mirror of
https://github.com/TigerVNC/tigervnc.git
synced 2024-08-21 17:54:34 +02:00
![Constantin Kaplinsky](/assets/img/avatar_default.png)
git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4 3789f03b-4d11-0410-bbf8-ca57d06f2519
834 lines
24 KiB
C
834 lines
24 KiB
C
/*
|
|
* jcphuff.c
|
|
*
|
|
* Copyright (C) 1995-1997, Thomas G. Lane.
|
|
* This file is part of the Independent JPEG Group's software.
|
|
* For conditions of distribution and use, see the accompanying README file.
|
|
*
|
|
* This file contains Huffman entropy encoding routines for progressive JPEG.
|
|
*
|
|
* We do not support output suspension in this module, since the library
|
|
* currently does not allow multiple-scan files to be written with output
|
|
* suspension.
|
|
*/
|
|
|
|
#define JPEG_INTERNALS
|
|
#include "jinclude.h"
|
|
#include "jpeglib.h"
|
|
#include "jchuff.h" /* Declarations shared with jchuff.c */
|
|
|
|
#ifdef C_PROGRESSIVE_SUPPORTED
|
|
|
|
/* Expanded entropy encoder object for progressive Huffman encoding. */
|
|
|
|
typedef struct {
|
|
struct jpeg_entropy_encoder pub; /* public fields */
|
|
|
|
/* Mode flag: TRUE for optimization, FALSE for actual data output */
|
|
boolean gather_statistics;
|
|
|
|
/* Bit-level coding status.
|
|
* next_output_byte/free_in_buffer are local copies of cinfo->dest fields.
|
|
*/
|
|
JOCTET * next_output_byte; /* => next byte to write in buffer */
|
|
size_t free_in_buffer; /* # of byte spaces remaining in buffer */
|
|
INT32 put_buffer; /* current bit-accumulation buffer */
|
|
int put_bits; /* # of bits now in it */
|
|
j_compress_ptr cinfo; /* link to cinfo (needed for dump_buffer) */
|
|
|
|
/* Coding status for DC components */
|
|
int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
|
|
|
|
/* Coding status for AC components */
|
|
int ac_tbl_no; /* the table number of the single component */
|
|
unsigned int EOBRUN; /* run length of EOBs */
|
|
unsigned int BE; /* # of buffered correction bits before MCU */
|
|
char * bit_buffer; /* buffer for correction bits (1 per char) */
|
|
/* packing correction bits tightly would save some space but cost time... */
|
|
|
|
unsigned int restarts_to_go; /* MCUs left in this restart interval */
|
|
int next_restart_num; /* next restart number to write (0-7) */
|
|
|
|
/* Pointers to derived tables (these workspaces have image lifespan).
|
|
* Since any one scan codes only DC or only AC, we only need one set
|
|
* of tables, not one for DC and one for AC.
|
|
*/
|
|
c_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
|
|
|
|
/* Statistics tables for optimization; again, one set is enough */
|
|
long * count_ptrs[NUM_HUFF_TBLS];
|
|
} phuff_entropy_encoder;
|
|
|
|
typedef phuff_entropy_encoder * phuff_entropy_ptr;
|
|
|
|
/* MAX_CORR_BITS is the number of bits the AC refinement correction-bit
|
|
* buffer can hold. Larger sizes may slightly improve compression, but
|
|
* 1000 is already well into the realm of overkill.
|
|
* The minimum safe size is 64 bits.
|
|
*/
|
|
|
|
#define MAX_CORR_BITS 1000 /* Max # of correction bits I can buffer */
|
|
|
|
/* IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than INT32.
|
|
* We assume that int right shift is unsigned if INT32 right shift is,
|
|
* which should be safe.
|
|
*/
|
|
|
|
#ifdef RIGHT_SHIFT_IS_UNSIGNED
|
|
#define ISHIFT_TEMPS int ishift_temp;
|
|
#define IRIGHT_SHIFT(x,shft) \
|
|
((ishift_temp = (x)) < 0 ? \
|
|
(ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \
|
|
(ishift_temp >> (shft)))
|
|
#else
|
|
#define ISHIFT_TEMPS
|
|
#define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
|
|
#endif
|
|
|
|
/* Forward declarations */
|
|
METHODDEF(boolean) encode_mcu_DC_first JPP((j_compress_ptr cinfo,
|
|
JBLOCKROW *MCU_data));
|
|
METHODDEF(boolean) encode_mcu_AC_first JPP((j_compress_ptr cinfo,
|
|
JBLOCKROW *MCU_data));
|
|
METHODDEF(boolean) encode_mcu_DC_refine JPP((j_compress_ptr cinfo,
|
|
JBLOCKROW *MCU_data));
|
|
METHODDEF(boolean) encode_mcu_AC_refine JPP((j_compress_ptr cinfo,
|
|
JBLOCKROW *MCU_data));
|
|
METHODDEF(void) finish_pass_phuff JPP((j_compress_ptr cinfo));
|
|
METHODDEF(void) finish_pass_gather_phuff JPP((j_compress_ptr cinfo));
|
|
|
|
|
|
/*
|
|
* Initialize for a Huffman-compressed scan using progressive JPEG.
|
|
*/
|
|
|
|
METHODDEF(void)
|
|
start_pass_phuff (j_compress_ptr cinfo, boolean gather_statistics)
|
|
{
|
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
|
boolean is_DC_band;
|
|
int ci, tbl;
|
|
jpeg_component_info * compptr;
|
|
|
|
entropy->cinfo = cinfo;
|
|
entropy->gather_statistics = gather_statistics;
|
|
|
|
is_DC_band = (cinfo->Ss == 0);
|
|
|
|
/* We assume jcmaster.c already validated the scan parameters. */
|
|
|
|
/* Select execution routines */
|
|
if (cinfo->Ah == 0) {
|
|
if (is_DC_band)
|
|
entropy->pub.encode_mcu = encode_mcu_DC_first;
|
|
else
|
|
entropy->pub.encode_mcu = encode_mcu_AC_first;
|
|
} else {
|
|
if (is_DC_band)
|
|
entropy->pub.encode_mcu = encode_mcu_DC_refine;
|
|
else {
|
|
entropy->pub.encode_mcu = encode_mcu_AC_refine;
|
|
/* AC refinement needs a correction bit buffer */
|
|
if (entropy->bit_buffer == NULL)
|
|
entropy->bit_buffer = (char *)
|
|
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
|
|
MAX_CORR_BITS * SIZEOF(char));
|
|
}
|
|
}
|
|
if (gather_statistics)
|
|
entropy->pub.finish_pass = finish_pass_gather_phuff;
|
|
else
|
|
entropy->pub.finish_pass = finish_pass_phuff;
|
|
|
|
/* Only DC coefficients may be interleaved, so cinfo->comps_in_scan = 1
|
|
* for AC coefficients.
|
|
*/
|
|
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
|
|
compptr = cinfo->cur_comp_info[ci];
|
|
/* Initialize DC predictions to 0 */
|
|
entropy->last_dc_val[ci] = 0;
|
|
/* Get table index */
|
|
if (is_DC_band) {
|
|
if (cinfo->Ah != 0) /* DC refinement needs no table */
|
|
continue;
|
|
tbl = compptr->dc_tbl_no;
|
|
} else {
|
|
entropy->ac_tbl_no = tbl = compptr->ac_tbl_no;
|
|
}
|
|
if (gather_statistics) {
|
|
/* Check for invalid table index */
|
|
/* (make_c_derived_tbl does this in the other path) */
|
|
if (tbl < 0 || tbl >= NUM_HUFF_TBLS)
|
|
ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);
|
|
/* Allocate and zero the statistics tables */
|
|
/* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
|
|
if (entropy->count_ptrs[tbl] == NULL)
|
|
entropy->count_ptrs[tbl] = (long *)
|
|
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
|
|
257 * SIZEOF(long));
|
|
MEMZERO(entropy->count_ptrs[tbl], 257 * SIZEOF(long));
|
|
} else {
|
|
/* Compute derived values for Huffman table */
|
|
/* We may do this more than once for a table, but it's not expensive */
|
|
jpeg_make_c_derived_tbl(cinfo, is_DC_band, tbl,
|
|
& entropy->derived_tbls[tbl]);
|
|
}
|
|
}
|
|
|
|
/* Initialize AC stuff */
|
|
entropy->EOBRUN = 0;
|
|
entropy->BE = 0;
|
|
|
|
/* Initialize bit buffer to empty */
|
|
entropy->put_buffer = 0;
|
|
entropy->put_bits = 0;
|
|
|
|
/* Initialize restart stuff */
|
|
entropy->restarts_to_go = cinfo->restart_interval;
|
|
entropy->next_restart_num = 0;
|
|
}
|
|
|
|
|
|
/* Outputting bytes to the file.
|
|
* NB: these must be called only when actually outputting,
|
|
* that is, entropy->gather_statistics == FALSE.
|
|
*/
|
|
|
|
/* Emit a byte */
|
|
#define emit_byte(entropy,val) \
|
|
{ *(entropy)->next_output_byte++ = (JOCTET) (val); \
|
|
if (--(entropy)->free_in_buffer == 0) \
|
|
dump_buffer(entropy); }
|
|
|
|
|
|
LOCAL(void)
|
|
dump_buffer (phuff_entropy_ptr entropy)
|
|
/* Empty the output buffer; we do not support suspension in this module. */
|
|
{
|
|
struct jpeg_destination_mgr * dest = entropy->cinfo->dest;
|
|
|
|
if (! (*dest->empty_output_buffer) (entropy->cinfo))
|
|
ERREXIT(entropy->cinfo, JERR_CANT_SUSPEND);
|
|
/* After a successful buffer dump, must reset buffer pointers */
|
|
entropy->next_output_byte = dest->next_output_byte;
|
|
entropy->free_in_buffer = dest->free_in_buffer;
|
|
}
|
|
|
|
|
|
/* Outputting bits to the file */
|
|
|
|
/* Only the right 24 bits of put_buffer are used; the valid bits are
|
|
* left-justified in this part. At most 16 bits can be passed to emit_bits
|
|
* in one call, and we never retain more than 7 bits in put_buffer
|
|
* between calls, so 24 bits are sufficient.
|
|
*/
|
|
|
|
INLINE
|
|
LOCAL(void)
|
|
emit_bits (phuff_entropy_ptr entropy, unsigned int code, int size)
|
|
/* Emit some bits, unless we are in gather mode */
|
|
{
|
|
/* This routine is heavily used, so it's worth coding tightly. */
|
|
register INT32 put_buffer = (INT32) code;
|
|
register int put_bits = entropy->put_bits;
|
|
|
|
/* if size is 0, caller used an invalid Huffman table entry */
|
|
if (size == 0)
|
|
ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
|
|
|
|
if (entropy->gather_statistics)
|
|
return; /* do nothing if we're only getting stats */
|
|
|
|
put_buffer &= (((INT32) 1)<<size) - 1; /* mask off any extra bits in code */
|
|
|
|
put_bits += size; /* new number of bits in buffer */
|
|
|
|
put_buffer <<= 24 - put_bits; /* align incoming bits */
|
|
|
|
put_buffer |= entropy->put_buffer; /* and merge with old buffer contents */
|
|
|
|
while (put_bits >= 8) {
|
|
int c = (int) ((put_buffer >> 16) & 0xFF);
|
|
|
|
emit_byte(entropy, c);
|
|
if (c == 0xFF) { /* need to stuff a zero byte? */
|
|
emit_byte(entropy, 0);
|
|
}
|
|
put_buffer <<= 8;
|
|
put_bits -= 8;
|
|
}
|
|
|
|
entropy->put_buffer = put_buffer; /* update variables */
|
|
entropy->put_bits = put_bits;
|
|
}
|
|
|
|
|
|
LOCAL(void)
|
|
flush_bits (phuff_entropy_ptr entropy)
|
|
{
|
|
emit_bits(entropy, 0x7F, 7); /* fill any partial byte with ones */
|
|
entropy->put_buffer = 0; /* and reset bit-buffer to empty */
|
|
entropy->put_bits = 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* Emit (or just count) a Huffman symbol.
|
|
*/
|
|
|
|
INLINE
|
|
LOCAL(void)
|
|
emit_symbol (phuff_entropy_ptr entropy, int tbl_no, int symbol)
|
|
{
|
|
if (entropy->gather_statistics)
|
|
entropy->count_ptrs[tbl_no][symbol]++;
|
|
else {
|
|
c_derived_tbl * tbl = entropy->derived_tbls[tbl_no];
|
|
emit_bits(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Emit bits from a correction bit buffer.
|
|
*/
|
|
|
|
LOCAL(void)
|
|
emit_buffered_bits (phuff_entropy_ptr entropy, char * bufstart,
|
|
unsigned int nbits)
|
|
{
|
|
if (entropy->gather_statistics)
|
|
return; /* no real work */
|
|
|
|
while (nbits > 0) {
|
|
emit_bits(entropy, (unsigned int) (*bufstart), 1);
|
|
bufstart++;
|
|
nbits--;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Emit any pending EOBRUN symbol.
|
|
*/
|
|
|
|
LOCAL(void)
|
|
emit_eobrun (phuff_entropy_ptr entropy)
|
|
{
|
|
register int temp, nbits;
|
|
|
|
if (entropy->EOBRUN > 0) { /* if there is any pending EOBRUN */
|
|
temp = entropy->EOBRUN;
|
|
nbits = 0;
|
|
while ((temp >>= 1))
|
|
nbits++;
|
|
/* safety check: shouldn't happen given limited correction-bit buffer */
|
|
if (nbits > 14)
|
|
ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
|
|
|
|
emit_symbol(entropy, entropy->ac_tbl_no, nbits << 4);
|
|
if (nbits)
|
|
emit_bits(entropy, entropy->EOBRUN, nbits);
|
|
|
|
entropy->EOBRUN = 0;
|
|
|
|
/* Emit any buffered correction bits */
|
|
emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE);
|
|
entropy->BE = 0;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Emit a restart marker & resynchronize predictions.
|
|
*/
|
|
|
|
LOCAL(void)
|
|
emit_restart (phuff_entropy_ptr entropy, int restart_num)
|
|
{
|
|
int ci;
|
|
|
|
emit_eobrun(entropy);
|
|
|
|
if (! entropy->gather_statistics) {
|
|
flush_bits(entropy);
|
|
emit_byte(entropy, 0xFF);
|
|
emit_byte(entropy, JPEG_RST0 + restart_num);
|
|
}
|
|
|
|
if (entropy->cinfo->Ss == 0) {
|
|
/* Re-initialize DC predictions to 0 */
|
|
for (ci = 0; ci < entropy->cinfo->comps_in_scan; ci++)
|
|
entropy->last_dc_val[ci] = 0;
|
|
} else {
|
|
/* Re-initialize all AC-related fields to 0 */
|
|
entropy->EOBRUN = 0;
|
|
entropy->BE = 0;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* MCU encoding for DC initial scan (either spectral selection,
|
|
* or first pass of successive approximation).
|
|
*/
|
|
|
|
METHODDEF(boolean)
|
|
encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
|
|
{
|
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
|
register int temp, temp2;
|
|
register int nbits;
|
|
int blkn, ci;
|
|
int Al = cinfo->Al;
|
|
JBLOCKROW block;
|
|
jpeg_component_info * compptr;
|
|
ISHIFT_TEMPS
|
|
|
|
entropy->next_output_byte = cinfo->dest->next_output_byte;
|
|
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
|
|
|
|
/* Emit restart marker if needed */
|
|
if (cinfo->restart_interval)
|
|
if (entropy->restarts_to_go == 0)
|
|
emit_restart(entropy, entropy->next_restart_num);
|
|
|
|
/* Encode the MCU data blocks */
|
|
for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
|
|
block = MCU_data[blkn];
|
|
ci = cinfo->MCU_membership[blkn];
|
|
compptr = cinfo->cur_comp_info[ci];
|
|
|
|
/* Compute the DC value after the required point transform by Al.
|
|
* This is simply an arithmetic right shift.
|
|
*/
|
|
temp2 = IRIGHT_SHIFT((int) ((*block)[0]), Al);
|
|
|
|
/* DC differences are figured on the point-transformed values. */
|
|
temp = temp2 - entropy->last_dc_val[ci];
|
|
entropy->last_dc_val[ci] = temp2;
|
|
|
|
/* Encode the DC coefficient difference per section G.1.2.1 */
|
|
temp2 = temp;
|
|
if (temp < 0) {
|
|
temp = -temp; /* temp is abs value of input */
|
|
/* For a negative input, want temp2 = bitwise complement of abs(input) */
|
|
/* This code assumes we are on a two's complement machine */
|
|
temp2--;
|
|
}
|
|
|
|
/* Find the number of bits needed for the magnitude of the coefficient */
|
|
nbits = 0;
|
|
while (temp) {
|
|
nbits++;
|
|
temp >>= 1;
|
|
}
|
|
/* Check for out-of-range coefficient values.
|
|
* Since we're encoding a difference, the range limit is twice as much.
|
|
*/
|
|
if (nbits > MAX_COEF_BITS+1)
|
|
ERREXIT(cinfo, JERR_BAD_DCT_COEF);
|
|
|
|
/* Count/emit the Huffman-coded symbol for the number of bits */
|
|
emit_symbol(entropy, compptr->dc_tbl_no, nbits);
|
|
|
|
/* Emit that number of bits of the value, if positive, */
|
|
/* or the complement of its magnitude, if negative. */
|
|
if (nbits) /* emit_bits rejects calls with size 0 */
|
|
emit_bits(entropy, (unsigned int) temp2, nbits);
|
|
}
|
|
|
|
cinfo->dest->next_output_byte = entropy->next_output_byte;
|
|
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
|
|
|
|
/* Update restart-interval state too */
|
|
if (cinfo->restart_interval) {
|
|
if (entropy->restarts_to_go == 0) {
|
|
entropy->restarts_to_go = cinfo->restart_interval;
|
|
entropy->next_restart_num++;
|
|
entropy->next_restart_num &= 7;
|
|
}
|
|
entropy->restarts_to_go--;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
/*
|
|
* MCU encoding for AC initial scan (either spectral selection,
|
|
* or first pass of successive approximation).
|
|
*/
|
|
|
|
METHODDEF(boolean)
|
|
encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
|
|
{
|
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
|
register int temp, temp2;
|
|
register int nbits;
|
|
register int r, k;
|
|
int Se = cinfo->Se;
|
|
int Al = cinfo->Al;
|
|
JBLOCKROW block;
|
|
|
|
entropy->next_output_byte = cinfo->dest->next_output_byte;
|
|
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
|
|
|
|
/* Emit restart marker if needed */
|
|
if (cinfo->restart_interval)
|
|
if (entropy->restarts_to_go == 0)
|
|
emit_restart(entropy, entropy->next_restart_num);
|
|
|
|
/* Encode the MCU data block */
|
|
block = MCU_data[0];
|
|
|
|
/* Encode the AC coefficients per section G.1.2.2, fig. G.3 */
|
|
|
|
r = 0; /* r = run length of zeros */
|
|
|
|
for (k = cinfo->Ss; k <= Se; k++) {
|
|
if ((temp = (*block)[jpeg_natural_order[k]]) == 0) {
|
|
r++;
|
|
continue;
|
|
}
|
|
/* We must apply the point transform by Al. For AC coefficients this
|
|
* is an integer division with rounding towards 0. To do this portably
|
|
* in C, we shift after obtaining the absolute value; so the code is
|
|
* interwoven with finding the abs value (temp) and output bits (temp2).
|
|
*/
|
|
if (temp < 0) {
|
|
temp = -temp; /* temp is abs value of input */
|
|
temp >>= Al; /* apply the point transform */
|
|
/* For a negative coef, want temp2 = bitwise complement of abs(coef) */
|
|
temp2 = ~temp;
|
|
} else {
|
|
temp >>= Al; /* apply the point transform */
|
|
temp2 = temp;
|
|
}
|
|
/* Watch out for case that nonzero coef is zero after point transform */
|
|
if (temp == 0) {
|
|
r++;
|
|
continue;
|
|
}
|
|
|
|
/* Emit any pending EOBRUN */
|
|
if (entropy->EOBRUN > 0)
|
|
emit_eobrun(entropy);
|
|
/* if run length > 15, must emit special run-length-16 codes (0xF0) */
|
|
while (r > 15) {
|
|
emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
|
|
r -= 16;
|
|
}
|
|
|
|
/* Find the number of bits needed for the magnitude of the coefficient */
|
|
nbits = 1; /* there must be at least one 1 bit */
|
|
while ((temp >>= 1))
|
|
nbits++;
|
|
/* Check for out-of-range coefficient values */
|
|
if (nbits > MAX_COEF_BITS)
|
|
ERREXIT(cinfo, JERR_BAD_DCT_COEF);
|
|
|
|
/* Count/emit Huffman symbol for run length / number of bits */
|
|
emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + nbits);
|
|
|
|
/* Emit that number of bits of the value, if positive, */
|
|
/* or the complement of its magnitude, if negative. */
|
|
emit_bits(entropy, (unsigned int) temp2, nbits);
|
|
|
|
r = 0; /* reset zero run length */
|
|
}
|
|
|
|
if (r > 0) { /* If there are trailing zeroes, */
|
|
entropy->EOBRUN++; /* count an EOB */
|
|
if (entropy->EOBRUN == 0x7FFF)
|
|
emit_eobrun(entropy); /* force it out to avoid overflow */
|
|
}
|
|
|
|
cinfo->dest->next_output_byte = entropy->next_output_byte;
|
|
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
|
|
|
|
/* Update restart-interval state too */
|
|
if (cinfo->restart_interval) {
|
|
if (entropy->restarts_to_go == 0) {
|
|
entropy->restarts_to_go = cinfo->restart_interval;
|
|
entropy->next_restart_num++;
|
|
entropy->next_restart_num &= 7;
|
|
}
|
|
entropy->restarts_to_go--;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
/*
|
|
* MCU encoding for DC successive approximation refinement scan.
|
|
* Note: we assume such scans can be multi-component, although the spec
|
|
* is not very clear on the point.
|
|
*/
|
|
|
|
METHODDEF(boolean)
|
|
encode_mcu_DC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
|
|
{
|
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
|
register int temp;
|
|
int blkn;
|
|
int Al = cinfo->Al;
|
|
JBLOCKROW block;
|
|
|
|
entropy->next_output_byte = cinfo->dest->next_output_byte;
|
|
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
|
|
|
|
/* Emit restart marker if needed */
|
|
if (cinfo->restart_interval)
|
|
if (entropy->restarts_to_go == 0)
|
|
emit_restart(entropy, entropy->next_restart_num);
|
|
|
|
/* Encode the MCU data blocks */
|
|
for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
|
|
block = MCU_data[blkn];
|
|
|
|
/* We simply emit the Al'th bit of the DC coefficient value. */
|
|
temp = (*block)[0];
|
|
emit_bits(entropy, (unsigned int) (temp >> Al), 1);
|
|
}
|
|
|
|
cinfo->dest->next_output_byte = entropy->next_output_byte;
|
|
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
|
|
|
|
/* Update restart-interval state too */
|
|
if (cinfo->restart_interval) {
|
|
if (entropy->restarts_to_go == 0) {
|
|
entropy->restarts_to_go = cinfo->restart_interval;
|
|
entropy->next_restart_num++;
|
|
entropy->next_restart_num &= 7;
|
|
}
|
|
entropy->restarts_to_go--;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
/*
|
|
* MCU encoding for AC successive approximation refinement scan.
|
|
*/
|
|
|
|
METHODDEF(boolean)
|
|
encode_mcu_AC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
|
|
{
|
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
|
register int temp;
|
|
register int r, k;
|
|
int EOB;
|
|
char *BR_buffer;
|
|
unsigned int BR;
|
|
int Se = cinfo->Se;
|
|
int Al = cinfo->Al;
|
|
JBLOCKROW block;
|
|
int absvalues[DCTSIZE2];
|
|
|
|
entropy->next_output_byte = cinfo->dest->next_output_byte;
|
|
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
|
|
|
|
/* Emit restart marker if needed */
|
|
if (cinfo->restart_interval)
|
|
if (entropy->restarts_to_go == 0)
|
|
emit_restart(entropy, entropy->next_restart_num);
|
|
|
|
/* Encode the MCU data block */
|
|
block = MCU_data[0];
|
|
|
|
/* It is convenient to make a pre-pass to determine the transformed
|
|
* coefficients' absolute values and the EOB position.
|
|
*/
|
|
EOB = 0;
|
|
for (k = cinfo->Ss; k <= Se; k++) {
|
|
temp = (*block)[jpeg_natural_order[k]];
|
|
/* We must apply the point transform by Al. For AC coefficients this
|
|
* is an integer division with rounding towards 0. To do this portably
|
|
* in C, we shift after obtaining the absolute value.
|
|
*/
|
|
if (temp < 0)
|
|
temp = -temp; /* temp is abs value of input */
|
|
temp >>= Al; /* apply the point transform */
|
|
absvalues[k] = temp; /* save abs value for main pass */
|
|
if (temp == 1)
|
|
EOB = k; /* EOB = index of last newly-nonzero coef */
|
|
}
|
|
|
|
/* Encode the AC coefficients per section G.1.2.3, fig. G.7 */
|
|
|
|
r = 0; /* r = run length of zeros */
|
|
BR = 0; /* BR = count of buffered bits added now */
|
|
BR_buffer = entropy->bit_buffer + entropy->BE; /* Append bits to buffer */
|
|
|
|
for (k = cinfo->Ss; k <= Se; k++) {
|
|
if ((temp = absvalues[k]) == 0) {
|
|
r++;
|
|
continue;
|
|
}
|
|
|
|
/* Emit any required ZRLs, but not if they can be folded into EOB */
|
|
while (r > 15 && k <= EOB) {
|
|
/* emit any pending EOBRUN and the BE correction bits */
|
|
emit_eobrun(entropy);
|
|
/* Emit ZRL */
|
|
emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
|
|
r -= 16;
|
|
/* Emit buffered correction bits that must be associated with ZRL */
|
|
emit_buffered_bits(entropy, BR_buffer, BR);
|
|
BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
|
|
BR = 0;
|
|
}
|
|
|
|
/* If the coef was previously nonzero, it only needs a correction bit.
|
|
* NOTE: a straight translation of the spec's figure G.7 would suggest
|
|
* that we also need to test r > 15. But if r > 15, we can only get here
|
|
* if k > EOB, which implies that this coefficient is not 1.
|
|
*/
|
|
if (temp > 1) {
|
|
/* The correction bit is the next bit of the absolute value. */
|
|
BR_buffer[BR++] = (char) (temp & 1);
|
|
continue;
|
|
}
|
|
|
|
/* Emit any pending EOBRUN and the BE correction bits */
|
|
emit_eobrun(entropy);
|
|
|
|
/* Count/emit Huffman symbol for run length / number of bits */
|
|
emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + 1);
|
|
|
|
/* Emit output bit for newly-nonzero coef */
|
|
temp = ((*block)[jpeg_natural_order[k]] < 0) ? 0 : 1;
|
|
emit_bits(entropy, (unsigned int) temp, 1);
|
|
|
|
/* Emit buffered correction bits that must be associated with this code */
|
|
emit_buffered_bits(entropy, BR_buffer, BR);
|
|
BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
|
|
BR = 0;
|
|
r = 0; /* reset zero run length */
|
|
}
|
|
|
|
if (r > 0 || BR > 0) { /* If there are trailing zeroes, */
|
|
entropy->EOBRUN++; /* count an EOB */
|
|
entropy->BE += BR; /* concat my correction bits to older ones */
|
|
/* We force out the EOB if we risk either:
|
|
* 1. overflow of the EOB counter;
|
|
* 2. overflow of the correction bit buffer during the next MCU.
|
|
*/
|
|
if (entropy->EOBRUN == 0x7FFF || entropy->BE > (MAX_CORR_BITS-DCTSIZE2+1))
|
|
emit_eobrun(entropy);
|
|
}
|
|
|
|
cinfo->dest->next_output_byte = entropy->next_output_byte;
|
|
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
|
|
|
|
/* Update restart-interval state too */
|
|
if (cinfo->restart_interval) {
|
|
if (entropy->restarts_to_go == 0) {
|
|
entropy->restarts_to_go = cinfo->restart_interval;
|
|
entropy->next_restart_num++;
|
|
entropy->next_restart_num &= 7;
|
|
}
|
|
entropy->restarts_to_go--;
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
/*
|
|
* Finish up at the end of a Huffman-compressed progressive scan.
|
|
*/
|
|
|
|
METHODDEF(void)
|
|
finish_pass_phuff (j_compress_ptr cinfo)
|
|
{
|
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
|
|
|
entropy->next_output_byte = cinfo->dest->next_output_byte;
|
|
entropy->free_in_buffer = cinfo->dest->free_in_buffer;
|
|
|
|
/* Flush out any buffered data */
|
|
emit_eobrun(entropy);
|
|
flush_bits(entropy);
|
|
|
|
cinfo->dest->next_output_byte = entropy->next_output_byte;
|
|
cinfo->dest->free_in_buffer = entropy->free_in_buffer;
|
|
}
|
|
|
|
|
|
/*
|
|
* Finish up a statistics-gathering pass and create the new Huffman tables.
|
|
*/
|
|
|
|
METHODDEF(void)
|
|
finish_pass_gather_phuff (j_compress_ptr cinfo)
|
|
{
|
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
|
boolean is_DC_band;
|
|
int ci, tbl;
|
|
jpeg_component_info * compptr;
|
|
JHUFF_TBL **htblptr;
|
|
boolean did[NUM_HUFF_TBLS];
|
|
|
|
/* Flush out buffered data (all we care about is counting the EOB symbol) */
|
|
emit_eobrun(entropy);
|
|
|
|
is_DC_band = (cinfo->Ss == 0);
|
|
|
|
/* It's important not to apply jpeg_gen_optimal_table more than once
|
|
* per table, because it clobbers the input frequency counts!
|
|
*/
|
|
MEMZERO(did, SIZEOF(did));
|
|
|
|
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
|
|
compptr = cinfo->cur_comp_info[ci];
|
|
if (is_DC_band) {
|
|
if (cinfo->Ah != 0) /* DC refinement needs no table */
|
|
continue;
|
|
tbl = compptr->dc_tbl_no;
|
|
} else {
|
|
tbl = compptr->ac_tbl_no;
|
|
}
|
|
if (! did[tbl]) {
|
|
if (is_DC_band)
|
|
htblptr = & cinfo->dc_huff_tbl_ptrs[tbl];
|
|
else
|
|
htblptr = & cinfo->ac_huff_tbl_ptrs[tbl];
|
|
if (*htblptr == NULL)
|
|
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
|
|
jpeg_gen_optimal_table(cinfo, *htblptr, entropy->count_ptrs[tbl]);
|
|
did[tbl] = TRUE;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Module initialization routine for progressive Huffman entropy encoding.
|
|
*/
|
|
|
|
GLOBAL(void)
|
|
jinit_phuff_encoder (j_compress_ptr cinfo)
|
|
{
|
|
phuff_entropy_ptr entropy;
|
|
int i;
|
|
|
|
entropy = (phuff_entropy_ptr)
|
|
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
|
|
SIZEOF(phuff_entropy_encoder));
|
|
cinfo->entropy = (struct jpeg_entropy_encoder *) entropy;
|
|
entropy->pub.start_pass = start_pass_phuff;
|
|
|
|
/* Mark tables unallocated */
|
|
for (i = 0; i < NUM_HUFF_TBLS; i++) {
|
|
entropy->derived_tbls[i] = NULL;
|
|
entropy->count_ptrs[i] = NULL;
|
|
}
|
|
entropy->bit_buffer = NULL; /* needed only in AC refinement scan */
|
|
}
|
|
|
|
#endif /* C_PROGRESSIVE_SUPPORTED */
|