Speed up String2Vector.

PiperOrigin-RevId: 612767185
Change-Id: I4a4de5e03bbd6653be7ccb3e730ad64a335e17b0

src/user/user_api.cc

@@ -490,7 +490,7 @@ mjtByte mjm_setInStringVec(mjStringVec dest, int i, const char* text) {
 // split text and copy into string array
 void mjm_setStringVec(mjStringVec dest, const char* text) {
   std::vector<std::string>* v = reinterpret_cast<std::vector<std::string>*>(dest);
-  mjXUtil::String2Vector(text, *v);
+  *v = mjXUtil::String2Vector<std::string>(text);
 }
 
 

src/user/user_composite.cc

@@ -420,9 +420,9 @@ bool mjCComposite::MakeParticle(mjCModel* model, mjmBody* body, char* error, int
       }
     }
     mjXUtil::Vector2String(userface, face);
-    } else {
+  } else {
     dim = 2;  // can only load a surface for now
-    mjXUtil::String2Vector(userface, face);
+    face = mjXUtil::String2Vector<int>(userface);
     for (int i=0; i<face.size(); face[i++]--) {};
     mjXUtil::Vector2String(userface, face);
   }
@@ -439,7 +439,7 @@ bool mjCComposite::MakeParticle(mjCModel* model, mjmBody* body, char* error, int
     }
   }
   if (!userface.empty()) {
-    mjXUtil::String2Vector(userface, face);
+    face = mjXUtil::String2Vector<int>(userface);
     for (int j=0; j<face.size()/3; j++) {
       mjtNum area[3];
       mjtNum edge1[3];
@@ -1306,7 +1306,7 @@ void mjCComposite::MakeSkin2(mjCModel* model, mjtNum inflate) {
   // copy skin from existing mesh
   if (type==mjCOMPTYPE_PARTICLE && username.empty()) {
     std::vector<int> skinface;
-    mjXUtil::String2Vector(userface, skinface);
+    skinface = mjXUtil::String2Vector<int>(userface);
     int nvert = uservert.size()/3;
 
     for (int j=0; j<2; j++) {

src/xml/xml_native_reader.cc

@@ -1304,18 +1304,15 @@ void mjXReader::OneFlex(XMLElement* elem, mjmFlex* pflex) {
     mjm_setStringVec(pflex->vertbody, text.c_str());
   }
   if (ReadAttrTxt(elem, "vertex", text)) {
-    std::vector<double> vert;
+    std::vector<double> vert = String2Vector<double>(text);
-    String2Vector(text, vert);
     mjm_setDouble(pflex->vert, vert.data(), vert.size());
   }
   if (ReadAttrTxt(elem, "element", text, true)) {
-    std::vector<int> elem;
+    std::vector<int> elem = String2Vector<int>(text);
-    String2Vector(text, elem);
     mjm_setInt(pflex->elem, elem.data(), elem.size());
   }
   if (ReadAttrTxt(elem, "texcoord", text)) {
-    std::vector<float> texcoord;
+    std::vector<float> texcoord = String2Vector<float>(text);
-    String2Vector(text, texcoord);
     mjm_setFloat(pflex->texcoord, texcoord.data(), texcoord.size());
   }
 
@@ -1447,22 +1444,19 @@ void mjXReader::OneSkin(XMLElement* elem, mjmSkin* pskin) {
 
   // read vertex data
   if (ReadAttrTxt(elem, "vertex", text)) {
-    std::vector<float> vert;
+    std::vector<float> vert = String2Vector<float>(text);
-    String2Vector(text, vert);
     mjm_setFloat(pskin->vert, vert.data(), vert.size());
   }
 
   // read texcoord data
   if (ReadAttrTxt(elem, "texcoord", text)) {
-    std::vector<float> texcoord;
+    std::vector<float> texcoord = String2Vector<float>(text);
-    String2Vector(text, texcoord);
     mjm_setFloat(pskin->texcoord, texcoord.data(), texcoord.size());
   }
 
   // read user face data
   if (ReadAttrTxt(elem, "face", text)) {
-    std::vector<int> face;
+    std::vector<int> face = String2Vector<int>(text);
-    String2Vector(text, face);
     mjm_setInt(pskin->face, face.data(), face.size());
   }
 
@@ -1490,15 +1484,13 @@ void mjXReader::OneSkin(XMLElement* elem, mjmSkin* pskin) {
     bindquat.push_back(data[3]);
 
     // read vertid
-    vector<int> tempid;
     ReadAttrTxt(bone, "vertid", text, true);
-    String2Vector(text, tempid);
+    vector<int> tempid = String2Vector<int>(text);
     mjm_appendIntVec(pskin->vertid, tempid.data(), tempid.size());
 
     // read vertweight
-    vector<float> tempweight;
     ReadAttrTxt(bone, "vertweight", text, true);
-    String2Vector(text, tempweight);
+    vector<float> tempweight = String2Vector<float>(text);
     mjm_appendFloatVec(pskin->vertweight, tempweight.data(), tempweight.size());
 
     // advance to next bone
@@ -2277,8 +2269,8 @@ void mjXReader::OneComposite(XMLElement* elem, mjmBody* pbody, mjmDefault* def)
   ReadAttrTxt(elem, "curve", curves);
   ReadAttrTxt(elem, "initial", comp.initial);
   ReadAttr(elem, "size", 3, comp.size, text, false, false);
-  if (ReadAttrTxt(elem, "vertex", text)){
+  if (ReadAttrTxt(elem, "vertex", text)) {
-    String2Vector(text, comp.uservert);
+    comp.uservert = String2Vector<float>(text);
   }
 
   // shell
@@ -2521,13 +2513,13 @@ void mjXReader::OneFlexcomp(XMLElement* elem, mjmBody* pbody) {
     fcomp.rigid = (n==1);
   }
   if (ReadAttrTxt(elem, "point", text)){
-    String2Vector(text, fcomp.point);
+    fcomp.point = String2Vector<mjtNum>(text);
   }
   if (ReadAttrTxt(elem, "element", text)){
-    String2Vector(text, fcomp.element);
+    fcomp.element = String2Vector<int>(text);
   }
   if (ReadAttrTxt(elem, "texcoord", text)) {
-    String2Vector(text, fcomp.texcoord);
+    fcomp.texcoord = String2Vector<float>(text);
   }
 
   // edge
@@ -2566,22 +2558,22 @@ void mjXReader::OneFlexcomp(XMLElement* elem, mjmBody* pbody) {
   XMLElement* epin = FirstChildElement(elem, "pin");
   while (epin) {
     // accumulate id, coord, range
-    vector<int> temp;
+    if (ReadAttrTxt(epin, "id", text)) {
-    if (ReadAttrTxt(epin, "id", text)){
+      vector<int> v = String2Vector<int>(text);
-      String2Vector(text, temp);
+      fcomp.pinid.insert(fcomp.pinid.end(), v.begin(), v.end());
-      fcomp.pinid.insert(fcomp.pinid.end(), temp.begin(), temp.end());
     }
-    if (ReadAttrTxt(epin, "range", text)){
+    if (ReadAttrTxt(epin, "range", text)) {
-      String2Vector(text, temp);
+      vector<int> v = String2Vector<int>(text);
-      fcomp.pinrange.insert(fcomp.pinrange.end(), temp.begin(), temp.end());
+      fcomp.pinrange.insert(fcomp.pinrange.end(), v.begin(), v.end());
     }
-    if (ReadAttrTxt(epin, "grid", text)){
+    if (ReadAttrTxt(epin, "grid", text)) {
-      String2Vector(text, temp);
+
-      fcomp.pingrid.insert(fcomp.pingrid.end(), temp.begin(), temp.end());
+      vector<int> v = String2Vector<int>(text);
+      fcomp.pingrid.insert(fcomp.pingrid.end(), v.begin(), v.end());
     }
-    if (ReadAttrTxt(epin, "gridrange", text)){
+    if (ReadAttrTxt(epin, "gridrange", text)) {
-      String2Vector(text, temp);
+      vector<int> v = String2Vector<int>(text);
-      fcomp.pingridrange.insert(fcomp.pingridrange.end(), temp.begin(), temp.end());
+      fcomp.pingridrange.insert(fcomp.pingridrange.end(), v.begin(), v.end());
     }
 
     // advance
@@ -2884,7 +2876,7 @@ void mjXReader::Custom(XMLElement* section) {
 
           // read name and assign
           ReadAttrTxt(obj, "objname", text, true);
-          objname += text + " ";
+          objname += " " + text;
 
           // read parameter and assign
           double oprm = 0;

src/xml/xml_util.cc

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include <algorithm>
+#include <cerrno>
 #include <climits>
 #include <cmath>
 #include <cstddef>
@@ -42,7 +43,6 @@
 
 namespace {
 
-using std::istringstream;
 using std::size_t;
 using std::string;
 using std::stringstream;
@@ -735,74 +735,52 @@ bool mjXUtil::ReadAttrInt(XMLElement* elem, const char* attr, int* data, bool re
 
 
 
-// read vector<string> from string
+template<> int mjXUtil::StrToNum(char* str, char** c) {
-void mjXUtil::String2Vector(const string& txt, vector<string>& vec) {
+  return std::strtol(str, c, 10);
-  stringstream strm(txt);
-  vec.clear();
-
-  while (!strm.eof()) {
-    string word;
-    strm >> word;
-    if (strm.fail()) {
-      break;
-    } else {
-      vec.push_back(word);
-    }
-  }
 }
 
-
+template<> float mjXUtil::StrToNum(char* str, char** c) {
-
+  return std::strtof(str, c);
-// read vector<mjtNum> from string
-void mjXUtil::String2Vector(const string& txt, vector<double>& vec) {
-  stringstream strm(txt);
-  vec.clear();
-
-  while (!strm.eof()) {
-    double num;
-    strm >> num;
-    if (strm.fail()) {
-      break;
-    } else {
-      vec.push_back(num);
-    }
-  }
 }
 
-
+template<> double mjXUtil::StrToNum(char* str, char** c) {
-
+  return std::strtod(str, c);
-// read vector<float> from string
-void mjXUtil::String2Vector(const string& txt, vector<float>& vec) {
-  stringstream strm(txt);
-  vec.clear();
-
-  while (!strm.eof()) {
-    float num;
-    strm >> num;
-    if (strm.fail()) {
-      break;
-    } else {
-      vec.push_back(num);
-    }
-  }
 }
 
+template <typename T>
+std::vector<T> mjXUtil::String2Vector(const std::string& s) {
+  errno = 0;
+  std::vector<T> v;
+  char* cs = (char*) s.c_str();
+  char* ch = cs;
 
+  // reserve worst case
+  v.reserve((s.size() >> 1) + 1);
 
-// read vector<int> from string
+  for (;;) {
-void mjXUtil::String2Vector(const string& txt, vector<int>& vec) {
+    cs = ch;
-  stringstream strm(txt);
+    T num = StrToNum<T>(cs, &ch);
-  vec.clear();
+    if (cs == ch) break;
-
+    if (errno) break;
-  while (!strm.eof()) {
+    v.push_back(num);
-    int num;
-    strm >> num;
-    if (strm.fail()) {
-      break;
-    } else {
-      vec.push_back(num);
-    }
   }
+
+  v.shrink_to_fit();
+  return v;
+}
+
+template std::vector<int> mjXUtil::String2Vector(const std::string& s);
+template std::vector<float> mjXUtil::String2Vector(const std::string& s);
+template std::vector<double> mjXUtil::String2Vector(const std::string& s);
+template<>
+std::vector<std::string> mjXUtil::String2Vector(const std::string& s) {
+  std::vector<std::string> v;
+  std::stringstream ss(s);
+  std::string word;
+  while (ss >> word) {
+    v.push_back(word);
+  }
+  return v;
 }
 
 

src/xml/xml_util.h

@@ -163,17 +163,9 @@ class mjXUtil {
   static bool ReadAttrInt(tinyxml2::XMLElement* elem, const char* attr, int* data,
                           bool required = false);
 
-  // read vector<string> from string
+  // convert string to vector
-  static void String2Vector(const std::string& txt, std::vector<std::string>& vec);
+  template<typename T>
-
+  static std::vector<T> String2Vector(const std::string& s);
-  // read vector<double> from string
-  static void String2Vector(const std::string& txt, std::vector<double>& vec);
-
-  // read vector<float> from string
-  static void String2Vector(const std::string& txt, std::vector<float>& vec);
-
-  // read vector<int> from string
-  static void String2Vector(const std::string& txt, std::vector<int>& vec);
 
   // write vector<string> to string
   static void Vector2String(std::string& txt, const std::vector<std::string>& vec);
@@ -220,6 +212,8 @@ class mjXUtil {
   template<typename T>
   static bool ReadAttrValues(tinyxml2::XMLElement* elem, const char* attr,
                              std::function<void (int, T)> push, int max = -1);
+  template<typename T> static T StrToNum(char* str, char** c);
+
 };
 
 #endif  // MUJOCO_SRC_XML_XML_UTIL_H_

test/xml/xml_util_test.cc

@@ -0,0 +1,57 @@
+// Copyright 2024 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string>
+#include <vector>
+
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+#include "src/xml/xml_util.h"
+#include "test/fixture.h"
+
+namespace mujoco {
+namespace {
+
+using XMLUtilTest = MujocoTest;
+
+using ::testing::ElementsAre;
+
+TEST_F(XMLUtilTest, String2VectorFloat) {
+  std::vector<float> v = mjXUtil::String2Vector<float>(" 1.2 3.2     5.3 6 ");
+  EXPECT_THAT(v, ElementsAre(1.2, 3.2, 5.3, 6));
+}
+
+TEST_F(XMLUtilTest, String2VectorEmpty) {
+  std::vector<float> v = mjXUtil::String2Vector<float>("");
+  EXPECT_THAT(v, ElementsAre());
+}
+
+TEST_F(XMLUtilTest, String2VectorError) {
+  std::vector<float> v = mjXUtil::String2Vector<float>("ABCD. /123/122/113");
+  EXPECT_THAT(v, ElementsAre());
+}
+
+
+TEST_F(XMLUtilTest, String2VectorInt) {
+  std::vector<int> v = mjXUtil::String2Vector<int>(" -1 3 5 6");
+  EXPECT_THAT(v, ElementsAre(-1, 3, 5, 6));
+}
+
+TEST_F(XMLUtilTest, String2VectorString) {
+  auto v = mjXUtil::String2Vector<std::string>(" abc  def ");
+  EXPECT_THAT(v, ElementsAre("abc", "def"));
+}
+
+}  // namespace
+}  // namespace mujoco