#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* 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 */ | |
#endif //_FX_JPEG_TURBO_ |