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hist.h File Reference
#include <stddef.h>
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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))

Definition at line 39 of file hist.h.

◆ HIST_WKSP_SIZE_U32

#define HIST_WKSP_SIZE_U32   1024

Definition at line 38 of file hist.h.

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.

Definition at line 178 of file hist.c.

180 {
181  unsigned tmpCounters[HIST_WKSP_SIZE_U32];
182  return HIST_count_wksp(count, maxSymbolValuePtr, src, srcSize, tmpCounters, sizeof(tmpCounters));
183 }
GLuint GLuint GLsizei count
Definition: gl.h:1545
#define HIST_WKSP_SIZE_U32
Definition: hist.h:38
size_t HIST_count_wksp(unsigned *count, unsigned *maxSymbolValuePtr, const void *source, size_t sourceSize, void *workSpace, size_t workSpaceSize)
Definition: hist.c:166
GLenum src
Definition: glext.h:6340

◆ 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).

Definition at line 29 of file hist.c.

31 {
32  const BYTE* ip = (const BYTE*)src;
33  const BYTE* const end = ip + srcSize;
34  unsigned maxSymbolValue = *maxSymbolValuePtr;
35  unsigned largestCount=0;
36 
37  memset(count, 0, (maxSymbolValue+1) * sizeof(*count));
38  if (srcSize==0) { *maxSymbolValuePtr = 0; return 0; }
39 
40  while (ip<end) {
41  assert(*ip <= maxSymbolValue);
42  count[*ip++]++;
43  }
44 
45  while (!count[maxSymbolValue]) maxSymbolValue--;
46  *maxSymbolValuePtr = maxSymbolValue;
47 
48  { U32 s;
49  for (s=0; s<=maxSymbolValue; s++)
50  if (count[s] > largestCount) largestCount = count[s];
51  }
52 
53  return largestCount;
54 }
GLuint GLuint GLsizei count
Definition: gl.h:1545
#define assert(x)
Definition: debug.h:53
Definition: dhcpd.h:61
GLuint GLuint end
Definition: gl.h:1545
GLdouble s
Definition: gl.h:2039
GLenum src
Definition: glext.h:6340
unsigned char BYTE
Definition: xxhash.c:193
#define memset(x, y, z)
Definition: compat.h:39
unsigned int U32
Definition: xxhash.c:195

Referenced by HIST_countFast_wksp(), HUF_compressWeights(), and ZSTD_rescaleFreqs().

◆ 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

Definition at line 166 of file hist.c.

169 {
170  if ((size_t)workSpace & 3) return ERROR(GENERIC); /* must be aligned on 4-bytes boundaries */
171  if (workSpaceSize < HIST_WKSP_SIZE) return ERROR(workSpace_tooSmall);
172  if (*maxSymbolValuePtr < 255)
173  return HIST_count_parallel_wksp(count, maxSymbolValuePtr, source, sourceSize, checkMaxSymbolValue, (U32*)workSpace);
174  *maxSymbolValuePtr = 255;
175  return HIST_countFast_wksp(count, maxSymbolValuePtr, source, sourceSize, workSpace, workSpaceSize);
176 }
#define HIST_WKSP_SIZE
Definition: hist.h:39
#define ERROR(name)
Definition: error_private.h:53
GLuint GLuint GLsizei count
Definition: gl.h:1545
static size_t HIST_count_parallel_wksp(unsigned *count, unsigned *maxSymbolValuePtr, const void *source, size_t sourceSize, HIST_checkInput_e check, U32 *const workSpace)
Definition: hist.c:66
unsigned int U32
Definition: xxhash.c:195
size_t HIST_countFast_wksp(unsigned *count, unsigned *maxSymbolValuePtr, const void *source, size_t sourceSize, void *workSpace, size_t workSpaceSize)
Definition: hist.c:144

Referenced by FSE_compress_wksp(), HIST_count(), HUF_compress_internal(), ZSTD_buildSuperBlockEntropy_literal(), and ZSTD_estimateSubBlockSize_literal().

◆ 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

Definition at line 156 of file hist.c.

158 {
159  unsigned tmpCounters[HIST_WKSP_SIZE_U32];
160  return HIST_countFast_wksp(count, maxSymbolValuePtr, source, sourceSize, tmpCounters, sizeof(tmpCounters));
161 }
GLuint GLuint GLsizei count
Definition: gl.h:1545
#define HIST_WKSP_SIZE_U32
Definition: hist.h:38
size_t HIST_countFast_wksp(unsigned *count, unsigned *maxSymbolValuePtr, const void *source, size_t sourceSize, void *workSpace, size_t workSpaceSize)
Definition: hist.c:144

◆ 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

Definition at line 144 of file hist.c.

147 {
148  if (sourceSize < 1500) /* heuristic threshold */
149  return HIST_count_simple(count, maxSymbolValuePtr, source, sourceSize);
150  if ((size_t)workSpace & 3) return ERROR(GENERIC); /* must be aligned on 4-bytes boundaries */
151  if (workSpaceSize < HIST_WKSP_SIZE) return ERROR(workSpace_tooSmall);
152  return HIST_count_parallel_wksp(count, maxSymbolValuePtr, source, sourceSize, trustInput, (U32*)workSpace);
153 }
#define HIST_WKSP_SIZE
Definition: hist.h:39
#define ERROR(name)
Definition: error_private.h:53
GLuint GLuint GLsizei count
Definition: gl.h:1545
unsigned HIST_count_simple(unsigned *count, unsigned *maxSymbolValuePtr, const void *src, size_t srcSize)
Definition: hist.c:29
static size_t HIST_count_parallel_wksp(unsigned *count, unsigned *maxSymbolValuePtr, const void *source, size_t sourceSize, HIST_checkInput_e check, U32 *const workSpace)
Definition: hist.c:66
unsigned int U32
Definition: xxhash.c:195

Referenced by HIST_count_wksp(), HIST_countFast(), ZSTD_buildSuperBlockEntropy_sequences(), ZSTD_compressSequences_internal(), and ZSTD_estimateSubBlockSize_symbolType().

◆ HIST_isError()

unsigned HIST_isError ( size_t  code)

tells if a return value is an error code

Definition at line 24 of file hist.c.

24 { return ERR_isError(code); }
ERR_STATIC unsigned ERR_isError(size_t code)
Definition: error_private.h:56
Definition: inflate.c:139