Add a StringBuilder class.
String builder is similar to SimpleStringBuilder, but the difference is
that StringBuilder is built around a std::string instance and supports
dynamic resizing.
Change-Id: I874d22e69e639ff9ef3d5929366f4ba71c545787
Bug: webrtc:8982
Reviewed-on: https://webrtc-review.googlesource.com/58980
Commit-Queue: Jonas Olsson <jonasolsson@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24526}diff --git a/rtc_base/strings/string_builder.cc b/rtc_base/strings/string_builder.cc
index 70a14da..2fd4aba 100644
--- a/rtc_base/strings/string_builder.cc
+++ b/rtc_base/strings/string_builder.cc
@@ -109,4 +109,24 @@
return *this;
}
+StringBuilder& StringBuilder::AppendFormat(const char* fmt, ...) {
+ va_list args, copy;
+ va_start(args, fmt);
+ va_copy(copy, args);
+ const int predicted_length = std::vsnprintf(nullptr, 0, fmt, copy);
+ va_end(copy);
+
+ RTC_DCHECK_GE(predicted_length, 0);
+ if (predicted_length > 0) {
+ const size_t size = str_.size();
+ str_.resize(size + predicted_length);
+ // Pass "+ 1" to vsnprintf to include space for the '\0'.
+ const int actual_length =
+ std::vsnprintf(&str_[size], predicted_length + 1, fmt, args);
+ RTC_DCHECK_GE(actual_length, 0);
+ }
+ va_end(args);
+ return *this;
+}
+
} // namespace rtc