hist.h File Reference

#include "../common/zstd_deps.h"

Go to the source code of this file.

Macros
#define	HIST_WKSP_SIZE_U32   1024
#define	HIST_WKSP_SIZE   (HIST_WKSP_SIZE_U32 * sizeof(unsigned))

Functions
size_t	HIST_count (unsigned *count, unsigned *maxSymbolValuePtr, const void *src, size_t srcSize)
unsigned	HIST_isError (size_t code)
size_t	HIST_count_wksp (unsigned *count, unsigned *maxSymbolValuePtr, const void *src, size_t srcSize, void *workSpace, size_t workSpaceSize)
size_t	HIST_countFast (unsigned *count, unsigned *maxSymbolValuePtr, const void *src, size_t srcSize)
size_t	HIST_countFast_wksp (unsigned *count, unsigned *maxSymbolValuePtr, const void *src, size_t srcSize, void *workSpace, size_t workSpaceSize)
unsigned	HIST_count_simple (unsigned *count, unsigned *maxSymbolValuePtr, const void *src, size_t srcSize)

Macro Definition Documentation

HIST_WKSP_SIZE

#define HIST_WKSP_SIZE   (HIST_WKSP_SIZE_U32 * sizeof(unsigned))

HIST_WKSP_SIZE_U32

#define HIST_WKSP_SIZE_U32   1024

Function Documentation

HIST_count()

size_t HIST_count	(	unsigned *	count,
		unsigned *	maxSymbolValuePtr,
		const void *	src,
		size_t	srcSize )

HIST_count(): Provides the precise count of each byte within a table 'count'. 'count' is a table of unsigned int, of minimum size (*maxSymbolValuePtr+1). Updates *maxSymbolValuePtr with actual largest symbol value detected.

Returns

: count of the most frequent symbol (which isn't identified). or an error code, which can be tested using HIST_isError(). note : if return == srcSize, there is only one symbol.

HIST_count_simple()

unsigned HIST_count_simple	(	unsigned *	count,
		unsigned *	maxSymbolValuePtr,
		const void *	src,
		size_t	srcSize )

HIST_count_simple() : Same as HIST_countFast(), this function is unsafe, and will segfault if any value within src is > *maxSymbolValuePtr. It is also a bit slower for large inputs. However, it does not need any additional memory (not even on stack).

Returns

: count of the most frequent symbol. Note this function doesn't produce any error (i.e. it must succeed).

HIST_count_wksp()

size_t HIST_count_wksp	(	unsigned *	count,
		unsigned *	maxSymbolValuePtr,
		const void *	src,
		size_t	srcSize,
		void *	workSpace,
		size_t	workSpaceSize )

HIST_count_wksp() : Same as HIST_count(), but using an externally provided scratch buffer. Benefit is this function will use very little stack space. workSpace is a writable buffer which must be 4-bytes aligned, workSpaceSize must be >= HIST_WKSP_SIZE

HIST_countFast()

size_t HIST_countFast	(	unsigned *	count,
		unsigned *	maxSymbolValuePtr,
		const void *	src,
		size_t	srcSize )

HIST_countFast() : same as HIST_count(), but blindly trusts that all byte values within src are <= *maxSymbolValuePtr. This function is unsafe, and will segfault if any value within src is > *maxSymbolValuePtr

HIST_countFast_wksp()

size_t HIST_countFast_wksp	(	unsigned *	count,
		unsigned *	maxSymbolValuePtr,
		const void *	src,
		size_t	srcSize,
		void *	workSpace,
		size_t	workSpaceSize )

HIST_countFast_wksp() : Same as HIST_countFast(), but using an externally provided scratch buffer. workSpace is a writable buffer which must be 4-bytes aligned, workSpaceSize must be >= HIST_WKSP_SIZE

HIST_isError()

unsigned HIST_isError

(

size_t

code

)

tells if a return value is an error code