From b493458e00f0bebac6b45466b411ace1d7d80b6d Mon Sep 17 00:00:00 2001
From: peter klausler <pklausler@nvidia.com>
Date: Mon, 2 Apr 2018 16:44:34 -0700
Subject: [PATCH] [flang] More clean-up in token-parsers.h.

Original-commit: flang-compiler/f18@320213454237dcda9011f2ee48c258c118d83f0c
Reviewed-on: https://github.com/flang-compiler/f18/pull/38
Tree-same-pre-rewrite: false
---
 flang/lib/parser/token-parsers.h | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/flang/lib/parser/token-parsers.h b/flang/lib/parser/token-parsers.h
index 39f2289..2e2094a 100644
--- a/flang/lib/parser/token-parsers.h
+++ b/flang/lib/parser/token-parsers.h
@@ -26,14 +26,13 @@ public:
   constexpr CharPredicateGuard(bool (*f)(char), MessageFixedText m)
     : predicate_{f}, messageText_{m} {}
   std::optional<const char *> Parse(ParseState *state) const {
-    const char *at{state->GetLocation()};
-    if (!state->IsAtEnd()) {
-      if (predicate_(*at)) {
+    if (std::optional<const char *> at{state->PeekAtNextChar()}) {
+      if (predicate_(**at)) {
         state->UncheckedAdvance();
-        return {at};
+        return at;
       }
     }
-    state->Say(at, messageText_);
+    state->Say(messageText_);
     return {};
   }
 
@@ -57,17 +56,17 @@ public:
   constexpr AnyOfChar(const char *chars, std::size_t n)
     : chars_{chars}, bytes_{n} {}
   std::optional<const char *> Parse(ParseState *state) const {
-    const char *at{state->GetLocation()};
-    if (!state->IsAtEnd()) {
+    if (std::optional<const char *> at{state->PeekAtNextChar()}) {
+      char ch{**at};
       const char *p{chars_};
       for (std::size_t j{0}; j < bytes_ && *p != '\0'; ++j, ++p) {
-        if (*at == ToLowerCaseLetter(*p)) {
+        if (ch == ToLowerCaseLetter(*p)) {
           state->UncheckedAdvance();
-          return {at};
+          return at;
         }
       }
     }
-    state->Say(at, MessageExpectedText{chars_, bytes_});
+    state->Say(MessageExpectedText{chars_, bytes_});
     return {};
   }
 
@@ -572,14 +571,13 @@ inline constexpr auto optionalListBeforeColons(const PA &p) {
 constexpr struct FormDirectivesAndEmptyLines {
   using resultType = Success;
   static std::optional<Success> Parse(ParseState *state) {
-    while (!state->IsAtEnd()) {
-      const char *at{state->GetLocation()};
+    while (std::optional<const char *> at{state->PeekAtNextChar()}) {
       static const char fixed[] = "!dir$ fixed\n", free[] = "!dir$ free\n";
-      if (*at == '\n') {
+      if (**at == '\n') {
         state->UncheckedAdvance();
-      } else if (std::memcmp(at, fixed, sizeof fixed - 1) == 0) {
+      } else if (std::memcmp(*at, fixed, sizeof fixed - 1) == 0) {
         state->set_inFixedForm(true).UncheckedAdvance(sizeof fixed - 1);
-      } else if (std::memcmp(at, free, sizeof free - 1) == 0) {
+      } else if (std::memcmp(*at, free, sizeof free - 1) == 0) {
         state->set_inFixedForm(false).UncheckedAdvance(sizeof free - 1);
       } else {
         break;
-- 
2.7.4