lldb/source/Utility/StringLexer.cpp

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