1.7 KiB
Index file
Each index file have 4 sections.
IdxHeaderExtraInfo(Being used but unnamed in source code)ChunksBtreeIndex
The IdxHeader are 32bits blocks of various meta info of the index. The most important info are chunksOffset and indexRootOffset pointing to the starting offset of BtreeIndex and Chunks.
Some dicts only have one ExtraInfo: the dictionaryName which is an uint32 size of a string followed and the string.
Each chunk contains uint32 size of uncompressed data, uint32 size of zlib compressed data, and the zlib compressed data.
The Chunks maybe used by both IdxHeader and BtreeIndex.
By adding new a new chunk to Chunks and store an offset to IdxHeader, ExtraInfo can store arbitrary long information.
BtreeIndex is a zlib compressed typical btree implementation in which each Node will include word info and a offset that pointing to corresponding chunk's position.
Note that a chunk only includes necessary data to find an article, and it does not contain the word.
The exact data in chunk is decided and interpreted by dictionary implementations. For example, the starting and ending position of an article in a dictionary file.
What's under the hood after a word is queried?
After typing a word into the search box and press enter, the embedded browser will load gdlookup://localhost?word=<wantted word>. This url will be handled by Qt webengine's Url Scheme handler. The returned html page will be composed in the ArticleMaker which will initiate some DataRequest on dictionary formats. Resource files will be requested via bres:// or qrc:// which will went through a similar process.
TODO: other subsystems.