WIP - command line experiment

base/command_line.h

Index: base/command_line.h
diff --git a/base/command_line.h b/base/command_line.h
index ed46c4f0d13c34778d390e86827b8e6db307d186..8be7523bd62bc405e131cc98f95274305e32255b 100644
--- a/base/command_line.h
+++ b/base/command_line.h
@@ -16,6 +16,7 @@
 #define BASE_COMMAND_LINE_H_
 
 #include <stddef.h>
+#include <stdint.h>
 #include <map>
 #include <string>
 #include <vector>
@@ -40,6 +41,11 @@ class BASE_EXPORT CommandLine {
   typedef std::vector<StringType> StringVector;
   typedef std::map<std::string, StringType> SwitchMap;
 
+  struct ExplicitStdString {
+    ExplicitStdString(const std::string& str) : s(str) {}
+    const std::string& s;
+  };
+
   // A constructor for CommandLines that only carry switches and arguments.
   enum NoProgram { NO_PROGRAM };
   explicit CommandLine(NoProgram no_program);
@@ -102,7 +108,23 @@ class BASE_EXPORT CommandLine {
 
   // Returns true if this command line contains the given switch.
   // (Switch names are case-insensitive).
-  bool HasSwitch(const std::string& switch_string) const;
+  bool HasStringSwitch(const std::string& switch_string) const;
+  bool HasSwitch(const ExplicitStdString& switch_string) const {
+    return HasStringSwitch(switch_string.s);
+  }
+  bool HasSwitch(const char* switch_string, size_t string_length) const;
+
+  template <size_t N>
+  bool HasSwitch(const char (&constant_switch_string)[N]) const {
+    // Note that N includes a null terminator, so this will generate a compile
+    // error if called with an empty string constant.
+    if (N <= 65 &&
+        (switch_lengths_mask_ & (static_cast<uint64_t>(1) << (N - 2))) == 0) {
+      return false;
+    }
+
+    return HasSwitch(constant_switch_string, N - 1);
+  }
 
   // Returns the value associated with the given switch. If the switch has no
   // value or isn't present, this method returns the empty string.
@@ -173,6 +195,10 @@ class BASE_EXPORT CommandLine {
 
   // The index after the program and switches, any arguments start here.
   size_t begin_args_;
+
+  // A bitset, with a 1 at bit postion |i| indicating that the command line
+  // includes a switch of string length |i| + 1 ascii characters.
+  uint64_t switch_lengths_mask_;
 };
 
 #endif  // BASE_COMMAND_LINE_H_