Convert to C++20 requires clauses in span_util.h
Change-Id: I03046490a41eac6f821faa413c852b4648790f0d
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/131177
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxcrt/span_util.h b/core/fxcrt/span_util.h
index fb03b5b..efe6c10 100644
--- a/core/fxcrt/span_util.h
+++ b/core/fxcrt/span_util.h
@@ -23,14 +23,13 @@
size_t N1,
size_t N2,
typename P1,
- typename P2,
- typename = std::enable_if_t<sizeof(T1) == sizeof(T2) &&
- std::is_trivially_copyable_v<T1> &&
- std::is_trivially_copyable_v<T2>>>
+ typename P2>
+ requires(sizeof(T1) == sizeof(T2) && std::is_trivially_copyable_v<T1> &&
+ std::is_trivially_copyable_v<T2>)
inline pdfium::span<T1> spancpy(pdfium::span<T1, N1, P1> dst,
pdfium::span<T2, N2, P2> src) {
CHECK_GE(dst.size(), src.size());
- // SAFETY: SFINAE ensures `sizeof(T1)` equals `sizeof(T2)`, so comparing
+ // SAFETY: requires() ensures `sizeof(T1)` equals `sizeof(T2)`, so comparing
// `size()` for equality ensures `size_bytes()` are equal, and `size_bytes()`
// accurately describes `data()`.
UNSAFE_BUFFERS(FXSYS_memcpy(dst.data(), src.data(), src.size_bytes()));
@@ -44,14 +43,13 @@
size_t N1,
size_t N2,
typename P1,
- typename P2,
- typename = std::enable_if_t<sizeof(T1) == sizeof(T2) &&
- std::is_trivially_copyable_v<T1> &&
- std::is_trivially_copyable_v<T2>>>
+ typename P2>
+ requires(sizeof(T1) == sizeof(T2) && std::is_trivially_copyable_v<T1> &&
+ std::is_trivially_copyable_v<T2>)
inline pdfium::span<T1> spanmove(pdfium::span<T1, N1, P1> dst,
pdfium::span<T2, N2, P2> src) {
CHECK_GE(dst.size(), src.size());
- // SAFETY: SFINAE ensures `sizeof(T1)` equals `sizeof(T2)`, so comparing
+ // SAFETY: requires() ensures `sizeof(T1)` equals `sizeof(T2)`, so comparing
// `size()` for equality ensures `size_bytes()` are equal, and `size_bytes()`
// accurately describes `data()`.
UNSAFE_BUFFERS(FXSYS_memmove(dst.data(), src.data(), src.size_bytes()));
@@ -66,16 +64,15 @@
size_t N1,
size_t N2,
typename P1,
- typename P2,
- typename = std::enable_if_t<sizeof(T1) == sizeof(T2) &&
- std::is_trivially_copyable_v<T1> &&
- std::is_trivially_copyable_v<T2>>>
+ typename P2>
+ requires(sizeof(T1) == sizeof(T2) && std::is_trivially_copyable_v<T1> &&
+ std::is_trivially_copyable_v<T2>)
inline bool try_spancpy(pdfium::span<T1, N1, P1> dst,
pdfium::span<T2, N2, P2> src) {
if (dst.size() < src.size()) {
return false;
}
- // SAFETY: SFINAE ensures `sizeof(T1)` equals `sizeof(T2)`, the test above
+ // SAFETY: requires() ensures `sizeof(T1)` equals `sizeof(T2)`, the test above
// ensures `src.size()` <= `dst.size()` which implies `src.size_bytes()`
// <= `dst.size_bytes()`, and `dst.size_bytes()` describes `dst.data()`.
UNSAFE_BUFFERS(FXSYS_memcpy(dst.data(), src.data(), src.size_bytes()));
@@ -90,16 +87,15 @@
size_t N1,
size_t N2,
typename P1,
- typename P2,
- typename = std::enable_if_t<sizeof(T1) == sizeof(T2) &&
- std::is_trivially_copyable_v<T1> &&
- std::is_trivially_copyable_v<T2>>>
+ typename P2>
+ requires(sizeof(T1) == sizeof(T2) && std::is_trivially_copyable_v<T1> &&
+ std::is_trivially_copyable_v<T2>)
inline bool try_spanmove(pdfium::span<T1, N1, P1> dst,
pdfium::span<T2, N2, P2> src) {
if (dst.size() < src.size()) {
return false;
}
- // SAFETY: SFINAE ensures `sizeof(T1)` equals `sizeof(T2)`, the test above
+ // SAFETY: requires ensures `sizeof(T1)` equals `sizeof(T2)`, the test above
// ensures `src.size()` <= `dst.size()` which implies `src.size_bytes()`
// <= `dst.size_bytes()`, and `dst.size_bytes()` describes `dst.data()`.
UNSAFE_BUFFERS(FXSYS_memmove(dst.data(), src.data(), src.size_bytes()));
@@ -113,10 +109,9 @@
size_t N1,
size_t N2,
typename P1,
- typename P2,
- typename = std::enable_if_t<sizeof(T1) == sizeof(T2) &&
- std::is_trivially_copyable_v<T1> &&
- std::is_trivially_copyable_v<T2>>>
+ typename P2>
+ requires(sizeof(T1) == sizeof(T2) && std::is_trivially_copyable_v<T1> &&
+ std::is_trivially_copyable_v<T2>)
bool span_equals(pdfium::span<T1, N1, P1> s1, pdfium::span<T2, N2, P2> s2) {
// SAFETY: For both `s1` and `s2`, there are `size_bytes()` valid bytes at
// the corresponding `data()`, and the sizes are the same.
@@ -126,13 +121,9 @@
}
// Returns the first position where `needle` occurs in `haystack`.
-template <typename T,
- typename U,
- size_t TS,
- size_t US,
- typename = std::enable_if_t<sizeof(T) == sizeof(U) &&
- std::is_trivially_copyable_v<T> &&
- std::is_trivially_copyable_v<U>>>
+template <typename T, typename U, size_t TS, size_t US>
+ requires(sizeof(T) == sizeof(U) && std::is_trivially_copyable_v<T> &&
+ std::is_trivially_copyable_v<U>)
std::optional<size_t> spanpos(pdfium::span<T, TS> haystack,
pdfium::span<U, US> needle) {
if (needle.empty() || needle.size() > haystack.size()) {
@@ -150,11 +141,8 @@
return std::nullopt;
}
-template <typename T,
- typename U,
- size_t M,
- typename = typename std::enable_if_t<std::is_const_v<T> ||
- !std::is_const_v<U>>>
+template <typename T, typename U, size_t M>
+ requires(std::is_const_v<T> || !std::is_const_v<U>)
inline pdfium::span<T> reinterpret_span(pdfium::span<U, M> s) noexcept {
CHECK(alignof(T) == alignof(U) ||
reinterpret_cast<uintptr_t>(s.data()) % alignof(T) == 0u);
