Some steps relied on step_push rejecting null inputs; this is no longer
the case. Additionally stepping now more rigorously filters null inputs.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1069 99668b35-9821-0410-8761-19e4c4f06640
Sometimes when evaluating the node set we don't need the entire set and
only need the first element in docorder or any element. In the absence of
iterator support we can still use this information to short-circuit
traversals.
This does not have any effect on straightforward node collection queries,
but frequently improves performance of complex queries with predicates
etc. XMark benchmark gets 15x faster with some queries enjoying 100x
speedup on 10 Mb dataset due to a significant complexity improvement.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1067 99668b35-9821-0410-8761-19e4c4f06640
select_node is shorter and mistyping nodes as node or vice versa should
not lead to any issues since return types are substantially different.
select_single_node method still works and will be deprecated with an
attribute and removed at some point.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1065 99668b35-9821-0410-8761-19e4c4f06640
This method is equivalent to xml_node::select_single_node. This makes
select_single_node faster in certain cases by avoiding an allocation and -
more importantly - paves the way for future step optimizations.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1064 99668b35-9821-0410-8761-19e4c4f06640
Use descendant-or-self::node() transformation for self, descendant and
descendant-or-self axis. Self axis should be semi-frequent; descendant
axes should not really be used with // but if they ever are the complexity
of the step becomes quadratic so it's better to optimize this if possible.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1063 99668b35-9821-0410-8761-19e4c4f06640
When looking for an attribute by name, finding the first attribute means
we can stop looking since attribute names are unique. This makes some
queries faster by 40%.
Another very common pattern in XPath queries is finding an attribute with
a specified value using a predicate (@name = 'value'). While we perform an
optimal amount of traversal in that case, there is a substantial overhead
with evaluating the nodes, saving and restoring the stack state, pushing
the attribute node into a set, etc. Detecting this pattern allows us to
use optimized code, resulting in up to 2x speedup for some queries.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1061 99668b35-9821-0410-8761-19e4c4f06640
The actual condition for the optimization is invariance from context list
-- this includes both position() and last().
Instead of splitting the posinv concept just include last() into
non-posinv expressions - this requires sorting for boolean predicates that
depend on last() and do not depend on position(). These cases should be
very rare.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1060 99668b35-9821-0410-8761-19e4c4f06640
Comment value can not contain the string "--" or end with "-". Since
comments do not support escaping, we're handling this by adding an extra
space after the first "-". A string of "-" thus turns into "- - - ...".
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1058 99668b35-9821-0410-8761-19e4c4f06640
Insert is now unsafe - since we don't have a way to handle rehash()
failures transparently we need to reserve space beforehand. Reserve is now
called before every tree-mutating operations and it guarantees that we
can perform 16 arbitrary pointer mutations after that.
This fixes all test crashes with compact mode.
All ad-hoc attribute operations are now implemented as explicit low-level
functions, and xml_node just uses them. Additionally extract commonly used
is_attribute_of and move detaching of node from append_node to remove_node
- append_node now only works on detached nodes (small increase in parsing
performance).
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1056 99668b35-9821-0410-8761-19e4c4f06640
Parent pointers need to be able to reach everywhere within a page to
minimize shared parent pointer reuse unless it's absolutely necessary.
This reduces parent hash utilization on all test cases to <1%.
Rename compact_parent to compact_shared_parent.
Split the implementation into a generic one with adjustable range and a
special implementation for parent (may need to use 2 bytes on that one
later).
Optimize compact_string and compact_pointer to use minimal amount of math
and move slow hash paths into no-inline functions so that compiler can
inline the fast-paths.
Merge compact_pointer_generic and compact_pointer_forward and optimize.
To make this possible name and value in the node structure had to be
merged into one contents field. Not sure what to do with node_pi, since it
is the only type that required both.
The storage uses one hash table for fallbacks and simple difference
encoding for node and string pointers.
This is a work in progress implementation - while node pointers seem to
work properly, string encoding is inefficient and parent pointers could
use more tuning.
No performance or compatibility work has been done either.
When xpath_string is heap-allocated we always know the length of the
string at some point - it is now stored in the object. This reduces
redundant string length calculations and makes string_value() much faster
in case it has to concatenate strings.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1053 99668b35-9821-0410-8761-19e4c4f06640
translate() with constant arguments now uses a 128-byte table and a table
lookup instead of searching characters in the source string. The table is
generated during query optimization.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1052 99668b35-9821-0410-8761-19e4c4f06640
Node ancestor search now terminates early if ancestor is found before the
document root (only happens if nodes were at the same depth).
Sibling search now steps synchronously for left and right nodes to avoid
worst-case performance when we go in the wrong direction and have to scan
a big list (this comes at the cost of average performance since in the
best case we do 2x more operations).
Node comparison is now done using node pointers to elide some null
comparisons since the structure of the search guarantees that they are
handled properly.
All of the above results in ~2x faster document order comparison on
complex documents.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1050 99668b35-9821-0410-8761-19e4c4f06640
XPath evaluation frequently produces sequences that are sorted but are not
tagged as such (area for improvement...). Doing a linear scan before
sorting is cheap and results in tremendous speedup for already sorted
sequences (especially if document_buffer_order optimization does not
apply).
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1049 99668b35-9821-0410-8761-19e4c4f06640
While gcc and clang can eliminate dependency on s in the inner loop of
PUGI__SCANWHILE_UNROLL, MSVC emits a series of register increments.
Rewriting the code to explicitly remove the dependency keeps similar
codegen on gcc/clang but improves codegen on MSVC for a 10% performance
boost.
Also use unrolled scanning in text_output_escaped (2% faster).
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1048 99668b35-9821-0410-8761-19e4c4f06640
The page no longer contains 'data' field to use sizeof everywhere instead
of offsetof/sizeof inconsistency (that is required because some compilers
don't recognize offsetof as compile-time constant).
The page no longer contains 'memory' field that is now encoded as an
offset byte before the page - this allows us to save one pointer from the
static page in the document to keep the size the same as in v1.2 (binary
compatibility).
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1046 99668b35-9821-0410-8761-19e4c4f06640
Use the same flag that is used for marking name/value in nodes/attributes
as shared. This reduces document structure size and makes some amount of
sense (although admittedly is a bit of a hack).
We need to bring document _memory size back down to 192 bytes and this is
the first step.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1045 99668b35-9821-0410-8761-19e4c4f06640
xml_node objects carry an overhead since they perform NULL checks - in
case of copying a hierarchy we know that we only traverse valid nodes so
we don't need to do this. This makes copyless copy 16% faster.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1043 99668b35-9821-0410-8761-19e4c4f06640
This bypasses the allow_insert check (which is redundant for copying since
we're mirroring an existing node structure that must be valid) and does
not cause an extra allocation for new declaration nodes. Overall results
in 15% faster copying,
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1036 99668b35-9821-0410-8761-19e4c4f06640
Moving nodes results in node order being different from order of allocated
names/values; since move is O(1) we can't mark the moved nodes in a
subtree so we have to disable the optimization for the entire document.
Similarly, if a node is composed of multiple buffers, comparing nodes in
different buffers does not result in meaningful order.
Since we value correctness over performance, mark the entire document in
these cases to disable sorting optimization.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1034 99668b35-9821-0410-8761-19e4c4f06640
Now copying nodes or attributes does not copy names/values if the source
strings are in a document buffer. As a result, several nodes can now share
the same string in document buffer - to support this we 'taint' both
source and destination with a special 'shared' bit.
Tainting disables offset_debug() and fast-path document order comparison;
it also prevents strcpy_insitu from reusing the document buffer memory for
the copied node.
The downsides include slower XPath queries in some (rare) cases and
slightly higher memory consumption in some (rare) cases.
XPath queries can execute slower if a lot of old nodes were copied to new
nodes *and* a query only touches old nodes (so it used to benefit a lot
from fast comparison path) *and* a query produces unsorted node sets that
need to be sorted later (both are relatively rare).
Higher memory consumption is possible if a lot of nodes were copied and
all nodes (both new and old) have their contents modified 'in place' --
previously we could modify the old node in place and the new node required
one allocation on copy, and now both nodes have to have their data
allocated during modification. This should also be rare.
On the bright side, in a lot of cases copying of string data can be
avoided - this makes the copy much faster and the document now occupies
less memory. For example, some uses of append_buffer are now actually slower
compared to building up a document by copying a template from the same
document and modifying the copy slightly.
In one of the internal benchmarks copying is now 4x faster (the difference
can be more dramatic with more string contents and less markup).
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1032 99668b35-9821-0410-8761-19e4c4f06640
This is required to make it possible to use a pointer to one of the
buffers with the document data in nodes but keep offset_debug and (more
importantly) XPath document order comparison optimization working.
The change increases memory page alignment to 64 bytes (so requires +32
bytes for every page allocation, which should not be a problem - even with
non-default 4k pages this is <1% extra cost, with default 32k pages the
overhead is 0.1%)
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1031 99668b35-9821-0410-8761-19e4c4f06640
Since xml_node/attribute are pointer wrappers it's cheaper to pass them by
value. This makes XPath evaluation 4% faster and node printing 2% faster.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1029 99668b35-9821-0410-8761-19e4c4f06640
This makes node copying 6% faster, prevents it from ever running out of
stack space and makes the profiling results more actionable for profilers
that can't merge information from recursive calls.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1027 99668b35-9821-0410-8761-19e4c4f06640
Renames write to write_string and write_buffer to make it easier to
distinguish between them in profiling runs and commit messages...
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1025 99668b35-9821-0410-8761-19e4c4f06640
Make it easier for the compiler to generate good code by loading bufsize
into a local once and returning new offset from flush(). This results in
7% performance gain.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1024 99668b35-9821-0410-8761-19e4c4f06640
Instead of computing the length and doing memcpy we now copy the head of
the string into the buffer (like strcpy) and then use memcpy for tail if
necessary. This results in 10-15% speedup for writing typical documents with
a mix of short and long strings.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1023 99668b35-9821-0410-8761-19e4c4f06640
//name means /descendant-or-self::node()/child::name, but we frequently
can replace it with /descendant::name. This means we do not have to build
up a temporary node set with all descendants that can lead to 3x speedups.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1021 99668b35-9821-0410-8761-19e4c4f06640
We now precompute indent length and have a fast path for lengths 0..4 that
avoids calling memcpy in a tight loop. This makes node output 20-30%
faster if indentation is enabled.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1018 99668b35-9821-0410-8761-19e4c4f06640
This makes node output 3% faster, prevents it from ever running out of
stack space and makes the profiling results more actionable for profilers
that can't merge information from recursive calls.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1014 99668b35-9821-0410-8761-19e4c4f06640
Use a special macro that unrolls the loop body and uses static branch prediction
to improve code generation.
This increases performance across all data sets from benchmark; clang x64 is 10%-40%
faster, clang x86 is 5%-20% faster, msvc is 5%-10% faster.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1008 99668b35-9821-0410-8761-19e4c4f06640
This makes it easier to optimize strconv. For consistency move all definitions of parser-internal macros to one place.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1007 99668b35-9821-0410-8761-19e4c4f06640
The operations itself are O(1) since they just rearrange pointers.
However, the validation step is O(logN) due to a sanity check to prevent recursive trees.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@1002 99668b35-9821-0410-8761-19e4c4f06640
When allocating new pages, make sure that the page has at least 1/4 of the
base page size free. This makes sure that we can do small allocations after
big allocations (i.e. huge node lists) without doing a heap alloc.
This is important because XPath stack code always reclaims extra pages after
evaluating sub-expressions, so allocating a small chunk of memory and then
rolling the state back is a common case (filtering a node list using a
predicate usually does this).
A better solution involves smarter allocation rollback strategy, but the
implemented solution is simple and practical.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@999 99668b35-9821-0410-8761-19e4c4f06640
Exposing true mutable iterators allows the user to violate sorting order
contract. However, some generic algorithms (i.e. Boost ForEach) require
iterator methods to be present.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@998 99668b35-9821-0410-8761-19e4c4f06640
Qmake treats all files that are #include-d as header files, even if the #include is
guarded by an #ifdef. It looks like the only solution that allows for transparent
header-only support based on preprocessor define involves moving the actual source
into a separate header file and including this file in pugixml.cpp.
Let's not do it yet.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@990 99668b35-9821-0410-8761-19e4c4f06640
Introduce a notable behavior change in default parsing mode: documents without a
document element node are now considered invalid. This is technically a breaking change,
however the amount of documents it affects is very small, all parsed data still persists,
and lack of this check results in very confusing behavior in a number of cases.
In order to be able to parse documents without an element node, a fragment parsing flag is
introduced.
Parsing a buffer in fragment mode treats the buffer as a fragment of a valid XML.
As a consequence, top-level PCDATA is added to the tree; additionally, there are no
restrictions on the number of nodes -- so documents without a document element are considered
valid.
Due to the way parsing works internally, load_buffer_inplace occasionally can not preserve
the document contents if it's parsed in a fragment mode. While unfortunate, this problem is
fundamental; since the use case is relatively obscure, hopefully documenting this shortcoming
will be enough.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@980 99668b35-9821-0410-8761-19e4c4f06640
Parsing used to work on a non null-terminated buffer, inserting a fake null terminator to increase performance.
This makes it impossible to implement fragment parsing that preserves PCDATA contents (as witnessed by some
tests for boundary conditions that actually depended on this behavior).
Since almost all uses result in us allocating an internal buffer anyway, the new policy is to make sure all buffers
that are allocated by pugixml are null-terminated - the only exception now is external calls to load_buffer_inplace
that don't trigger encoding conversion.
git-svn-id: https://pugixml.googlecode.com/svn/trunk@977 99668b35-9821-0410-8761-19e4c4f06640
Add tentative changelog for 1.4 to the documentation.
Since Google Code no longer allows file upload, replace download links with GitHub release links.
git-svn-id: http://pugixml.googlecode.com/svn/trunk@968 99668b35-9821-0410-8761-19e4c4f06640
