Adopt absl::string_view in rtc_base/string_encode.*

Bug: webrtc:13579
Change-Id: If52108d151a12bde0e8d552ce7940948c08cef3a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/256812
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Jakob Ivarsson‎ <jakobi@webrtc.org>
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Commit-Queue: Ali Tofigh <alito@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36424}

rtc_base/string_encode.h

@@ -19,6 +19,7 @@
 
 #include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
+#include "api/array_view.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/string_to_number.h"
 
@@ -29,29 +30,18 @@ namespace rtc {
 //////////////////////////////////////////////////////////////////////
 
 std::string hex_encode(absl::string_view str);
-std::string hex_encode(const char* source, size_t srclen);
-std::string hex_encode_with_delimiter(const char* source,
-                                      size_t srclen,
-                                      char delimiter);
+std::string hex_encode_with_delimiter(absl::string_view source, char delimiter);
 
 // hex_decode converts ascii hex to binary.
-size_t hex_decode(char* buffer,
-                  size_t buflen,
-                  const char* source,
-                  size_t srclen);
+size_t hex_decode(ArrayView<char> buffer, absl::string_view source);
 
 // hex_decode, assuming that there is a delimiter between every byte
 // pair.
 // `delimiter` == 0 means no delimiter
 // If the buffer is too short or the data is invalid, we return 0.
-size_t hex_decode_with_delimiter(char* buffer,
-                                 size_t buflen,
-                                 const char* source,
-                                 size_t srclen,
+size_t hex_decode_with_delimiter(ArrayView<char> buffer,
+                                 absl::string_view source,
                                  char delimiter);
-
-// Helper functions for hex_decode.
-size_t hex_decode(char* buffer, size_t buflen, absl::string_view source);
 size_t hex_decode_with_delimiter(char* buffer,
                                  size_t buflen,
                                  absl::string_view source,
@@ -88,8 +78,10 @@ bool tokenize_first(absl::string_view source,
 // TODO(jonasolsson): Remove these when absl::StrCat becomes available.
 std::string ToString(bool b);
 
-std::string ToString(const char* s);
 std::string ToString(absl::string_view s);
+// The const char* overload is needed for correct overload resolution because of
+// the const void* version of ToString() below.
+std::string ToString(const char* s);
 
 std::string ToString(short s);
 std::string ToString(unsigned short s);
@@ -109,7 +101,7 @@ template <typename T,
           typename std::enable_if<std::is_arithmetic<T>::value &&
                                       !std::is_same<T, bool>::value,
                                   int>::type = 0>
-static bool FromString(const std::string& s, T* t) {
+static bool FromString(absl::string_view s, T* t) {
   RTC_DCHECK(t);
   absl::optional<T> result = StringToNumber<T>(s);
 
@@ -119,10 +111,10 @@ static bool FromString(const std::string& s, T* t) {
   return result.has_value();
 }
 
-bool FromString(const std::string& s, bool* b);
+bool FromString(absl::string_view s, bool* b);
 
 template <typename T>
-static inline T FromString(const std::string& str) {
+static inline T FromString(absl::string_view str) {
   T val;
   FromString(str, &val);
   return val;