1 // Copyright 2020 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "util/stringprintf.h"
6
7 #include <cstdarg>
8 #include <cstdio>
9 #include <iomanip>
10 #include <sstream>
11
12 #include "util/osp_logging.h"
13
14 namespace openscreen {
15
StringPrintf(const char * format,...)16 std::string StringPrintf(const char* format, ...) {
17 va_list vlist;
18 va_start(vlist, format);
19 const int length = std::vsnprintf(nullptr, 0, format, vlist);
20 OSP_CHECK_GE(length, 0) << "Invalid format string: " << format;
21 va_end(vlist);
22
23 std::string result(length, '\0');
24 // Note: There's no need to add one for the extra terminating NUL char since
25 // the standard, since C++11, requires that "data() + size() points to [the
26 // NUL terminator]". Thus, std::vsnprintf() will write the NUL to a valid
27 // memory location.
28 va_start(vlist, format);
29 std::vsnprintf(&result[0], length + 1, format, vlist);
30 va_end(vlist);
31
32 return result;
33 }
34
HexEncode(absl::Span<const uint8_t> bytes)35 std::string HexEncode(absl::Span<const uint8_t> bytes) {
36 std::ostringstream hex_dump;
37 hex_dump << std::setfill('0') << std::hex;
38 for (const uint8_t byte : bytes) {
39 hex_dump << std::setw(2) << static_cast<int>(byte);
40 }
41 return hex_dump.str();
42 }
43
44 } // namespace openscreen
45