gecko-dev/xpcom/ds/Tokenizer.cpp

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C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "Tokenizer.h"
#include "nsUnicharUtils.h"
namespace mozilla {
static const char sWhitespaces[] = " \t";
Tokenizer::Tokenizer(const nsACString& aSource,
const char* aWhitespaces,
const char* aAdditionalWordChars)
: mPastEof(false)
, mHasFailed(false)
, mWhitespaces(aWhitespaces ? aWhitespaces : sWhitespaces)
, mAdditionalWordChars(aAdditionalWordChars)
{
aSource.BeginReading(mCursor);
mRecord = mRollback = mCursor;
aSource.EndReading(mEnd);
}
Tokenizer::Tokenizer(const char* aSource,
const char* aWhitespaces,
const char* aAdditionalWordChars)
: Tokenizer(nsDependentCString(aSource), aWhitespaces, aAdditionalWordChars)
{
}
bool
Tokenizer::Next(Token& aToken)
{
if (!HasInput()) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
mCursor = Parse(aToken);
aToken.AssignFragment(mRollback, mCursor);
mPastEof = aToken.Type() == TOKEN_EOF;
mHasFailed = false;
return true;
}
bool
Tokenizer::Check(const TokenType aTokenType, Token& aResult)
{
if (!HasInput()) {
mHasFailed = true;
return false;
}
nsACString::const_char_iterator next = Parse(aResult);
if (aTokenType != aResult.Type()) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
mCursor = next;
aResult.AssignFragment(mRollback, mCursor);
mPastEof = aResult.Type() == TOKEN_EOF;
mHasFailed = false;
return true;
}
bool
Tokenizer::Check(const Token& aToken)
{
if (!HasInput()) {
mHasFailed = true;
return false;
}
Token parsed;
nsACString::const_char_iterator next = Parse(parsed);
if (!aToken.Equals(parsed)) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
mCursor = next;
mPastEof = parsed.Type() == TOKEN_EOF;
mHasFailed = false;
return true;
}
bool
Tokenizer::HasFailed() const
{
return mHasFailed;
}
void
Tokenizer::SkipWhites(WhiteSkipping aIncludeNewLines)
{
if (!CheckWhite() && (aIncludeNewLines == DONT_INCLUDE_NEW_LINE || !CheckEOL())) {
return;
}
nsACString::const_char_iterator rollback = mRollback;
while (CheckWhite() || (aIncludeNewLines == INCLUDE_NEW_LINE && CheckEOL())) {
}
mHasFailed = false;
mRollback = rollback;
}
void
Tokenizer::SkipUntil(Token const& aToken)
{
nsACString::const_char_iterator rollback = mCursor;
const Token eof = Token::EndOfFile();
Token t;
while (Next(t)) {
if (aToken.Equals(t) || eof.Equals(t)) {
Rollback();
break;
}
}
mRollback = rollback;
}
bool
Tokenizer::CheckChar(bool (*aClassifier)(const char aChar))
{
if (!aClassifier) {
MOZ_ASSERT(false);
return false;
}
if (!HasInput() || mCursor == mEnd) {
mHasFailed = true;
return false;
}
if (!aClassifier(*mCursor)) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
++mCursor;
mHasFailed = false;
return true;
}
bool
Tokenizer::ReadChar(char* aValue)
{
MOZ_RELEASE_ASSERT(aValue);
Token t;
if (!Check(TOKEN_CHAR, t)) {
return false;
}
*aValue = t.AsChar();
return true;
}
bool
Tokenizer::ReadChar(bool (*aClassifier)(const char aChar), char* aValue)
{
MOZ_RELEASE_ASSERT(aValue);
if (!CheckChar(aClassifier)) {
return false;
}
*aValue = *mRollback;
return true;
}
bool
Tokenizer::ReadWord(nsACString& aValue)
{
Token t;
if (!Check(TOKEN_WORD, t)) {
return false;
}
aValue.Assign(t.AsString());
return true;
}
bool
Tokenizer::ReadWord(nsDependentCSubstring& aValue)
{
Token t;
if (!Check(TOKEN_WORD, t)) {
return false;
}
aValue.Rebind(t.AsString().BeginReading(), t.AsString().Length());
return true;
}
bool
Tokenizer::ReadUntil(Token const& aToken, nsACString& aResult, ClaimInclusion aInclude)
{
nsDependentCSubstring substring;
bool rv = ReadUntil(aToken, substring, aInclude);
aResult.Assign(substring);
return rv;
}
bool
Tokenizer::ReadUntil(Token const& aToken, nsDependentCSubstring& aResult, ClaimInclusion aInclude)
{
Record();
nsACString::const_char_iterator rollback = mCursor;
bool found = false;
Token t;
while (Next(t)) {
if (aToken.Equals(t)) {
found = true;
break;
}
}
Claim(aResult, aInclude);
mRollback = rollback;
return found;
}
void
Tokenizer::Rollback()
{
MOZ_ASSERT(mCursor > mRollback || mPastEof,
"Tokenizer::Rollback() cannot use twice or before any parsing");
mPastEof = false;
mHasFailed = false;
mCursor = mRollback;
}
void
Tokenizer::Record(ClaimInclusion aInclude)
{
mRecord = aInclude == INCLUDE_LAST
? mRollback
: mCursor;
}
void
Tokenizer::Claim(nsACString& aResult, ClaimInclusion aInclusion)
{
nsACString::const_char_iterator close = aInclusion == EXCLUDE_LAST
? mRollback
: mCursor;
aResult.Assign(Substring(mRecord, close));
}
void
Tokenizer::Claim(nsDependentCSubstring& aResult, ClaimInclusion aInclusion)
{
nsACString::const_char_iterator close = aInclusion == EXCLUDE_LAST
? mRollback
: mCursor;
aResult.Rebind(mRecord, close - mRecord);
}
// protected
bool
Tokenizer::HasInput() const
{
return !mPastEof;
}
nsACString::const_char_iterator
Tokenizer::Parse(Token& aToken) const
{
if (mCursor == mEnd) {
aToken = Token::EndOfFile();
return mEnd;
}
nsACString::const_char_iterator next = mCursor;
enum State {
PARSE_INTEGER,
PARSE_WORD,
PARSE_CRLF,
PARSE_LF,
PARSE_WS,
PARSE_CHAR,
} state;
if (IsWordFirst(*next)) {
state = PARSE_WORD;
} else if (IsNumber(*next)) {
state = PARSE_INTEGER;
} else if (strchr(mWhitespaces, *next)) { // not UTF-8 friendly?
state = PARSE_WS;
} else if (*next == '\r') {
state = PARSE_CRLF;
} else if (*next == '\n') {
state = PARSE_LF;
} else {
state = PARSE_CHAR;
}
mozilla::CheckedUint64 resultingNumber = 0;
while (next < mEnd) {
switch (state) {
case PARSE_INTEGER:
// Keep it simple for now
resultingNumber *= 10;
resultingNumber += static_cast<uint64_t>(*next - '0');
++next;
if (IsEnd(next) || !IsNumber(*next)) {
if (!resultingNumber.isValid()) {
aToken = Token::Error();
} else {
aToken = Token::Number(resultingNumber.value());
}
return next;
}
break;
case PARSE_WORD:
++next;
if (IsEnd(next) || !IsWord(*next)) {
aToken = Token::Word(Substring(mCursor, next));
return next;
}
break;
case PARSE_CRLF:
++next;
if (!IsEnd(next) && *next == '\n') { // LF is optional
++next;
}
aToken = Token::NewLine();
return next;
case PARSE_LF:
++next;
aToken = Token::NewLine();
return next;
case PARSE_WS:
++next;
aToken = Token::Whitespace();
return next;
case PARSE_CHAR:
++next;
aToken = Token::Char(*mCursor);
return next;
} // switch (state)
} // while (next < end)
return next;
}
bool
Tokenizer::IsEnd(const nsACString::const_char_iterator& caret) const
{
return caret == mEnd;
}
bool
Tokenizer::IsWordFirst(const char aInput) const
{
// TODO: make this fully work with unicode
return (ToLowerCase(static_cast<uint32_t>(aInput)) !=
ToUpperCase(static_cast<uint32_t>(aInput))) ||
'_' == aInput ||
(mAdditionalWordChars ? !!strchr(mAdditionalWordChars, aInput) : false);
}
bool
Tokenizer::IsWord(const char aInput) const
{
return IsWordFirst(aInput) || IsNumber(aInput);
}
bool
Tokenizer::IsNumber(const char aInput) const
{
// TODO: are there unicode numbers?
return aInput >= '0' && aInput <= '9';
}
// Tokenizer::Token
Tokenizer::Token::Token(const Token& aOther)
: mType(aOther.mType)
, mChar(aOther.mChar)
, mInteger(aOther.mInteger)
{
if (mType == TOKEN_WORD) {
mWord.Rebind(aOther.mWord.BeginReading(), aOther.mWord.Length());
}
}
Tokenizer::Token&
Tokenizer::Token::operator=(const Token& aOther)
{
mType = aOther.mType;
mChar = aOther.mChar;
mWord.Rebind(aOther.mWord.BeginReading(), aOther.mWord.Length());
mInteger = aOther.mInteger;
return *this;
}
void
Tokenizer::Token::AssignFragment(nsACString::const_char_iterator begin,
nsACString::const_char_iterator end)
{
mFragment.Rebind(begin, end - begin);
}
// static
Tokenizer::Token
Tokenizer::Token::Word(const nsACString& aValue)
{
Token t;
t.mType = TOKEN_WORD;
t.mWord.Rebind(aValue.BeginReading(), aValue.Length());
return t;
}
// static
Tokenizer::Token
Tokenizer::Token::Char(const char aValue)
{
Token t;
t.mType = TOKEN_CHAR;
t.mChar = aValue;
return t;
}
// static
Tokenizer::Token
Tokenizer::Token::Number(const uint64_t aValue)
{
Token t;
t.mType = TOKEN_INTEGER;
t.mInteger = aValue;
return t;
}
// static
Tokenizer::Token
Tokenizer::Token::Whitespace()
{
Token t;
t.mType = TOKEN_WS;
t.mChar = '\0';
return t;
}
// static
Tokenizer::Token
Tokenizer::Token::NewLine()
{
Token t;
t.mType = TOKEN_EOL;
return t;
}
// static
Tokenizer::Token
Tokenizer::Token::EndOfFile()
{
Token t;
t.mType = TOKEN_EOF;
return t;
}
// static
Tokenizer::Token
Tokenizer::Token::Error()
{
Token t;
t.mType = TOKEN_ERROR;
return t;
}
bool
Tokenizer::Token::Equals(const Token& aOther) const
{
if (mType != aOther.mType) {
return false;
}
switch (mType) {
case TOKEN_INTEGER:
return AsInteger() == aOther.AsInteger();
case TOKEN_WORD:
return AsString() == aOther.AsString();
case TOKEN_CHAR:
return AsChar() == aOther.AsChar();
default:
return true;
}
}
char
Tokenizer::Token::AsChar() const
{
MOZ_ASSERT(mType == TOKEN_CHAR || mType == TOKEN_WS);
return mChar;
}
nsDependentCSubstring
Tokenizer::Token::AsString() const
{
MOZ_ASSERT(mType == TOKEN_WORD);
return mWord;
}
uint64_t
Tokenizer::Token::AsInteger() const
{
MOZ_ASSERT(mType == TOKEN_INTEGER);
return mInteger;
}
} // mozilla