StringLexer.cpp revision 360784 
1//===--------------------- StringLexer.cpp -----------------------*- 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 "lldb/Utility/StringLexer.h"
10
11#include <algorithm>
12#include <assert.h>
13
14using namespace lldb_private;
15
16StringLexer::StringLexer(std::string s) : m_data(s), m_position(0) {}
17
18StringLexer::Character StringLexer::Peek() { return m_data[m_position]; }
19
20bool StringLexer::NextIf(Character c) {
21  auto val = Peek();
22  if (val == c) {
23    Next();
24    return true;
25  }
26  return false;
27}
28
29std::pair<bool, StringLexer::Character>
30StringLexer::NextIf(std::initializer_list<Character> cs) {
31  auto val = Peek();
32  for (auto c : cs) {
33    if (val == c) {
34      Next();
35      return {true, c};
36    }
37  }
38  return {false, 0};
39}
40
41bool StringLexer::AdvanceIf(const std::string &token) {
42  auto pos = m_position;
43  bool matches = true;
44  for (auto c : token) {
45    if (!NextIf(c)) {
46      matches = false;
47      break;
48    }
49  }
50  if (!matches) {
51    m_position = pos;
52    return false;
53  }
54  return true;
55}
56
57StringLexer::Character StringLexer::Next() {
58  auto val = Peek();
59  Consume();
60  return val;
61}
62
63bool StringLexer::HasAtLeast(Size s) {
64  return (m_data.size() - m_position) >= s;
65}
66
67void StringLexer::PutBack(Size s) {
68  assert(m_position >= s);
69  m_position -= s;
70}
71
72std::string StringLexer::GetUnlexed() {
73  return std::string(m_data, m_position);
74}
75
76void StringLexer::Consume() { m_position++; }
77
78StringLexer &StringLexer::operator=(const StringLexer &rhs) {
79  if (this != &rhs) {
80    m_data = rhs.m_data;
81    m_position = rhs.m_position;
82  }
83  return *this;
84}
85