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)   (((int) (get_buffer >> (bits_left -= (nbits)))) & ((1<<(nbits))-1))
#define	PEEK_BITS(nbits)   (((int) (get_buffer >> (bits_left - (nbits)))) & ((1<<(nbits))-1))
#define	DROP_BITS(nbits)   (bits_left -= (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, JHUFF_TBL *htbl, d_derived_tbl **pdtbl))
EXTERN boolean jpeg_fill_bit_buffer	JPP ((bitread_working_state *state, register bit_buf_type get_buffer, register int bits_left, int nbits))
EXTERN int jpeg_huff_decode	JPP ((bitread_working_state *state, register bit_buf_type get_buffer, register int bits_left, d_derived_tbl *htbl, int min_bits))

Macro Definition Documentation

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

Definition at line 69 of file jdhuff.h.

#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; \
        br_state.unread_marker = cinfop->unread_marker; \
        get_buffer = permstate.get_buffer; \
        bits_left = permstate.bits_left; \
        br_state.printed_eod_ptr = & permstate.printed_eod

Definition at line 105 of file jdhuff.h.

#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; \
        cinfop->unread_marker = br_state.unread_marker; \
        permstate.get_buffer = get_buffer; \
        permstate.bits_left = bits_left

Definition at line 114 of file jdhuff.h.

#define BITREAD_STATE_VARS

Value:

register bit_buf_type get_buffer;  \
        register int bits_left;  \
        bitread_working_state br_state

Definition at line 100 of file jdhuff.h.

#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; } }

Definition at line 139 of file jdhuff.h.

#define DROP_BITS

(

nbits

)

(bits_left -= (nbits))

Definition at line 151 of file jdhuff.h.

#define GET_BITS

(

nbits

)

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

Definition at line 145 of file jdhuff.h.

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

Value:

{ register 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; \
  } \
}

Definition at line 177 of file jdhuff.h.

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

Definition at line 24 of file jdhuff.h.

#define PEEK_BITS

(

nbits

)

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

Definition at line 148 of file jdhuff.h.

Typedef Documentation

typedef INT32 bit_buf_type

Definition at line 68 of file jdhuff.h.

Function Documentation

EXTERN void jpeg_make_d_derived_tbl JPP

(

(j_decompress_ptr cinfo, JHUFF_TBL *htbl, d_derived_tbl **pdtbl)

)

EXTERN boolean jpeg_fill_bit_buffer JPP

(

(bitread_working_state *state, register bit_buf_type get_buffer, register int bits_left, int nbits)

)

EXTERN int jpeg_huff_decode JPP

(

(bitread_working_state *state, register bit_buf_type get_buffer, register int bits_left, d_derived_tbl *htbl, int min_bits)

)