Export of internal Abseil changes

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d8ddeda8e52132b908fae89b25f117a055d78c04 by Abseil Team <absl-team@google.com>:

Improve performance of ByteStringFromAscii by changing kHexValue to have -1 in invalid value slots. This way a single load can do both the validation and conversion.

PiperOrigin-RevId: 284167344

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5037e97e2eaaac8ced9a5290949deda4b43b9ceb by Mark Barolak <mbar@google.com>:

Change the underlying symbol name of Cord to absl::Cord.

PiperOrigin-RevId: 284005429

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4ef66c72aedf135f2b4fd0ba7a73de6642decfff by Abseil Team <absl-team@google.com>:

Eliminate an unnecessary load when futex is contended in Waiter::Wait()

The first argument to compare_exchange_weak() is a reference and will be
updated upon failure.  There is no need to do an additional load on the
same variable.

PiperOrigin-RevId: 284002752
GitOrigin-RevId: d8ddeda8e52132b908fae89b25f117a055d78c04
Change-Id: Idac68a1901eb8c30050adc3860765b1a6fa085c7

1 files changed, 5 insertions, 4 deletions

diff --git a/absl/strings/escaping.cc b/absl/strings/escaping.cc
index 88390fbf..18b746e3 100644
--- a/absl/strings/escaping.cc
+++ b/absl/strings/escaping.cc
@@ -961,7 +961,7 @@ bool Base64UnescapeInternal(const char* src, size_t slen, String* dest,
 }
 
 /* clang-format off */
-constexpr char kHexValue[256] = {
+constexpr char kHexValueLenient[256] = {
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -977,8 +977,9 @@ constexpr char kHexValue[256] = {
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+    0,  0,  0,  0,  0,  0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 };
+
 /* clang-format on */
 
 // This is a templated function so that T can be either a char*
@@ -987,8 +988,8 @@ constexpr char kHexValue[256] = {
 template <typename T>
 void HexStringToBytesInternal(const char* from, T to, ptrdiff_t num) {
   for (int i = 0; i < num; i++) {
-    to[i] = (kHexValue[from[i * 2] & 0xFF] << 4) +
-            (kHexValue[from[i * 2 + 1] & 0xFF]);
+    to[i] = (kHexValueLenient[from[i * 2] & 0xFF] << 4) +
+            (kHexValueLenient[from[i * 2 + 1] & 0xFF]);
   }
 }