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Include dependency graph for blosc.h: This graph shows which files directly or indirectly include this file:Go to the source code of this file.
Macros | |
| #define | BLOSC_VERSION_MAJOR 1 /* for major interface/format changes */ |
| #define | BLOSC_VERSION_MINOR 20 /* for minor interface/format changes */ |
| #define | BLOSC_VERSION_RELEASE 1 /* for tweaks, bug-fixes, or development */ |
| #define | BLOSC_VERSION_STRING "1.20.1" /* string version. Sync with above! */ |
| #define | BLOSC_VERSION_REVISION "$Rev$" /* revision version */ |
| #define | BLOSC_VERSION_DATE "$Date:: 2020-09-08 #$" /* date version */ |
| #define | BLOSCLZ_VERSION_STRING "2.3.0" /* the internal compressor version */ |
| #define | BLOSC_VERSION_FORMAT 2 /* Blosc format version, starting at 1 */ |
| #define | BLOSC_MIN_HEADER_LENGTH 16 |
| #define | BLOSC_MAX_OVERHEAD BLOSC_MIN_HEADER_LENGTH |
| #define | BLOSC_MAX_BUFFERSIZE (INT_MAX - BLOSC_MAX_OVERHEAD) |
| #define | BLOSC_MAX_TYPESIZE 255 /* Cannot be larger than 255 */ |
| #define | BLOSC_MAX_BLOCKSIZE ((INT_MAX - BLOSC_MAX_TYPESIZE * sizeof(int32_t)) / 3) |
| #define | BLOSC_MAX_THREADS 256 |
| #define | BLOSC_NOSHUFFLE 0 /* no shuffle */ |
| #define | BLOSC_SHUFFLE 1 /* byte-wise shuffle */ |
| #define | BLOSC_BITSHUFFLE 2 /* bit-wise shuffle */ |
| #define | BLOSC_DOSHUFFLE 0x1 /* byte-wise shuffle */ |
| #define | BLOSC_MEMCPYED 0x2 /* plain copy */ |
| #define | BLOSC_DOBITSHUFFLE 0x4 /* bit-wise shuffle */ |
| #define | BLOSC_BLOSCLZ 0 |
| #define | BLOSC_LZ4 1 |
| #define | BLOSC_LZ4HC 2 |
| #define | BLOSC_SNAPPY 3 |
| #define | BLOSC_ZLIB 4 |
| #define | BLOSC_ZSTD 5 |
| #define | BLOSC_BLOSCLZ_COMPNAME "blosclz" |
| #define | BLOSC_LZ4_COMPNAME "lz4" |
| #define | BLOSC_LZ4HC_COMPNAME "lz4hc" |
| #define | BLOSC_SNAPPY_COMPNAME "snappy" |
| #define | BLOSC_ZLIB_COMPNAME "zlib" |
| #define | BLOSC_ZSTD_COMPNAME "zstd" |
| #define | BLOSC_BLOSCLZ_LIB 0 |
| #define | BLOSC_LZ4_LIB 1 |
| #define | BLOSC_SNAPPY_LIB 2 |
| #define | BLOSC_ZLIB_LIB 3 |
| #define | BLOSC_ZSTD_LIB 4 |
| #define | BLOSC_BLOSCLZ_LIBNAME "BloscLZ" |
| #define | BLOSC_LZ4_LIBNAME "LZ4" |
| #define | BLOSC_SNAPPY_LIBNAME "Snappy" |
| #define | BLOSC_ZLIB_LIBNAME "Zlib" |
| #define | BLOSC_ZSTD_LIBNAME "Zstd" |
| #define | BLOSC_BLOSCLZ_FORMAT BLOSC_BLOSCLZ_LIB |
| #define | BLOSC_LZ4_FORMAT BLOSC_LZ4_LIB |
| #define | BLOSC_LZ4HC_FORMAT BLOSC_LZ4_LIB /* LZ4HC and LZ4 share the same format */ |
| #define | BLOSC_SNAPPY_FORMAT BLOSC_SNAPPY_LIB |
| #define | BLOSC_ZLIB_FORMAT BLOSC_ZLIB_LIB |
| #define | BLOSC_ZSTD_FORMAT BLOSC_ZSTD_LIB |
| #define | BLOSC_BLOSCLZ_VERSION_FORMAT 1 |
| #define | BLOSC_LZ4_VERSION_FORMAT 1 |
| #define | BLOSC_LZ4HC_VERSION_FORMAT 1 /* LZ4HC and LZ4 share the same format */ |
| #define | BLOSC_SNAPPY_VERSION_FORMAT 1 |
| #define | BLOSC_ZLIB_VERSION_FORMAT 1 |
| #define | BLOSC_ZSTD_VERSION_FORMAT 1 |
| #define | BLOSC_ALWAYS_SPLIT 1 |
| #define | BLOSC_NEVER_SPLIT 2 |
| #define | BLOSC_AUTO_SPLIT 3 |
| #define | BLOSC_FORWARD_COMPAT_SPLIT 4 |
| #define BLOSC_BLOSCLZ_FORMAT BLOSC_BLOSCLZ_LIB |
| #define BLOSC_LZ4_FORMAT BLOSC_LZ4_LIB |
| #define BLOSC_LZ4HC_FORMAT BLOSC_LZ4_LIB /* LZ4HC and LZ4 share the same format */ |
| #define BLOSC_LZ4HC_VERSION_FORMAT 1 /* LZ4HC and LZ4 share the same format */ |
| #define BLOSC_MAX_BLOCKSIZE ((INT_MAX - BLOSC_MAX_TYPESIZE * sizeof(int32_t)) / 3) |
| #define BLOSC_MAX_BUFFERSIZE (INT_MAX - BLOSC_MAX_OVERHEAD) |
| #define BLOSC_MAX_OVERHEAD BLOSC_MIN_HEADER_LENGTH |
| #define BLOSC_MAX_TYPESIZE 255 /* Cannot be larger than 255 */ |
| #define BLOSC_SNAPPY_FORMAT BLOSC_SNAPPY_LIB |
| #define BLOSC_VERSION_DATE "$Date:: 2020-09-08 #$" /* date version */ |
| #define BLOSC_VERSION_FORMAT 2 /* Blosc format version, starting at 1 */ |
| #define BLOSC_VERSION_RELEASE 1 /* for tweaks, bug-fixes, or development */ |
| #define BLOSC_VERSION_REVISION "$Rev$" /* revision version */ |
| #define BLOSC_ZLIB_FORMAT BLOSC_ZLIB_LIB |
| #define BLOSC_ZSTD_FORMAT BLOSC_ZSTD_LIB |
| #define BLOSCLZ_VERSION_STRING "2.3.0" /* the internal compressor version */ |
| BLOSC_EXPORT const char* blosc_cbuffer_complib | ( | const void * | cbuffer | ) |
Return the compressor library/format used in a compressed buffer.
This function should always succeed.
| BLOSC_EXPORT void blosc_cbuffer_metainfo | ( | const void * | cbuffer, |
| size_t * | typesize, | ||
| int * | flags | ||
| ) |
Return meta-information about a compressed buffer, namely the type size (typesize), as well as some internal flags.
The flags is a set of bits, where the used ones are: bit 0: whether the shuffle filter has been applied or not bit 1: whether the internal buffer is a pure memcpy or not bit 2: whether the bit shuffle filter has been applied or not
You can use the BLOSC_DOSHUFFLE, BLOSC_DOBITSHUFFLE and BLOSC_MEMCPYED symbols for extracting the interesting bits (e.g. flags & BLOSC_DOSHUFFLE says whether the buffer is byte-shuffled or not).
You only need to pass the first BLOSC_MIN_HEADER_LENGTH bytes of a compressed buffer for this call to work.
If the format is not supported by the library, all output arguments will be filled with zeros.
| BLOSC_EXPORT void blosc_cbuffer_sizes | ( | const void * | cbuffer, |
| size_t * | nbytes, | ||
| size_t * | cbytes, | ||
| size_t * | blocksize | ||
| ) |
Return information about a compressed buffer, namely the number of uncompressed bytes (nbytes) and compressed (cbytes). It also returns the blocksize (which is used internally for doing the compression by blocks).
You only need to pass the first BLOSC_MIN_HEADER_LENGTH bytes of a compressed buffer for this call to work.
If the format is not supported by the library, all output arguments will be filled with zeros.
| BLOSC_EXPORT int blosc_cbuffer_validate | ( | const void * | cbuffer, |
| size_t | cbytes, | ||
| size_t * | nbytes | ||
| ) |
Checks that the compressed buffer starting at cbuffer of length cbytes may contain valid blosc compressed data, and that it is safe to call blosc_decompress/blosc_decompress_ctx/blosc_getitem.
On success, returns 0 and sets *nbytes to the size of the uncompressed data. This does not guarantee that the decompression function won't return an error, but does guarantee that it is safe to attempt decompression.
On failure, returns -1.
| BLOSC_EXPORT void blosc_cbuffer_versions | ( | const void * | cbuffer, |
| int * | version, | ||
| int * | compversion | ||
| ) |
Return information about a compressed buffer, namely the internal Blosc format version (version) and the format for the internal compressor used (compversion).
This function should always succeed.
| BLOSC_EXPORT int blosc_compcode_to_compname | ( | int | compcode, |
| const char ** | compname | ||
| ) |
Get the compname associated with the compcode.
If the compressor code is not recognized, or there is not support for it in this build, -1 is returned. Else, the compressor code is returned.
| BLOSC_EXPORT int blosc_compname_to_compcode | ( | const char * | compname | ) |
Return the compressor code associated with the compressor name.
If the compressor name is not recognized, or there is not support for it in this build, -1 is returned instead.
| BLOSC_EXPORT int blosc_compress | ( | int | clevel, |
| int | doshuffle, | ||
| size_t | typesize, | ||
| size_t | nbytes, | ||
| const void * | src, | ||
| void * | dest, | ||
| size_t | destsize | ||
| ) |
Compress a block of data in the src buffer and returns the size of the compressed block. The size of src buffer is specified by nbytes. There is not a minimum for src buffer size (nbytes).
clevel is the desired compression level and must be a number between 0 (no compression) and 9 (maximum compression).
doshuffle specifies whether the shuffle compression filters should be applied or not. BLOSC_NOSHUFFLE means not applying it, BLOSC_SHUFFLE means applying it at a byte level and BLOSC_BITSHUFFLE at a bit level (slower but may achieve better entropy alignment).
typesize is the number of bytes for the atomic type in binary src buffer. This is mainly useful for the shuffle filters. For implementation reasons, only a 1 < typesize < 256 will allow the shuffle filter to work. When typesize is not in this range, shuffle will be silently disabled.
The dest buffer must have at least the size of destsize. Blosc guarantees that if you set destsize to, at least, (nbytes + BLOSC_MAX_OVERHEAD), the compression will always succeed. The src buffer and the dest buffer can not overlap.
Compression is memory safe and guaranteed not to write the dest buffer beyond what is specified in destsize.
If src buffer cannot be compressed into destsize, the return value is zero and you should discard the contents of the dest buffer.
A negative return value means that an internal error happened. This should never happen. If you see this, please report it back together with the buffer data causing this and compression settings.
blosc_compress() honors different environment variables to control internal parameters without the need of doing that programatically. Here are the ones supported:
BLOSC_CLEVEL=(INTEGER): This will overwrite the clevel parameter before the compression process starts.
BLOSC_SHUFFLE=[NOSHUFFLE | SHUFFLE | BITSHUFFLE]: This will overwrite the doshuffle parameter before the compression process starts.
BLOSC_TYPESIZE=(INTEGER): This will overwrite the typesize parameter before the compression process starts.
BLOSC_COMPRESSOR=[BLOSCLZ | LZ4 | LZ4HC | SNAPPY | ZLIB]: This will call blosc_set_compressor(BLOSC_COMPRESSOR) before the compression process starts.
BLOSC_NTHREADS=(INTEGER): This will call blosc_set_nthreads(BLOSC_NTHREADS) before the compression process starts.
BLOSC_BLOCKSIZE=(INTEGER): This will call blosc_set_blocksize(BLOSC_BLOCKSIZE) before the compression process starts. NOTE: The blocksize is a critical parameter with important restrictions in the allowed values, so use this with care.
BLOSC_NOLOCK=(ANY VALUE): This will call blosc_compress_ctx() under the hood, with the compressor, blocksize and numinternalthreads parameters set to the same as the last calls to blosc_set_compressor(), blosc_set_blocksize() and blosc_set_nthreads(). BLOSC_CLEVEL, BLOSC_SHUFFLE, BLOSC_TYPESIZE environment vars will also be honored.
BLOSC_SPLITMODE=[ FORWARD_COMPAT | AUTO | ALWAYS | NEVER ]: This will call blosc_set_splitmode() with the different supported values. See blosc_set_splitmode() docstrings for more info on each mode.
BLOSC_WARN=(INTEGER): This will print some warning message on stderr showing more info in situations where data inputs cannot be compressed. The values can range from 1 (less verbose) to 10 (full verbose). 0 is the same as if the BLOSC_WARN envvar was not defined.
| BLOSC_EXPORT int blosc_compress_ctx | ( | int | clevel, |
| int | doshuffle, | ||
| size_t | typesize, | ||
| size_t | nbytes, | ||
| const void * | src, | ||
| void * | dest, | ||
| size_t | destsize, | ||
| const char * | compressor, | ||
| size_t | blocksize, | ||
| int | numinternalthreads | ||
| ) |
Context interface to blosc compression. This does not require a call to blosc_init() and can be called from multithreaded applications without the global lock being used, so allowing Blosc be executed simultaneously in those scenarios.
It uses the same parameters than the blosc_compress() function plus:
compressor: the string representing the type of compressor to use.
blocksize: the requested size of the compressed blocks. If 0, an automatic blocksize will be used.
numinternalthreads: the number of threads to use internally.
A negative return value means that an internal error happened. This should never happen. If you see this, please report it back together with the buffer data causing this and compression settings.
| BLOSC_EXPORT int blosc_decompress | ( | const void * | src, |
| void * | dest, | ||
| size_t | destsize | ||
| ) |
Decompress a block of compressed data in src, put the result in dest and returns the size of the decompressed block.
Call blosc_cbuffer_validate to determine the size of the destination buffer.
The src buffer and the dest buffer can not overlap.
Decompression is memory safe and guaranteed not to write the dest buffer beyond what is specified in destsize.
If an error occurs, e.g. the compressed data is corrupted or the output buffer is not large enough, then 0 (zero) or a negative value will be returned instead.
blosc_decompress() honors different environment variables to control internal parameters without the need of doing that programatically. Here are the ones supported:
BLOSC_NTHREADS=(INTEGER): This will call blosc_set_nthreads(BLOSC_NTHREADS) before the proper decompression process starts.
BLOSC_NOLOCK=(ANY VALUE): This will call blosc_decompress_ctx() under the hood, with the numinternalthreads parameter set to the same value as the last call to blosc_set_nthreads().
| BLOSC_EXPORT int blosc_decompress_ctx | ( | const void * | src, |
| void * | dest, | ||
| size_t | destsize, | ||
| int | numinternalthreads | ||
| ) |
Context interface to blosc decompression. This does not require a call to blosc_init() and can be called from multithreaded applications without the global lock being used, so allowing Blosc be executed simultaneously in those scenarios.
Call blosc_cbuffer_validate to determine the size of the destination buffer.
It uses the same parameters than the blosc_decompress() function plus:
numinternalthreads: number of threads to use internally.
Decompression is memory safe and guaranteed not to write the dest buffer more than what is specified in destsize.
If an error occurs, e.g. the compressed data is corrupted or the output buffer is not large enough, then 0 (zero) or a negative value will be returned instead.
| BLOSC_EXPORT void blosc_destroy | ( | void | ) |
Destroy the Blosc library environment.
You must call this after to you are done with all the Blosc calls, unless you have not used blosc_init() before (see blosc_init() above).
| BLOSC_EXPORT int blosc_free_resources | ( | void | ) |
Free possible memory temporaries and thread resources. Use this when you are not going to use Blosc for a long while. In case of problems releasing the resources, it returns a negative number, else it returns 0.
| BLOSC_EXPORT int blosc_get_blocksize | ( | void | ) |
Get the internal blocksize to be used during compression. 0 means that an automatic blocksize is computed internally (the default).
| BLOSC_EXPORT int blosc_get_complib_info | ( | const char * | compname, |
| char ** | complib, | ||
| char ** | version | ||
| ) |
Get info from compression libraries included in the current build. In compname you pass the compressor name that you want info from.
In complib and version you get a pointer to the compressor library name and the version in string format respectively. After using the name and version, you should free() them so as to avoid leaks. If any of complib and version are NULL, they will not be assigned to anything, and the user should not need to free them.
If the compressor is supported, it returns the code for the library (>=0). If it is not supported, this function returns -1.
| BLOSC_EXPORT const char* blosc_get_compressor | ( | void | ) |
Returns the current compressor that is being used for compression.
| BLOSC_EXPORT int blosc_get_nthreads | ( | void | ) |
Returns the current number of threads that are used for compression/decompression.
| BLOSC_EXPORT const char* blosc_get_version_string | ( | void | ) |
Return the version of the C-Blosc library in string format.
Useful for dynamic libraries.
Get nitems (of typesize size) in src buffer starting in start. The items are returned in dest buffer, which has to have enough space for storing all items.
Returns the number of bytes copied to dest or a negative value if some error happens.
| BLOSC_EXPORT void blosc_init | ( | void | ) |
Initialize the Blosc library environment.
You must call this previous to any other Blosc call, unless you want Blosc to be used simultaneously in a multi-threaded environment, in which case you should exclusively use the blosc_compress_ctx()/blosc_decompress_ctx() pair (see below).
| BLOSC_EXPORT const char* blosc_list_compressors | ( | void | ) |
Get a list of compressors supported in the current build. The returned value is a string with a concatenation of "blosclz", "lz4", "lz4hc", "snappy", "zlib" or "zstd "separated by commas, depending on which ones are present in the build.
This function does not leak, so you should not free() the returned list.
This function should always succeed.
| BLOSC_EXPORT void blosc_set_blocksize | ( | size_t | blocksize | ) |
Force the use of a specific blocksize. If 0, an automatic blocksize will be used (the default).
The blocksize is a critical parameter with important restrictions in the allowed values, so use this with care.
| BLOSC_EXPORT int blosc_set_compressor | ( | const char * | compname | ) |
Select the compressor to be used. The supported ones are "blosclz", "lz4", "lz4hc", "snappy", "zlib" and "zstd". If this function is not called, then "blosclz" will be used by default.
In case the compressor is not recognized, or there is not support for it in this build, it returns a -1. Else it returns the code for the compressor (>=0).
| BLOSC_EXPORT int blosc_set_nthreads | ( | int | nthreads | ) |
Initialize a pool of threads for compression/decompression. If nthreads is 1, then the serial version is chosen and a possible previous existing pool is ended. If this is not called, nthreads is set to 1 internally.
Returns the previous number of threads.
| BLOSC_EXPORT void blosc_set_splitmode | ( | int | splitmode | ) |
Set the split mode.
This function can take the next values: BLOSC_FORWARD_COMPAT_SPLIT BLOSC_AUTO_SPLIT BLOSC_NEVER_SPLIT BLOSC_ALWAYS_SPLIT
BLOSC_FORWARD_COMPAT offers reasonably forward compatibility, BLOSC_AUTO_SPLIT is for nearly optimal results (based on heuristics), BLOSC_NEVER_SPLIT and BLOSC_ALWAYS_SPLIT are for the user experimenting when trying to get best compression ratios and/or speed.
If not called, the default mode is BLOSC_FORWARD_COMPAT_SPLIT.
This function should always succeed.
1.8.6 
