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Diffstat (limited to 'src/formats/osxml/OsxmlAttributeLocator.cpp')
| -rw-r--r-- | src/formats/osxml/OsxmlAttributeLocator.cpp | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/src/formats/osxml/OsxmlAttributeLocator.cpp b/src/formats/osxml/OsxmlAttributeLocator.cpp new file mode 100644 index 0000000..e37446a --- /dev/null +++ b/src/formats/osxml/OsxmlAttributeLocator.cpp @@ -0,0 +1,144 @@ +/* + Ousía + Copyright (C) 2014, 2015 Benjamin Paaßen, Andreas Stöckel + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include <core/common/Location.hpp> +#include <core/common/CharReader.hpp> +#include <core/common/Utils.hpp> + +#include "OsxmlAttributeLocator.hpp" + +namespace ousia { + +/** + * Enum used internally in the statemachine of the xml argument parser. + */ +enum class XmlAttributeState { + IN_TAG_NAME, + SEARCH_ATTR, + IN_ATTR_NAME, + HAS_ATTR_NAME, + HAS_ATTR_EQUALS, + IN_ATTR_DATA +}; + +std::map<std::string, SourceLocation> OsxmlAttributeLocator::locate( + CharReader &reader, size_t offs) +{ + std::map<std::string, SourceLocation> res; + + // Fork the reader, we don't want to mess up the XML parsing process, do we? + CharReaderFork readerFork = reader.fork(); + + // Move the read cursor to the start location, abort if this does not work + if (offs != readerFork.seek(offs)) { + return res; + } + + // Now all we need to do is to implement one half of an XML parser. As this + // is inherently complicated we'll totaly fail at it. Don't care. All we + // want to get is those darn offsets for pretty error messages... (and we + // can assume the XML is valid as it was already read by expat) + XmlAttributeState state = XmlAttributeState::IN_TAG_NAME; + char c; + std::stringstream attrName; + while (readerFork.read(c)) { + // Abort at the end of the tag + if (c == '>' && state != XmlAttributeState::IN_ATTR_DATA) { + return res; + } + + // One state machine to rule them all, one state machine to find them, + // One state machine to bring them all and in the darkness bind them + // (the byte offsets) + switch (state) { + case XmlAttributeState::IN_TAG_NAME: + if (Utils::isWhitespace(c)) { + res.emplace("$tag", + SourceLocation{reader.getSourceId(), offs + 1, + readerFork.getOffset() - 1}); + state = XmlAttributeState::SEARCH_ATTR; + } + break; + case XmlAttributeState::SEARCH_ATTR: + if (!Utils::isWhitespace(c)) { + state = XmlAttributeState::IN_ATTR_NAME; + attrName << c; + } + break; + case XmlAttributeState::IN_ATTR_NAME: + if (Utils::isWhitespace(c)) { + state = XmlAttributeState::HAS_ATTR_NAME; + } else if (c == '=') { + state = XmlAttributeState::HAS_ATTR_EQUALS; + } else { + attrName << c; + } + break; + case XmlAttributeState::HAS_ATTR_NAME: + if (!Utils::isWhitespace(c)) { + if (c == '=') { + state = XmlAttributeState::HAS_ATTR_EQUALS; + break; + } + // Well, this is a strange XML file... We expected to + // see a '=' here! Try to continue with the + // "HAS_ATTR_EQUALS" state as this state will hopefully + // inlcude some error recovery + } else { + // Skip whitespace here + break; + } + // Fallthrough + case XmlAttributeState::HAS_ATTR_EQUALS: + if (!Utils::isWhitespace(c)) { + if (c == '"') { + // Here we are! We have found the beginning of an + // attribute. Let's quickly lock the current offset away + // in the result map + res.emplace(attrName.str(), + SourceLocation{reader.getSourceId(), + readerFork.getOffset()}); + state = XmlAttributeState::IN_ATTR_DATA; + } else { + // No, this XML file is not well formed. Assume we're in + // an attribute name once again + attrName.str(std::string{&c, 1}); + state = XmlAttributeState::IN_ATTR_NAME; + } + } + break; + case XmlAttributeState::IN_ATTR_DATA: + if (c == '"') { + // We're at the end of the attribute data, set the end + // location + auto it = res.find(attrName.str()); + if (it != res.end()) { + it->second.setEnd(readerFork.getOffset() - 1); + } + + // Reset the attribute name and restart the search + attrName.str(std::string{}); + state = XmlAttributeState::SEARCH_ATTR; + } + break; + } + } + return res; +} +} + |