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authorGravatar Martijn Vels <mvels@google.com>2022-09-29 18:14:53 -0700
committerGravatar Copybara-Service <copybara-worker@google.com>2022-09-29 18:15:59 -0700
commit92bc0b6b68cd138aefeb94d566499f5bf14f859f (patch)
treea2558321254062576ad4fc30c792ae88b7542ba6 /absl
parentb39aa365e14984035bbbe60f52ec40a66419f18e (diff)
Cleanup: Move BitwiseCompare() to InlineData, and make it layout independent.
This removes layout specific details from InlineData from cord.h, making future platform specific internal layout changes easier to land. PiperOrigin-RevId: 477869206 Change-Id: I1d417af47d7f04e34a98ba7b93ae591ece8f9151
Diffstat (limited to 'absl')
-rw-r--r--absl/strings/cord.h16
-rw-r--r--absl/strings/internal/cord_internal.h23
2 files changed, 24 insertions, 15 deletions
diff --git a/absl/strings/cord.h b/absl/strings/cord.h
index e8267ab1..d7e5a45e 100644
--- a/absl/strings/cord.h
+++ b/absl/strings/cord.h
@@ -876,20 +876,6 @@ class Cord {
bool IsSame(const InlineRep& other) const {
return memcmp(&data_, &other.data_, sizeof(data_)) == 0;
}
- int BitwiseCompare(const InlineRep& other) const {
- uint64_t x, y;
- // Use memcpy to avoid aliasing issues.
- memcpy(&x, &data_, sizeof(x));
- memcpy(&y, &other.data_, sizeof(y));
- if (x == y) {
- memcpy(&x, reinterpret_cast<const char*>(&data_) + 8, sizeof(x));
- memcpy(&y, reinterpret_cast<const char*>(&other.data_) + 8, sizeof(y));
- if (x == y) return 0;
- }
- return absl::big_endian::FromHost64(x) < absl::big_endian::FromHost64(y)
- ? -1
- : 1;
- }
void CopyTo(std::string* dst) const {
// memcpy is much faster when operating on a known size. On most supported
// platforms, the small string optimization is large enough that resizing
@@ -1387,7 +1373,7 @@ extern template void Cord::Prepend(std::string&& src);
inline int Cord::Compare(const Cord& rhs) const {
if (!contents_.is_tree() && !rhs.contents_.is_tree()) {
- return contents_.BitwiseCompare(rhs.contents_);
+ return contents_.data_.Compare(rhs.contents_.data_);
}
return CompareImpl(rhs);
diff --git a/absl/strings/internal/cord_internal.h b/absl/strings/internal/cord_internal.h
index 601457ee..f32fd416 100644
--- a/absl/strings/internal/cord_internal.h
+++ b/absl/strings/internal/cord_internal.h
@@ -582,6 +582,29 @@ class InlineData {
tag() = static_cast<char>(size << 1);
}
+ // Compares 'this' inlined data with rhs. The comparison is a straightforward
+ // lexicographic comparison. `Compare()` returns values as follows:
+ //
+ // -1 'this' InlineData instance is smaller
+ // 0 the InlineData instances are equal
+ // 1 'this' InlineData instance larger
+ int Compare(const InlineData& rhs) const {
+ uint64_t x, y;
+ memcpy(&x, as_chars(), sizeof(x));
+ memcpy(&y, rhs.as_chars(), sizeof(y));
+ if (x == y) {
+ memcpy(&x, as_chars() + 7, sizeof(x));
+ memcpy(&y, rhs.as_chars() + 7, sizeof(y));
+ if (x == y) {
+ if (inline_size() == rhs.inline_size()) return 0;
+ return inline_size() < rhs.inline_size() ? -1 : 1;
+ }
+ }
+ x = absl::big_endian::FromHost64(x);
+ y = absl::big_endian::FromHost64(y);
+ return x < y ? -1 : 1;
+ }
+
private:
// See cordz_info_t for forced alignment and size of `cordz_info` details.
struct AsTree {