From 738fef71f497d2297c36606f90ab838e9d0f2efb Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Wed, 15 Apr 2020 06:32:33 +0300
Subject: [PATCH] Allow to parse +inf #1839

---
 src/IO/readFloatText.h                        | 27 +++++++++++++++++--
 .../0_stateless/01198_plus_inf.reference      |  3 +++
 tests/queries/0_stateless/01198_plus_inf.sql  |  3 +++
 3 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 tests/queries/0_stateless/01198_plus_inf.reference
 create mode 100644 tests/queries/0_stateless/01198_plus_inf.sql

diff --git a/src/IO/readFloatText.h b/src/IO/readFloatText.h
index fc3ffc43a91..4e0825222a7 100644
--- a/src/IO/readFloatText.h
+++ b/src/IO/readFloatText.h
@@ -156,6 +156,9 @@ ReturnType readFloatTextPreciseImpl(T & x, ReadBuffer & buf)
     {
         switch (*buf.position())
         {
+            case '+':
+                continue;
+
             case '-':
             {
                 negative = true;
@@ -335,6 +338,7 @@ ReturnType readFloatTextFastImpl(T & x, ReadBuffer & in)
         ++in.position();
     }
 
+
     auto count_after_sign = in.count();
 
     constexpr int significant_digits = std::numeric_limits<UInt64>::digits10;
@@ -380,7 +384,7 @@ ReturnType readFloatTextFastImpl(T & x, ReadBuffer & in)
         if (in.eof())
         {
             if constexpr (throw_exception)
-                throw Exception("Cannot read floating point value", ErrorCodes::CANNOT_PARSE_NUMBER);
+                throw Exception("Cannot read floating point value: nothing after exponent", ErrorCodes::CANNOT_PARSE_NUMBER);
             else
                 return false;
         }
@@ -418,11 +422,30 @@ ReturnType readFloatTextFastImpl(T & x, ReadBuffer & in)
         if (in.eof())
         {
             if constexpr (throw_exception)
-                throw Exception("Cannot read floating point value", ErrorCodes::CANNOT_PARSE_NUMBER);
+                throw Exception("Cannot read floating point value: no digits read", ErrorCodes::CANNOT_PARSE_NUMBER);
             else
                 return false;
         }
 
+        if (*in.position() == '+')
+        {
+            ++in.position();
+            if (in.eof())
+            {
+                if constexpr (throw_exception)
+                    throw Exception("Cannot read floating point value: nothing after plus sign", ErrorCodes::CANNOT_PARSE_NUMBER);
+                else
+                    return false;
+            }
+            else if (negative)
+            {
+                if constexpr (throw_exception)
+                    throw Exception("Cannot read floating point value: plus after minus sign", ErrorCodes::CANNOT_PARSE_NUMBER);
+                else
+                    return false;
+            }
+        }
+
         if (*in.position() == 'i' || *in.position() == 'I')
         {
             if (assertOrParseInfinity<throw_exception>(in))
diff --git a/tests/queries/0_stateless/01198_plus_inf.reference b/tests/queries/0_stateless/01198_plus_inf.reference
new file mode 100644
index 00000000000..f726b8429b6
--- /dev/null
+++ b/tests/queries/0_stateless/01198_plus_inf.reference
@@ -0,0 +1,3 @@
+inf
+-inf
+inf
diff --git a/tests/queries/0_stateless/01198_plus_inf.sql b/tests/queries/0_stateless/01198_plus_inf.sql
new file mode 100644
index 00000000000..e06faa2fd21
--- /dev/null
+++ b/tests/queries/0_stateless/01198_plus_inf.sql
@@ -0,0 +1,3 @@
+SELECT DISTINCT toFloat64(arrayJoin(['+inf', '+Inf', '+INF', '+infinity', '+Infinity']));
+SELECT DISTINCT toFloat64(arrayJoin(['-inf', '-Inf', '-INF', '-infinity', '-Infinity']));
+SELECT DISTINCT toFloat64(arrayJoin(['inf', 'Inf', 'INF', 'infinity', 'Infinity']));