UTFDecoder now works directly with a buffer, not a stream.

This commit is contained in:
Ferdinand Majerech 2014-07-22 02:37:06 +02:00
parent 7d4df103a7
commit e30f6e0e80

View file

@ -401,10 +401,10 @@ struct UTFBlockDecoder(size_t bufferSize_) if (bufferSize_ % 2 == 0)
UTFEncoding encoding_;
// Maximum number of characters that might be in the stream.
size_t maxChars_;
// Bytes available in the stream.
size_t available_;
// Input stream.
MemoryStream stream_;
// The entire input buffer.
ubyte[] inputAll_;
// Part of the input buffer that has not yet been decoded.
ubyte[] input_;
// Buffer used to store raw UTF-8 or UTF-16 code points.
union
@ -415,23 +415,23 @@ struct UTFBlockDecoder(size_t bufferSize_) if (bufferSize_ % 2 == 0)
// Used space (in items) in rawBuffer8_/rawBuffer16_.
size_t rawUsed_;
// Space used by decodedBuffer_.
dchar[bufferSize_] decodedBufferSpace_;
// Buffer of decoded, UTF-32 characters. This is a slice into decodedBufferSpace_.
dchar[] decodedBuffer_;
// Space used by decoded_.
dchar[bufferSize_] decodedSpace_;
// Buffer of decoded, UTF-32 characters. This is a slice into decodedSpace_.
dchar[] decoded_;
public:
/// Construct a UTFBlockDecoder decoding data from a buffer.
this(ubyte[] buffer, UTFEncoding encoding) @trusted
{
stream_ = new MemoryStream(buffer);
available_ = stream_.available;
encoding_ = encoding;
inputAll_ = buffer;
input_ = inputAll_[];
encoding_ = encoding;
final switch(encoding_)
{
case UTFEncoding.UTF_8: maxChars_ = available_; break;
case UTFEncoding.UTF_16: maxChars_ = available_ / 2; break;
case UTFEncoding.UTF_32: maxChars_ = available_ / 2; break;
case UTFEncoding.UTF_8: maxChars_ = input_.length; break;
case UTFEncoding.UTF_16: maxChars_ = input_.length / 2; break;
case UTFEncoding.UTF_32: maxChars_ = input_.length / 2; break;
}
}
@ -441,27 +441,27 @@ struct UTFBlockDecoder(size_t bufferSize_) if (bufferSize_ % 2 == 0)
/// Get encoding we're decoding from.
UTFEncoding encoding() const pure @safe nothrow @nogc { return encoding_; }
/// Get the current position in stream.
size_t position() @trusted { return stream_.position; }
/// Get the current position in buffer.
size_t position() @trusted { return inputAll_.length - input_.length; }
/// Are we done decoding?
bool done() const pure @safe nothrow @nogc
{
return rawUsed_ == 0 && decodedBuffer_.length == 0 && available_ == 0;
return rawUsed_ == 0 && decoded_.length == 0 && input_.length == 0;
}
/// Get next character.
dchar getDChar()
@safe
{
if(decodedBuffer_.length)
if(decoded_.length)
{
const result = decodedBuffer_[0];
decodedBuffer_ = decodedBuffer_[1 .. $];
const result = decoded_[0];
decoded_ = decoded_[1 .. $];
return result;
}
assert(available_ > 0 || rawUsed_ > 0);
assert(input_.length > 0 || rawUsed_ > 0);
updateBuffer();
return getDChar();
}
@ -470,15 +470,15 @@ struct UTFBlockDecoder(size_t bufferSize_) if (bufferSize_ % 2 == 0)
const(dchar[]) getDChars(size_t maxChars = size_t.max)
@safe
{
if(decodedBuffer_.length)
if(decoded_.length)
{
const slice = min(decodedBuffer_.length, maxChars);
const result = decodedBuffer_[0 .. slice];
decodedBuffer_ = decodedBuffer_[slice .. $];
const slice = min(decoded_.length, maxChars);
const result = decoded_[0 .. slice];
decoded_ = decoded_[slice .. $];
return result;
}
assert(available_ > 0 || rawUsed_ > 0);
assert(input_.length > 0 || rawUsed_ > 0);
updateBuffer();
return getDChars(maxChars);
}
@ -487,37 +487,37 @@ struct UTFBlockDecoder(size_t bufferSize_) if (bufferSize_ % 2 == 0)
// Read and decode characters from file and store them in the buffer.
void updateBuffer() @trusted
{
assert(decodedBuffer_.length == 0,
assert(decoded_.length == 0,
"updateBuffer can only be called when the buffer is empty");
final switch(encoding_)
{
case UTFEncoding.UTF_8:
const bytes = min(bufferSize_ - rawUsed_, available_);
const bytes = min(bufferSize_ - rawUsed_, input_.length);
// Current length of valid data in rawBuffer8_.
const rawLength = rawUsed_ + bytes;
stream_.readExact(rawBuffer8_.ptr + rawUsed_, bytes);
available_ -= bytes;
rawBuffer8_[rawUsed_ .. rawUsed_ + bytes] = cast(char[])input_[0 .. bytes];
input_ = input_[bytes .. $];
decodeRawBuffer(rawBuffer8_, rawLength);
break;
case UTFEncoding.UTF_16:
const words = min((bufferSize_ / 2) - rawUsed_, available_ / 2);
const words = min((bufferSize_ / 2) - rawUsed_, input_.length / 2);
// Current length of valid data in rawBuffer16_.
const rawLength = rawUsed_ + words;
foreach(c; rawUsed_ .. rawLength)
{
stream_.read(rawBuffer16_[c]);
available_ -= 2;
rawBuffer16_[c] = *cast(wchar*)input_.ptr;
input_ = input_[2 .. $];
}
decodeRawBuffer(rawBuffer16_, rawLength);
break;
case UTFEncoding.UTF_32:
const chars = min(bufferSize_ / 4, available_ / 4);
const chars = min(bufferSize_ / 4, input_.length / 4);
foreach(c; 0 .. chars)
{
stream_.read(decodedBufferSpace_[c]);
available_ -= 4;
decodedSpace_[c] = *cast(dchar*)input_.ptr;
input_ = input_[4 .. $];
}
decodedBuffer_ = decodedBufferSpace_[0 .. chars];
decoded_ = decodedSpace_[0 .. chars];
break;
}
}
@ -584,15 +584,15 @@ struct UTFBlockDecoder(size_t bufferSize_) if (bufferSize_ % 2 == 0)
const c = source[srcpos];
if(c < 0x80)
{
decodedBufferSpace_[bufpos++] = c;
decodedSpace_[bufpos++] = c;
++srcpos;
}
else
{
decodedBufferSpace_[bufpos++] = decode(source, srcpos);
decodedSpace_[bufpos++] = decode(source, srcpos);
}
}
decodedBuffer_ = decodedBufferSpace_[0 .. bufpos];
decoded_ = decodedSpace_[0 .. bufpos];
}
}