AP_Param: added copy_name_token()

this avoids an expensive var_info traversal on every copy_name call

libraries/AP_Param/AP_Param.cpp

@@ -388,6 +388,41 @@ const struct AP_Param::Info *AP_Param::find_var_info(uint32_t *
     return NULL;
 }
 
+
+// find the info structure for a variable
+const struct AP_Param::Info *AP_Param::find_var_info_token(const ParamToken *token,
+                                                           uint32_t *                 group_element,
+                                                           const struct GroupInfo **  group_ret,
+                                                           uint8_t *                  idx)
+{
+    uint8_t i = token->key;
+    uint8_t type = PGM_UINT8(&_var_info[i].type);
+    uintptr_t base = PGM_POINTER(&_var_info[i].ptr);
+    if (type == AP_PARAM_GROUP) {
+        const struct GroupInfo *group_info = (const struct GroupInfo *)PGM_POINTER(&_var_info[i].group_info);
+        const struct AP_Param::Info *info;
+        info = find_var_info_group(group_info, i, 0, 0, group_element, group_ret, idx);
+        if (info != NULL) {
+            return info;
+        }
+    } else if (base == (uintptr_t) this) {
+        *group_element = 0;
+        *group_ret = NULL;
+        *idx = 0;
+        return &_var_info[i];
+    } else if (type == AP_PARAM_VECTOR3F &&
+               (base+sizeof(float) == (uintptr_t) this ||
+                base+2*sizeof(float) == (uintptr_t) this)) {
+        // we are inside a Vector3f. Work out which element we are
+        // referring to.
+        *idx = (((uintptr_t) this) - base)/sizeof(float);
+        *group_element = 0;
+        *group_ret = NULL;
+        return &_var_info[i];
+    }
+    return NULL;
+}
+
 // return the storage size for a AP_PARAM_* type
 uint8_t AP_Param::type_size(enum ap_var_type type)
 {
@@ -498,6 +533,36 @@ void AP_Param::copy_name(char *buffer, size_t buffer_size, bool force_scalar)
     }
 }
 
+// Copy the variable's whole name to the supplied buffer.
+//
+// If the variable is a group member, prepend the group name.
+//
+void AP_Param::copy_name_token(const ParamToken *token, char *buffer, size_t buffer_size, bool force_scalar)
+{
+    uint32_t group_element;
+    const struct GroupInfo *ginfo;
+    uint8_t idx;
+    const struct AP_Param::Info *info = find_var_info_token(token, &group_element, &ginfo, &idx);
+    if (info == NULL) {
+        *buffer = 0;
+        serialDebug("no info found");
+        return;
+    }
+    strncpy_P(buffer, info->name, buffer_size);
+    if (ginfo != NULL) {
+        uint8_t len = strnlen(buffer, buffer_size);
+        if (len < buffer_size) {
+            strncpy_P(&buffer[len], ginfo->name, buffer_size-len);
+        }
+        if ((force_scalar || idx != 0) && AP_PARAM_VECTOR3F == PGM_UINT8(&ginfo->type)) {
+            // the caller wants a specific element in a Vector3f
+            add_vector3f_suffix(buffer, buffer_size, idx);
+        }
+    } else if ((force_scalar || idx != 0) && AP_PARAM_VECTOR3F == PGM_UINT8(&info->type)) {
+        add_vector3f_suffix(buffer, buffer_size, idx);
+    }
+}
+
 // Find a variable by name in a group
 AP_Param *
 AP_Param::find_group(const char *name, uint8_t vindex, const struct GroupInfo *group_info, enum ap_var_type *ptype)

libraries/AP_Param/AP_Param.h

@@ -126,6 +126,8 @@ public:
     ///
     void copy_name(char *buffer, size_t bufferSize, bool force_scalar=false);
 
+    void copy_name_token(const ParamToken *token, char *buffer, size_t bufferSize, bool force_scalar=false);
+
     /// Find a variable by name.
     ///
     /// If the variable has no name, it cannot be found by this interface.
@@ -263,6 +265,10 @@ private:
                                     uint32_t *                group_element,
                                     const struct GroupInfo ** group_ret,
                                     uint8_t *                 idx);
+    const struct Info *			find_var_info_token(const ParamToken *token,
+                                                    uint32_t *                 group_element,
+                                                    const struct GroupInfo **  group_ret,
+                                                    uint8_t *                  idx);
     static const struct Info *  find_by_header_group(
                                     struct Param_header phdr, void **ptr,
                                     uint8_t vindex,