jdhuff.h File Reference

Go to the source code of this file.

Classes
struct	d_derived_tbl
struct	bitread_perm_state
struct	bitread_working_state

Macros
#define	HUFF_LOOKAHEAD   8 /* # of bits of lookahead */
#define	BIT_BUF_SIZE   32 /* size of buffer in bits */
#define	BITREAD_STATE_VARS
#define	BITREAD_LOAD_STATE(cinfop, permstate)
#define	BITREAD_SAVE_STATE(cinfop, permstate)
#define	CHECK_BIT_BUFFER(state, nbits, action)
#define	GET_BITS(nbits)
#define	PEEK_BITS(nbits)
#define	DROP_BITS(nbits)
#define	HUFF_DECODE(result, state, htbl, failaction, slowlabel)

Typedefs
typedef INT32	bit_buf_type

Functions
	EXTERN (void) jpeg_make_d_derived_tbl JPP((j_decompress_ptr cinfo
	EXTERN (boolean) jpeg_fill_bit_buffer JPP((bitread_working_state *state
	EXTERN (int) jpeg_huff_decode JPP((bitread_working_state *state

Variables
boolean	isDC
boolean int	tblno
boolean int d_derived_tbl **	pdtbl
bit_buf_type	get_buffer
bit_buf_type int	bits_left
bit_buf_type int int	nbits
bit_buf_type int d_derived_tbl *	htbl
bit_buf_type int d_derived_tbl int	min_bits

Macro Definition Documentation

BIT_BUF_SIZE

#define BIT_BUF_SIZE   32 /* size of buffer in bits */

BITREAD_LOAD_STATE

#define BITREAD_LOAD_STATE	(		cinfop,
			permstate )

Value:

br_state.cinfo = cinfop; \
br_state.next_input_byte = cinfop->src->next_input_byte; \
br_state.bytes_in_buffer = cinfop->src->bytes_in_buffer; \
get_buffer = permstate.get_buffer; \
bits_left = permstate.bits_left;

BITREAD_SAVE_STATE

#define BITREAD_SAVE_STATE	(		cinfop,
			permstate )

Value:

cinfop->src->next_input_byte = br_state.next_input_byte; \
cinfop->src->bytes_in_buffer = br_state.bytes_in_buffer; \
permstate.get_buffer = get_buffer; \
permstate.bits_left = bits_left

BITREAD_STATE_VARS

#define BITREAD_STATE_VARS

Value:

bit_buf_type get_buffer;  \
int bits_left;  \
bitread_working_state br_state

CHECK_BIT_BUFFER

#define CHECK_BIT_BUFFER	(		state,
			nbits,
			action )

Value:

{ if (bits_left < (nbits)) {  \
    if (! jpeg_fill_bit_buffer(&(state),get_buffer,bits_left,nbits))  \
      { action; }  \
    get_buffer = (state).get_buffer; bits_left = (state).bits_left; } }

DROP_BITS

#define DROP_BITS

(

nbits

)

Value:

(bits_left -= (nbits))

GET_BITS

#define GET_BITS

(

nbits

)

Value:

(((int) (get_buffer >> (bits_left -= (nbits)))) & ((1<<(nbits))-1))

HUFF_DECODE

#define HUFF_DECODE	(		result,
			state,
			htbl,
			failaction,
			slowlabel )

Value:

{ int nb, look; \
  if (bits_left < HUFF_LOOKAHEAD) { \
    if (! jpeg_fill_bit_buffer(&state,get_buffer,bits_left, 0)) {failaction;} \
    get_buffer = state.get_buffer; bits_left = state.bits_left; \
    if (bits_left < HUFF_LOOKAHEAD) { \
      nb = 1; goto slowlabel; \
    } \
  } \
  look = PEEK_BITS(HUFF_LOOKAHEAD); \
  if ((nb = htbl->look_nbits[look]) != 0) { \
    DROP_BITS(nb); \
    result = htbl->look_sym[look]; \
  } else { \
    nb = HUFF_LOOKAHEAD+1; \
slowlabel: \
    if ((result=jpeg_huff_decode(&state,get_buffer,bits_left,htbl,nb)) < 0) \
        { failaction; } \
    get_buffer = state.get_buffer; bits_left = state.bits_left; \
  } \
}

HUFF_LOOKAHEAD

#define HUFF_LOOKAHEAD   8 /* # of bits of lookahead */

PEEK_BITS

#define PEEK_BITS

(

nbits

)

Value:

(((int) (get_buffer >> (bits_left -  (nbits)))) & ((1<<(nbits))-1))

Typedef Documentation

bit_buf_type

typedef INT32 bit_buf_type

Function Documentation

EXTERN() [1/3]

EXTERN

(

boolean

)

EXTERN() [2/3]

EXTERN

(

int

)

EXTERN() [3/3]

EXTERN

(

void

)

Variable Documentation

bits_left

bit_buf_type int bits_left

get_buffer

bit_buf_type get_buffer

htbl

bit_buf_type int d_derived_tbl* htbl

isDC

boolean isDC

min_bits

bit_buf_type int d_derived_tbl int min_bits

nbits

bit_buf_type int int nbits

pdtbl

boolean int d_derived_tbl** pdtbl

tblno

boolean int tblno