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ajacoutot
459a30b174
XML is slow to parse and strings inside the document cannot be memory mapped as they do not have a trailing NUL char. The libxmlb library takes XML source, and converts it to a structured binary representation with a deduplicated string table -- where the strings have the NULs included. <...> ok robert@
21 lines
1.2 KiB
Plaintext
21 lines
1.2 KiB
Plaintext
XML is slow to parse and strings inside the document cannot be memory mapped as
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they do not have a trailing NUL char. The libxmlb library takes XML source, and
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converts it to a structured binary representation with a deduplicated string
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table -- where the strings have the NULs included.
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This allows an application to mmap the binary XML file, do an XPath query and
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return some strings without actually parsing the entire document. This is all
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done using (almost) zero allocations and no actual copying of the binary data.
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As each node in the binary XML file encodes the 'next' node at the same level
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it makes skipping whole subtrees trivial. A 10Mb binary XML file can be loaded
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from disk **and** queried in less than a few milliseconds.
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The binary XML is not supposed to be small. It's usually about half the size of
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the text XML data where a lot of the tag content is duplicated, but can actually
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be larger than the original XML file. This isn't important; the fast query speed
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and the ability to mmap strings without copies more than makes up for the larger
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on-disk size. If you want to compress your XML, this library probably isn't for
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you -- just use gzip -- it gives you an almost a perfect compression ratio for
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data like this.
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