[GitHub] [incubator-kvrocks] git-hulk commented on a diff in pull request #644: Refactor Trim/Split/Split2KV functions in util.h

[GitBox <gi...@apache.org>]

git-hulk commented on code in PR #644:
URL: https://github.com/apache/incubator-kvrocks/pull/644#discussion_r903205197


##########
src/util.cc:
##########
@@ -359,42 +359,54 @@ std::string ToLower(std::string in) {
   return in;
 }
 
-void Trim(const std::string &in, const std::string &chars, std::string *out) {
-  out->clear();
-  if (in.empty()) return;
-  out->assign(in);
-  out->erase(0, out->find_first_not_of(chars));
-  out->erase(out->find_last_not_of(chars)+1);
+std::string Trim(std::string in, const std::string &chars) {
+  if (in.empty()) return in;
+
+  in.erase(0, in.find_first_not_of(chars));
+  in.erase(in.find_last_not_of(chars) + 1);
+
+  return in;
 }
 
-void Split(std::string in, std::string delim, std::vector<std::string> *out) {
-  if (in.empty() || !out) return;
-  out->clear();
+std::vector<std::string> Split(const std::string &in, const std::string &delim) {
+  std::vector<std::string> out;
+
+  if (in.empty()) {
+    return out;
+  }
+
+  if (delim.empty()) {
+    out.resize(in.size());
+    std::transform(in.begin(), in.end(), out.begin(),
+      [](char c) -> std::string { return {c}; });
+    return out;
+  }
 
-  std::string::size_type pos = 0;
-  std::string elem, trimed_elem;
+  size_t begin = 0, end = in.find_first_of(delim);
   do {
-    pos = in.find_first_of(delim);
-    elem = in.substr(0, pos);
-    Trim(elem, delim, &trimed_elem);
-    if (!trimed_elem.empty()) out->push_back(trimed_elem);
-    in = in.substr(pos+1);
-  } while (pos != std::string::npos);
+    std::string elem = in.substr(begin, end - begin);
+    if (!elem.empty()) out.push_back(std::move(elem));

Review Comment:
   Yes, this `split` function has a bit different from most languages
   since we want to ignore the empty value.



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