518 lines
18 KiB
D
518 lines
18 KiB
D
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// Copyright Ferdinand Majerech 2011-2014.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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module dyaml.reader;
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import core.stdc.stdlib;
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import core.stdc.string;
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import core.thread;
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import std.algorithm;
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import std.array;
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import std.conv;
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import std.exception;
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import std.stdio;
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import std.string;
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import std.system;
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import std.utf;
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import tinyendian;
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import dyaml.fastcharsearch;
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import dyaml.encoding;
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import dyaml.exception;
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import dyaml.streamcompat;
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package:
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//XXX VIM STUFF:
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//XXX THE f/t COLORING PLUGIN, AND TRY TO REMOVE THE f/t AUTOREPEAT PLUGIN
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// (AND MAYBE DO THE REPEAT WITH ALT-T/ALT-F
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//XXX DDOC snippets such as $D, $BIGOH, anything else
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// OR MAYBE JUST $ - EXPANDING TO $(${1} ${2})
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// WHERE DEFAULT ${1} IS 'D' AND SPECIAL SNIPPETS FOR SPECIFIC DDOC MACROS
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// (E.G. XREF HAS 2 ARGS)
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// XXX DON'T FORGET TO COMMIT DSNIPS CHANGES
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// XXX SNIPPETS: WHY CAN'T WE USE NEW IN NEW? FIX!
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// XXX ALSO WRITELN VISUAL! (print whatever we have selected)
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// XXX AND ``fun`` VISUAL TOO!
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// XXX snippet to print variable along its name AND
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// OR MULTIPLE VARS - USE std.format!
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///Exception thrown at Reader errors.
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class ReaderException : YAMLException
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{
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this(string msg, string file = __FILE__, int line = __LINE__)
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@safe pure nothrow
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{
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super("Reader error: " ~ msg, file, line);
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}
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}
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/// Lazily reads and decodes data from a buffer, only storing as much as needed at any
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/// moment.
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///
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/// Adds a '\0' to the end of the data.
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final class Reader
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{
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private:
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// Buffer of currently loaded characters.
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dchar[] buffer_ = null;
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// Current position within buffer. Only data after this position can be read.
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uint bufferOffset_ = 0;
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// Index of the current character in the buffer.
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size_t charIndex_ = 0;
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// Current line in file.
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uint line_;
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// Current column in file.
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uint column_;
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// Decoder reading data from file and decoding it to UTF-32.
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UTFFastDecoder decoder_;
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version(unittest)
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{
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// Endianness of the input before it was converted (for testing)
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Endian endian_;
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}
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public:
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import std.stream;
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/// Construct a Reader.
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///
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/// Params: stream = Input stream. Must be readable and seekable.
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///
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/// Throws: ReaderException if the stream is invalid, on a UTF decoding error
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/// or if there are nonprintable unicode characters illegal in YAML.
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this(Stream stream) @trusted //!nothrow
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{
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auto streamBytes = streamToBytesGC(stream);
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auto result = fixUTFByteOrder(streamBytes);
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if(result.bytesStripped > 0)
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{
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throw new ReaderException("Size of UTF-16 or UTF-32 input not aligned "
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"to 2 or 4 bytes, respectively");
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}
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version(unittest) { endian_ = result.endian; }
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decoder_ = UTFFastDecoder(result.array, result.encoding);
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decoder_.decodeAll();
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const msg = decoder_.getAndClearErrorMessage();
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if(msg !is null)
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{
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throw new ReaderException("UTF decoding error: " ~ msg);
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}
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buffer_ = decoder_.decoded;
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// The part of buffer excluding trailing zeroes.
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auto noZeros = buffer_;
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while(!noZeros.empty && noZeros.back == '\0') { noZeros.popBack(); }
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enforce(printable(noZeros[]),
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new ReaderException("Special unicode characters are not allowed"));
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}
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/// Get character at specified index relative to current position.
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///
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/// Params: index = Index of the character to get relative to current position
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/// in the buffer.
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///
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/// Returns: Character at specified position.
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///
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// XXX removed; search for 'risky' to find why.
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// Throws: ReaderException if trying to read past the end of the buffer.
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dchar peek(size_t index = 0) @safe pure const
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{
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if(buffer_.length <= bufferOffset_ + index)
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{
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// XXX This is risky; revert this and the 'risky' change in UTF decoder
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// if any bugs are introduced. We rely on the assumption that Reader
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// only uses peek() to detect the of buffer. The test suite passes.
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// throw new ReaderException("Trying to read past the end of the buffer");
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return '\0';
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}
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return buffer_[bufferOffset_ + index];
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}
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/// Get specified number of characters starting at current position.
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///
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/// Note: This gets only a "view" into the internal buffer,
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/// which WILL get invalidated after other Reader calls.
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///
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/// Params: length = Number of characters to get. May reach past the end of the
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/// buffer; in that case the returned slice will be shorter.
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///
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/// Returns: Characters starting at current position or an empty slice if out of bounds.
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const(dstring) prefix(size_t length) @safe pure nothrow const @nogc
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{
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return slice(0, length);
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}
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/// Get a slice view of the internal buffer.
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///
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/// Note: This gets only a "view" into the internal buffer,
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/// which WILL get invalidated after other Reader calls.
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///
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/// Params: start = Start of the slice relative to current position.
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/// end = End of the slice relative to current position. May reach
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/// past the end of the buffer; in that case the returned
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/// slice will be shorter.
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///
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/// Returns: Slice into the internal buffer or an empty slice if out of bounds.
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const(dstring) slice(size_t start, size_t end) @trusted pure nothrow const @nogc
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{
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end += bufferOffset_;
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start += bufferOffset_;
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end = min(buffer_.length, end);
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return end > start ? cast(dstring)buffer_[start .. end] : "";
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}
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/// Get the next character, moving buffer position beyond it.
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///
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/// Returns: Next character.
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///
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/// Throws: ReaderException if trying to read past the end of the buffer
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/// or if invalid data is read.
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dchar get() @safe pure
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{
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const result = peek();
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forward();
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return result;
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}
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/// Get specified number of characters, moving buffer position beyond them.
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///
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/// Params: length = Number or characters to get.
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///
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/// Returns: Characters starting at current position.
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dstring get(size_t length) @safe pure nothrow
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{
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auto result = prefix(length).idup;
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forward(length);
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return result;
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}
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/// Move current position forward.
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///
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/// Params: length = Number of characters to move position forward.
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void forward(size_t length = 1) @safe pure nothrow @nogc
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{
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mixin FastCharSearch!"\n\u0085\u2028\u2029"d search;
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for(; length > 0; --length)
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{
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const c = buffer_[bufferOffset_];
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++bufferOffset_;
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++charIndex_;
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//New line.
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if(search.canFind(c) || (c == '\r' && buffer_[bufferOffset_] != '\n'))
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{
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++line_;
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column_ = 0;
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}
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else if(c != '\uFEFF') { ++column_; }
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}
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}
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/// Get a string describing current buffer position, used for error messages.
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final Mark mark() @safe pure nothrow const @nogc { return Mark(line_, column_); }
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/// Get current line number.
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final uint line() @safe pure nothrow const @nogc { return line_; }
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/// Get current column number.
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final uint column() @safe pure nothrow const @nogc { return column_; }
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/// Get index of the current character in the buffer.
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final size_t charIndex() @safe pure nothrow const @nogc { return charIndex_; }
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/// Get encoding of the input buffer.
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final Encoding encoding() @safe pure nothrow const @nogc { return decoder_.encoding; }
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}
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private:
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alias UTFDecoder UTFFastDecoder;
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struct UTFDecoder
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{
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private:
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// UTF-8 codepoint strides (0xFF are codepoints that can't start a sequence).
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static immutable ubyte[256] utf8Stride =
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[
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
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4,4,4,4,4,4,4,4,5,5,5,5,6,6,0xFF,0xFF,
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];
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// Encoding of the input buffer.
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UTFEncoding encoding_;
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// Maximum number of characters that might be in the buffer.
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size_t maxChars_;
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// Part of the input buffer that has not yet been decoded.
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ubyte[] input_;
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// Decoded (UTF-32) version of the entire input_. If input is UTF-32, this is
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// just a reference to input_.
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dchar[] decoded_;
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// Current error message.
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//
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// To be fully nothrow, we use return values and the user (Reader) can check
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// for a detailed error message if they get an error return.
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string errorMessage_;
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public:
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/// Construct a UTFBlockDecoder decoding data from a buffer.
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this(ubyte[] buffer, UTFEncoding encoding) @safe pure nothrow @nogc
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{
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input_ = buffer;
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encoding_ = encoding;
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final switch(encoding_)
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{
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case UTFEncoding.UTF_8: maxChars_ = input_.length; break;
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case UTFEncoding.UTF_16: maxChars_ = input_.length / 2; break;
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case UTFEncoding.UTF_32: maxChars_ = input_.length / 2; break;
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}
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}
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/// Decode all data passed to the constructor.
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///
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/// On error, getAndClearErrorMessage() will return a non-null string.
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void decodeAll() @safe
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{
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assert(decoded_ is null, "Calling decodeAll more than once");
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final switch(encoding_)
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{
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case UTFEncoding.UTF_8: decode(cast(char[])input_); break;
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case UTFEncoding.UTF_16:
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assert(input_.length % 2 == 0, "UTF-16 buffer size must be even");
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decode(cast(wchar[])input_);
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break;
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case UTFEncoding.UTF_32:
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assert(input_.length % 4 == 0,
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"UTF-32 buffer size must be a multiple of 4");
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// No need to decode anything
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decoded_ = cast(dchar[])input_;
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break;
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}
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// XXX This is risky. We rely on the assumption that the scanner only uses
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// peek() to detect the end of the buffer. Should this cause any bugs,
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// revert.
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//
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// The buffer must be zero terminated for scanner to detect its end.
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// if(decoded_.empty || decoded_.back() != '\0')
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// {
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// decoded_ ~= cast(dchar)'\0';
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// }
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}
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/// Get encoding we're decoding from.
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UTFEncoding encoding() const pure @safe nothrow @nogc { return encoding_; }
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/// Get all decoded characters.
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const(dchar[]) decoded() @safe pure nothrow @nogc { return decoded_; }
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/// Get the error message and clear it.
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string getAndClearErrorMessage() @safe pure nothrow @nogc
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{
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const result = errorMessage_;
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errorMessage_ = null;
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return result;
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}
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private:
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// Decode input_ if it's encoded as UTF-8 or UTF-16.
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//
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// On error, errorMessage_ will be set.
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void decode(C)(C[] buffer) @safe pure nothrow
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{
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// End of part of buffer that contains complete characters that can be decoded.
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const size_t end = endOfLastUTFSequence(buffer);
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// If end is 0, there are no full chars.
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// This can happen at the end of file if there is an incomplete UTF sequence.
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if(end < buffer.length)
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{
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errorMessage_ = "Invalid UTF character at the end of buffer";
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return;
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}
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const srclength = buffer.length;
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try for(size_t srcpos = 0; srcpos < srclength;)
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{
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const c = buffer[srcpos];
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if(c < 0x80)
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{
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decoded_ ~= c;
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++srcpos;
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}
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else
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{
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decoded_ ~= std.utf.decode(buffer, srcpos);
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}
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}
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catch(UTFException e)
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{
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errorMessage_ = e.msg;
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return;
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}
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catch(Exception e)
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{
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assert(false, "Unexpected exception in decode(): " ~ e.msg);
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}
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}
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// Determine the end of last UTF-8 or UTF-16 sequence in a raw buffer.
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size_t endOfLastUTFSequence(C)(const C[] buffer)
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@safe pure nothrow const @nogc
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{
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static if(is(C == char))
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{
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for(long end = buffer.length - 1; end >= 0; --end)
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{
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const stride = utf8Stride[buffer[cast(size_t)end]];
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if(stride != 0xFF)
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{
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// If stride goes beyond end of the buffer, return end.
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// Otherwise the last sequence ends at buffer.length, so we can
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// return that. (Unless there is an invalid code point, which is
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// caught at decoding)
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return (stride > buffer.length - end) ? cast(size_t)end : buffer.length;
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}
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}
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return 0;
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}
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else static if(is(C == wchar))
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{
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// TODO this is O(N), which is slow. Find out if we can somehow go
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// from the end backwards with UTF-16.
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size_t end = 0;
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while(end < buffer.length)
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{
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const s = stride(buffer, end);
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if(s + end > buffer.length) { break; }
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end += s;
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}
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return end;
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}
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}
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}
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/// Determine if all characters in an array are printable.
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///
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/// Params: chars = Characters to check.
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///
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/// Returns: True if all the characters are printable, false otherwise.
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bool printable(const dchar[] chars) @safe pure nothrow @nogc
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{
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foreach(c; chars)
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{
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if(!((c == 0x09 || c == 0x0A || c == 0x0D || c == 0x85) ||
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(c >= 0x20 && c <= 0x7E) ||
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(c >= 0xA0 && c <= '\uD7FF') ||
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(c >= '\uE000' && c <= '\uFFFD')))
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{
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return false;
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}
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}
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return true;
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}
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// Unittests.
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import std.stream;
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void testEndian(R)()
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{
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writeln(typeid(R).toString() ~ ": endian unittest");
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void endian_test(ubyte[] data, Encoding encoding_expected, Endian endian_expected)
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{
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auto reader = new R(new MemoryStream(data));
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assert(reader.encoding == encoding_expected);
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assert(reader.endian_ == endian_expected);
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}
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ubyte[] little_endian_utf_16 = [0xFF, 0xFE, 0x7A, 0x00];
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ubyte[] big_endian_utf_16 = [0xFE, 0xFF, 0x00, 0x7A];
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endian_test(little_endian_utf_16, Encoding.UTF_16, Endian.littleEndian);
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endian_test(big_endian_utf_16, Encoding.UTF_16, Endian.bigEndian);
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}
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void testPeekPrefixForward(R)()
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{
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writeln(typeid(R).toString() ~ ": peek/prefix/forward unittest");
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ubyte[] data = ByteOrderMarks[BOM.UTF8] ~ cast(ubyte[])"data";
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auto reader = new R(new MemoryStream(data));
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assert(reader.peek() == 'd');
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assert(reader.peek(1) == 'a');
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assert(reader.peek(2) == 't');
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assert(reader.peek(3) == 'a');
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assert(reader.peek(4) == '\0');
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assert(reader.prefix(4) == "data");
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// assert(reader.prefix(6) == "data\0");
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reader.forward(2);
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assert(reader.peek(1) == 'a');
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// assert(collectException(reader.peek(3)));
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}
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void testUTF(R)()
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{
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writeln(typeid(R).toString() ~ ": UTF formats unittest");
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dchar[] data = cast(dchar[])"data";
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void utf_test(T)(T[] data, BOM bom)
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{
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ubyte[] bytes = ByteOrderMarks[bom] ~
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(cast(ubyte*)data.ptr)[0 .. data.length * T.sizeof];
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auto reader = new R(new MemoryStream(bytes));
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assert(reader.peek() == 'd');
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assert(reader.peek(1) == 'a');
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assert(reader.peek(2) == 't');
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assert(reader.peek(3) == 'a');
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}
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utf_test!char(to!(char[])(data), BOM.UTF8);
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utf_test!wchar(to!(wchar[])(data), endian == Endian.bigEndian ? BOM.UTF16BE : BOM.UTF16LE);
|
|
utf_test(data, endian == Endian.bigEndian ? BOM.UTF32BE : BOM.UTF32LE);
|
|
}
|
|
|
|
void test1Byte(R)()
|
|
{
|
|
writeln(typeid(R).toString() ~ ": 1 byte file unittest");
|
|
ubyte[] data = [97];
|
|
|
|
auto reader = new R(new MemoryStream(data));
|
|
assert(reader.peek() == 'a');
|
|
assert(reader.peek(1) == '\0');
|
|
// assert(collectException(reader.peek(2)));
|
|
}
|
|
|
|
unittest
|
|
{
|
|
testEndian!Reader();
|
|
testPeekPrefixForward!Reader();
|
|
testUTF!Reader();
|
|
test1Byte!Reader();
|
|
}
|