Changes imported from Abseil "staging" branch:

  - a0405e7870a80a9dbc6784b06795e7df5a8c90f5 Internal change by Daniel Katz <katzdm@google.com>
  - 2888fe17796d7afa45f4b6ca7eb8e88f52739c39 StrCat: Support zero-padding and space-padding for decima... by Jorg Brown <jorg@google.com>
  - feebc521195241783730df9700394f6585550ff2 Merge GitHub PR #91. by Derek Mauro <dmauro@google.com>
  - e8164335efefb7335f407c17a16fce2ba4f24e3e This changes the value base_internal::kOnceDone from 32-b... by Abseil Team <absl-team@google.com>
  - 0f6085f3f0ee1d6baf9a558d07a25c2fcde93273 Remove `compliant` field from some type trait structs. by Matt Armstrong <marmstrong@google.com>

GitOrigin-RevId: a0405e7870a80a9dbc6784b06795e7df5a8c90f5
Change-Id: Ic2efd40f6ec35f79a8aa12d4475cbea3150756d7

1 files changed, 31 insertions, 0 deletions

diff --git a/absl/strings/str_cat.cc b/absl/strings/str_cat.cc
index 99eb28908c19..3fe8c95eca9e 100644
--- a/absl/strings/str_cat.cc
+++ b/absl/strings/str_cat.cc
@@ -45,6 +45,37 @@ AlphaNum::AlphaNum(Hex hex) {
   piece_ = absl::string_view(beg, end - beg);
 }
 
+AlphaNum::AlphaNum(Dec dec) {
+  assert(dec.width <= numbers_internal::kFastToBufferSize);
+  char* const end = &digits_[numbers_internal::kFastToBufferSize];
+  char* const minfill = end - dec.width;
+  char* writer = end;
+  uint64_t value = dec.value;
+  bool neg = dec.neg;
+  while (value > 9) {
+    *--writer = '0' + (value % 10);
+    value /= 10;
+  }
+  *--writer = '0' + value;
+  if (neg) *--writer = '-';
+
+  ptrdiff_t fillers = writer - minfill;
+  if (fillers > 0) {
+    // Tricky: if the fill character is ' ', then it's <fill><+/-><digits>
+    // But...: if the fill character is '0', then it's <+/-><fill><digits>
+    bool add_sign_again = false;
+    if (neg && dec.fill == '0') {  // If filling with '0',
+      ++writer;                    // ignore the sign we just added
+      add_sign_again = true;       // and re-add the sign later.
+    }
+    writer -= fillers;
+    std::fill_n(writer, fillers, dec.fill);
+    if (add_sign_again) *--writer = '-';
+  }
+
+  piece_ = absl::string_view(writer, end - writer);
+}
+
 // ----------------------------------------------------------------------
 // StrCat()
 //    This merges the given strings or integers, with no delimiter.  This