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Plain scalars are now scanned into Reader slices, without allocations.

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This commit is contained in:
Ferdinand Majerech 2014-07-24 02:44:43 +02:00
parent a2cbb90d4e
commit 2d445dbc22
1 changed files with 80 additions and 46 deletions
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126
source/dyaml/scanner.d
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@ -1415,12 +1415,10 @@ final class Scanner
}
/// Scan plain scalar token (no block, no quotes).
Token scanPlain() @system pure
Token scanPlain() @system pure nothrow
{
// We keep track of the allowSimpleKey_ flag here.
// Indentation rules are loosed for the flow context
// Using appender_, so clear it when we're done.
scope(exit) { appender_.clear(); }
const startMark = reader_.mark;
Mark endMark = startMark;
const indent = indent_ + 1;
@ -1432,12 +1430,15 @@ final class Scanner
mixin FastCharSearch!" \t\0\n\r\u0085\u2028\u2029"d search;
for(;;)
reader_.sliceBuilder.begin();
alias Transaction = SliceBuilder.Transaction;
Transaction spacesTransaction;
// Stop at a comment.
while(reader_.peek() != '#')
{
if(reader_.peek() == '#') { break; }
// Scan the entire plain scalar.
uint length = 0;
dchar c;
for(;;)
{
@ -1454,79 +1455,112 @@ final class Scanner
!search.canFind(reader_.peek(length + 1)) &&
!",[]{}"d.canFind(reader_.peek(length + 1)))
{
// This is an error; throw the slice away.
spacesTransaction.commit();
reader_.sliceBuilder.finish();
reader_.forward(length);
throw new Error("While scanning a plain scalar", startMark,
"found unexpected ':' . Please check "
"http://pyyaml.org/wiki/YAMLColonInFlowContext "
"for details.", reader_.mark);
errorData_ = ErrorData("While scanning a plain scalar", startMark,
"found unexpected ':' . Please check "
"http://pyyaml.org/wiki/YAMLColonInFlowContext "
"for details.", reader_.mark);
error_ = true;
return Token.init;
}
if(length == 0) { break; }
allowSimpleKey_ = false;
appender_.put(spaces);
appender_.put(reader_.get(length));
reader_.sliceBuilder.write(reader_.get(length));
endMark = reader_.mark;
spaces = scanPlainSpaces(startMark);
if(spaces.length == 0 || reader_.peek() == '#' ||
(flowLevel_ == 0 && reader_.column < indent))
spacesTransaction.commit();
spacesTransaction = Transaction(reader_.sliceBuilder);
const bool anySpaces = scanPlainSpacesToSlice(startMark);
if(!anySpaces || (flowLevel_ == 0 && reader_.column < indent))
{
break;
}
}
return scalarToken(startMark, endMark,
to!string(cast(dstring)appender_.data),
ScalarStyle.Plain);
spacesTransaction.__dtor();
const dstring slice = reader_.sliceBuilder.finish();
return scalarToken(startMark, endMark, slice.utf32To8, ScalarStyle.Plain);
}
/// Scan spaces in a plain scalar.
dstring scanPlainSpaces(const Mark startMark) @safe pure nothrow
///
/// Assumes that the caller is building a slice in Reader, and puts the spaces
/// into that slice.
bool scanPlainSpacesToSlice(const Mark startMark) @system pure nothrow @nogc
{
// The specification is really confusing about tabs in plain scalars.
// We just forbid them completely. Do not use tabs in YAML!
auto appender = appender!dstring();
uint length = 0;
// Get as many plain spaces as there are.
size_t length = 0;
while(reader_.peek(length) == ' ') { ++length; }
dstring whitespaces = reader_.get(length);
const dstring whitespaces = reader_.get(length);
dchar c = reader_.peek();
if("\n\r\u0085\u2028\u2029"d.canFind(c))
// No newline after the spaces (if any)
if(!"\n\r\u0085\u2028\u2029"d.canFind(c))
{
const lineBreak = scanLineBreak();
allowSimpleKey_ = true;
static bool end(Reader reader) nothrow
// We have spaces, but no newline.
if(whitespaces.length > 0)
{
return ["---"d, "..."d].canFind(reader.prefix(3)) &&
" \t\0\n\r\u0085\u2028\u2029"d.canFind(reader.peek(3));
reader_.sliceBuilder.write(whitespaces);
return true;
}
// No spaces or newline.
return false;
}
if(end(reader_)) { return ""; }
// Newline after the spaces (if any)
bool anySpaces = false;
const lineBreak = scanLineBreak();
allowSimpleKey_ = true;
dstring breaks;
while(" \n\r\u0085\u2028\u2029"d.canFind(reader_.peek()))
static bool end(Reader reader_) @safe pure nothrow @nogc
{
return ("---"d == reader_.prefix(3) || "..."d == reader_.prefix(3))
&& " \t\0\n\r\u0085\u2028\u2029"d.canFind(reader_.peek(3));
}
if(end(reader_)) { return false; }
bool extraBreaks = false;
alias Transaction = SliceBuilder.Transaction;
auto transaction = Transaction(reader_.sliceBuilder);
if(lineBreak != '\n') { reader_.sliceBuilder.write(lineBreak); }
while(" \n\r\u0085\u2028\u2029"d.canFind(reader_.peek()))
{
if(reader_.peek() == ' ') { reader_.forward(); }
else
{
if(reader_.peek() == ' ') { reader_.forward(); }
else
const lBreak = scanLineBreak();
extraBreaks = true;
reader_.sliceBuilder.write(lBreak);
if(end(reader_))
{
breaks ~= scanLineBreak();
if(end(reader_)) { return ""; }
return false;
}
}
if(lineBreak != '\n') { appender.put(lineBreak); }
else if(breaks.length == 0) { appender.put(' '); }
appender.put(breaks);
}
else if(whitespaces.length > 0)
{
appender.put(whitespaces);
}
transaction.commit();
return appender.data;
// No line breaks, only a space.
if(lineBreak == '\n' && !extraBreaks) { reader_.sliceBuilder.write(' '); }
// We've written some spaces into the slice if:
// (lineBreak != '\n' || extraBreaks || lineBreak == '\n' && !extraBreaks).
// That simplifies to (lineBreak != '\n' || lineBreak == '\n') which
// simplifies to (true)
return true;
}
/// Scan handle of a tag token.