Add more constexpr to StringRef

src/catch2/catch_stringref.cpp

@@ -22,17 +22,7 @@ namespace Catch {
         CATCH_ENFORCE(isNullTerminated(), "Called StringRef::c_str() on a non-null-terminated instance");
         return m_start;
     }
-    auto StringRef::data() const noexcept -> char const* {
-        return m_start;
-    }
 
-    auto StringRef::substr( size_type start, size_type size ) const noexcept -> StringRef {
-        if (start < m_size) {
-            return StringRef(m_start + start, (std::min)(m_size - start, size));
-        } else {
-            return StringRef();
-        }
-    }
     auto StringRef::operator == ( StringRef const& other ) const noexcept -> bool {
         return m_size == other.m_size
             && (std::memcmp( m_start, other.m_start, m_size ) == 0);

src/catch2/catch_stringref.h

@@ -74,12 +74,21 @@ namespace Catch {
 
     public: // substrings and searches
         // Returns a substring of [start, start + length).
-        // If start + length > size(), then the substring is [start, size()).
+        // If start + length > size(), then the substring is [start, start + size()).
         // If start > size(), then the substring is empty.
-        auto substr( size_type start, size_type length ) const noexcept -> StringRef;
+        constexpr StringRef substr(size_type start, size_type length) const noexcept {
+            if (start < m_size) {
+                const auto shortened_size = m_size - start;
+                return StringRef(m_start + start, (shortened_size < length) ? shortened_size : length);
+            } else {
+                return StringRef();
+            }
+        }
 
         // Returns the current start pointer. May not be null-terminated.
-        auto data() const noexcept -> char const*;
+        constexpr char const* data() const noexcept {
+            return m_start;
+        }
 
         constexpr auto isNullTerminated() const noexcept -> bool {
             return m_start[m_size] == '\0';

tests/SelfTest/Baselines/compact.sw.approved.txt

@@ -1193,6 +1193,7 @@ String.tests.cpp:<line number>: passed: s.data() == s2.data() for: "hello world!
 String.tests.cpp:<line number>: passed: s.data() == ss.data() for: "hello world!" == "hello world!"
 String.tests.cpp:<line number>: passed: s.substr(s.size() + 1, 123).empty() for: true
 String.tests.cpp:<line number>: passed: std::strcmp(ss.c_str(), "world!") == 0 for: 0 == 0
+String.tests.cpp:<line number>: passed: s.substr(1'000'000, 1).empty() for: true
 String.tests.cpp:<line number>: passed: (char*)buffer1 != (char*)buffer2 for: "Hello" != "Hello"
 String.tests.cpp:<line number>: passed: left == right for: Hello == Hello
 String.tests.cpp:<line number>: passed: left != left.substr(0, 3) for: Hello != Hel
@@ -1206,11 +1207,20 @@ String.tests.cpp:<line number>: passed: stdStr == "a stringref" for: "a stringre
 String.tests.cpp:<line number>: passed: stdStr.size() == sr.size() for: 11 == 11
 String.tests.cpp:<line number>: passed: stdStr == "a stringref" for: "a stringref" == "a stringref"
 String.tests.cpp:<line number>: passed: stdStr.size() == sr.size() for: 11 == 11
-String.tests.cpp:<line number>: passed: with 1 message: 'StringRef{}.size() == 0'
+String.tests.cpp:<line number>: passed: with 1 message: 'empty.size() == 0'
-String.tests.cpp:<line number>: passed: with 1 message: 'StringRef{ "abc", 3 }.size() == 3'
+String.tests.cpp:<line number>: passed: with 1 message: 'empty.begin() == empty.end()'
-String.tests.cpp:<line number>: passed: with 1 message: 'StringRef{ "abc", 3 }.isNullTerminated()'
+String.tests.cpp:<line number>: passed: with 1 message: 'stringref.size() == 3'
-String.tests.cpp:<line number>: passed: with 1 message: 'StringRef{ "abc", 2 }.size() == 2'
+String.tests.cpp:<line number>: passed: with 1 message: 'stringref.isNullTerminated()'
-String.tests.cpp:<line number>: passed: with 1 message: '!(StringRef{ "abc", 2 }.isNullTerminated())'
+String.tests.cpp:<line number>: passed: with 1 message: 'stringref.data() == abc'
+String.tests.cpp:<line number>: passed: with 1 message: 'stringref.begin() == abc'
+String.tests.cpp:<line number>: passed: with 1 message: 'stringref.begin() != stringref.end()'
+String.tests.cpp:<line number>: passed: with 1 message: 'stringref.substr(10, 0).empty()'
+String.tests.cpp:<line number>: passed: with 1 message: 'stringref.substr(2, 1).data() == abc + 2'
+String.tests.cpp:<line number>: passed: with 1 message: 'shortened.size() == 2'
+String.tests.cpp:<line number>: passed: with 1 message: 'shortened.data() == abc'
+String.tests.cpp:<line number>: passed: with 1 message: 'shortened.begin() != shortened.end()'
+String.tests.cpp:<line number>: passed: with 1 message: '!(shortened.isNullTerminated())'
+String.tests.cpp:<line number>: passed: with 1 message: '!(shortened.substr(1, 3).isNullTerminated())'
 String.tests.cpp:<line number>: passed: with 1 message: '!(sr1.empty())'
 String.tests.cpp:<line number>: passed: with 1 message: 'sr1.size() == 3'
 String.tests.cpp:<line number>: passed: with 1 message: 'sr1.isNullTerminated()'

tests/SelfTest/Baselines/console.std.approved.txt

@@ -1381,5 +1381,5 @@ due to unexpected exception with message:
 
 ===============================================================================
 test cases:  320 |  246 passed |  70 failed |  4 failed as expected
-assertions: 1782 | 1630 passed | 131 failed | 21 failed as expected
+assertions: 1792 | 1640 passed | 131 failed | 21 failed as expected
 

tests/SelfTest/Baselines/console.sw.approved.txt

@@ -8715,6 +8715,19 @@ String.tests.cpp:<line number>: PASSED:
 with expansion:
   0 == 0
 
+-------------------------------------------------------------------------------
+StringRef
+  Substrings
+  substring start after the end is empty
+-------------------------------------------------------------------------------
+String.tests.cpp:<line number>
+...............................................................................
+
+String.tests.cpp:<line number>: PASSED:
+  REQUIRE( s.substr(1'000'000, 1).empty() )
+with expansion:
+  true
+
 -------------------------------------------------------------------------------
 StringRef
   Comparisons are deep
@@ -8836,23 +8849,59 @@ String.tests.cpp:<line number>
 
 String.tests.cpp:<line number>: PASSED:
 with message:
-  StringRef{}.size() == 0
+  empty.size() == 0
 
 String.tests.cpp:<line number>: PASSED:
 with message:
-  StringRef{ "abc", 3 }.size() == 3
+  empty.begin() == empty.end()
 
 String.tests.cpp:<line number>: PASSED:
 with message:
-  StringRef{ "abc", 3 }.isNullTerminated()
+  stringref.size() == 3
 
 String.tests.cpp:<line number>: PASSED:
 with message:
-  StringRef{ "abc", 2 }.size() == 2
+  stringref.isNullTerminated()
 
 String.tests.cpp:<line number>: PASSED:
 with message:
-  !(StringRef{ "abc", 2 }.isNullTerminated())
+  stringref.data() == abc
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  stringref.begin() == abc
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  stringref.begin() != stringref.end()
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  stringref.substr(10, 0).empty()
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  stringref.substr(2, 1).data() == abc + 2
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  shortened.size() == 2
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  shortened.data() == abc
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  shortened.begin() != shortened.end()
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  !(shortened.isNullTerminated())
+
+String.tests.cpp:<line number>: PASSED:
+with message:
+  !(shortened.substr(1, 3).isNullTerminated())
 
 -------------------------------------------------------------------------------
 StringRef at compilation time
@@ -14005,5 +14054,5 @@ Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
 test cases:  320 |  230 passed |  86 failed |  4 failed as expected
-assertions: 1799 | 1630 passed | 148 failed | 21 failed as expected
+assertions: 1809 | 1640 passed | 148 failed | 21 failed as expected
 

tests/SelfTest/Baselines/junit.sw.approved.txt

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuitesloose text artifact
 >
-  <testsuite name="<exe-name>" errors="17" failures="132" tests="1800" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="132" tests="1810" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <properties>
       <property name="filters" value="~[!nonportable]~[!benchmark]~[approvals] *"/>
       <property name="random-seed" value="1"/>
@@ -1114,6 +1114,7 @@ Matchers.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="StringRef/Substrings/Pointer values of substring refs should also match" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="StringRef/Substrings/Past the end substring" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="StringRef/Substrings/Substring off the end are trimmed" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="StringRef/Substrings/substring start after the end is empty" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="StringRef/Comparisons are deep" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="StringRef/from std::string/implicitly constructed" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="StringRef/from std::string/explicitly constructed" time="{duration}"/>

tests/SelfTest/Baselines/sonarqube.sw.approved.txt

@@ -142,6 +142,7 @@
     <testCase name="StringRef/Substrings/Pointer values of substring refs should also match" duration="{duration}"/>
     <testCase name="StringRef/Substrings/Past the end substring" duration="{duration}"/>
     <testCase name="StringRef/Substrings/Substring off the end are trimmed" duration="{duration}"/>
+    <testCase name="StringRef/Substrings/substring start after the end is empty" duration="{duration}"/>
     <testCase name="StringRef/Comparisons are deep" duration="{duration}"/>
     <testCase name="StringRef/from std::string/implicitly constructed" duration="{duration}"/>
     <testCase name="StringRef/from std::string/explicitly constructed" duration="{duration}"/>

tests/SelfTest/Baselines/tap.sw.approved.txt

@@ -2300,6 +2300,8 @@ ok {test-number} - s.substr(s.size() + 1, 123).empty() for: true
 # StringRef
 ok {test-number} - std::strcmp(ss.c_str(), "world!") == 0 for: 0 == 0
 # StringRef
+ok {test-number} - s.substr(1'000'000, 1).empty() for: true
+# StringRef
 ok {test-number} - (char*)buffer1 != (char*)buffer2 for: "Hello" != "Hello"
 # StringRef
 ok {test-number} - left == right for: Hello == Hello
@@ -2326,15 +2328,33 @@ ok {test-number} - stdStr == "a stringref" for: "a stringref" == "a stringref"
 # StringRef
 ok {test-number} - stdStr.size() == sr.size() for: 11 == 11
 # StringRef at compilation time
-ok {test-number} - with 1 message: 'StringRef{}.size() == 0'
+ok {test-number} - with 1 message: 'empty.size() == 0'
 # StringRef at compilation time
-ok {test-number} - with 1 message: 'StringRef{ "abc", 3 }.size() == 3'
+ok {test-number} - with 1 message: 'empty.begin() == empty.end()'
 # StringRef at compilation time
-ok {test-number} - with 1 message: 'StringRef{ "abc", 3 }.isNullTerminated()'
+ok {test-number} - with 1 message: 'stringref.size() == 3'
 # StringRef at compilation time
-ok {test-number} - with 1 message: 'StringRef{ "abc", 2 }.size() == 2'
+ok {test-number} - with 1 message: 'stringref.isNullTerminated()'
 # StringRef at compilation time
-ok {test-number} - with 1 message: '!(StringRef{ "abc", 2 }.isNullTerminated())'
+ok {test-number} - with 1 message: 'stringref.data() == abc'
+# StringRef at compilation time
+ok {test-number} - with 1 message: 'stringref.begin() == abc'
+# StringRef at compilation time
+ok {test-number} - with 1 message: 'stringref.begin() != stringref.end()'
+# StringRef at compilation time
+ok {test-number} - with 1 message: 'stringref.substr(10, 0).empty()'
+# StringRef at compilation time
+ok {test-number} - with 1 message: 'stringref.substr(2, 1).data() == abc + 2'
+# StringRef at compilation time
+ok {test-number} - with 1 message: 'shortened.size() == 2'
+# StringRef at compilation time
+ok {test-number} - with 1 message: 'shortened.data() == abc'
+# StringRef at compilation time
+ok {test-number} - with 1 message: 'shortened.begin() != shortened.end()'
+# StringRef at compilation time
+ok {test-number} - with 1 message: '!(shortened.isNullTerminated())'
+# StringRef at compilation time
+ok {test-number} - with 1 message: '!(shortened.substr(1, 3).isNullTerminated())'
 # StringRef at compilation time
 ok {test-number} - with 1 message: '!(sr1.empty())'
 # StringRef at compilation time
@@ -3590,5 +3610,5 @@ ok {test-number} - q3 == 23. for: 23.0 == 23.0
 ok {test-number} -
 # xmlentitycheck
 ok {test-number} -
-1..1791
+1..1801
 

tests/SelfTest/Baselines/xml.sw.approved.txt

@@ -10906,6 +10906,20 @@ Message from section two
         </Section>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
+      <Section name="Substrings" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <Section name="substring start after the end is empty" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+            <Original>
+              s.substr(1'000'000, 1).empty()
+            </Original>
+            <Expanded>
+              true
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
       <Section name="Comparisons are deep" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
         <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
           <Original>
@@ -11047,7 +11061,7 @@ Message from section two
     </TestCase>
     <TestCase name="StringRef at compilation time" tags="[constexpr][StringRef][Strings]" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
       <Section name="Simple constructors" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-        <OverallResults successes="5" failures="0" expectedFailures="0"/>
+        <OverallResults successes="14" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="UDL construction" filename="tests/<exe-name>/IntrospectiveTests/String.tests.cpp" >
         <OverallResults successes="6" failures="0" expectedFailures="0"/>
@@ -16895,7 +16909,7 @@ loose text artifact
       </Section>
       <OverallResult success="true"/>
     </TestCase>
-    <OverallResults successes="1630" failures="149" expectedFailures="21"/>
+    <OverallResults successes="1640" failures="149" expectedFailures="21"/>
   </Group>
-  <OverallResults successes="1630" failures="148" expectedFailures="21"/>
+  <OverallResults successes="1640" failures="148" expectedFailures="21"/>
 </Catch>

tests/SelfTest/IntrospectiveTests/String.tests.cpp

@@ -72,7 +72,9 @@ TEST_CASE( "StringRef", "[Strings][StringRef]" ) {
             ss = s.substr(6, 123);
             REQUIRE(std::strcmp(ss.c_str(), "world!") == 0);
         }
-        // TODO: substring into string + size is longer than end
+        SECTION("substring start after the end is empty") {
+            REQUIRE(s.substr(1'000'000, 1).empty());
+        }
     }
 
     SECTION( "Comparisons are deep" ) {
@@ -124,15 +126,32 @@ TEST_CASE( "StringRef", "[Strings][StringRef]" ) {
 }
 
 TEST_CASE("StringRef at compilation time", "[Strings][StringRef][constexpr]") {
+    //TODO:
+    //  * substr
     using Catch::StringRef;
     SECTION("Simple constructors") {
-        STATIC_REQUIRE(StringRef{}.size() == 0);
+        constexpr StringRef empty;
+        STATIC_REQUIRE(empty.size() == 0);
+        STATIC_REQUIRE(empty.begin() == empty.end());
 
-        STATIC_REQUIRE(StringRef{ "abc", 3 }.size() == 3);
+        constexpr char const* const abc = "abc";
-        STATIC_REQUIRE(StringRef{ "abc", 3 }.isNullTerminated());
 
-        STATIC_REQUIRE(StringRef{ "abc", 2 }.size() == 2);
+        constexpr StringRef stringref(abc, 3);
-        STATIC_REQUIRE_FALSE(StringRef{ "abc", 2 }.isNullTerminated());
+        STATIC_REQUIRE(stringref.size() == 3);
+        STATIC_REQUIRE(stringref.isNullTerminated());
+        STATIC_REQUIRE(stringref.data() == abc);
+        STATIC_REQUIRE(stringref.begin() == abc);
+        STATIC_REQUIRE(stringref.begin() != stringref.end());
+        STATIC_REQUIRE(stringref.substr(10, 0).empty());
+        STATIC_REQUIRE(stringref.substr(2, 1).data() == abc + 2);
+
+
+        constexpr StringRef shortened(abc, 2);
+        STATIC_REQUIRE(shortened.size() == 2);
+        STATIC_REQUIRE(shortened.data() == abc);
+        STATIC_REQUIRE(shortened.begin() != shortened.end());
+        STATIC_REQUIRE_FALSE(shortened.isNullTerminated());
+        STATIC_REQUIRE_FALSE(shortened.substr(1, 3).isNullTerminated());
     }
     SECTION("UDL construction") {
         constexpr auto sr1 = "abc"_catch_sr;