diff options
Diffstat (limited to 'abseil-cpp/absl/strings/str_cat.cc')
-rw-r--r-- | abseil-cpp/absl/strings/str_cat.cc | 76 |
1 files changed, 18 insertions, 58 deletions
diff --git a/abseil-cpp/absl/strings/str_cat.cc b/abseil-cpp/absl/strings/str_cat.cc index dd5d25b..2e49c31 100644 --- a/abseil-cpp/absl/strings/str_cat.cc +++ b/abseil-cpp/absl/strings/str_cat.cc @@ -17,65 +17,19 @@ #include <assert.h> #include <algorithm> +#include <cstddef> #include <cstdint> #include <cstring> +#include <string> #include "absl/strings/ascii.h" #include "absl/strings/internal/resize_uninitialized.h" #include "absl/strings/numbers.h" +#include "absl/strings/string_view.h" 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' + value; - if (neg) *--writer = '-'; - - ptrdiff_t fillers = writer - minfill; - if (fillers > 0) { - // Tricky: if the fill character is ' ', then it's <fill><+/-><digits> - // But...: if the fill character is '0', then it's <+/-><fill><digits> - 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, end - writer); -} - // ---------------------------------------------------------------------- // StrCat() // This merges the given strings or integers, with no delimiter. This @@ -141,12 +95,12 @@ namespace strings_internal { std::string CatPieces(std::initializer_list<absl::string_view> pieces) { std::string result; size_t total_size = 0; - for (const absl::string_view& piece : pieces) total_size += piece.size(); + for (absl::string_view piece : pieces) total_size += piece.size(); strings_internal::STLStringResizeUninitialized(&result, total_size); char* const begin = &result[0]; char* out = begin; - for (const absl::string_view& piece : pieces) { + for (absl::string_view piece : pieces) { const size_t this_size = piece.size(); if (this_size != 0) { memcpy(out, piece.data(), this_size); @@ -170,15 +124,15 @@ void AppendPieces(std::string* dest, std::initializer_list<absl::string_view> pieces) { size_t old_size = dest->size(); size_t total_size = old_size; - for (const absl::string_view& piece : pieces) { + for (absl::string_view piece : pieces) { ASSERT_NO_OVERLAP(*dest, piece); total_size += piece.size(); } - strings_internal::STLStringResizeUninitialized(dest, total_size); + strings_internal::STLStringResizeUninitializedAmortized(dest, total_size); char* const begin = &(*dest)[0]; char* out = begin + old_size; - for (const absl::string_view& piece : pieces) { + for (absl::string_view piece : pieces) { const size_t this_size = piece.size(); if (this_size != 0) { memcpy(out, piece.data(), this_size); @@ -192,14 +146,20 @@ void AppendPieces(std::string* dest, void StrAppend(std::string* dest, const AlphaNum& a) { ASSERT_NO_OVERLAP(*dest, a); - dest->append(a.data(), a.size()); + std::string::size_type old_size = dest->size(); + strings_internal::STLStringResizeUninitializedAmortized(dest, + old_size + a.size()); + char* const begin = &(*dest)[0]; + char* out = begin + old_size; + out = Append(out, a); + assert(out == begin + dest->size()); } void StrAppend(std::string* dest, const AlphaNum& a, const AlphaNum& b) { ASSERT_NO_OVERLAP(*dest, a); ASSERT_NO_OVERLAP(*dest, b); std::string::size_type old_size = dest->size(); - strings_internal::STLStringResizeUninitialized( + strings_internal::STLStringResizeUninitializedAmortized( dest, old_size + a.size() + b.size()); char* const begin = &(*dest)[0]; char* out = begin + old_size; @@ -214,7 +174,7 @@ void StrAppend(std::string* dest, const AlphaNum& a, const AlphaNum& b, ASSERT_NO_OVERLAP(*dest, b); ASSERT_NO_OVERLAP(*dest, c); std::string::size_type old_size = dest->size(); - strings_internal::STLStringResizeUninitialized( + strings_internal::STLStringResizeUninitializedAmortized( dest, old_size + a.size() + b.size() + c.size()); char* const begin = &(*dest)[0]; char* out = begin + old_size; @@ -231,7 +191,7 @@ void StrAppend(std::string* dest, const AlphaNum& a, const AlphaNum& b, ASSERT_NO_OVERLAP(*dest, c); ASSERT_NO_OVERLAP(*dest, d); std::string::size_type old_size = dest->size(); - strings_internal::STLStringResizeUninitialized( + strings_internal::STLStringResizeUninitializedAmortized( dest, old_size + a.size() + b.size() + c.size() + d.size()); char* const begin = &(*dest)[0]; char* out = begin + old_size; |