+    if (param_overrides == nullptr) {
+        AP_HAL::panic("AP_Param: Failed to allocate overrides");
+        return false;
+    }
+
+    if (! read_param_defaults_file(filename)) {
+        return false;
+    }
 
     num_param_overrides = num_defaults;
 

libraries/AP_Param/AP_Param.h

@@ -510,6 +510,8 @@ private:
       load a parameter defaults file. This happens as part of load_all()
      */
     static bool parse_param_line(char *line, char **vname, float &value);
+    static uint16_t count_defaults_in_file(const char *filename, uint16_t &num_defaults, bool panic_on_error);
+    static bool read_param_defaults_file(const char *filename);
     static bool load_defaults_file(const char *filename, bool panic_on_error);
 #endif