Major property-manager rewrite, using const char * throughout

interface instead of string. This will result in a lot more efficiency later, once I add in a simple hash table for caching lookups, since it will avoid creating a lot of temporary string objects. The major considerations for users will be that they cannot use node->getName() == "foo"; any more, and will have to use c_str() when setting a string value from a C++ string.
2002-03-19 16:07:47 +00:00
parent f9824aa7de
commit 4d0bc0ae39
4 changed files with 246 additions and 171 deletions
--- a/simgear/misc/props.cxx
+++ b/simgear/misc/props.cxx
@@ -6,17 +6,25 @@
 //
 // $Id$

-#include <simgear/compiler.h>
-#include <simgear/debug/logstream.hxx>
-
-#include <stdio.h>
-#include <stdlib.h>
-#include STL_IOSTREAM
-#include <algorithm>
 #include "props.hxx"

+#if PROPS_STANDALONE
+
+#include <iostream>
+using std::cerr;
+using std::endl;
+using std::sort;
+
+#else
+
+#include <simgear/compiler.h>
+#include <simgear/debug/logstream.hxx>
 SG_USING_STD(sort);

+#endif
+
+#include <string.h>
+


 ////////////////////////////////////////////////////////////////////////
@@ -54,7 +62,7 @@ const int SGRawValue<int>::DefaultValue = 0;
 const long SGRawValue<long>::DefaultValue = 0L;
 const float SGRawValue<float>::DefaultValue = 0.0;
 const double SGRawValue<double>::DefaultValue = 0.0L;
-const string SGRawValue<string>::DefaultValue = "";
+const char * const SGRawValue<const char *>::DefaultValue = "";



@@ -76,7 +84,7 @@ struct PathComponent
 *
 * Name: [_a-zA-Z][-._a-zA-Z0-9]*
 */
-static inline string
+static inline const string
 parse_name (const string &path, int &i)
 {
  string name = "";
@@ -204,16 +212,35 @@ parse_path (const string &path, vector<PathComponent> &components)
 ////////////////////////////////////////////////////////////////////////


+static const char *
+copy_string (const char * s)
+{
+				// FIXME: potential buffer overflow.
+				// For some reason, strnlen and
+				// strncpy cause all kinds of crashes.
+  string str = s;
+  size_t len = strlen(s);
+  char * copy = new char[str.size() + 1];
+  strcpy(copy, str.c_str());
+  return copy;
+}
+
+static bool
+compare_strings (const char * s1, const char * s2)
+{
+  return !strncmp(s1, s2, SGPropertyNode::MAX_STRING_LEN);
+}
+
 /**
 * Locate a child node by name and index.
 */
 static int
-find_child (const string &name, int index, vector<SGPropertyNode *> nodes)
+find_child (const char * name, int index, vector<SGPropertyNode *> nodes)
 {
  int nNodes = nodes.size();
  for (int i = 0; i < nNodes; i++) {
    SGPropertyNode * node = nodes[i];
-    if (node->getName() == name && node->getIndex() == index)
+    if (compare_strings(node->getName(), name) && node->getIndex() == index)
      return i;
  }
  return -1;
@@ -261,7 +288,7 @@ find_node (SGPropertyNode * current,
 				// Otherwise, a child name
  else {
    SGPropertyNode * child =
-      current->getChild(components[position].name,
+      current->getChild(components[position].name.c_str(),
 			components[position].index,
 			create);
    return find_node(child, components, position + 1, create);
@@ -319,13 +346,13 @@ SGPropertyNode::get_double () const
    return _local_val.double_val;
 }

-inline const string
+inline const char *
 SGPropertyNode::get_string () const
 {
  if (_tied)
    return _value.string_val->getValue();
  else
-    return *(_local_val.string_val);
+    return _local_val.string_val;
 }

 inline bool
@@ -384,12 +411,13 @@ SGPropertyNode::set_double (double val)
 }

 inline bool
-SGPropertyNode::set_string (const string &val)
+SGPropertyNode::set_string (const char * val)
 {
  if (_tied) {
    return _value.string_val->setValue(val);
  } else {
-    (*_local_val.string_val) = val;
+    delete _local_val.string_val;
+    _local_val.string_val = copy_string(val);
    return true;
  }
 }
@@ -443,12 +471,11 @@ SGPropertyNode::clear_value ()
 /**
 * Get the value as a string.
 */
-string
+const char *
 SGPropertyNode::make_string () const
 {
  if (!getAttribute(READ))
    return "";
-  char buf[128];

  switch (_type) {
  case ALIAS:
@@ -459,17 +486,17 @@ SGPropertyNode::make_string () const
    else
      return "false";
  case INT:
-    sprintf(buf, "%d", get_int());
-    return buf;
+    sprintf(_buffer, "%d", get_int());
+    return _buffer;
  case LONG:
-    sprintf(buf, "%ld", get_long());
-    return buf;
+    sprintf(_buffer, "%ld", get_long());
+    return _buffer;
  case FLOAT:
-    sprintf(buf, "%f", get_float());
-    return buf;
+    sprintf(_buffer, "%f", get_float());
+    return _buffer;
  case DOUBLE:
-    sprintf(buf, "%f", get_double());
-    return buf;
+    sprintf(_buffer, "%f", get_double());
+    return _buffer;
  case STRING:
  case UNSPECIFIED:
    return get_string();
@@ -485,8 +512,13 @@ SGPropertyNode::make_string () const
 void
 SGPropertyNode::trace_write () const
 {
+#if PROPS_STANDALONE
+  cerr << "TRACE: Write node " << getPath () << ", value\""
+       << make_string() << '"' << endl;
+#else
  SG_LOG(SG_GENERAL, SG_INFO, "TRACE: Write node " << getPath()
 	 << ", value\"" << make_string() << '"');
+#endif
 }

 /**
@@ -495,8 +527,13 @@ SGPropertyNode::trace_write () const
 void
 SGPropertyNode::trace_read () const
 {
+#if PROPS_STANDALONE
+  cerr << "TRACE: Write node " << getPath () << ", value \""
+       << make_string() << '"' << endl;
+#else
  SG_LOG(SG_GENERAL, SG_INFO, "TRACE: Read node " << getPath()
 	 << ", value \"" << make_string() << '"');
+#endif
 }


@@ -509,7 +546,7 @@ SGPropertyNode::trace_read () const
 * Default constructor: always creates a root node.
 */
 SGPropertyNode::SGPropertyNode ()
-  : _name(""),
+  : _name(copy_string("")),
    _index(0),
    _parent(0),
    _path_cache(0),
@@ -517,6 +554,7 @@ SGPropertyNode::SGPropertyNode ()
    _tied(false),
    _attr(READ|WRITE)
 {
+  _local_val.string_val = 0;
 }


@@ -524,14 +562,15 @@ SGPropertyNode::SGPropertyNode ()
 * Copy constructor.
 */
 SGPropertyNode::SGPropertyNode (const SGPropertyNode &node)
-  : _name(node._name),
-    _index(node._index),
+  : _index(node._index),
    _parent(0),			// don't copy the parent
    _path_cache(0),
    _type(node._type),
    _tied(node._tied),
    _attr(node._attr)
 {
+  _name = copy_string(node._name);
+  _local_val.string_val = 0;
  switch (_type) {
  case NONE:
    break;
@@ -591,7 +630,6 @@ SGPropertyNode::SGPropertyNode (const SGPropertyNode &node)
      _value.string_val = node._value.string_val->clone();
    } else {
      _tied = false;
-      _local_val.string_val = new string;
      set_string(node.get_string());
    }
    break;
@@ -602,16 +640,18 @@ SGPropertyNode::SGPropertyNode (const SGPropertyNode &node)
 /**
 * Convenience constructor.
 */
-SGPropertyNode::SGPropertyNode (const string &name,
-				int index, SGPropertyNode * parent)
-  : _name(name),
-    _index(index),
+SGPropertyNode::SGPropertyNode (const char * name,
+				int index,
+				SGPropertyNode * parent)
+  : _index(index),
    _parent(parent),
    _path_cache(0),
    _type(NONE),
    _tied(false),
    _attr(READ|WRITE)
 {
+  _name = copy_string(name);
+  _local_val.string_val = 0;
 }


@@ -620,10 +660,11 @@ SGPropertyNode::SGPropertyNode (const string &name,
 */
 SGPropertyNode::~SGPropertyNode ()
 {
+  delete _name;
  for (int i = 0; i < (int)_children.size(); i++) {
    delete _children[i];
  }
-  delete _path_cache;
+//   delete _path_cache;
  clear_value();
 }

@@ -647,7 +688,7 @@ SGPropertyNode::alias (SGPropertyNode * target)
 * Alias to another node by path.
 */
 bool
-SGPropertyNode::alias (const string &path)
+SGPropertyNode::alias (const char * path)
 {
  return alias(getNode(path, true));
 }
@@ -714,7 +755,7 @@ SGPropertyNode::getChild (int position) const
 * Get a non-const child by name and index, creating if necessary.
 */
 SGPropertyNode *
-SGPropertyNode::getChild (const string &name, int index, bool create)
+SGPropertyNode::getChild (const char * name, int index, bool create)
 {
  int pos = find_child(name, index, _children);
  if (pos >= 0) {
@@ -732,7 +773,7 @@ SGPropertyNode::getChild (const string &name, int index, bool create)
 * Get a const child by name and index.
 */
 const SGPropertyNode *
-SGPropertyNode::getChild (const string &name, int index) const
+SGPropertyNode::getChild (const char * name, int index) const
 {
  int pos = find_child(name, index, _children);
  if (pos >= 0)
@@ -746,13 +787,13 @@ SGPropertyNode::getChild (const string &name, int index) const
 * Get all children with the same name (but different indices).
 */
 vector<SGPropertyNode *>
-SGPropertyNode::getChildren (const string &name)
+SGPropertyNode::getChildren (const char * name)
 {
  vector<SGPropertyNode *> children;
  int max = _children.size();

  for (int i = 0; i < max; i++)
-    if (_children[i]->getName() == name)
+    if (compare_strings(_children[i]->getName(), name))
      children.push_back(_children[i]);

  sort(children.begin(), children.end(), CompareIndices());
@@ -764,13 +805,13 @@ SGPropertyNode::getChildren (const string &name)
 * Get all children const with the same name (but different indices).
 */
 vector<const SGPropertyNode *>
-SGPropertyNode::getChildren (const string &name) const
+SGPropertyNode::getChildren (const char * name) const
 {
  vector<const SGPropertyNode *> children;
  int max = _children.size();

  for (int i = 0; i < max; i++)
-    if (_children[i]->getName() == name)
+    if (compare_strings(_children[i]->getName(), name))
      children.push_back(_children[i]);

  sort(children.begin(), children.end(), CompareIndices());
@@ -778,7 +819,7 @@ SGPropertyNode::getChildren (const string &name) const
 }


-string
+const char *
 SGPropertyNode::getPath (bool simplify) const
 {
  if (_parent == 0)
@@ -792,7 +833,7 @@ SGPropertyNode::getPath (bool simplify) const
    sprintf(buffer, "[%d]", _index);
    path += buffer;
  }
-  return path;
+  return path.c_str();
 }

 SGPropertyNode::Type
@@ -831,7 +872,7 @@ SGPropertyNode::getBoolValue () const
    return get_double() == 0.0L ? false : true;
  case STRING:
  case UNSPECIFIED:
-    return (get_string() == "true" || getDoubleValue() != 0.0L);
+    return (compare_strings(get_string(), "true") || getDoubleValue() != 0.0L);
  case NONE:
  default:
    return SGRawValue<bool>::DefaultValue;
@@ -864,7 +905,7 @@ SGPropertyNode::getIntValue () const
    return int(get_double());
  case STRING:
  case UNSPECIFIED:
-    return atoi(get_string().c_str());
+    return atoi(get_string());
  case NONE:
  default:
    return SGRawValue<int>::DefaultValue;
@@ -897,7 +938,7 @@ SGPropertyNode::getLongValue () const
    return long(get_double());
  case STRING:
  case UNSPECIFIED:
-    return strtol(get_string().c_str(), 0, 0);
+    return strtol(get_string(), 0, 0);
  case NONE:
  default:
    return SGRawValue<long>::DefaultValue;
@@ -930,7 +971,7 @@ SGPropertyNode::getFloatValue () const
    return float(get_double());
  case STRING:
  case UNSPECIFIED:
-    return atof(get_string().c_str());
+    return atof(get_string());
  case NONE:
  default:
    return SGRawValue<float>::DefaultValue;
@@ -964,14 +1005,14 @@ SGPropertyNode::getDoubleValue () const
    return get_double();
  case STRING:
  case UNSPECIFIED:
-    return strtod(get_string().c_str(), 0);
+    return strtod(get_string(), 0);
  case NONE:
  default:
    return SGRawValue<double>::DefaultValue;
  }
 }

-string
+const char *
 SGPropertyNode::getStringValue () const
 {
 				// Shortcut for common case
@@ -981,7 +1022,7 @@ SGPropertyNode::getStringValue () const
  if (getAttribute(TRACE_READ))
    trace_read();
  if (!getAttribute(READ))
-    return SGRawValue<string>::DefaultValue;
+    return SGRawValue<const char *>::DefaultValue;
  return make_string();
 }

@@ -1238,7 +1279,7 @@ SGPropertyNode::setDoubleValue (double value)
 }

 bool
-SGPropertyNode::setStringValue (string value)
+SGPropertyNode::setStringValue (const char * value)
 {
 				// Shortcut for common case
  if (_attr == (READ|WRITE) && _type == STRING)
@@ -1248,7 +1289,6 @@ SGPropertyNode::setStringValue (string value)
  TEST_WRITE;
  if (_type == NONE || _type == UNSPECIFIED) {
    clear_value();
-    _local_val.string_val = new string;
    _type = STRING;
  }

@@ -1257,19 +1297,20 @@ SGPropertyNode::setStringValue (string value)
    result = _value.alias->setStringValue(value);
    break;
  case BOOL:
-    result = set_bool((value == "true" || atoi(value.c_str())) ? true : false);
+    result = set_bool((compare_strings(value, "true")
+		       || atoi(value)) ? true : false);
    break;
  case INT:
-    result = set_int(atoi(value.c_str()));
+    result = set_int(atoi(value));
    break;
  case LONG:
-    result = set_long(strtol(value.c_str(), 0, 0));
+    result = set_long(strtol(value, 0, 0));
    break;
  case FLOAT:
-    result = set_float(atof(value.c_str()));
+    result = set_float(atof(value));
    break;
  case DOUBLE:
-    result = set_double(strtod(value.c_str(), 0));
+    result = set_double(strtod(value, 0));
    break;
  case STRING:
  case UNSPECIFIED:
@@ -1286,13 +1327,12 @@ SGPropertyNode::setStringValue (string value)
 }

 bool
-SGPropertyNode::setUnspecifiedValue (string value)
+SGPropertyNode::setUnspecifiedValue (const char * value)
 {
  bool result = false;
  TEST_WRITE;
  if (_type == NONE) {
    clear_value();
-    _local_val.string_val = new string;
    _type = UNSPECIFIED;
  }

@@ -1301,19 +1341,20 @@ SGPropertyNode::setUnspecifiedValue (string value)
    result = _value.alias->setUnspecifiedValue(value);
    break;
  case BOOL:
-    result = set_bool((value == "true" || atoi(value.c_str())) ? true : false);
+    result = set_bool((compare_strings(value, "true")
+		       || atoi(value)) ? true : false);
    break;
  case INT:
-    result = set_int(atoi(value.c_str()));
+    result = set_int(atoi(value));
    break;
  case LONG:
-    result = set_long(strtol(value.c_str(), 0, 0));
+    result = set_long(strtol(value, 0, 0));
    break;
  case FLOAT:
-    result = set_float(atof(value.c_str()));
+    result = set_float(atof(value));
    break;
  case DOUBLE:
-    result = set_double(strtod(value.c_str(), 0));
+    result = set_double(strtod(value, 0));
    break;
  case STRING:
  case UNSPECIFIED:
@@ -1441,7 +1482,7 @@ SGPropertyNode::tie (const SGRawValue<double> &rawValue, bool useDefault)
 }

 bool
-SGPropertyNode::tie (const SGRawValue<string> &rawValue, bool useDefault)
+SGPropertyNode::tie (const SGRawValue<const char *> &rawValue, bool useDefault)
 {
  if (_type == ALIAS || _tied)
    return false;
@@ -1457,7 +1498,7 @@ SGPropertyNode::tie (const SGRawValue<string> &rawValue, bool useDefault)
  _value.string_val = rawValue.clone();

  if (useDefault)
-    setStringValue(old_val);
+    setStringValue(old_val.c_str());

  return true;
 }
@@ -1509,7 +1550,7 @@ SGPropertyNode::untie ()
    string val = getStringValue();
    clear_value();
    _type = STRING;
-    _local_val.string_val = new string(val);
+    _local_val.string_val = copy_string(val.c_str());
    break;
  }
  case NONE:
@@ -1540,25 +1581,28 @@ SGPropertyNode::getRootNode () const
 }

 SGPropertyNode *
-SGPropertyNode::getNode (const string &relative_path, bool create)
+SGPropertyNode::getNode (const char * relative_path, bool create)
 {
-  if (_path_cache == 0)
-    _path_cache = new cache_map;
+//   if (_path_cache == 0)
+//     _path_cache = new cache_map;

-  SGPropertyNode * result = (*_path_cache)[relative_path];
-  if (result == 0) {
-    vector<PathComponent> components;
-    parse_path(relative_path, components);
-    result = find_node(this, components, 0, create);
-    if (result != 0)
-      (*_path_cache)[relative_path] = result;
-  }
+//   SGPropertyNode * result = (*_path_cache)[relative_path];
+//   if (result == 0) {
+//     vector<PathComponent> components;
+//     parse_path(relative_path, components);
+//     result = find_node(this, components, 0, create);
+//     if (result != 0)
+//       (*_path_cache)[relative_path] = result;
+//   }
  
-  return result;
+//   return result;
+  vector<PathComponent> components;
+  parse_path(relative_path, components);
+  return find_node(this, components, 0, create);
 }

 SGPropertyNode *
-SGPropertyNode::getNode (const string &relative_path, int index, bool create)
+SGPropertyNode::getNode (const char * relative_path, int index, bool create)
 {
  vector<PathComponent> components;
  parse_path(relative_path, components);
@@ -1568,13 +1612,13 @@ SGPropertyNode::getNode (const string &relative_path, int index, bool create)
 }

 const SGPropertyNode *
-SGPropertyNode::getNode (const string &relative_path) const
+SGPropertyNode::getNode (const char * relative_path) const
 {
  return ((SGPropertyNode *)this)->getNode(relative_path, false);
 }

 const SGPropertyNode *
-SGPropertyNode::getNode (const string &relative_path, int index) const
+SGPropertyNode::getNode (const char * relative_path, int index) const
 {
  return ((SGPropertyNode *)this)->getNode(relative_path, index, false);
 }
@@ -1589,7 +1633,7 @@ SGPropertyNode::getNode (const string &relative_path, int index) const
 * Test whether another node has a value attached.
 */
 bool
-SGPropertyNode::hasValue (const string &relative_path) const
+SGPropertyNode::hasValue (const char * relative_path) const
 {
  const SGPropertyNode * node = getNode(relative_path);
  return (node == 0 ? false : node->hasValue());
@@ -1600,7 +1644,7 @@ SGPropertyNode::hasValue (const string &relative_path) const
 * Get the value type for another node.
 */
 SGPropertyNode::Type
-SGPropertyNode::getType (const string &relative_path) const
+SGPropertyNode::getType (const char * relative_path) const
 {
  const SGPropertyNode * node = getNode(relative_path);
  return (node == 0 ? UNSPECIFIED : (Type)(node->getType()));
@@ -1611,7 +1655,7 @@ SGPropertyNode::getType (const string &relative_path) const
 * Get a bool value for another node.
 */
 bool
-SGPropertyNode::getBoolValue (const string &relative_path,
+SGPropertyNode::getBoolValue (const char * relative_path,
 			      bool defaultValue) const
 {
  const SGPropertyNode * node = getNode(relative_path);
@@ -1623,7 +1667,7 @@ SGPropertyNode::getBoolValue (const string &relative_path,
 * Get an int value for another node.
 */
 int
-SGPropertyNode::getIntValue (const string &relative_path,
+SGPropertyNode::getIntValue (const char * relative_path,
 			     int defaultValue) const
 {
  const SGPropertyNode * node = getNode(relative_path);
@@ -1635,7 +1679,7 @@ SGPropertyNode::getIntValue (const string &relative_path,
 * Get a long value for another node.
 */
 long
-SGPropertyNode::getLongValue (const string &relative_path,
+SGPropertyNode::getLongValue (const char * relative_path,
 			      long defaultValue) const
 {
  const SGPropertyNode * node = getNode(relative_path);
@@ -1647,7 +1691,7 @@ SGPropertyNode::getLongValue (const string &relative_path,
 * Get a float value for another node.
 */
 float
-SGPropertyNode::getFloatValue (const string &relative_path,
+SGPropertyNode::getFloatValue (const char * relative_path,
 			       float defaultValue) const
 {
  const SGPropertyNode * node = getNode(relative_path);
@@ -1659,7 +1703,7 @@ SGPropertyNode::getFloatValue (const string &relative_path,
 * Get a double value for another node.
 */
 double
-SGPropertyNode::getDoubleValue (const string &relative_path,
+SGPropertyNode::getDoubleValue (const char * relative_path,
 				double defaultValue) const
 {
  const SGPropertyNode * node = getNode(relative_path);
@@ -1670,9 +1714,9 @@ SGPropertyNode::getDoubleValue (const string &relative_path,
 /**
 * Get a string value for another node.
 */
-string
-SGPropertyNode::getStringValue (const string &relative_path,
-				string defaultValue) const
+const char *
+SGPropertyNode::getStringValue (const char * relative_path,
+				const char * defaultValue) const
 {
  const SGPropertyNode * node = getNode(relative_path);
  return (node == 0 ? defaultValue : node->getStringValue());
@@ -1683,7 +1727,7 @@ SGPropertyNode::getStringValue (const string &relative_path,
 * Set a bool value for another node.
 */
 bool
-SGPropertyNode::setBoolValue (const string &relative_path, bool value)
+SGPropertyNode::setBoolValue (const char * relative_path, bool value)
 {
  return getNode(relative_path, true)->setBoolValue(value);
 }
@@ -1693,7 +1737,7 @@ SGPropertyNode::setBoolValue (const string &relative_path, bool value)
 * Set an int value for another node.
 */
 bool
-SGPropertyNode::setIntValue (const string &relative_path, int value)
+SGPropertyNode::setIntValue (const char * relative_path, int value)
 {
  return getNode(relative_path, true)->setIntValue(value);
 }
@@ -1703,7 +1747,7 @@ SGPropertyNode::setIntValue (const string &relative_path, int value)
 * Set a long value for another node.
 */
 bool
-SGPropertyNode::setLongValue (const string &relative_path, long value)
+SGPropertyNode::setLongValue (const char * relative_path, long value)
 {
  return getNode(relative_path, true)->setLongValue(value);
 }
@@ -1713,7 +1757,7 @@ SGPropertyNode::setLongValue (const string &relative_path, long value)
 * Set a float value for another node.
 */
 bool
-SGPropertyNode::setFloatValue (const string &relative_path, float value)
+SGPropertyNode::setFloatValue (const char * relative_path, float value)
 {
  return getNode(relative_path, true)->setFloatValue(value);
 }
@@ -1723,7 +1767,7 @@ SGPropertyNode::setFloatValue (const string &relative_path, float value)
 * Set a double value for another node.
 */
 bool
-SGPropertyNode::setDoubleValue (const string &relative_path, double value)
+SGPropertyNode::setDoubleValue (const char * relative_path, double value)
 {
  return getNode(relative_path, true)->setDoubleValue(value);
 }
@@ -1733,7 +1777,7 @@ SGPropertyNode::setDoubleValue (const string &relative_path, double value)
 * Set a string value for another node.
 */
 bool
-SGPropertyNode::setStringValue (const string &relative_path, string value)
+SGPropertyNode::setStringValue (const char * relative_path, const char * value)
 {
  return getNode(relative_path, true)->setStringValue(value);
 }
@@ -1743,7 +1787,8 @@ SGPropertyNode::setStringValue (const string &relative_path, string value)
 * Set an unknown value for another node.
 */
 bool
-SGPropertyNode::setUnspecifiedValue (const string &relative_path, string value)
+SGPropertyNode::setUnspecifiedValue (const char * relative_path,
+				     const char * value)
 {
  return getNode(relative_path, true)->setUnspecifiedValue(value);
 }
@@ -1753,7 +1798,7 @@ SGPropertyNode::setUnspecifiedValue (const string &relative_path, string value)
 * Test whether another node is tied.
 */
 bool
-SGPropertyNode::isTied (const string &relative_path) const
+SGPropertyNode::isTied (const char * relative_path) const
 {
  const SGPropertyNode * node = getNode(relative_path);
  return (node == 0 ? false : node->isTied());
@@ -1764,7 +1809,7 @@ SGPropertyNode::isTied (const string &relative_path) const
 * Tie a node reached by a relative path, creating it if necessary.
 */
 bool
-SGPropertyNode::tie (const string &relative_path,
+SGPropertyNode::tie (const char * relative_path,
 		     const SGRawValue<bool> &rawValue,
 		     bool useDefault)
 {
@@ -1776,7 +1821,7 @@ SGPropertyNode::tie (const string &relative_path,
 * Tie a node reached by a relative path, creating it if necessary.
 */
 bool
-SGPropertyNode::tie (const string &relative_path,
+SGPropertyNode::tie (const char * relative_path,
 		     const SGRawValue<int> &rawValue,
 		     bool useDefault)
 {
@@ -1788,7 +1833,7 @@ SGPropertyNode::tie (const string &relative_path,
 * Tie a node reached by a relative path, creating it if necessary.
 */
 bool
-SGPropertyNode::tie (const string &relative_path,
+SGPropertyNode::tie (const char * relative_path,
 		     const SGRawValue<long> &rawValue,
 		     bool useDefault)
 {
@@ -1800,7 +1845,7 @@ SGPropertyNode::tie (const string &relative_path,
 * Tie a node reached by a relative path, creating it if necessary.
 */
 bool
-SGPropertyNode::tie (const string &relative_path,
+SGPropertyNode::tie (const char * relative_path,
 		     const SGRawValue<float> &rawValue,
 		     bool useDefault)
 {
@@ -1812,7 +1857,7 @@ SGPropertyNode::tie (const string &relative_path,
 * Tie a node reached by a relative path, creating it if necessary.
 */
 bool
-SGPropertyNode::tie (const string &relative_path,
+SGPropertyNode::tie (const char * relative_path,
 		     const SGRawValue<double> &rawValue,
 		     bool useDefault)
 {
@@ -1824,8 +1869,8 @@ SGPropertyNode::tie (const string &relative_path,
 * Tie a node reached by a relative path, creating it if necessary.
 */
 bool
-SGPropertyNode::tie (const string &relative_path,
-		     const SGRawValue<string> &rawValue,
+SGPropertyNode::tie (const char * relative_path,
+		     const SGRawValue<const char *> &rawValue,
 		     bool useDefault)
 {
  return getNode(relative_path, true)->tie(rawValue, useDefault);
@@ -1836,7 +1881,7 @@ SGPropertyNode::tie (const string &relative_path,
 * Attempt to untie another node reached by a relative path.
 */
 bool
-SGPropertyNode::untie (const string &relative_path)
+SGPropertyNode::untie (const char * relative_path)
 {
  SGPropertyNode * node = getNode(relative_path);
  return (node == 0 ? false : node->untie());
--- a/simgear/misc/props.hxx
+++ b/simgear/misc/props.hxx
@@ -12,16 +12,30 @@
 #ifndef __PROPS_HXX
 #define __PROPS_HXX

-#include <simgear/compiler.h>
-#include <simgear/debug/logstream.hxx>
+#ifndef PROPS_STANDALONE
+#define PROPS_STANDALONE 0
+#endif

-#include <stdio.h>
-
-#include STL_STRING
 #include <vector>
 #include <map>
-#include STL_IOSTREAM

+#if PROPS_STANDALONE
+
+#include <string>
+#include <iostream>
+
+using std::string;
+using std::vector;
+using std::map;
+using std::istream;
+using std::ostream;
+
+#else
+
+#include <simgear/compiler.h>
+#include <simgear/debug/logstream.hxx>
+#include STL_STRING
+#include STL_IOSTREAM
 SG_USING_STD(string);
 SG_USING_STD(vector);
 SG_USING_STD(map);
@@ -30,6 +44,9 @@ SG_USING_STD(istream);
 SG_USING_STD(ostream);
 #endif

+#endif
+
+
 #ifdef NONE
 #pragma warn A sloppy coder has defined NONE as a macro!
 #undef NONE
@@ -444,6 +461,13 @@ class SGPropertyNode
 {
 public:

+  /**
+   * Public constants.
+   */
+  enum {
+    MAX_STRING_LEN = 1024
+  };
+
  /**
   * Property value types.
   */
@@ -507,7 +531,7 @@ public:
  /**
   * Get the node's simple (XML) name.
   */
-  const string &getName () const { return _name; }
+  const char * getName () const { return _name; }


  /**
@@ -554,26 +578,26 @@ public:
  /**
   * Get a child node by name and index.
   */
-  SGPropertyNode * getChild (const string &name, int index = 0,
+  SGPropertyNode * getChild (const char * name, int index = 0,
 			     bool create = false);


  /**
   * Get a const child node by name and index.
   */
-  const SGPropertyNode * getChild (const string &name, int index = 0) const;
+  const SGPropertyNode * getChild (const char * name, int index = 0) const;


  /**
   * Get a vector of all children with the specified name.
   */
-  vector<SGPropertyNode *> getChildren (const string &name);
+  vector<SGPropertyNode *> getChildren (const char * name);


  /**
   * Get a vector all all children (const) with the specified name.
   */
-  vector<const SGPropertyNode *> getChildren (const string &name) const;
+  vector<const SGPropertyNode *> getChildren (const char * name) const;


  //
@@ -590,7 +614,7 @@ public:
  /**
   * Alias this node's leaf value to another's by relative path.
   */
-  bool alias (const string &path);
+  bool alias (const char * path);


  /**
@@ -625,7 +649,7 @@ public:
  /**
   * Get the path to this node from the root.
   */
-  string getPath (bool simplify = false) const;
+  const char * getPath (bool simplify = false) const;


  /**
@@ -643,7 +667,7 @@ public:
  /**
   * Get a pointer to another node by relative path.
   */
-  SGPropertyNode * getNode (const string &relative_path, bool create = false);
+  SGPropertyNode * getNode (const char * relative_path, bool create = false);


  /**
@@ -656,14 +680,14 @@ public:
   * provided overrides any given in the path itself for the last
   * component.
   */
-  SGPropertyNode * getNode (const string &relative_path, int index,
+  SGPropertyNode * getNode (const char * relative_path, int index,
 			    bool create = false);


  /**
   * Get a const pointer to another node by relative path.
   */
-  const SGPropertyNode * getNode (const string &relative_path) const;
+  const SGPropertyNode * getNode (const char * relative_path) const;


  /**
@@ -672,7 +696,7 @@ public:
   * This method leaves the index off the last member of the path,
   * so that the user can specify it separate.
   */
-  const SGPropertyNode * getNode (const string &relative_path,
+  const SGPropertyNode * getNode (const char * relative_path,
 				  int index) const;


@@ -750,7 +774,7 @@ public:
  /**
   * Get a string value for this node.
   */
-  string getStringValue () const;
+  const char * getStringValue () const;



@@ -787,13 +811,13 @@ public:
  /**
   * Set a string value for this node.
   */
-  bool setStringValue (string value);
+  bool setStringValue (const char * value);


  /**
   * Set a value of unspecified type for this node.
   */
-  bool setUnspecifiedValue (string value);
+  bool setUnspecifiedValue (const char * value);


  //
@@ -840,7 +864,7 @@ public:
  /**
   * Bind this node to an external string source.
   */
-  bool tie (const SGRawValue<string> &rawValue, bool useDefault = true);
+  bool tie (const SGRawValue<const char *> &rawValue, bool useDefault = true);


  /**
@@ -858,151 +882,151 @@ public:
  /**
   * Get another node's type.
   */
-  Type getType (const string &relative_path) const;
+  Type getType (const char * relative_path) const;


  /**
   * Test whether another node has a leaf value.
   */
-  bool hasValue (const string &relative_path) const;
+  bool hasValue (const char * relative_path) const;


  /**
   * Get another node's value as a bool.
   */
-  bool getBoolValue (const string &relative_path,
+  bool getBoolValue (const char * relative_path,
 		     bool defaultValue = false) const;


  /**
   * Get another node's value as an int.
   */
-  int getIntValue (const string &relative_path,
+  int getIntValue (const char * relative_path,
 		   int defaultValue = 0) const;


  /**
   * Get another node's value as a long int.
   */
-  long getLongValue (const string &relative_path,
+  long getLongValue (const char * relative_path,
 		     long defaultValue = 0L) const;


  /**
   * Get another node's value as a float.
   */
-  float getFloatValue (const string &relative_path,
+  float getFloatValue (const char * relative_path,
 		       float defaultValue = 0.0) const;


  /**
   * Get another node's value as a double.
   */
-  double getDoubleValue (const string &relative_path,
+  double getDoubleValue (const char * relative_path,
 			 double defaultValue = 0.0L) const;


  /**
   * Get another node's value as a string.
   */
-  string getStringValue (const string &relative_path,
-			 string defaultValue = "") const;
+  const char * getStringValue (const char * relative_path,
+			       const char * defaultValue = "") const;


  /**
   * Set another node's value as a bool.
   */
-  bool setBoolValue (const string &relative_path, bool value);
+  bool setBoolValue (const char * relative_path, bool value);


  /**
   * Set another node's value as an int.
   */
-  bool setIntValue (const string &relative_path, int value);
+  bool setIntValue (const char * relative_path, int value);


  /**
   * Set another node's value as a long int.
   */
-  bool setLongValue (const string &relative_path, long value);
+  bool setLongValue (const char * relative_path, long value);


  /**
   * Set another node's value as a float.
   */
-  bool setFloatValue (const string &relative_path, float value);
+  bool setFloatValue (const char * relative_path, float value);


  /**
   * Set another node's value as a double.
   */
-  bool setDoubleValue (const string &relative_path, double value);
+  bool setDoubleValue (const char * relative_path, double value);


  /**
   * Set another node's value as a string.
   */
-  bool setStringValue (const string &relative_path, string value);
+  bool setStringValue (const char * relative_path, const char * value);


  /**
   * Set another node's value with no specified type.
   */
-  bool setUnspecifiedValue (const string &relative_path, string value);
+  bool setUnspecifiedValue (const char * relative_path, const char * value);


  /**
   * Test whether another node is bound to an external data source.
   */
-  bool isTied (const string &relative_path) const;
+  bool isTied (const char * relative_path) const;


  /**
   * Bind another node to an external bool source.
   */
-  bool tie (const string &relative_path, const SGRawValue<bool> &rawValue,
+  bool tie (const char * relative_path, const SGRawValue<bool> &rawValue,
 	    bool useDefault = true);


  /**
   * Bind another node to an external int source.
   */
-  bool tie (const string &relative_path, const SGRawValue<int> &rawValue,
+  bool tie (const char * relative_path, const SGRawValue<int> &rawValue,
 	    bool useDefault = true);


  /**
   * Bind another node to an external long int source.
   */
-  bool tie (const string &relative_path, const SGRawValue<long> &rawValue,
+  bool tie (const char * relative_path, const SGRawValue<long> &rawValue,
 	    bool useDefault = true);


  /**
   * Bind another node to an external float source.
   */
-  bool tie (const string &relative_path, const SGRawValue<float> &rawValue,
+  bool tie (const char * relative_path, const SGRawValue<float> &rawValue,
 	    bool useDefault = true);


  /**
   * Bind another node to an external double source.
   */
-  bool tie (const string &relative_path, const SGRawValue<double> &rawValue,
+  bool tie (const char * relative_path, const SGRawValue<double> &rawValue,
 	    bool useDefault = true);


  /**
   * Bind another node to an external string source.
   */
-  bool tie (const string &relative_path, const SGRawValue<string> &rawValue,
+  bool tie (const char * relative_path, const SGRawValue<const char *> &rawValue,
 	    bool useDefault = true);


  /**
   * Unbind another node from any external data source.
   */
-  bool untie (const string &relative_path);
+  bool untie (const char * relative_path);


 protected:
@@ -1011,7 +1035,7 @@ protected:
  /**
   * Protected constructor for making new nodes on demand.
   */
-  SGPropertyNode (const string &name, int index, SGPropertyNode * parent);
+  SGPropertyNode (const char * name, int index, SGPropertyNode * parent);


 private:
@@ -1022,7 +1046,7 @@ private:
  long get_long () const;
  float get_float () const;
  double get_double () const;
-  const string get_string () const;
+  const char * get_string () const;

 				// Set the raw value
  bool set_bool (bool value);
@@ -1030,7 +1054,7 @@ private:
  bool set_long (long value);
  bool set_float (float value);
  bool set_double (double value);
-  bool set_string (const string &value);
+  bool set_string (const char * value);


  /**
@@ -1042,7 +1066,7 @@ private:
  /**
   * Get the value as a string.
   */
-  string make_string () const;
+  const char * make_string () const;


  /**
@@ -1056,7 +1080,9 @@ private:
   */
  void trace_write () const;

-  string _name;
+  mutable char _buffer[MAX_STRING_LEN+1];
+
+  const char * _name;
  int _index;
  SGPropertyNode * _parent;
  vector<SGPropertyNode *> _children;
@@ -1074,7 +1100,7 @@ private:
    SGRawValue<long> * long_val;
    SGRawValue<float> * float_val;
    SGRawValue<double> * double_val;
-    SGRawValue<string> * string_val;
+    SGRawValue<const char *> * string_val;
  } _value;

  union {
@@ -1083,7 +1109,7 @@ private:
    long long_val;
    float float_val;
    double double_val;
-    string * string_val;
+    const char * string_val;
  } _local_val;


--- a/simgear/misc/props_io.cxx
+++ b/simgear/misc/props_io.cxx
@@ -235,9 +235,9 @@ PropsVisitor::endElement (const char * name)
    } else if (st.type == "double") {
      ret = st.node->setDoubleValue(strtod(_data.c_str(), 0));
    } else if (st.type == "string") {
-      ret = st.node->setStringValue(_data);
+      ret = st.node->setStringValue(_data.c_str());
    } else if (st.type == "unspecified") {
-      ret = st.node->setUnspecifiedValue(_data);
+      ret = st.node->setUnspecifiedValue(_data.c_str());
    } else {
      string message = "Unrecognized data type '";
      message += st.type;
@@ -438,7 +438,7 @@ writeNode (ostream &output, const SGPropertyNode * node,
  if (!write_all && !isArchivable(node))
    return true;		// Everything's OK, but we won't write.

-  const string &name = node->getName();
+  const string name = node->getName();
  int nChildren = node->nChildren();

 				// If there is a literal value,
--- a/simgear/misc/props_test.cxx
+++ b/simgear/misc/props_test.cxx
@@ -53,7 +53,7 @@ static double getNum (int index) { return 1.0 / index; }
 static void
 show_values (const SGPropertyNode * node)
 {
-  cout << "Bool: " << node->getBoolValue() << endl;
+  cout << "Bool: " << (node->getBoolValue() ? "true" : "false") << endl;
  cout << "Int: " << node->getIntValue() << endl;
  cout << "Float: " << node->getFloatValue() << endl;
  cout << "Double: " << node->getDoubleValue() << endl;
@@ -275,7 +275,7 @@ test_value ()
 static void
 dump_node (const SGPropertyNode * node)
 {
-  writeProperties(cout, node);
+  writeProperties(cout, node, true);
 }

 static void
@@ -333,11 +333,15 @@ int main (int ac, char ** av)
  test_property_nodes();

  for (int i = 1; i < ac; i++) {
-    cout << "Reading " << av[i] << endl;
-    SGPropertyNode root;
-    readProperties(av[i], &root);
-    writeProperties(cout, &root);
-    cout << endl;
+    try {
+      cout << "Reading " << av[i] << endl;
+      SGPropertyNode root;
+      readProperties(av[i], &root);
+      writeProperties(cout, &root, true);
+      cout << endl;
+    } catch (string &message) {
+      cout << "Aborted with " << message << endl;
+    }
  }

  return 0;