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Odin/vendor/compress/lz4/lz4.odin
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gingerBill 527c0b3202 Change lib for lz4
2024-07-23 00:19:42 +01:00

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package vendor_compress_lz4
when ODIN_OS == .Windows {
@(extra_linker_flags="/NODEFAULTLIB:libcmt")
foreign import lib "lib/liblz4_static.lib"
}
import "core:c"
VERSION_MAJOR :: 1 /* for breaking interface changes */
VERSION_MINOR :: 10 /* for new (non-breaking) interface capabilities */
VERSION_RELEASE :: 0 /* for tweaks, bug-fixes, or development */
VERSION_NUMBER :: VERSION_MAJOR *100*100 + VERSION_MINOR *100 + VERSION_RELEASE
MEMORY_USAGE_MIN :: 10
MEMORY_USAGE_DEFAULT :: 14
MEMORY_USAGE_MAX :: 20
MEMORY_USAGE :: MEMORY_USAGE_DEFAULT
MAX_INPUT_SIZE :: 0x7E000000 /* 2_113_929_216 bytes */
COMPRESSBOUND :: #force_inline proc "c" (isize: c.int) -> c.int {
return u32(isize) > MAX_INPUT_SIZE ? 0 : isize + (isize/255) + 16
}
DECODER_RING_BUFFER_SIZE :: #force_inline proc "c" (maxBlockSize: c.int) -> c.int {
return 65536 + 14 + maxBlockSize /* for static allocation; maxBlockSize presumed valid */
}
@(default_calling_convention="c", link_prefix="LZ4_")
foreign lib {
versionNumber :: proc() -> c.int --- /**< library version number; useful to check dll version; requires v1.3.0+ */
versionString :: proc() -> cstring --- /**< library version string; useful to check dll version; requires v1.7.5+ */
/*! LZ4_compress_default() :
* Compresses 'srcSize' bytes from buffer 'src'
* into already allocated 'dst' buffer of size 'dstCapacity'.
* Compression is guaranteed to succeed if 'dstCapacity' >= LZ4_compressBound(srcSize).
* It also runs faster, so it's a recommended setting.
* If the function cannot compress 'src' into a more limited 'dst' budget,
* compression stops *immediately*, and the function result is zero.
* In which case, 'dst' content is undefined (invalid).
* srcSize : max supported value is LZ4_MAX_INPUT_SIZE.
* dstCapacity : size of buffer 'dst' (which must be already allocated)
* @return : the number of bytes written into buffer 'dst' (necessarily <= dstCapacity)
* or 0 if compression fails
* Note : This function is protected against buffer overflow scenarios (never writes outside 'dst' buffer, nor read outside 'source' buffer).
*/
compress_default :: proc(src, dst: [^]byte, srcSize, dstCapacity: c.int) -> c.int ---
/*! LZ4_decompress_safe() :
* @compressedSize : is the exact complete size of the compressed block.
* @dstCapacity : is the size of destination buffer (which must be already allocated),
* presumed an upper bound of decompressed size.
* @return : the number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
* If destination buffer is not large enough, decoding will stop and output an error code (negative value).
* If the source stream is detected malformed, the function will stop decoding and return a negative result.
* Note 1 : This function is protected against malicious data packets :
* it will never writes outside 'dst' buffer, nor read outside 'source' buffer,
* even if the compressed block is maliciously modified to order the decoder to do these actions.
* In such case, the decoder stops immediately, and considers the compressed block malformed.
* Note 2 : compressedSize and dstCapacity must be provided to the function, the compressed block does not contain them.
* The implementation is free to send / store / derive this information in whichever way is most beneficial.
* If there is a need for a different format which bundles together both compressed data and its metadata, consider looking at lz4frame.h instead.
*/
decompress_safe :: proc(src, dst: [^]byte, compressedSize, dstCapacity: c.int) -> c.int ---
/*! LZ4_compressBound() :
Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible)
This function is primarily useful for memory allocation purposes (destination buffer size).
Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example).
Note that LZ4_compress_default() compresses faster when dstCapacity is >= LZ4_compressBound(srcSize)
inputSize : max supported value is LZ4_MAX_INPUT_SIZE
return : maximum output size in a "worst case" scenario
or 0, if input size is incorrect (too large or negative)
*/
compressBound :: proc(inputSize: c.int) -> c.int ---
/*! LZ4_compress_fast() :
Same as LZ4_compress_default(), but allows selection of "acceleration" factor.
The larger the acceleration value, the faster the algorithm, but also the lesser the compression.
It's a trade-off. It can be fine tuned, with each successive value providing roughly +~3% to speed.
An acceleration value of "1" is the same as regular LZ4_compress_default()
Values <= 0 will be replaced by LZ4_ACCELERATION_DEFAULT (currently == 1, see lz4.c).
Values > LZ4_ACCELERATION_MAX will be replaced by LZ4_ACCELERATION_MAX (currently == 65537, see lz4.c).
*/
compress_fast :: proc(src, dst: [^]byte, srcSize, dstCapacity: c.int, acceleration: c.int) -> c.int ---
/*! LZ4_compress_fast_extState() :
* Same as LZ4_compress_fast(), using an externally allocated memory space for its state.
* Use LZ4_sizeofState() to know how much memory must be allocated,
* and allocate it on 8-bytes boundaries (using `malloc()` typically).
* Then, provide this buffer as `void* state` to compression function.
*/
sizeofState :: proc() -> c.int ---
compress_fast_extState :: proc (state: rawptr, src, dst: [^]byte, srcSize, dstCapacity: c.int, acceleration: c.int) -> c.int ---
/*! LZ4_compress_destSize() :
* Reverse the logic : compresses as much data as possible from 'src' buffer
* into already allocated buffer 'dst', of size >= 'dstCapacity'.
* This function either compresses the entire 'src' content into 'dst' if it's large enough,
* or fill 'dst' buffer completely with as much data as possible from 'src'.
* note: acceleration parameter is fixed to "default".
*
* *srcSizePtr : in+out parameter. Initially contains size of input.
* Will be modified to indicate how many bytes where read from 'src' to fill 'dst'.
* New value is necessarily <= input value.
* @return : Nb bytes written into 'dst' (necessarily <= dstCapacity)
* or 0 if compression fails.
*
* Note : from v1.8.2 to v1.9.1, this function had a bug (fixed in v1.9.2+):
* the produced compressed content could, in specific circumstances,
* require to be decompressed into a destination buffer larger
* by at least 1 byte than the content to decompress.
* If an application uses `LZ4_compress_destSize()`,
* it's highly recommended to update liblz4 to v1.9.2 or better.
* If this can't be done or ensured,
* the receiving decompression function should provide
* a dstCapacity which is > decompressedSize, by at least 1 byte.
* See https://github.com/lz4/lz4/issues/859 for details
*/
compress_destSize :: proc(src, dst: [^]byte, srcSizePtr: ^c.int, targetDstSize: c.int) -> c.int ---
/*! LZ4_decompress_safe_partial() :
* Decompress an LZ4 compressed block, of size 'srcSize' at position 'src',
* into destination buffer 'dst' of size 'dstCapacity'.
* Up to 'targetOutputSize' bytes will be decoded.
* The function stops decoding on reaching this objective.
* This can be useful to boost performance
* whenever only the beginning of a block is required.
*
* @return : the number of bytes decoded in `dst` (necessarily <= targetOutputSize)
* If source stream is detected malformed, function returns a negative result.
*
* Note 1 : @return can be < targetOutputSize, if compressed block contains less data.
*
* Note 2 : targetOutputSize must be <= dstCapacity
*
* Note 3 : this function effectively stops decoding on reaching targetOutputSize,
* so dstCapacity is kind of redundant.
* This is because in older versions of this function,
* decoding operation would still write complete sequences.
* Therefore, there was no guarantee that it would stop writing at exactly targetOutputSize,
* it could write more bytes, though only up to dstCapacity.
* Some "margin" used to be required for this operation to work properly.
* Thankfully, this is no longer necessary.
* The function nonetheless keeps the same signature, in an effort to preserve API compatibility.
*
* Note 4 : If srcSize is the exact size of the block,
* then targetOutputSize can be any value,
* including larger than the block's decompressed size.
* The function will, at most, generate block's decompressed size.
*
* Note 5 : If srcSize is _larger_ than block's compressed size,
* then targetOutputSize **MUST** be <= block's decompressed size.
* Otherwise, *silent corruption will occur*.
*/
decompress_safe_partial :: proc (src, dst: [^]byte, srcSize, targetOutputSize, dstCapacity: c.int) -> c.int ---
createStream :: proc() -> ^stream_t ---
freeStream :: proc(streamPtr: ^stream_t) -> c.int ---
/*! LZ4_resetStream_fast() : v1.9.0+
* Use this to prepare an LZ4_stream_t for a new chain of dependent blocks
* (e.g., LZ4_compress_fast_continue()).
*
* An LZ4_stream_t must be initialized once before usage.
* This is automatically done when created by LZ4_createStream().
* However, should the LZ4_stream_t be simply declared on stack (for example),
* it's necessary to initialize it first, using LZ4_initStream().
*
* After init, start any new stream with LZ4_resetStream_fast().
* A same LZ4_stream_t can be re-used multiple times consecutively
* and compress multiple streams,
* provided that it starts each new stream with LZ4_resetStream_fast().
*
* LZ4_resetStream_fast() is much faster than LZ4_initStream(),
* but is not compatible with memory regions containing garbage data.
*
* Note: it's only useful to call LZ4_resetStream_fast()
* in the context of streaming compression.
* The *extState* functions perform their own resets.
* Invoking LZ4_resetStream_fast() before is redundant, and even counterproductive.
*/
resetStream_fast :: proc(streamPtr: ^stream_t) ---
/*! LZ4_loadDict() :
* Use this function to reference a static dictionary into LZ4_stream_t.
* The dictionary must remain available during compression.
* LZ4_loadDict() triggers a reset, so any previous data will be forgotten.
* The same dictionary will have to be loaded on decompression side for successful decoding.
* Dictionary are useful for better compression of small data (KB range).
* While LZ4 itself accepts any input as dictionary, dictionary efficiency is also a topic.
* When in doubt, employ the Zstandard's Dictionary Builder.
* Loading a size of 0 is allowed, and is the same as reset.
* @return : loaded dictionary size, in bytes (note: only the last 64 KB are loaded)
*/
loadDict :: proc(streamPtr: ^stream_t, dictionary: [^]byte, dictSize: c.int) -> c.int ---
/*! LZ4_loadDictSlow() : v1.10.0+
* Same as LZ4_loadDict(),
* but uses a bit more cpu to reference the dictionary content more thoroughly.
* This is expected to slightly improve compression ratio.
* The extra-cpu cost is likely worth it if the dictionary is re-used across multiple sessions.
* @return : loaded dictionary size, in bytes (note: only the last 64 KB are loaded)
*/
loadDictSlow :: proc(streamPtr: ^stream_t, dictionary: [^]byte, dictSize: c.int) -> c.int ---
/*! LZ4_attach_dictionary() : stable since v1.10.0
*
* This allows efficient re-use of a static dictionary multiple times.
*
* Rather than re-loading the dictionary buffer into a working context before
* each compression, or copying a pre-loaded dictionary's LZ4_stream_t into a
* working LZ4_stream_t, this function introduces a no-copy setup mechanism,
* in which the working stream references @dictionaryStream in-place.
*
* Several assumptions are made about the state of @dictionaryStream.
* Currently, only states which have been prepared by LZ4_loadDict() or
* LZ4_loadDictSlow() should be expected to work.
*
* Alternatively, the provided @dictionaryStream may be NULL,
* in which case any existing dictionary stream is unset.
*
* If a dictionary is provided, it replaces any pre-existing stream history.
* The dictionary contents are the only history that can be referenced and
* logically immediately precede the data compressed in the first subsequent
* compression call.
*
* The dictionary will only remain attached to the working stream through the
* first compression call, at the end of which it is cleared.
* @dictionaryStream stream (and source buffer) must remain in-place / accessible / unchanged
* through the completion of the compression session.
*
* Note: there is no equivalent LZ4_attach_*() method on the decompression side
* because there is no initialization cost, hence no need to share the cost across multiple sessions.
* To decompress LZ4 blocks using dictionary, attached or not,
* just employ the regular LZ4_setStreamDecode() for streaming,
* or the stateless LZ4_decompress_safe_usingDict() for one-shot decompression.
*/
attach_dictionary :: proc(workingStream, dictionaryStream: ^stream_t) ---
/*! LZ4_compress_fast_continue() :
* Compress 'src' content using data from previously compressed blocks, for better compression ratio.
* 'dst' buffer must be already allocated.
* If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster.
*
* @return : size of compressed block
* or 0 if there is an error (typically, cannot fit into 'dst').
*
* Note 1 : Each invocation to LZ4_compress_fast_continue() generates a new block.
* Each block has precise boundaries.
* Each block must be decompressed separately, calling LZ4_decompress_*() with relevant metadata.
* It's not possible to append blocks together and expect a single invocation of LZ4_decompress_*() to decompress them together.
*
* Note 2 : The previous 64KB of source data is __assumed__ to remain present, unmodified, at same address in memory !
*
* Note 3 : When input is structured as a double-buffer, each buffer can have any size, including < 64 KB.
* Make sure that buffers are separated, by at least one byte.
* This construction ensures that each block only depends on previous block.
*
* Note 4 : If input buffer is a ring-buffer, it can have any size, including < 64 KB.
*
* Note 5 : After an error, the stream status is undefined (invalid), it can only be reset or freed.
*/
compress_fast_continue :: proc(streamPtr: ^stream_t, src, dst: [^]byte, srcSize, dstCapacity: c.int, acceleration: c.int) -> c.int ---
/*! LZ4_saveDict() :
* If last 64KB data cannot be guaranteed to remain available at its current memory location,
* save it into a safer place (char* safeBuffer).
* This is schematically equivalent to a memcpy() followed by LZ4_loadDict(),
* but is much faster, because LZ4_saveDict() doesn't need to rebuild tables.
* @return : saved dictionary size in bytes (necessarily <= maxDictSize), or 0 if error.
*/
saveDict :: proc(streamPtr: ^stream_t, safeBuffer: [^]byte, maxDictSize: c.int) -> c.int ---
createStreamDecode :: proc() -> ^streamDecode_t ---
freeStreamDecode :: proc(LZ4_stream: ^streamDecode_t) -> c.int ---
/*! LZ4_setStreamDecode() :
* An LZ4_streamDecode_t context can be allocated once and re-used multiple times.
* Use this function to start decompression of a new stream of blocks.
* A dictionary can optionally be set. Use NULL or size 0 for a reset order.
* Dictionary is presumed stable : it must remain accessible and unmodified during next decompression.
* @return : 1 if OK, 0 if error
*/
setStreamDecode :: proc(LZ4_streamDecode: ^streamDecode_t, dictionary: [^]byte, dictSize: c.int) -> c.int ---
/*! LZ4_decoderRingBufferSize() : v1.8.2+
* Note : in a ring buffer scenario (optional),
* blocks are presumed decompressed next to each other
* up to the moment there is not enough remaining space for next block (remainingSize < maxBlockSize),
* at which stage it resumes from beginning of ring buffer.
* When setting such a ring buffer for streaming decompression,
* provides the minimum size of this ring buffer
* to be compatible with any source respecting maxBlockSize condition.
* @return : minimum ring buffer size,
* or 0 if there is an error (invalid maxBlockSize).
*/
decoderRingBufferSize :: proc(maxBlockSize: c.int) -> c.int ---
/*! LZ4_decompress_safe_continue() :
* This decoding function allows decompression of consecutive blocks in "streaming" mode.
* The difference with the usual independent blocks is that
* new blocks are allowed to find references into former blocks.
* A block is an unsplittable entity, and must be presented entirely to the decompression function.
* LZ4_decompress_safe_continue() only accepts one block at a time.
* It's modeled after `LZ4_decompress_safe()` and behaves similarly.
*
* @LZ4_streamDecode : decompression state, tracking the position in memory of past data
* @compressedSize : exact complete size of one compressed block.
* @dstCapacity : size of destination buffer (which must be already allocated),
* must be an upper bound of decompressed size.
* @return : number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
* If destination buffer is not large enough, decoding will stop and output an error code (negative value).
* If the source stream is detected malformed, the function will stop decoding and return a negative result.
*
* The last 64KB of previously decoded data *must* remain available and unmodified
* at the memory position where they were previously decoded.
* If less than 64KB of data has been decoded, all the data must be present.
*
* Special : if decompression side sets a ring buffer, it must respect one of the following conditions :
* - Decompression buffer size is _at least_ LZ4_decoderRingBufferSize(maxBlockSize).
* maxBlockSize is the maximum size of any single block. It can have any value > 16 bytes.
* In which case, encoding and decoding buffers do not need to be synchronized.
* Actually, data can be produced by any source compliant with LZ4 format specification, and respecting maxBlockSize.
* - Synchronized mode :
* Decompression buffer size is _exactly_ the same as compression buffer size,
* and follows exactly same update rule (block boundaries at same positions),
* and decoding function is provided with exact decompressed size of each block (exception for last block of the stream),
* _then_ decoding & encoding ring buffer can have any size, including small ones ( < 64 KB).
* - Decompression buffer is larger than encoding buffer, by a minimum of maxBlockSize more bytes.
* In which case, encoding and decoding buffers do not need to be synchronized,
* and encoding ring buffer can have any size, including small ones ( < 64 KB).
*
* Whenever these conditions are not possible,
* save the last 64KB of decoded data into a safe buffer where it can't be modified during decompression,
* then indicate where this data is saved using LZ4_setStreamDecode(), before decompressing next block.
*/
decompress_safe_continue :: proc(LZ4_streamDecode: ^streamDecode_t, src, dst: [^]byte, srcSize, dstCapacity: c.int) -> c.int ---
/*! LZ4_decompress_safe_usingDict() :
* Works the same as
* a combination of LZ4_setStreamDecode() followed by LZ4_decompress_safe_continue()
* However, it's stateless: it doesn't need any LZ4_streamDecode_t state.
* Dictionary is presumed stable : it must remain accessible and unmodified during decompression.
* Performance tip : Decompression speed can be substantially increased
* when dst == dictStart + dictSize.
*/
decompress_safe_usingDict :: proc(src, dst: [^]byte, srcSize, dstCapacity: c.int, dictStart: [^]byte, dictSize: c.int) -> c.int ---
/*! LZ4_decompress_safe_partial_usingDict() :
* Behaves the same as LZ4_decompress_safe_partial()
* with the added ability to specify a memory segment for past data.
* Performance tip : Decompression speed can be substantially increased
* when dst == dictStart + dictSize.
*/
decompress_safe_partial_usingDict :: proc(src, dst: [^]byte, compressedSize, targetOutputSize, maxOutputSize: c.int, dictStart: [^]byte, dictSize: c.int) -> c.int ---
}
STREAM_MINSIZE :: (1 << MEMORY_USAGE) + 32 /* static size, for inter-version compatibility */
stream_t :: struct #raw_union {
minStateSize: [STREAM_MINSIZE]byte,
internal_donotuse: stream_t_internal,
}
HASHLOG :: MEMORY_USAGE-2
HASHTABLESIZE :: 1 << MEMORY_USAGE
HASH_SIZE_U32 :: 1 << HASHLOG /* required as macro for static allocation */
stream_t_internal :: struct {
hashTable: [HASH_SIZE_U32]u32,
dictionary: [^]byte,
dictCtx: ^stream_t_internal,
currentOffset: u32,
tableType: u32,
dictSize: u32,
/* Implicit padding to ensure structure is aligned */
}
STREAMDECODE_MINSIZE :: 32
streamDecode_t :: struct #raw_union {
minStateSize: [STREAMDECODE_MINSIZE]byte,
internal_donotuse: streamDecode_t_internal,
}
streamDecode_t_internal :: struct {
externalDict: [^]byte,
prefixEnd: [^]byte,
extDictSize: c.size_t,
prefixSize: c.size_t,
}
///////////////////
// lz4hc
CLEVEL_MIN :: 2
CLEVEL_DEFAULT :: 9
CLEVEL_OPT_MIN :: 10
CLEVEL_MAX :: 12
@(default_calling_convention="c", link_prefix="LZ4_")
foreign lib {
/*! LZ4_compress_HC() :
* Compress data from `src` into `dst`, using the powerful but slower "HC" algorithm.
* `dst` must be already allocated.
* Compression is guaranteed to succeed if `dstCapacity >= LZ4_compressBound(srcSize)` (see "lz4.h")
* Max supported `srcSize` value is LZ4_MAX_INPUT_SIZE (see "lz4.h")
* `compressionLevel` : any value between 1 and LZ4HC_CLEVEL_MAX will work.
* Values > LZ4HC_CLEVEL_MAX behave the same as LZ4HC_CLEVEL_MAX.
* @return : the number of bytes written into 'dst'
* or 0 if compression fails.
*/
compress_HC :: proc(src, dst: [^]byte, srcSize, dstCapacity, compressionLevel: c.int) -> c.int ---
/*! LZ4_compress_HC_extStateHC() :
* Same as LZ4_compress_HC(), but using an externally allocated memory segment for `state`.
* `state` size is provided by LZ4_sizeofStateHC().
* Memory segment must be aligned on 8-bytes boundaries (which a normal malloc() should do properly).
*/
sizeofStateHC :: proc() -> c.int ---
compress_HC_extStateHC :: proc(stateHC: rawptr, src, dst: [^]byte, srcSize, maxDstSize: c.int, compressionLevel: c.int) -> c.int ---
/*! LZ4_compress_HC_destSize() : v1.9.0+
* Will compress as much data as possible from `src`
* to fit into `targetDstSize` budget.
* Result is provided in 2 parts :
* @return : the number of bytes written into 'dst' (necessarily <= targetDstSize)
* or 0 if compression fails.
* `srcSizePtr` : on success, *srcSizePtr is updated to indicate how much bytes were read from `src`
*/
compress_HC_destSize :: proc(stateHC: rawptr, src, dst: [^]byte, srcSizePtr: ^c.int, targetDstSize: c.int, compressionLevel: c.int) -> c.int ---
/*! LZ4_createStreamHC() and LZ4_freeStreamHC() :
* These functions create and release memory for LZ4 HC streaming state.
* Newly created states are automatically initialized.
* A same state can be used multiple times consecutively,
* starting with LZ4_resetStreamHC_fast() to start a new stream of blocks.
*/
createStreamHC :: proc() -> ^streamHC_t ---
freeStreamHC :: proc(streamHCPtr: ^streamHC_t) -> c.int ---
resetStreamHC_fast :: proc(streamHCPtr: ^streamHC_t, compressionLevel: c.int) --- /* v1.9.0+ */
loadDictHC :: proc(streamHCPtr: ^streamHC_t, dictionary: [^]byte, dictSize: c.int) -> c.int ---
compress_HC_continue :: proc(streamHCPtr: ^streamHC_t, src, dst: [^]byte, srcSize, maxDstSize: c.int) -> c.int ---
/*! LZ4_compress_HC_continue_destSize() : v1.9.0+
* Similar to LZ4_compress_HC_continue(),
* but will read as much data as possible from `src`
* to fit into `targetDstSize` budget.
* Result is provided into 2 parts :
* @return : the number of bytes written into 'dst' (necessarily <= targetDstSize)
* or 0 if compression fails.
* `srcSizePtr` : on success, *srcSizePtr will be updated to indicate how much bytes were read from `src`.
* Note that this function may not consume the entire input.
*/
compress_HC_continue_destSize:: proc(LZ4_streamHCPtr: ^streamHC_t, src, dst: [^]byte, srcSizePtr: ^c.int, targetDstSize: c.int) -> c.int ---
saveDictHC :: proc(streamHCPtr: ^streamHC_t, safeBuffer: [^]byte, maxDictSize: c.int) -> c.int ---
/*! LZ4_attach_HC_dictionary() : stable since v1.10.0
* This API allows for the efficient re-use of a static dictionary many times.
*
* Rather than re-loading the dictionary buffer into a working context before
* each compression, or copying a pre-loaded dictionary's LZ4_streamHC_t into a
* working LZ4_streamHC_t, this function introduces a no-copy setup mechanism,
* in which the working stream references the dictionary stream in-place.
*
* Several assumptions are made about the state of the dictionary stream.
* Currently, only streams which have been prepared by LZ4_loadDictHC() should
* be expected to work.
*
* Alternatively, the provided dictionary stream pointer may be NULL, in which
* case any existing dictionary stream is unset.
*
* A dictionary should only be attached to a stream without any history (i.e.,
* a stream that has just been reset).
*
* The dictionary will remain attached to the working stream only for the
* current stream session. Calls to LZ4_resetStreamHC(_fast) will remove the
* dictionary context association from the working stream. The dictionary
* stream (and source buffer) must remain in-place / accessible / unchanged
* through the lifetime of the stream session.
*/
attach_HC_dictionary :: proc(working_stream, dictionary_stream: ^streamHC_t) ---
}
HC_DICTIONARY_LOGSIZE :: 16
HC_MAXD :: 1<<HC_DICTIONARY_LOGSIZE
HC_MAXD_MASK :: HC_MAXD - 1
HC_HASH_LOG :: 15
HC_HASHTABLESIZE :: 1 << HC_HASH_LOG
HC_HASH_MASK :: HC_HASHTABLESIZE - 1
streamHC_internal_t :: struct {
hashTable: [HC_HASHTABLESIZE]u32,
chainTable: [HC_MAXD]u16,
end: [^]byte, /* next block here to continue on current prefix */
prefixStart: [^]byte, /* Indexes relative to this position */
dictStart: [^]byte, /* alternate reference for extDict */
dictLimit: u32, /* below that point, need extDict */
lowLimit: u32, /* below that point, no more history */
nextToUpdate: u32, /* index from which to continue dictionary update */
compressionLevel: c.short,
favorDecSpeed: i8, /* favor decompression speed if this flag set,
otherwise, favor compression ratio */
dirty: i8, /* stream has to be fully reset if this flag is set */
dictCtx: ^streamHC_internal_t,
}
STREAMHC_MINSIZE :: 262200
streamHC_t :: struct #raw_union {
minStateSize: [STREAMHC_MINSIZE]byte,
internal_donotuse: streamHC_internal_t,
}
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