Allows absl::StrCat to accept types that implement AbslStringify()

PiperOrigin-RevId: 478050535
Change-Id: I8e4a4b01aceb8d712476101633eac0ce8647823a

1 files changed, 36 insertions, 0 deletions

diff --git a/absl/strings/str_cat.cc b/absl/strings/str_cat.cc
index 2f9df673..6981347a 100644
--- a/absl/strings/str_cat.cc
+++ b/absl/strings/str_cat.cc
@@ -17,16 +17,52 @@
 #include <assert.h>
 
 #include <algorithm>
+#include <cstddef>
 #include <cstdint>
 #include <cstring>
+#include <string>
 
 #include "absl/strings/ascii.h"
 #include "absl/strings/internal/resize_uninitialized.h"
 #include "absl/strings/numbers.h"
+#include "absl/strings/string_view.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
 
+namespace strings_internal {
+void StringifySink::Append(size_t count, char ch) { buffer_.append(count, ch); }
+
+void StringifySink::Append(string_view v) {
+  buffer_.append(v.data(), v.size());
+}
+
+bool StringifySink::PutPaddedString(string_view v, int width, int precision,
+                                    bool left) {
+  size_t space_remaining = 0;
+
+  if (width >= 0) space_remaining = static_cast<size_t>(width);
+
+  size_t n = v.size();
+
+  if (precision >= 0) n = (std::min)(n, static_cast<size_t>(precision));
+
+  string_view shown(v.data(), n);
+
+  if (shown.size() < space_remaining) {
+    space_remaining = space_remaining - shown.size();
+  } else {
+    space_remaining = 0;
+  }
+
+  if (!left) Append(space_remaining, ' ');
+  Append(shown);
+  if (left) Append(space_remaining, ' ');
+  return true;
+}
+
+}  // namespace strings_internal
+
 AlphaNum::AlphaNum(Hex hex) {
   static_assert(numbers_internal::kFastToBufferSize >= 32,
                 "This function only works when output buffer >= 32 bytes long");