Convert DCLib documentation to Markdown

Author: dustsigns

DataCompressor/DCLib/doc/overview.txt

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+Overview
+---
+
+DCLib is a library which allows compressing and decompressing (referred to as encoding and decoding henceforth) data from buffers (see DCIOLib).
+
+`enc_dec.h`: Allows listing and using all implemented encoders/decoders as well as their options. Life cycle: `GetEncoder` -> (optional option configuration, see below) -> `enc_dec_t.encoder` (for encoding) or `enc_dec_t.decoder` (for decoding) call on initialized input and output bit buffers. Optional option configuration: (optional) `OptionNameExists` -> (optional) `EncoderSupportsOption` -> `GetOptionType` -> `GetAllowedOptionValueRange` -> `SetOptionValue<Type>`.
+
+Encoders/decoders
+---
+
+* aggregate: Sums of `num_values` (option name) consecutive floating-point values (no decoder!).
+* bac: Performs binary arithmetic coding as implemented by Witten et al.
+* copy: Copies the input to the output, i.e., it performs no compression whatsoever. This encoder/decoder operates on blocks of `blocksize` (option name) bits size.
+* csv: Reads lines of comma-separated values and converts the strings in column number `column` (option name) of each line to a list of (binary) floating-point values when encoding; performs the reverse conversion when decoding and inserts blank columns if necessary.
+* diff: Encodes (signed) differences between consecutive (unsigned) values of `valuesize` (option name) bits size when encoding; reconstructs (unsigned) values of `valuesize` (option name) bits size from their consecutive (signed) differences when decoding
+* lzmh: Performs LZMH coding and decoding from Ringwelski et al. This is an integrated third-party implementation.
+* normalize: Converts floating-point values to (signed) integer values of `valuesize` (option name) bits size when encoding; performs the reverse conversion when decoding. To preserve decimal places after the decimal point, all values are multiplied by `normalization_factor` (option name) when encoding, and divided when decoding.
+* seg: Creates Exponential Golomb code words from values when encoding; reconstructs Exponential Golomb code words when decoding. All values are `valuesize` (option name) bits in size and signed.
+
+Supported encoder input and output formats
+---
+
+Note: Decoder input and formats are reversed, if there is a decoder).
+
+* aggregate: binary float in, binary float out
+* bac: arbitrary in, binary out
+* copy: arbitrary in, arbitrary out
+* csv: ASCII float in, binary float out
+* diff: unsigned int in, signed int out
+* lzmh: ASCII float in, binary out
+* normalize: float in, signed int out
+* seg: signed int in, binary out
+
+Notes on usage
+---
+
+* GetEncoderNames requires a `char*` array with `GetNumberOfEncoders` fields.
+* When adding or renaming encoders/decoders or options, make sure the arrays remain sorted by name. Otherwise, the find operations will not work as expected.