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Diffstat (limited to 'third_party/protobuf/3.6.0/src/google/protobuf/io/tokenizer.cc')
| -rw-r--r-- | third_party/protobuf/3.6.0/src/google/protobuf/io/tokenizer.cc | 1139 |
1 files changed, 1139 insertions, 0 deletions
diff --git a/third_party/protobuf/3.6.0/src/google/protobuf/io/tokenizer.cc b/third_party/protobuf/3.6.0/src/google/protobuf/io/tokenizer.cc new file mode 100644 index 0000000000..916d1606b7 --- /dev/null +++ b/third_party/protobuf/3.6.0/src/google/protobuf/io/tokenizer.cc @@ -0,0 +1,1139 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// https://developers.google.com/protocol-buffers/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// Author: kenton@google.com (Kenton Varda) +// Based on original Protocol Buffers design by +// Sanjay Ghemawat, Jeff Dean, and others. +// +// Here we have a hand-written lexer. At first you might ask yourself, +// "Hand-written text processing? Is Kenton crazy?!" Well, first of all, +// yes I am crazy, but that's beside the point. There are actually reasons +// why I ended up writing this this way. +// +// The traditional approach to lexing is to use lex to generate a lexer for +// you. Unfortunately, lex's output is ridiculously ugly and difficult to +// integrate cleanly with C++ code, especially abstract code or code meant +// as a library. Better parser-generators exist but would add dependencies +// which most users won't already have, which we'd like to avoid. (GNU flex +// has a C++ output option, but it's still ridiculously ugly, non-abstract, +// and not library-friendly.) +// +// The next approach that any good software engineer should look at is to +// use regular expressions. And, indeed, I did. I have code which +// implements this same class using regular expressions. It's about 200 +// lines shorter. However: +// - Rather than error messages telling you "This string has an invalid +// escape sequence at line 5, column 45", you get error messages like +// "Parse error on line 5". Giving more precise errors requires adding +// a lot of code that ends up basically as complex as the hand-coded +// version anyway. +// - The regular expression to match a string literal looks like this: +// kString = new RE("(\"([^\"\\\\]|" // non-escaped +// "\\\\[abfnrtv?\"'\\\\0-7]|" // normal escape +// "\\\\x[0-9a-fA-F])*\"|" // hex escape +// "\'([^\'\\\\]|" // Also support single-quotes. +// "\\\\[abfnrtv?\"'\\\\0-7]|" +// "\\\\x[0-9a-fA-F])*\')"); +// Verifying the correctness of this line noise is actually harder than +// verifying the correctness of ConsumeString(), defined below. I'm not +// even confident that the above is correct, after staring at it for some +// time. +// - PCRE is fast, but there's still more overhead involved than the code +// below. +// - Sadly, regular expressions are not part of the C standard library, so +// using them would require depending on some other library. For the +// open source release, this could be really annoying. Nobody likes +// downloading one piece of software just to find that they need to +// download something else to make it work, and in all likelihood +// people downloading Protocol Buffers will already be doing so just +// to make something else work. We could include a copy of PCRE with +// our code, but that obligates us to keep it up-to-date and just seems +// like a big waste just to save 200 lines of code. +// +// On a similar but unrelated note, I'm even scared to use ctype.h. +// Apparently functions like isalpha() are locale-dependent. So, if we used +// that, then if this code is being called from some program that doesn't +// have its locale set to "C", it would behave strangely. We can't just set +// the locale to "C" ourselves since we might break the calling program that +// way, particularly if it is multi-threaded. WTF? Someone please let me +// (Kenton) know if I'm missing something here... +// +// I'd love to hear about other alternatives, though, as this code isn't +// exactly pretty. + +#include <google/protobuf/io/tokenizer.h> +#include <google/protobuf/stubs/common.h> +#include <google/protobuf/stubs/logging.h> +#include <google/protobuf/stubs/stringprintf.h> +#include <google/protobuf/io/strtod.h> +#include <google/protobuf/io/zero_copy_stream.h> +#include <google/protobuf/stubs/strutil.h> +#include <google/protobuf/stubs/stl_util.h> + +namespace google { +namespace protobuf { +namespace io { +namespace { + +// As mentioned above, I don't trust ctype.h due to the presence of "locales". +// So, I have written replacement functions here. Someone please smack me if +// this is a bad idea or if there is some way around this. +// +// These "character classes" are designed to be used in template methods. +// For instance, Tokenizer::ConsumeZeroOrMore<Whitespace>() will eat +// whitespace. + +// Note: No class is allowed to contain '\0', since this is used to mark end- +// of-input and is handled specially. + +#define CHARACTER_CLASS(NAME, EXPRESSION) \ + class NAME { \ + public: \ + static inline bool InClass(char c) { \ + return EXPRESSION; \ + } \ + } + +CHARACTER_CLASS(Whitespace, c == ' ' || c == '\n' || c == '\t' || + c == '\r' || c == '\v' || c == '\f'); +CHARACTER_CLASS(WhitespaceNoNewline, c == ' ' || c == '\t' || + c == '\r' || c == '\v' || c == '\f'); + +CHARACTER_CLASS(Unprintable, c < ' ' && c > '\0'); + +CHARACTER_CLASS(Digit, '0' <= c && c <= '9'); +CHARACTER_CLASS(OctalDigit, '0' <= c && c <= '7'); +CHARACTER_CLASS(HexDigit, ('0' <= c && c <= '9') || + ('a' <= c && c <= 'f') || + ('A' <= c && c <= 'F')); + +CHARACTER_CLASS(Letter, ('a' <= c && c <= 'z') || + ('A' <= c && c <= 'Z') || + (c == '_')); + +CHARACTER_CLASS(Alphanumeric, ('a' <= c && c <= 'z') || + ('A' <= c && c <= 'Z') || + ('0' <= c && c <= '9') || + (c == '_')); + +CHARACTER_CLASS(Escape, c == 'a' || c == 'b' || c == 'f' || c == 'n' || + c == 'r' || c == 't' || c == 'v' || c == '\\' || + c == '?' || c == '\'' || c == '\"'); + +#undef CHARACTER_CLASS + +// Given a char, interpret it as a numeric digit and return its value. +// This supports any number base up to 36. +inline int DigitValue(char digit) { + if ('0' <= digit && digit <= '9') return digit - '0'; + if ('a' <= digit && digit <= 'z') return digit - 'a' + 10; + if ('A' <= digit && digit <= 'Z') return digit - 'A' + 10; + return -1; +} + +// Inline because it's only used in one place. +inline char TranslateEscape(char c) { + switch (c) { + case 'a': return '\a'; + case 'b': return '\b'; + case 'f': return '\f'; + case 'n': return '\n'; + case 'r': return '\r'; + case 't': return '\t'; + case 'v': return '\v'; + case '\\': return '\\'; + case '?': return '\?'; // Trigraphs = :( + case '\'': return '\''; + case '"': return '\"'; + + // We expect escape sequences to have been validated separately. + default: return '?'; + } +} + +} // anonymous namespace + +ErrorCollector::~ErrorCollector() {} + +// =================================================================== + +Tokenizer::Tokenizer(ZeroCopyInputStream* input, + ErrorCollector* error_collector) + : input_(input), + error_collector_(error_collector), + buffer_(NULL), + buffer_size_(0), + buffer_pos_(0), + read_error_(false), + line_(0), + column_(0), + record_target_(NULL), + record_start_(-1), + allow_f_after_float_(false), + comment_style_(CPP_COMMENT_STYLE), + require_space_after_number_(true), + allow_multiline_strings_(false) { + + current_.line = 0; + current_.column = 0; + current_.end_column = 0; + current_.type = TYPE_START; + + Refresh(); +} + +Tokenizer::~Tokenizer() { + // If we had any buffer left unread, return it to the underlying stream + // so that someone else can read it. + if (buffer_size_ > buffer_pos_) { + input_->BackUp(buffer_size_ - buffer_pos_); + } +} + +// ------------------------------------------------------------------- +// Internal helpers. + +void Tokenizer::NextChar() { + // Update our line and column counters based on the character being + // consumed. + if (current_char_ == '\n') { + ++line_; + column_ = 0; + } else if (current_char_ == '\t') { + column_ += kTabWidth - column_ % kTabWidth; + } else { + ++column_; + } + + // Advance to the next character. + ++buffer_pos_; + if (buffer_pos_ < buffer_size_) { + current_char_ = buffer_[buffer_pos_]; + } else { + Refresh(); + } +} + +void Tokenizer::Refresh() { + if (read_error_) { + current_char_ = '\0'; + return; + } + + // If we're in a token, append the rest of the buffer to it. + if (record_target_ != NULL && record_start_ < buffer_size_) { + record_target_->append(buffer_ + record_start_, buffer_size_ - record_start_); + record_start_ = 0; + } + + const void* data = NULL; + buffer_ = NULL; + buffer_pos_ = 0; + do { + if (!input_->Next(&data, &buffer_size_)) { + // end of stream (or read error) + buffer_size_ = 0; + read_error_ = true; + current_char_ = '\0'; + return; + } + } while (buffer_size_ == 0); + + buffer_ = static_cast<const char*>(data); + + current_char_ = buffer_[0]; +} + +inline void Tokenizer::RecordTo(string* target) { + record_target_ = target; + record_start_ = buffer_pos_; +} + +inline void Tokenizer::StopRecording() { + // Note: The if() is necessary because some STL implementations crash when + // you call string::append(NULL, 0), presumably because they are trying to + // be helpful by detecting the NULL pointer, even though there's nothing + // wrong with reading zero bytes from NULL. + if (buffer_pos_ != record_start_) { + record_target_->append(buffer_ + record_start_, buffer_pos_ - record_start_); + } + record_target_ = NULL; + record_start_ = -1; +} + +inline void Tokenizer::StartToken() { + current_.type = TYPE_START; // Just for the sake of initializing it. + current_.text.clear(); + current_.line = line_; + current_.column = column_; + RecordTo(¤t_.text); +} + +inline void Tokenizer::EndToken() { + StopRecording(); + current_.end_column = column_; +} + +// ------------------------------------------------------------------- +// Helper methods that consume characters. + +template<typename CharacterClass> +inline bool Tokenizer::LookingAt() { + return CharacterClass::InClass(current_char_); +} + +template<typename CharacterClass> +inline bool Tokenizer::TryConsumeOne() { + if (CharacterClass::InClass(current_char_)) { + NextChar(); + return true; + } else { + return false; + } +} + +inline bool Tokenizer::TryConsume(char c) { + if (current_char_ == c) { + NextChar(); + return true; + } else { + return false; + } +} + +template<typename CharacterClass> +inline void Tokenizer::ConsumeZeroOrMore() { + while (CharacterClass::InClass(current_char_)) { + NextChar(); + } +} + +template<typename CharacterClass> +inline void Tokenizer::ConsumeOneOrMore(const char* error) { + if (!CharacterClass::InClass(current_char_)) { + AddError(error); + } else { + do { + NextChar(); + } while (CharacterClass::InClass(current_char_)); + } +} + +// ------------------------------------------------------------------- +// Methods that read whole patterns matching certain kinds of tokens +// or comments. + +void Tokenizer::ConsumeString(char delimiter) { + while (true) { + switch (current_char_) { + case '\0': + AddError("Unexpected end of string."); + return; + + case '\n': { + if (!allow_multiline_strings_) { + AddError("String literals cannot cross line boundaries."); + return; + } + NextChar(); + break; + } + + case '\\': { + // An escape sequence. + NextChar(); + if (TryConsumeOne<Escape>()) { + // Valid escape sequence. + } else if (TryConsumeOne<OctalDigit>()) { + // Possibly followed by two more octal digits, but these will + // just be consumed by the main loop anyway so we don't need + // to do so explicitly here. + } else if (TryConsume('x')) { + if (!TryConsumeOne<HexDigit>()) { + AddError("Expected hex digits for escape sequence."); + } + // Possibly followed by another hex digit, but again we don't care. + } else if (TryConsume('u')) { + if (!TryConsumeOne<HexDigit>() || + !TryConsumeOne<HexDigit>() || + !TryConsumeOne<HexDigit>() || + !TryConsumeOne<HexDigit>()) { + AddError("Expected four hex digits for \\u escape sequence."); + } + } else if (TryConsume('U')) { + // We expect 8 hex digits; but only the range up to 0x10ffff is + // legal. + if (!TryConsume('0') || + !TryConsume('0') || + !(TryConsume('0') || TryConsume('1')) || + !TryConsumeOne<HexDigit>() || + !TryConsumeOne<HexDigit>() || + !TryConsumeOne<HexDigit>() || + !TryConsumeOne<HexDigit>() || + !TryConsumeOne<HexDigit>()) { + AddError("Expected eight hex digits up to 10ffff for \\U escape " + "sequence"); + } + } else { + AddError("Invalid escape sequence in string literal."); + } + break; + } + + default: { + if (current_char_ == delimiter) { + NextChar(); + return; + } + NextChar(); + break; + } + } + } +} + +Tokenizer::TokenType Tokenizer::ConsumeNumber(bool started_with_zero, + bool started_with_dot) { + bool is_float = false; + + if (started_with_zero && (TryConsume('x') || TryConsume('X'))) { + // A hex number (started with "0x"). + ConsumeOneOrMore<HexDigit>("\"0x\" must be followed by hex digits."); + + } else if (started_with_zero && LookingAt<Digit>()) { + // An octal number (had a leading zero). + ConsumeZeroOrMore<OctalDigit>(); + if (LookingAt<Digit>()) { + AddError("Numbers starting with leading zero must be in octal."); + ConsumeZeroOrMore<Digit>(); + } + + } else { + // A decimal number. + if (started_with_dot) { + is_float = true; + ConsumeZeroOrMore<Digit>(); + } else { + ConsumeZeroOrMore<Digit>(); + + if (TryConsume('.')) { + is_float = true; + ConsumeZeroOrMore<Digit>(); + } + } + + if (TryConsume('e') || TryConsume('E')) { + is_float = true; + TryConsume('-') || TryConsume('+'); + ConsumeOneOrMore<Digit>("\"e\" must be followed by exponent."); + } + + if (allow_f_after_float_ && (TryConsume('f') || TryConsume('F'))) { + is_float = true; + } + } + + if (LookingAt<Letter>() && require_space_after_number_) { + AddError("Need space between number and identifier."); + } else if (current_char_ == '.') { + if (is_float) { + AddError( + "Already saw decimal point or exponent; can't have another one."); + } else { + AddError("Hex and octal numbers must be integers."); + } + } + + return is_float ? TYPE_FLOAT : TYPE_INTEGER; +} + +void Tokenizer::ConsumeLineComment(string* content) { + if (content != NULL) RecordTo(content); + + while (current_char_ != '\0' && current_char_ != '\n') { + NextChar(); + } + TryConsume('\n'); + + if (content != NULL) StopRecording(); +} + +void Tokenizer::ConsumeBlockComment(string* content) { + int start_line = line_; + int start_column = column_ - 2; + + if (content != NULL) RecordTo(content); + + while (true) { + while (current_char_ != '\0' && + current_char_ != '*' && + current_char_ != '/' && + current_char_ != '\n') { + NextChar(); + } + + if (TryConsume('\n')) { + if (content != NULL) StopRecording(); + + // Consume leading whitespace and asterisk; + ConsumeZeroOrMore<WhitespaceNoNewline>(); + if (TryConsume('*')) { + if (TryConsume('/')) { + // End of comment. + break; + } + } + + if (content != NULL) RecordTo(content); + } else if (TryConsume('*') && TryConsume('/')) { + // End of comment. + if (content != NULL) { + StopRecording(); + // Strip trailing "*/". + content->erase(content->size() - 2); + } + break; + } else if (TryConsume('/') && current_char_ == '*') { + // Note: We didn't consume the '*' because if there is a '/' after it + // we want to interpret that as the end of the comment. + AddError( + "\"/*\" inside block comment. Block comments cannot be nested."); + } else if (current_char_ == '\0') { + AddError("End-of-file inside block comment."); + error_collector_->AddError( + start_line, start_column, " Comment started here."); + if (content != NULL) StopRecording(); + break; + } + } +} + +Tokenizer::NextCommentStatus Tokenizer::TryConsumeCommentStart() { + if (comment_style_ == CPP_COMMENT_STYLE && TryConsume('/')) { + if (TryConsume('/')) { + return LINE_COMMENT; + } else if (TryConsume('*')) { + return BLOCK_COMMENT; + } else { + // Oops, it was just a slash. Return it. + current_.type = TYPE_SYMBOL; + current_.text = "/"; + current_.line = line_; + current_.column = column_ - 1; + current_.end_column = column_; + return SLASH_NOT_COMMENT; + } + } else if (comment_style_ == SH_COMMENT_STYLE && TryConsume('#')) { + return LINE_COMMENT; + } else { + return NO_COMMENT; + } +} + +// ------------------------------------------------------------------- + +bool Tokenizer::Next() { + previous_ = current_; + + while (!read_error_) { + ConsumeZeroOrMore<Whitespace>(); + + switch (TryConsumeCommentStart()) { + case LINE_COMMENT: + ConsumeLineComment(NULL); + continue; + case BLOCK_COMMENT: + ConsumeBlockComment(NULL); + continue; + case SLASH_NOT_COMMENT: + return true; + case NO_COMMENT: + break; + } + + // Check for EOF before continuing. + if (read_error_) break; + + if (LookingAt<Unprintable>() || current_char_ == '\0') { + AddError("Invalid control characters encountered in text."); + NextChar(); + // Skip more unprintable characters, too. But, remember that '\0' is + // also what current_char_ is set to after EOF / read error. We have + // to be careful not to go into an infinite loop of trying to consume + // it, so make sure to check read_error_ explicitly before consuming + // '\0'. + while (TryConsumeOne<Unprintable>() || + (!read_error_ && TryConsume('\0'))) { + // Ignore. + } + + } else { + // Reading some sort of token. + StartToken(); + + if (TryConsumeOne<Letter>()) { + ConsumeZeroOrMore<Alphanumeric>(); + current_.type = TYPE_IDENTIFIER; + } else if (TryConsume('0')) { + current_.type = ConsumeNumber(true, false); + } else if (TryConsume('.')) { + // This could be the beginning of a floating-point number, or it could + // just be a '.' symbol. + + if (TryConsumeOne<Digit>()) { + // It's a floating-point number. + if (previous_.type == TYPE_IDENTIFIER && + current_.line == previous_.line && + current_.column == previous_.end_column) { + // We don't accept syntax like "blah.123". + error_collector_->AddError(line_, column_ - 2, + "Need space between identifier and decimal point."); + } + current_.type = ConsumeNumber(false, true); + } else { + current_.type = TYPE_SYMBOL; + } + } else if (TryConsumeOne<Digit>()) { + current_.type = ConsumeNumber(false, false); + } else if (TryConsume('\"')) { + ConsumeString('\"'); + current_.type = TYPE_STRING; + } else if (TryConsume('\'')) { + ConsumeString('\''); + current_.type = TYPE_STRING; + } else { + // Check if the high order bit is set. + if (current_char_ & 0x80) { + error_collector_->AddError(line_, column_, + StringPrintf("Interpreting non ascii codepoint %d.", + static_cast<unsigned char>(current_char_))); + } + NextChar(); + current_.type = TYPE_SYMBOL; + } + + EndToken(); + return true; + } + } + + // EOF + current_.type = TYPE_END; + current_.text.clear(); + current_.line = line_; + current_.column = column_; + current_.end_column = column_; + return false; +} + +namespace { + +// Helper class for collecting comments and putting them in the right places. +// +// This basically just buffers the most recent comment until it can be decided +// exactly where that comment should be placed. When Flush() is called, the +// current comment goes into either prev_trailing_comments or detached_comments. +// When the CommentCollector is destroyed, the last buffered comment goes into +// next_leading_comments. +class CommentCollector { + public: + CommentCollector(string* prev_trailing_comments, + std::vector<string>* detached_comments, + string* next_leading_comments) + : prev_trailing_comments_(prev_trailing_comments), + detached_comments_(detached_comments), + next_leading_comments_(next_leading_comments), + has_comment_(false), + is_line_comment_(false), + can_attach_to_prev_(true) { + if (prev_trailing_comments != NULL) prev_trailing_comments->clear(); + if (detached_comments != NULL) detached_comments->clear(); + if (next_leading_comments != NULL) next_leading_comments->clear(); + } + + ~CommentCollector() { + // Whatever is in the buffer is a leading comment. + if (next_leading_comments_ != NULL && has_comment_) { + comment_buffer_.swap(*next_leading_comments_); + } + } + + // About to read a line comment. Get the comment buffer pointer in order to + // read into it. + string* GetBufferForLineComment() { + // We want to combine with previous line comments, but not block comments. + if (has_comment_ && !is_line_comment_) { + Flush(); + } + has_comment_ = true; + is_line_comment_ = true; + return &comment_buffer_; + } + + // About to read a block comment. Get the comment buffer pointer in order to + // read into it. + string* GetBufferForBlockComment() { + if (has_comment_) { + Flush(); + } + has_comment_ = true; + is_line_comment_ = false; + return &comment_buffer_; + } + + void ClearBuffer() { + comment_buffer_.clear(); + has_comment_ = false; + } + + // Called once we know that the comment buffer is complete and is *not* + // connected to the next token. + void Flush() { + if (has_comment_) { + if (can_attach_to_prev_) { + if (prev_trailing_comments_ != NULL) { + prev_trailing_comments_->append(comment_buffer_); + } + can_attach_to_prev_ = false; + } else { + if (detached_comments_ != NULL) { + detached_comments_->push_back(comment_buffer_); + } + } + ClearBuffer(); + } + } + + void DetachFromPrev() { + can_attach_to_prev_ = false; + } + + private: + string* prev_trailing_comments_; + std::vector<string>* detached_comments_; + string* next_leading_comments_; + + string comment_buffer_; + + // True if any comments were read into comment_buffer_. This can be true even + // if comment_buffer_ is empty, namely if the comment was "/**/". + bool has_comment_; + + // Is the comment in the comment buffer a line comment? + bool is_line_comment_; + + // Is it still possible that we could be reading a comment attached to the + // previous token? + bool can_attach_to_prev_; +}; + +} // namespace + +bool Tokenizer::NextWithComments(string* prev_trailing_comments, + std::vector<string>* detached_comments, + string* next_leading_comments) { + CommentCollector collector(prev_trailing_comments, detached_comments, + next_leading_comments); + + if (current_.type == TYPE_START) { + // Ignore unicode byte order mark(BOM) if it appears at the file + // beginning. Only UTF-8 BOM (0xEF 0xBB 0xBF) is accepted. + if (TryConsume((char)0xEF)) { + if (!TryConsume((char)0xBB) || !TryConsume((char)0xBF)) { + AddError("Proto file starts with 0xEF but not UTF-8 BOM. " + "Only UTF-8 is accepted for proto file."); + return false; + } + } + collector.DetachFromPrev(); + } else { + // A comment appearing on the same line must be attached to the previous + // declaration. + ConsumeZeroOrMore<WhitespaceNoNewline>(); + switch (TryConsumeCommentStart()) { + case LINE_COMMENT: + ConsumeLineComment(collector.GetBufferForLineComment()); + + // Don't allow comments on subsequent lines to be attached to a trailing + // comment. + collector.Flush(); + break; + case BLOCK_COMMENT: + ConsumeBlockComment(collector.GetBufferForBlockComment()); + + ConsumeZeroOrMore<WhitespaceNoNewline>(); + if (!TryConsume('\n')) { + // Oops, the next token is on the same line. If we recorded a comment + // we really have no idea which token it should be attached to. + collector.ClearBuffer(); + return Next(); + } + + // Don't allow comments on subsequent lines to be attached to a trailing + // comment. + collector.Flush(); + break; + case SLASH_NOT_COMMENT: + return true; + case NO_COMMENT: + if (!TryConsume('\n')) { + // The next token is on the same line. There are no comments. + return Next(); + } + break; + } + } + + // OK, we are now on the line *after* the previous token. + while (true) { + ConsumeZeroOrMore<WhitespaceNoNewline>(); + + switch (TryConsumeCommentStart()) { + case LINE_COMMENT: + ConsumeLineComment(collector.GetBufferForLineComment()); + break; + case BLOCK_COMMENT: + ConsumeBlockComment(collector.GetBufferForBlockComment()); + + // Consume the rest of the line so that we don't interpret it as a + // blank line the next time around the loop. + ConsumeZeroOrMore<WhitespaceNoNewline>(); + TryConsume('\n'); + break; + case SLASH_NOT_COMMENT: + return true; + case NO_COMMENT: + if (TryConsume('\n')) { + // Completely blank line. + collector.Flush(); + collector.DetachFromPrev(); + } else { + bool result = Next(); + if (!result || + current_.text == "}" || + current_.text == "]" || + current_.text == ")") { + // It looks like we're at the end of a scope. In this case it + // makes no sense to attach a comment to the following token. + collector.Flush(); + } + return result; + } + break; + } + } +} + +// ------------------------------------------------------------------- +// Token-parsing helpers. Remember that these don't need to report +// errors since any errors should already have been reported while +// tokenizing. Also, these can assume that whatever text they +// are given is text that the tokenizer actually parsed as a token +// of the given type. + +bool Tokenizer::ParseInteger(const string& text, uint64 max_value, + uint64* output) { + // Sadly, we can't just use strtoul() since it is only 32-bit and strtoull() + // is non-standard. I hate the C standard library. :( + +// return strtoull(text.c_str(), NULL, 0); + + const char* ptr = text.c_str(); + int base = 10; + if (ptr[0] == '0') { + if (ptr[1] == 'x' || ptr[1] == 'X') { + // This is hex. + base = 16; + ptr += 2; + } else { + // This is octal. + base = 8; + } + } + + uint64 result = 0; + for (; *ptr != '\0'; ptr++) { + int digit = DigitValue(*ptr); + if (digit < 0 || digit >= base) { + // The token provided by Tokenizer is invalid. i.e., 099 is an invalid + // token, but Tokenizer still think it's integer. + return false; + } + if (digit > max_value || result > (max_value - digit) / base) { + // Overflow. + return false; + } + result = result * base + digit; + } + + *output = result; + return true; +} + +double Tokenizer::ParseFloat(const string& text) { + const char* start = text.c_str(); + char* end; + double result = NoLocaleStrtod(start, &end); + + // "1e" is not a valid float, but if the tokenizer reads it, it will + // report an error but still return it as a valid token. We need to + // accept anything the tokenizer could possibly return, error or not. + if (*end == 'e' || *end == 'E') { + ++end; + if (*end == '-' || *end == '+') ++end; + } + + // If the Tokenizer had allow_f_after_float_ enabled, the float may be + // suffixed with the letter 'f'. + if (*end == 'f' || *end == 'F') { + ++end; + } + + GOOGLE_LOG_IF(DFATAL, end - start != text.size() || *start == '-') + << " Tokenizer::ParseFloat() passed text that could not have been" + " tokenized as a float: " << CEscape(text); + return result; +} + +// Helper to append a Unicode code point to a string as UTF8, without bringing +// in any external dependencies. +static void AppendUTF8(uint32 code_point, string* output) { + uint32 tmp = 0; + int len = 0; + if (code_point <= 0x7f) { + tmp = code_point; + len = 1; + } else if (code_point <= 0x07ff) { + tmp = 0x0000c080 | + ((code_point & 0x07c0) << 2) | + (code_point & 0x003f); + len = 2; + } else if (code_point <= 0xffff) { + tmp = 0x00e08080 | + ((code_point & 0xf000) << 4) | + ((code_point & 0x0fc0) << 2) | + (code_point & 0x003f); + len = 3; + } else if (code_point <= 0x1fffff) { + tmp = 0xf0808080 | + ((code_point & 0x1c0000) << 6) | + ((code_point & 0x03f000) << 4) | + ((code_point & 0x000fc0) << 2) | + (code_point & 0x003f); + len = 4; + } else { + // UTF-16 is only defined for code points up to 0x10FFFF, and UTF-8 is + // normally only defined up to there as well. + StringAppendF(output, "\\U%08x", code_point); + return; + } + tmp = ghtonl(tmp); + output->append(reinterpret_cast<const char*>(&tmp) + sizeof(tmp) - len, len); +} + +// Try to read <len> hex digits from ptr, and stuff the numeric result into +// *result. Returns true if that many digits were successfully consumed. +static bool ReadHexDigits(const char* ptr, int len, uint32* result) { + *result = 0; + if (len == 0) return false; + for (const char* end = ptr + len; ptr < end; ++ptr) { + if (*ptr == '\0') return false; + *result = (*result << 4) + DigitValue(*ptr); + } + return true; +} + +// Handling UTF-16 surrogate pairs. UTF-16 encodes code points in the range +// 0x10000...0x10ffff as a pair of numbers, a head surrogate followed by a trail +// surrogate. These numbers are in a reserved range of Unicode code points, so +// if we encounter such a pair we know how to parse it and convert it into a +// single code point. +static const uint32 kMinHeadSurrogate = 0xd800; +static const uint32 kMaxHeadSurrogate = 0xdc00; +static const uint32 kMinTrailSurrogate = 0xdc00; +static const uint32 kMaxTrailSurrogate = 0xe000; + +static inline bool IsHeadSurrogate(uint32 code_point) { + return (code_point >= kMinHeadSurrogate) && (code_point < kMaxHeadSurrogate); +} + +static inline bool IsTrailSurrogate(uint32 code_point) { + return (code_point >= kMinTrailSurrogate) && + (code_point < kMaxTrailSurrogate); +} + +// Combine a head and trail surrogate into a single Unicode code point. +static uint32 AssembleUTF16(uint32 head_surrogate, uint32 trail_surrogate) { + GOOGLE_DCHECK(IsHeadSurrogate(head_surrogate)); + GOOGLE_DCHECK(IsTrailSurrogate(trail_surrogate)); + return 0x10000 + (((head_surrogate - kMinHeadSurrogate) << 10) | + (trail_surrogate - kMinTrailSurrogate)); +} + +// Convert the escape sequence parameter to a number of expected hex digits. +static inline int UnicodeLength(char key) { + if (key == 'u') return 4; + if (key == 'U') return 8; + return 0; +} + +// Given a pointer to the 'u' or 'U' starting a Unicode escape sequence, attempt +// to parse that sequence. On success, returns a pointer to the first char +// beyond that sequence, and fills in *code_point. On failure, returns ptr +// itself. +static const char* FetchUnicodePoint(const char* ptr, uint32* code_point) { + const char* p = ptr; + // Fetch the code point. + const int len = UnicodeLength(*p++); + if (!ReadHexDigits(p, len, code_point)) + return ptr; + p += len; + + // Check if the code point we read is a "head surrogate." If so, then we + // expect it to be immediately followed by another code point which is a valid + // "trail surrogate," and together they form a UTF-16 pair which decodes into + // a single Unicode point. Trail surrogates may only use \u, not \U. + if (IsHeadSurrogate(*code_point) && *p == '\\' && *(p + 1) == 'u') { + uint32 trail_surrogate; + if (ReadHexDigits(p + 2, 4, &trail_surrogate) && + IsTrailSurrogate(trail_surrogate)) { + *code_point = AssembleUTF16(*code_point, trail_surrogate); + p += 6; + } + // If this failed, then we just emit the head surrogate as a code point. + // It's bogus, but so is the string. + } + + return p; +} + +// The text string must begin and end with single or double quote +// characters. +void Tokenizer::ParseStringAppend(const string& text, string* output) { + // Reminder: text[0] is always a quote character. (If text is + // empty, it's invalid, so we'll just return). + const size_t text_size = text.size(); + if (text_size == 0) { + GOOGLE_LOG(DFATAL) + << " Tokenizer::ParseStringAppend() passed text that could not" + " have been tokenized as a string: " << CEscape(text); + return; + } + + // Reserve room for new string. The branch is necessary because if + // there is already space available the reserve() call might + // downsize the output. + const size_t new_len = text_size + output->size(); + if (new_len > output->capacity()) { + output->reserve(new_len); + } + + // Loop through the string copying characters to "output" and + // interpreting escape sequences. Note that any invalid escape + // sequences or other errors were already reported while tokenizing. + // In this case we do not need to produce valid results. + for (const char* ptr = text.c_str() + 1; *ptr != '\0'; ptr++) { + if (*ptr == '\\' && ptr[1] != '\0') { + // An escape sequence. + ++ptr; + + if (OctalDigit::InClass(*ptr)) { + // An octal escape. May one, two, or three digits. + int code = DigitValue(*ptr); + if (OctalDigit::InClass(ptr[1])) { + ++ptr; + code = code * 8 + DigitValue(*ptr); + } + if (OctalDigit::InClass(ptr[1])) { + ++ptr; + code = code * 8 + DigitValue(*ptr); + } + output->push_back(static_cast<char>(code)); + + } else if (*ptr == 'x') { + // A hex escape. May zero, one, or two digits. (The zero case + // will have been caught as an error earlier.) + int code = 0; + if (HexDigit::InClass(ptr[1])) { + ++ptr; + code = DigitValue(*ptr); + } + if (HexDigit::InClass(ptr[1])) { + ++ptr; + code = code * 16 + DigitValue(*ptr); + } + output->push_back(static_cast<char>(code)); + + } else if (*ptr == 'u' || *ptr == 'U') { + uint32 unicode; + const char* end = FetchUnicodePoint(ptr, &unicode); + if (end == ptr) { + // Failure: Just dump out what we saw, don't try to parse it. + output->push_back(*ptr); + } else { + AppendUTF8(unicode, output); + ptr = end - 1; // Because we're about to ++ptr. + } + } else { + // Some other escape code. + output->push_back(TranslateEscape(*ptr)); + } + + } else if (*ptr == text[0] && ptr[1] == '\0') { + // Ignore final quote matching the starting quote. + } else { + output->push_back(*ptr); + } + } +} + +template<typename CharacterClass> +static bool AllInClass(const string& s) { + for (int i = 0; i < s.size(); ++i) { + if (!CharacterClass::InClass(s[i])) + return false; + } + return true; +} + +bool Tokenizer::IsIdentifier(const string& text) { + // Mirrors IDENTIFIER definition in Tokenizer::Next() above. + if (text.size() == 0) + return false; + if (!Letter::InClass(text.at(0))) + return false; + if (!AllInClass<Alphanumeric>(text.substr(1))) + return false; + return true; +} + +} // namespace io +} // namespace protobuf +} // namespace google |