[libcxx-commits] [libcxx] [libc++] Fix regression about parsing leading decimal points (PR #93989)

A. Jiang via libcxx-commits libcxx-commits at lists.llvm.org
Fri May 31 10:14:43 PDT 2024


https://github.com/frederick-vs-ja created https://github.com/llvm/llvm-project/pull/93989

PR #77948 mistakenly rejected floating-point representation with a leading decimal point, e.g. ".5".

This PR fixes the regression mentioned in https://github.com/llvm/llvm-project/pull/77948#issuecomment-2141740346.

>From ef8143d667dfd0e2044b1e5dda970bbad0cc450b Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34 at live.cn>
Date: Sat, 1 Jun 2024 01:08:25 +0800
Subject: [PATCH] [libc++] Fix regression about parsing leading decimal points

PR #77948 mistakenly rejected floating-point representation with a
leading decimal point, e.g. ".5".

This PR fixes the regression.
---
 libcxx/include/locale                         |  4 +-
 .../facet.num.get.members/get_double.pass.cpp | 60 +++++++++++++++++++
 .../facet.num.get.members/get_float.pass.cpp  | 60 +++++++++++++++++++
 .../get_long_double.pass.cpp                  | 60 +++++++++++++++++++
 4 files changed, 182 insertions(+), 2 deletions(-)

diff --git a/libcxx/include/locale b/libcxx/include/locale
index 041d7bcd27fc5..c25861ff66987 100644
--- a/libcxx/include/locale
+++ b/libcxx/include/locale
@@ -986,12 +986,12 @@ _InputIterator num_get<_CharT, _InputIterator>::__do_get_floating_point(
     // the leading character excluding the sign must be a decimal digit
     if (!__is_leading_parsed) {
       if (__a_end - __a >= 1 && __a[0] != '-' && __a[0] != '+') {
-        if ('0' <= __a[0] && __a[0] <= '9')
+        if (('0' <= __a[0] && __a[0] <= '9') || __a[0] == '.')
           __is_leading_parsed = true;
         else
           break;
       } else if (__a_end - __a >= 2 && (__a[0] == '-' || __a[0] == '+')) {
-        if ('0' <= __a[1] && __a[1] <= '9')
+        if (('0' <= __a[1] && __a[1] <= '9') || __a[1] == '.')
           __is_leading_parsed = true;
         else
           break;
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp
index fbd1c7c5715ea..b16be0bdaacd6 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_double.pass.cpp
@@ -401,6 +401,66 @@ int main(int, char**)
         assert(err == ios.goodbit);
         assert(std::abs(v - 3.14159265358979e+10)/3.14159265358979e+10 < 1.e-8);
     }
+    {
+      v                                      = -1;
+      const char str[]                       = ".5";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 2);
+      assert(err == ios.goodbit);
+      assert(v == 0.5);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.5";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 3);
+      assert(err == ios.goodbit);
+      assert(v == -0.5);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = ".5E1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 4);
+      assert(err == ios.goodbit);
+      assert(v == 5.0);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.5e+1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 6);
+      assert(err == ios.goodbit);
+      assert(v == -5.0);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = ".625E-1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 7);
+      assert(err == ios.goodbit);
+      assert(v == 0.0625);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.3125e-1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 9);
+      assert(err == ios.goodbit);
+      assert(v == -0.03125);
+    }
 
   return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp
index b5ac7d876157c..bc6cec45d89a3 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_float.pass.cpp
@@ -331,6 +331,66 @@ int main(int, char**)
         assert(err == ios.goodbit);
         assert(v == 2);
     }
+    {
+      v                                      = -1;
+      const char str[]                       = ".5";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 2);
+      assert(err == ios.goodbit);
+      assert(v == 0.5f);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.5";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 3);
+      assert(err == ios.goodbit);
+      assert(v == -0.5f);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = ".5E1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 4);
+      assert(err == ios.goodbit);
+      assert(v == 5.0f);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.5e+1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 6);
+      assert(err == ios.goodbit);
+      assert(v == -5.0f);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = ".625E-1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 7);
+      assert(err == ios.goodbit);
+      assert(v == 0.0625f);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.3125e-1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 9);
+      assert(err == ios.goodbit);
+      assert(v == -0.03125f);
+    }
 
   return 0;
 }
diff --git a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp
index 9617899f749c6..f455981e89780 100644
--- a/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.numeric/locale.num.get/facet.num.get.members/get_long_double.pass.cpp
@@ -390,6 +390,66 @@ int main(int, char**)
         assert(err == ios.goodbit);
         assert(v == 2);
     }
+    {
+      v                                      = -1;
+      const char str[]                       = ".5";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 2);
+      assert(err == ios.goodbit);
+      assert(v == 0.5l);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.5";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 3);
+      assert(err == ios.goodbit);
+      assert(v == -0.5l);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = ".5E1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 4);
+      assert(err == ios.goodbit);
+      assert(v == 5.0l);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.5e+1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 6);
+      assert(err == ios.goodbit);
+      assert(v == -5.0l);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = ".625E-1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 7);
+      assert(err == ios.goodbit);
+      assert(v == 0.0625l);
+    }
+    {
+      v                                      = -1;
+      const char str[]                       = "-.3125e-1";
+      std::ios_base::iostate err             = ios.goodbit;
+      cpp17_input_iterator<const char*> iter = f.get(
+          cpp17_input_iterator<const char*>(str), cpp17_input_iterator<const char*>(str + sizeof(str)), ios, err, v);
+      assert(base(iter) == str + 9);
+      assert(err == ios.goodbit);
+      assert(v == -0.03125l);
+    }
 
   return 0;
 }



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