Merge branch 'master' into pair-potential-file-unit-convert

src/utils.cpp

@@ -430,6 +430,86 @@ size_t utils::trim_and_count_words(const std::string & text, const std::string &
   return utils::count_words(utils::trim_comment(text), separators);
 }
 
+/* ----------------------------------------------------------------------
+   Convert string into words on whitespace while handling single and
+   double quotes.
+------------------------------------------------------------------------- */
+std::vector<std::string> utils::split_words(const std::string &text)
+{
+  std::vector<std::string> list;
+  const char *buf = text.c_str();
+  std::size_t beg = 0;
+  std::size_t len = 0;
+  char c = *buf;
+
+  while (c) {
+    // leading whitespace
+    if (c == ' ' || c == '\t' || c == '\r' ||  c == '\n' || c == '\f') {
+      c = *++buf;
+      ++beg;
+      continue;
+    };
+    len = 0;
+
+    // handle escaped/quoted text.
+    quoted:
+
+    // handle single quote
+    if (c == '\'') {
+      c = *++buf;
+      ++len;
+      while (((c != '\'') && (c != '\0'))
+             || ((c == '\\') && (buf[1] == '\''))) {
+        if ((c == '\\') && (buf[1] == '\'')) {
+          ++buf;
+          ++len;
+        }
+        c = *++buf;
+        ++len;
+      }
+      c = *++buf;
+      ++len;
+
+      // handle double quote
+    } else if (c == '"') {
+      c = *++buf;
+      ++len;
+      while (((c != '"') && (c != '\0'))
+             || ((c == '\\') && (buf[1] == '"'))) {
+        if ((c == '\\') && (buf[1] == '"')) {
+          ++buf;
+          ++len;
+        }
+        c = *++buf;
+        ++len;
+      }
+      c = *++buf;
+      ++len;
+    }
+
+    // unquoted
+    while (1) {
+      if ((c == '\'') || (c == '"')) goto quoted;
+      // skip escaped quote
+      if ((c == '\\') && ((buf[1] == '\'') || (buf[1] == '"'))) {
+        ++buf;
+        ++len;
+        c = *++buf;
+        ++len;
+      }
+      if ((c == ' ') || (c == '\t') || (c == '\r') || (c == '\n')
+          || (c == '\f') || (c == '\0')) {
+          list.push_back(text.substr(beg,len));
+          beg += len;
+          break;
+      }
+      c = *++buf;
+      ++len;
+    }
+  }
+  return list;
+}
+
 /* ----------------------------------------------------------------------
    Return whether string is a valid integer number
 ------------------------------------------------------------------------- */