hist.c File Reference

#include "../common/mem.h"
#include "../common/debug.h"
#include "../common/error_private.h"
#include "hist.h"

Enumerations
enum	HIST_checkInput_e { trustInput , checkMaxSymbolValue }

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

Enumeration Type Documentation

HIST_checkInput_e

enum HIST_checkInput_e

Enumerator
trustInput
checkMaxSymbolValue

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