From 8a0693b2a75f21e508ffcd172efda3bbb638a275 Mon Sep 17 00:00:00 2001 From: Phoebe Liang Date: Fri, 27 Jan 2023 10:54:21 -0800 Subject: Adds `AbslStringify` support to `absl::Hex` and `absl::Dec` `absl::Hex` and `absl::Dec` are now stringifiable through `AbslStringify`. This means that they can be passed to logging, `absl::StrFormat`, `absl::StrCat` and `absl::Substitute`. Note that this change will break unsupported usages of `absl::AlphaNum`. `absl::AlphaNum` is not intended to be instantiated as a stack variable due to lifetime issues. Unsupported usages include: * constructing an `absl::AlphaNum` as a local variable. * For example, `absl::AlphaNum a = absl::Hex(...);` * declaring an `absl::AlphaNum` as a member variable Usage of `absl::AlphaNum` as a function parameter will continue to be supported. PiperOrigin-RevId: 505158534 Change-Id: Idecdf0b3d137482e86b393c7480229343d68eb36 --- absl/strings/str_cat.cc | 49 ----------------------------------------- absl/strings/str_cat.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 55 insertions(+), 52 deletions(-) diff --git a/absl/strings/str_cat.cc b/absl/strings/str_cat.cc index 114a2ff2..6c198f85 100644 --- a/absl/strings/str_cat.cc +++ b/absl/strings/str_cat.cc @@ -30,55 +30,6 @@ namespace absl { ABSL_NAMESPACE_BEGIN -AlphaNum::AlphaNum(Hex hex) { - static_assert(numbers_internal::kFastToBufferSize >= 32, - "This function only works when output buffer >= 32 bytes long"); - char* const end = &digits_[numbers_internal::kFastToBufferSize]; - auto real_width = - absl::numbers_internal::FastHexToBufferZeroPad16(hex.value, end - 16); - if (real_width >= hex.width) { - piece_ = absl::string_view(end - real_width, real_width); - } else { - // Pad first 16 chars because FastHexToBufferZeroPad16 pads only to 16 and - // max pad width can be up to 20. - std::memset(end - 32, hex.fill, 16); - // Patch up everything else up to the real_width. - std::memset(end - real_width - 16, hex.fill, 16); - piece_ = absl::string_view(end - hex.width, hex.width); - } -} - -AlphaNum::AlphaNum(Dec dec) { - assert(dec.width <= numbers_internal::kFastToBufferSize); - char* const end = &digits_[numbers_internal::kFastToBufferSize]; - char* const minfill = end - dec.width; - char* writer = end; - uint64_t value = dec.value; - bool neg = dec.neg; - while (value > 9) { - *--writer = '0' + (value % 10); - value /= 10; - } - *--writer = '0' + static_cast(value); - if (neg) *--writer = '-'; - - ptrdiff_t fillers = writer - minfill; - if (fillers > 0) { - // Tricky: if the fill character is ' ', then it's <+/-> - // But...: if the fill character is '0', then it's <+/-> - bool add_sign_again = false; - if (neg && dec.fill == '0') { // If filling with '0', - ++writer; // ignore the sign we just added - add_sign_again = true; // and re-add the sign later. - } - writer -= fillers; - std::fill_n(writer, fillers, dec.fill); - if (add_sign_again) *--writer = '-'; - } - - piece_ = absl::string_view(writer, static_cast(end - writer)); -} - // ---------------------------------------------------------------------- // StrCat() // This merges the given strings or integers, with no delimiter. This diff --git a/absl/strings/str_cat.h b/absl/strings/str_cat.h index 8b68dac0..fcd48c4e 100644 --- a/absl/strings/str_cat.h +++ b/absl/strings/str_cat.h @@ -87,8 +87,10 @@ #ifndef ABSL_STRINGS_STR_CAT_H_ #define ABSL_STRINGS_STR_CAT_H_ +#include #include #include +#include #include #include #include @@ -202,6 +204,27 @@ struct Hex { explicit Hex(Pointee* v, PadSpec spec = absl::kNoPad) : Hex(spec, reinterpret_cast(v)) {} + template + friend void AbslStringify(S& sink, Hex hex) { + static_assert( + numbers_internal::kFastToBufferSize >= 32, + "This function only works when output buffer >= 32 bytes long"); + char buffer[numbers_internal::kFastToBufferSize]; + char* const end = &buffer[numbers_internal::kFastToBufferSize]; + auto real_width = + absl::numbers_internal::FastHexToBufferZeroPad16(hex.value, end - 16); + if (real_width >= hex.width) { + sink.Append(absl::string_view(end - real_width, real_width)); + } else { + // Pad first 16 chars because FastHexToBufferZeroPad16 pads only to 16 and + // max pad width can be up to 20. + std::memset(end - 32, hex.fill, 16); + // Patch up everything else up to the real_width. + std::memset(end - real_width - 16, hex.fill, 16); + sink.Append(absl::string_view(end - hex.width, hex.width)); + } + } + private: Hex(PadSpec spec, uint64_t v) : value(v), @@ -236,6 +259,38 @@ struct Dec { : spec - absl::kZeroPad2 + 2), fill(spec >= absl::kSpacePad2 ? ' ' : '0'), neg(v < 0) {} + + template + friend void AbslStringify(S& sink, Dec dec) { + assert(dec.width <= numbers_internal::kFastToBufferSize); + char buffer[numbers_internal::kFastToBufferSize]; + char* const end = &buffer[numbers_internal::kFastToBufferSize]; + char* const minfill = end - dec.width; + char* writer = end; + uint64_t val = dec.value; + while (val > 9) { + *--writer = '0' + (val % 10); + val /= 10; + } + *--writer = '0' + static_cast(val); + if (dec.neg) *--writer = '-'; + + ptrdiff_t fillers = writer - minfill; + if (fillers > 0) { + // Tricky: if the fill character is ' ', then it's <+/-> + // But...: if the fill character is '0', then it's <+/-> + bool add_sign_again = false; + if (dec.neg && dec.fill == '0') { // If filling with '0', + ++writer; // ignore the sign we just added + add_sign_again = true; // and re-add the sign later. + } + writer -= fillers; + std::fill_n(writer, fillers, dec.fill); + if (add_sign_again) *--writer = '-'; + } + + sink.Append(absl::string_view(writer, static_cast(end - writer))); + } }; // ----------------------------------------------------------------------------- @@ -283,9 +338,6 @@ class AlphaNum { AlphaNum(double f) // NOLINT(runtime/explicit) : piece_(digits_, numbers_internal::SixDigitsToBuffer(f, digits_)) {} - AlphaNum(Hex hex); // NOLINT(runtime/explicit) - AlphaNum(Dec dec); // NOLINT(runtime/explicit) - template AlphaNum( // NOLINT(runtime/explicit) const strings_internal::AlphaNumBuffer& buf -- cgit v1.2.3