Fix compilation error when using more than 11 arguments with scn::scan

eliaskosunen · May 18, 2024 · 12d503c · 12d503c
1 parent ff77a65
commit 12d503c
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Showing 3 changed files with 38 additions and 5 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,7 @@ _Released 2024-05-xx_
  * Fix documentation: default format type specifier for integers is `i`, not `d`:
    when not explicitly specified by a format specifier, the base of an integer is determined based on its prefix:
    `0x...` is hexadecimal, `0...` or `0o...` is octal, `0b...` is binary, and everything else is decimal.
+ * Fix a compilation error which would occur when scanning more than 11 arguments with `scn::scan`.
  * Small CMake adjustments to better support use as a subproject (#113, thanks [@frankmiller (Frank Miller)](https://github.com/frankmiller))
  * Fix misplaced include of `GNUInstallDirs` in CMake (#111, thanks [@WangWeiLin-MV](https://github.com/WangWeiLin-MV))
  * Allow for externally installed versions for GTest and Google Benchmark (#112, thanks [@xvitaly (Vitaly)](https://github.com/xvitaly))

diff --git a/include/scn/detail/args.h b/include/scn/detail/args.h
@@ -152,7 +152,7 @@ class arg_value {
     SCN_STD > SCN_STD_20
     constexpr
 #endif
-        arg_value() = default;
+    arg_value() = default;
 
     template <typename T>
     explicit constexpr arg_value(T& val) : ref_value{std::addressof(val)}
@@ -333,9 +333,14 @@ constexpr size_t encode_types_impl()
 template <typename CharT, typename... Ts>
 constexpr size_t encode_types()
 {
-    static_assert(sizeof...(Ts) < (1 << packed_arg_bits));
-    return sizeof...(Ts) |
-           (encode_types_impl<CharT, Ts...>() << packed_arg_bits);
+    if constexpr (sizeof...(Ts) < (1 << packed_arg_bits)) {
+        return sizeof...(Ts) |
+               (encode_types_impl<CharT, Ts...>() << packed_arg_bits);
+    }
+    else {
+        SCN_EXPECT(false);
+        SCN_UNREACHABLE;
+    }
 }
 
 template <typename Arg>
@@ -695,7 +700,7 @@ class basic_scan_args {
         : m_desc{desc}, m_values{values}
     {
     }
-    constexpr basic_scan_args(size_t desc, basic_scan_args<Context>* args)
+    constexpr basic_scan_args(size_t desc, basic_scan_arg<Context>* args)
         : m_desc{desc}, m_args{args}
     {
     }

diff --git a/tests/unittests/scan_test.cpp b/tests/unittests/scan_test.cpp
@@ -205,3 +205,30 @@ TEST(ScanTest, DeconstructedTimestamp2)
     EXPECT_EQ(std::get<4>(res->values()), 20);
     EXPECT_STREQ(res->range().data(), "33.576864");
 }
+
+TEST(ScanTest, LotsOfArguments)
+{
+    auto res = scn::scan<int, int, int, int, int, int, int, double>(
+        "1 2 3 4 5 6 7 8.9", "{} {} {} {} {} {} {} {}");
+    ASSERT_TRUE(res);
+    auto [a1, a2, a3, a4, a5, a6, a7, a8] = res->values();
+    EXPECT_EQ(a1, 1);
+    EXPECT_EQ(a2, 2);
+    EXPECT_EQ(a3, 3);
+    EXPECT_EQ(a4, 4);
+    EXPECT_EQ(a5, 5);
+    EXPECT_EQ(a6, 6);
+    EXPECT_EQ(a7, 7);
+    EXPECT_DOUBLE_EQ(a8, 8.9);
+}
+TEST(ScanTest, EvenMoreArguments)
+{
+    auto res = scn::scan<int, int, int, int, int, int, int, int, int, int, int,
+                         int, int, int, int, int, int, int, int, int, int, int,
+                         int, int, int, int, int, int, int, int, int, int, int>(
+        "1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 "
+        "27 28 29 30 31 32 33",
+        "{} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {} "
+        "{} {} {} {} {} {} {} {} {} {}");
+    ASSERT_TRUE(res);
+}