+++ /dev/null
-// Copyright (C) 2009 Internet Systems Consortium, Inc. ("ISC")
-//
-// Permission to use, copy, modify, and/or distribute this software for any
-// purpose with or without fee is hereby granted, provided that the above
-// copyright notice and this permission notice appear in all copies.
-//
-// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
-// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
-// AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
-// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
-// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
-// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
-// PERFORMANCE OF THIS SOFTWARE.
-
-#include <exceptions/exceptions.h>
-#include <util/buffer.h>
-#include <dns/name.h>
-#include <dns/labelsequence.h>
-#include <dns/expmessagerenderer.h>
-
-#include <cassert>
-#include <vector>
-
-using namespace std;
-using namespace isc::util;
-
-namespace isc {
-namespace dns {
-
-///
-/// \brief The \c MessageRendererImpl class is the actual implementation of
-/// \c MessageRenderer.
-///
-/// The implementation is hidden from applications. We can refer to specific
-/// members of this class only within the implementation source file.
-///
-/// It internally holds a hash table for LabelSequence objects corresponding
-/// to portions of names rendered in this renderer with their offset from
-/// the beginning to the entire rendered data. It's used to handle name
-/// compression.
-struct ExpMessageRenderer::MessageRendererImpl {
- // The size of hash buckets
- static const size_t BUCKETS = 64;
- // Number of hash entries per bucket for which space is preallocated and
- // keep reserved for subsequent rendering, inneding to provide better
- // performance.
- static const size_t RESERVED_ITEMS = 16;
- static const uint16_t NO_OFFSET = 65535; // used as a marker of 'not found'
-
- // Structure used as hash entries
- struct OffsetItem {
- OffsetItem(const LabelSequence& labels_param, uint16_t offset_param) :
- labels(labels_param), offset(offset_param)
- {}
- LabelSequence labels;
- uint16_t offset;
- };
-
- MessageRendererImpl() :
- msglength_limit_(512), truncated_(false),
- compress_mode_(ExpMessageRenderer::CASE_INSENSITIVE)
- {
- // Reserve some spaces for hash and name placeholders.
- for (size_t i = 0; i < BUCKETS; ++i) {
- table_[i].reserve(RESERVED_ITEMS);
- }
- names_.reserve(BUCKETS);
- }
-
- // A helper structure to find the hash entry whose labelsequence is
- // equal to the search key ("target").
- struct SequenceComp {
- SequenceComp(const LabelSequence& target, bool case_sensitive) :
- target_(target), case_sensitive_(case_sensitive)
- {}
- bool operator()(const OffsetItem& item) const {
- return (item.labels.equals(target_, case_sensitive_));
- }
- private:
- const LabelSequence& target_;
- bool case_sensitive_;
- };
-
- uint16_t findOffset(const LabelSequence& sequence) const {
- const bool case_sensitive = (compress_mode_ ==
- ExpMessageRenderer::CASE_SENSITIVE);
- const size_t bucket = (sequence.getHash(case_sensitive) % BUCKETS);
-
- // Find a matching entry, if any. We use some heuristics here: often
- // the same name appers consecutively (like repeating the same owner
- // name for a single RRset), so in case there's a collision in the
- // bucket it will be more likely to find it in the tail side of the
- // bucket.
- vector<OffsetItem>::const_reverse_iterator found =
- find_if(table_[bucket].rbegin(), table_[bucket].rend(),
- SequenceComp(sequence, case_sensitive));
- if (found != table_[bucket].rend()) {
- return (found->offset);
- }
- return (NO_OFFSET);
- }
-
- void addOffset(const LabelSequence& sequence, uint16_t offset) {
- const bool case_sensitive = (compress_mode_ ==
- ExpMessageRenderer::CASE_SENSITIVE);
- const size_t bucket = (sequence.getHash(case_sensitive) % BUCKETS);
- table_[bucket].push_back(OffsetItem(sequence, offset));
- }
-
- /// The maximum length of rendered data that can fit without
- /// truncation.
- uint16_t msglength_limit_;
- /// A boolean flag that indicates truncation has occurred while rendering
- /// the data.
- bool truncated_;
- /// The name compression mode.
- CompressMode compress_mode_;
-
- // The hash table for the (LabelSequence * offset) entries
- vector<OffsetItem> table_[BUCKETS];
- // Placeholder for names referenced from the stored LabelSequences
- vector<Name> names_;
-};
-
-ExpMessageRenderer::ExpMessageRenderer() :
- AbstractMessageRenderer(),
- impl_(new MessageRendererImpl)
-{}
-
-ExpMessageRenderer::~ExpMessageRenderer() {
- delete impl_;
-}
-
-void
-ExpMessageRenderer::clear() {
- AbstractMessageRenderer::clear();
- impl_->msglength_limit_ = 512;
- impl_->truncated_ = false;
- impl_->compress_mode_ = CASE_INSENSITIVE;
-
- // Clear the hash table and name placeholders. We reserve the minimum
- // space for possible subsequent use of the renderer.
- for (size_t i = 0; i < MessageRendererImpl::BUCKETS; ++i) {
- if (impl_->table_[i].size() > MessageRendererImpl::RESERVED_ITEMS) {
- impl_->table_[i].reserve(MessageRendererImpl::RESERVED_ITEMS);
- vector<MessageRendererImpl::OffsetItem>(impl_->table_[i].begin(),
- impl_->table_[i].end()).
- swap(impl_->table_[i]);
- }
- impl_->table_[i].clear();
- }
- if (impl_->names_.size() > MessageRendererImpl::BUCKETS) {
- impl_->names_.reserve(MessageRendererImpl::BUCKETS);
- vector<Name>(impl_->names_.begin(), impl_->names_.end()).
- swap(impl_->names_);
- }
- impl_->names_.clear();
-}
-
-size_t
-ExpMessageRenderer::getLengthLimit() const {
- return (impl_->msglength_limit_);
-}
-
-void
-ExpMessageRenderer::setLengthLimit(const size_t len) {
- impl_->msglength_limit_ = len;
-}
-
-bool
-ExpMessageRenderer::isTruncated() const {
- return (impl_->truncated_);
-}
-
-void
-ExpMessageRenderer::setTruncated() {
- impl_->truncated_ = true;
-}
-
-ExpMessageRenderer::CompressMode
-ExpMessageRenderer::getCompressMode() const {
- return (impl_->compress_mode_);
-}
-
-void
-ExpMessageRenderer::setCompressMode(const CompressMode mode) {
- if (!impl_->names_.empty()) {
- isc_throw(isc::InvalidParameter,
- "compress mode cannot be changed during rendering");
- }
- impl_->compress_mode_ = mode;
-}
-
-void
-ExpMessageRenderer::writeName(const Name& name, const bool compress) {
- LabelSequence sequence(name);
- const size_t nlabels = sequence.getLabelCount();
- size_t data_len;
- const char* data;
-
- // Find the offset in the offset table whose name gives the longest
- // match against the name to be rendered.
- size_t nlabels_uncomp;
- uint16_t ptr_offset = MessageRendererImpl::NO_OFFSET;
- for (nlabels_uncomp = 0; nlabels_uncomp < nlabels; ++nlabels_uncomp) {
- if (sequence.getDataLength() == 1) { // trailing dot.
- ++nlabels_uncomp;
- break;
- }
- ptr_offset = impl_->findOffset(sequence);
- if (ptr_offset != MessageRendererImpl::NO_OFFSET) {
- break;
- }
- sequence.stripLeft(1);
- }
-
- // Record the current offset before updating the offset table
- size_t offset = getLength();
- // Write uncompress part:
- if (nlabels_uncomp > 0 || !compress) {
- LabelSequence uncomp_sequence(name);
- if (compress && nlabels > nlabels_uncomp) {
- // If there's compressed part, strip off that part.
- uncomp_sequence.stripRight(nlabels - nlabels_uncomp);
- }
- data = uncomp_sequence.getData(&data_len);
- writeData(data, data_len);
- }
- // And write compression pointer if available:
- if (compress && ptr_offset != MessageRendererImpl::NO_OFFSET) {
- ptr_offset |= Name::COMPRESS_POINTER_MARK16;
- writeUint16(ptr_offset);
- }
-
- // Finally, add the newly rendered name and its ancestors that
- // have not been in the set. We need to make our copy of name and generate
- // sequence(s) from the copied name because it's not guaranteed that
- // the caller keeps the name valid after this call.
- if (nlabels_uncomp > 0) {
- impl_->names_.push_back(name);
- LabelSequence saved_sequence(impl_->names_.back());
- size_t seqlen = saved_sequence.getDataLength();
- while (nlabels_uncomp-- > 0) {
- if (seqlen == 1) { // root name doesn't need to be stored.
- break;
- }
- if (offset > Name::MAX_COMPRESS_POINTER) {
- break;
- }
- impl_->addOffset(saved_sequence, offset);
- saved_sequence.stripLeft(1);
- const size_t new_seqlen = saved_sequence.getDataLength();
- offset += (seqlen - new_seqlen);
- seqlen = new_seqlen;
- }
- }
-}
-
-}
-}
+++ /dev/null
-// Copyright (C) 2009 Internet Systems Consortium, Inc. ("ISC")
-//
-// Permission to use, copy, modify, and/or distribute this software for any
-// purpose with or without fee is hereby granted, provided that the above
-// copyright notice and this permission notice appear in all copies.
-//
-// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
-// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
-// AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
-// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
-// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
-// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
-// PERFORMANCE OF THIS SOFTWARE.
-
-#ifndef __EXPMESSAGERENDERER_H
-#define __EXPMESSAGERENDERER_H 1
-
-#include <dns/messagerenderer.h>
-
-namespace isc {
-namespace dns {
-
-class ExpMessageRenderer : public AbstractMessageRenderer {
-public:
- using AbstractMessageRenderer::CASE_INSENSITIVE;
- using AbstractMessageRenderer::CASE_SENSITIVE;
-
- /// \brief Constructor from an output buffer.
- ExpMessageRenderer();
-
- virtual ~ExpMessageRenderer();
- virtual bool isTruncated() const;
- virtual size_t getLengthLimit() const;
- virtual CompressMode getCompressMode() const;
- virtual void setTruncated();
- virtual void setLengthLimit(size_t len);
- virtual void setCompressMode(CompressMode mode);
- virtual void clear();
- virtual void writeName(const Name& name, bool compress = true);
-private:
- struct MessageRendererImpl;
- MessageRendererImpl* impl_;
-};
-}
-}
-#endif // __EXPMESSAGERENDERER_H
-
-// Local Variables:
-// mode: c++
-// End:
projects / thirdparty / kea.git / commitdiff
