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Diffstat (limited to 'contrib/llvm/lib/Support/FormatVariadic.cpp')
-rw-r--r-- | contrib/llvm/lib/Support/FormatVariadic.cpp | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/FormatVariadic.cpp b/contrib/llvm/lib/Support/FormatVariadic.cpp new file mode 100644 index 0000000..de61dae --- /dev/null +++ b/contrib/llvm/lib/Support/FormatVariadic.cpp @@ -0,0 +1,156 @@ +//===- FormatVariadic.cpp - Format string parsing and analysis ----*-C++-*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +//===----------------------------------------------------------------------===// + +#include "llvm/Support/FormatVariadic.h" + +using namespace llvm; + +static Optional<AlignStyle> translateLocChar(char C) { + switch (C) { + case '-': + return AlignStyle::Left; + case '=': + return AlignStyle::Center; + case '+': + return AlignStyle::Right; + default: + return None; + } + LLVM_BUILTIN_UNREACHABLE; +} + +bool formatv_object_base::consumeFieldLayout(StringRef &Spec, AlignStyle &Where, + size_t &Align, char &Pad) { + Where = AlignStyle::Right; + Align = 0; + Pad = ' '; + if (Spec.empty()) + return true; + + if (Spec.size() > 1) { + // A maximum of 2 characters at the beginning can be used for something + // other + // than the width. + // If Spec[1] is a loc char, then Spec[0] is a pad char and Spec[2:...] + // contains the width. + // Otherwise, if Spec[0] is a loc char, then Spec[1:...] contains the width. + // Otherwise, Spec[0:...] contains the width. + if (auto Loc = translateLocChar(Spec[1])) { + Pad = Spec[0]; + Where = *Loc; + Spec = Spec.drop_front(2); + } else if (auto Loc = translateLocChar(Spec[0])) { + Where = *Loc; + Spec = Spec.drop_front(1); + } + } + + bool Failed = Spec.consumeInteger(0, Align); + return !Failed; +} + +Optional<ReplacementItem> +formatv_object_base::parseReplacementItem(StringRef Spec) { + StringRef RepString = Spec.trim("{}"); + + // If the replacement sequence does not start with a non-negative integer, + // this is an error. + char Pad = ' '; + std::size_t Align = 0; + AlignStyle Where = AlignStyle::Right; + StringRef Options; + size_t Index = 0; + RepString = RepString.trim(); + if (RepString.consumeInteger(0, Index)) { + assert(false && "Invalid replacement sequence index!"); + return ReplacementItem{}; + } + RepString = RepString.trim(); + if (!RepString.empty() && RepString.front() == ',') { + RepString = RepString.drop_front(); + if (!consumeFieldLayout(RepString, Where, Align, Pad)) + assert(false && "Invalid replacement field layout specification!"); + } + RepString = RepString.trim(); + if (!RepString.empty() && RepString.front() == ':') { + Options = RepString.drop_front().trim(); + RepString = StringRef(); + } + RepString = RepString.trim(); + if (!RepString.empty()) { + assert(false && "Unexpected characters found in replacement string!"); + } + + return ReplacementItem{Spec, Index, Align, Where, Pad, Options}; +} + +std::pair<ReplacementItem, StringRef> +formatv_object_base::splitLiteralAndReplacement(StringRef Fmt) { + StringRef Rep; + StringRef Remainder; + std::size_t From = 0; + while (From < Fmt.size() && From != StringRef::npos) { + std::size_t BO = Fmt.find_first_of('{', From); + // Everything up until the first brace is a literal. + if (BO != 0) + return std::make_pair(ReplacementItem{Fmt.substr(0, BO)}, Fmt.substr(BO)); + + StringRef Braces = + Fmt.drop_front(BO).take_while([](char C) { return C == '{'; }); + // If there is more than one brace, then some of them are escaped. Treat + // these as replacements. + if (Braces.size() > 1) { + size_t NumEscapedBraces = Braces.size() / 2; + StringRef Middle = Fmt.substr(BO, NumEscapedBraces); + StringRef Right = Fmt.drop_front(BO + NumEscapedBraces * 2); + return std::make_pair(ReplacementItem{Middle}, Right); + } + // An unterminated open brace is undefined. We treat the rest of the string + // as a literal replacement, but we assert to indicate that this is + // undefined and that we consider it an error. + std::size_t BC = Fmt.find_first_of('}', BO); + if (BC == StringRef::npos) { + assert( + false && + "Unterminated brace sequence. Escape with {{ for a literal brace."); + return std::make_pair(ReplacementItem{Fmt}, StringRef()); + } + + // Even if there is a closing brace, if there is another open brace before + // this closing brace, treat this portion as literal, and try again with the + // next one. + std::size_t BO2 = Fmt.find_first_of('{', BO + 1); + if (BO2 < BC) + return std::make_pair(ReplacementItem{Fmt.substr(0, BO2)}, + Fmt.substr(BO2)); + + StringRef Spec = Fmt.slice(BO + 1, BC); + StringRef Right = Fmt.substr(BC + 1); + + auto RI = parseReplacementItem(Spec); + if (RI.hasValue()) + return std::make_pair(*RI, Right); + + // If there was an error parsing the replacement item, treat it as an + // invalid replacement spec, and just continue. + From = BC + 1; + } + return std::make_pair(ReplacementItem{Fmt}, StringRef()); +} + +std::vector<ReplacementItem> +formatv_object_base::parseFormatString(StringRef Fmt) { + std::vector<ReplacementItem> Replacements; + ReplacementItem I; + while (!Fmt.empty()) { + std::tie(I, Fmt) = splitLiteralAndReplacement(Fmt); + if (I.Type != ReplacementType::Empty) + Replacements.push_back(I); + } + return Replacements; +} |