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-exception
6//
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 options
17// precede any other options which prefix them). Additionally, if two options
18// are identical ignoring case, they are ordered according to case sensitive
19// ordering if `FallbackCaseSensitive` is true.
20int llvm::StrCmpOptionName(StringRef A, StringRef B,
21 bool FallbackCaseSensitive) {
22 size_t MinSize = std::min(a: A.size(), b: B.size());
23 if (int Res = A.substr(Start: 0, N: MinSize).compare_insensitive(RHS: B.substr(Start: 0, N: 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(RHS: 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(t&: APrefixes, u&: BPrefixes)) {
38 if (int Cmp = StrCmpOptionName(A: APre, B: BPre))
39 return Cmp;
40 }
41 // Both prefixes are identical.
42 return 0;
43}
44