From 5baf5d3daeece33e0767a1c8fbd1b85daa84f45e Mon Sep 17 00:00:00 2001 From: EnilPajic Date: Fri, 26 Jun 2020 21:25:39 +0200 Subject: [PATCH] Fixed potential bug with -MINIMUM_VALUE Original code had something like `N < 0 ? -N : N` which could fail if `N` has minimum value of appropriate type. For example, in original code this could fail: ```cpp const long long int LL_MIN = std::numeric_limits::min(); //probably: -9223372036854775808 static const char *number = to_string; ``` Also note that this code relies on "modulo on negative first operands" which was implementation defined in C++03 and before, but with C++11 and later it is defined by standard (see `ISO14882:2011(e)`), and this code anyway targets C++17 so we're safe here. --- to_string.hpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/to_string.hpp b/to_string.hpp index 116cdd8..6117258 100644 --- a/to_string.hpp +++ b/to_string.hpp @@ -23,7 +23,7 @@ struct to_string_t { // fits to the number perfectly. char buf[([] { unsigned int len = N >= 0 ? 1 : 2; - for (auto n = N < 0 ? -N : N; n; len++, n /= base); + for (auto n = N; n; len++, n /= base); return len; }())]; @@ -33,8 +33,8 @@ struct to_string_t { constexpr to_string_t() { auto ptr = buf + sizeof(buf) / sizeof(buf[0]); *--ptr = '\0'; - for (auto n = N < 0 ? -N : N; n; n /= base) - *--ptr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[n % base]; + for (auto n = N; n; n /= base) + *--ptr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[(N < 0 ? -1 : 1) * (n % base)]; if (N < 0) *--ptr = '-'; }