From b9c9c2576658706939d20b1861309fefa7f20889 Mon Sep 17 00:00:00 2001 From: Andreas Rammhold Date: Fri, 30 Jul 2021 20:08:54 +0200 Subject: [PATCH] libutil: initialize the base64 decode array only once Previously, despite having a boolean that tracked initialization, the decode characters have been "calculated" every single time a base64 string was being decoded. With this change we only initialize the decode array once in a thread-safe manner. --- src/libutil/util.cc | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/src/libutil/util.cc b/src/libutil/util.cc index d876315c8..d1270cd31 100644 --- a/src/libutil/util.cc +++ b/src/libutil/util.cc @@ -6,14 +6,15 @@ #include #include +#include #include #include #include -#include +#include #include +#include #include #include -#include #include #include @@ -1447,7 +1448,7 @@ std::string filterANSIEscapes(const std::string & s, bool filterAll, unsigned in static char base64Chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; - +static std::array base64DecodeChars; string base64Encode(std::string_view s) { @@ -1472,15 +1473,12 @@ string base64Encode(std::string_view s) string base64Decode(std::string_view s) { - bool init = false; - char decode[256]; - if (!init) { - // FIXME: not thread-safe. - memset(decode, -1, sizeof(decode)); + static std::once_flag flag; + std::call_once(flag, [](){ + base64DecodeChars = { (char)-1 }; for (int i = 0; i < 64; i++) - decode[(int) base64Chars[i]] = i; - init = true; - } + base64DecodeChars[(int) base64Chars[i]] = i; + }); string res; unsigned int d = 0, bits = 0; @@ -1489,7 +1487,7 @@ string base64Decode(std::string_view s) if (c == '=') break; if (c == '\n') continue; - char digit = decode[(unsigned char) c]; + char digit = base64DecodeChars[(unsigned char) c]; if (digit == -1) throw Error("invalid character in Base64 string: '%c'", c);