44 lines · cpp
1//===- OptionStrCmp.cpp - Option String Comparison --------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/Support/OptionStrCmp.h"10#include "llvm/ADT/STLExtras.h"11 12using namespace llvm;13 14// Comparison function for Option strings (option names & prefixes).15// The ordering is *almost* case-insensitive lexicographic, with an exception.16// '\0' comes at the end of the alphabet instead of the beginning (thus options17// precede any other options which prefix them). Additionally, if two options18// are identical ignoring case, they are ordered according to case sensitive19// ordering if `FallbackCaseSensitive` is true.20int llvm::StrCmpOptionName(StringRef A, StringRef B,21 bool FallbackCaseSensitive) {22 size_t MinSize = std::min(A.size(), B.size());23 if (int Res = A.substr(0, MinSize).compare_insensitive(B.substr(0, MinSize)))24 return Res;25 26 // If they are identical ignoring case, use case sensitive ordering.27 if (A.size() == B.size())28 return FallbackCaseSensitive ? A.compare(B) : 0;29 30 return (A.size() == MinSize) ? 1 /* A is a prefix of B. */31 : -1 /* B is a prefix of A */;32}33 34// Comparison function for Option prefixes.35int llvm::StrCmpOptionPrefixes(ArrayRef<StringRef> APrefixes,36 ArrayRef<StringRef> BPrefixes) {37 for (const auto &[APre, BPre] : zip(APrefixes, BPrefixes)) {38 if (int Cmp = StrCmpOptionName(APre, BPre))39 return Cmp;40 }41 // Both prefixes are identical.42 return 0;43}44