sp_attribute_lookup with std::map

- replace linear array search with std::map lookup
- remove duplicated name lookup logic in SPStylePropHelper

3 files changed, 38 insertions, 18 deletions

diff --git a/src/attributes.cpp b/src/attributes.cpp
index 1222d2669..d7081d4c9 100644
--- a/src/attributes.cpp
+++ b/src/attributes.cpp
@@ -9,6 +9,9 @@
  * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
+#include <cstring>
+#include <map>
+
 #include <glib.h> // g_assert()
 #include "attributes.h"
 
@@ -555,15 +558,34 @@ static SPStyleProp const props[] = {
 
 #define n_attrs (sizeof(props) / sizeof(props[0]))
 
-/** Returns an SPAttributeEnum; SP_ATTR_INVALID (of value 0) if key isn't recognized. */
+/**
+ * Inverse to the \c props array for lookup by name.
+ */
+struct AttributeLookupImpl {
+    struct cstrless {
+        bool operator()(char const *lhs, char const *rhs) const { return std::strcmp(lhs, rhs) < 0; }
+    };
+
+    std::map<char const *, SPAttributeEnum, cstrless> m_map;
+
+    AttributeLookupImpl()
+    {
+        for (unsigned int i = 1; i < n_attrs; i++) {
+            // sanity check: order of props array must match SPAttributeEnum
+            g_assert(props[i].code == i);
+
+            m_map[props[i].name] = props[i].code;
+        }
+    }
+};
+
 SPAttributeEnum
 sp_attribute_lookup(gchar const *key)
 {
-    for (unsigned int i = 1; i < n_attrs; i++) {
-        g_assert(props[i].code == static_cast< gint >(i) );
-        // If this g_assert fails, then the sort order of SPAttributeEnum does not match the order in props[]!
-        if(g_str_equal(const_cast<void *>(static_cast<void const *>(props[i].name)), key))
-            return props[i].code;
+    static AttributeLookupImpl const _instance;
+    auto it = _instance.m_map.find(key);
+    if (it != _instance.m_map.end()) {
+        return it->second;
     }
     // std::cerr << "sp_attribute_lookup: invalid attribute: "
     //           << (key?key:"Null") << std::endl;
diff --git a/src/attributes.h b/src/attributes.h
index 1f0178fae..512c00499 100644
--- a/src/attributes.h
+++ b/src/attributes.h
@@ -564,7 +564,14 @@ enum SPAttributeEnum : unsigned {
     SP_PROP_PATH_EFFECT,
 };
 
+/**
+ * Get attribute id by name. Return SP_ATTR_INVALID for invalid names.
+ */
 SPAttributeEnum sp_attribute_lookup(gchar const *key);
+
+/**
+ * Get attribute name by id. Return NULL for invalid ids.
+ */
 gchar const *sp_attribute_name(SPAttributeEnum id);
 
 #endif
diff --git a/src/style.cpp b/src/style.cpp
index aab8f2695..b11a92749 100644
--- a/src/style.cpp
+++ b/src/style.cpp
@@ -76,7 +76,7 @@ static CRSelEng *sp_repr_sel_eng();
 class SPStylePropHelper {
     SPStylePropHelper() {
 #define REGISTER_PROPERTY(id, member, name) \
-        _register(reinterpret_cast<SPIBasePtr>(&SPStyle::member), id, name)
+        _register(reinterpret_cast<SPIBasePtr>(&SPStyle::member), id) /* name unused */
 
         // SVG 2: Attributes promoted to properties
         REGISTER_PROPERTY(SP_ATTR_D, d, "d");
@@ -215,11 +215,7 @@ public:
      * Get property pointer by name
      */
     SPIBase *get(SPStyle *style, const std::string &name) {
-        auto it = m_name_map.find(name);
-        if (it != m_name_map.end()) {
-            return _get(style, it->second);
-        }
-        return nullptr;
+        return get(style, sp_attribute_lookup(name.c_str()));
     }
 
     /**
@@ -238,19 +234,14 @@ public:
 private:
     SPIBase *_get(SPStyle *style, SPIBasePtr ptr) { return &(style->*ptr); }
 
-    void _register(SPIBasePtr ptr, SPAttributeEnum id, const char *name) {
+    void _register(SPIBasePtr ptr, SPAttributeEnum id) {
         m_vector.push_back(ptr);
 
         if (id != SP_ATTR_INVALID) {
             m_id_map[id] = ptr;
         }
-
-        if (name[0]) {
-            m_name_map[name] = ptr;
-        }
     }
 
-    std::unordered_map<std::string, SPIBasePtr> m_name_map;
     std::unordered_map</* SPAttributeEnum */ int, SPIBasePtr> m_id_map;
     std::vector<SPIBasePtr> m_vector;
 };