791 lines
24 KiB
C++
791 lines
24 KiB
C++
// * jcphuff.c
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// *
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// * Copyright (C) 1995, Thomas G. Lane.
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// * This file is part of the Independent JPEG Group's software.
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// * For conditions of distribution and use, see the accompanying README file.
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// *
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// * This file contains Huffman entropy encoding routines for progressive JPEG.
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// *
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// * We do not support output suspension in this module, since the library
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// * currently does not allow multiple-scan files to be written with output
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// * suspension.
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#define JPEG_INTERNALS
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#include "JINCLUDE.h"
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#include "JPEGLIB.h"
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#include "JCHUFF.h" // Declarations shared with jchuff.c
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#ifdef C_PROGRESSIVE_SUPPORTED
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// Expanded entropy encoder object for progressive Huffman encoding.
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typedef struct {
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struct jpeg_entropy_encoder pub; // public fields
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// Mode flag: TRUE for optimization, FALSE for actual data output
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boolean gather_statistics;
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// Bit-level coding status.
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// * next_output_byte/free_in_buffer are local copies of cinfo->dest fields.
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JOCTET * next_output_byte; // => next byte to write in buffer
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size_t free_in_buffer; // # of byte spaces remaining in buffer
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INT32 put_buffer; // current bit-accumulation buffer
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int put_bits; // # of bits now in it
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j_compress_ptr cinfo; // link to cinfo (needed for dump_buffer)
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// Coding status for DC components
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int last_dc_val[MAX_COMPS_IN_SCAN]; // last DC coef for each component
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// Coding status for AC components
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int ac_tbl_no; // the table number of the single component
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unsigned int EOBRUN; // run length of EOBs
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unsigned int BE; // # of buffered correction bits before MCU
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char * bit_buffer; // buffer for correction bits (1 per char)
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// packing correction bits tightly would save some space but cost time...
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unsigned int restarts_to_go; // MCUs left in this restart interval
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int next_restart_num; // next restart number to write (0-7)
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// Pointers to derived tables (these workspaces have image lifespan).
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// * Since any one scan codes only DC or only AC, we only need one set
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// * of tables, not one for DC and one for AC.
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c_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
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// Statistics tables for optimization; again, one set is enough
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LONG * count_ptrs[NUM_HUFF_TBLS];
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} phuff_entropy_encoder;
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typedef phuff_entropy_encoder * phuff_entropy_ptr;
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// MAX_CORR_BITS is the number of bits the AC refinement correction-bit
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// * buffer can hold. Larger sizes may slightly improve compression, but
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// * 1000 is already well into the realm of overkill.
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// * The minimum safe size is 64 bits.
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#define MAX_CORR_BITS 1000 // Max # of correction bits I can buffer
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// IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than INT32.
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// * We assume that int right shift is unsigned if INT32 right shift is,
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// * which should be safe.
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#ifdef RIGHT_SHIFT_IS_UNSIGNED
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#define ISHIFT_TEMPS int ishift_temp;
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#define IRIGHT_SHIFT(x,shft) \
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((ishift_temp = (x)) < 0 ? \
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(ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \
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(ishift_temp >> (shft)))
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#else
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#define ISHIFT_TEMPS
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#define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
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#endif
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// Forward declarations
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METHODDEF boolean encode_mcu_DC_first JPP((j_compress_ptr cinfo,
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JBLOCKROW *MCU_data));
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METHODDEF boolean encode_mcu_AC_first JPP((j_compress_ptr cinfo,
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JBLOCKROW *MCU_data));
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METHODDEF boolean encode_mcu_DC_refine JPP((j_compress_ptr cinfo,
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JBLOCKROW *MCU_data));
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METHODDEF boolean encode_mcu_AC_refine JPP((j_compress_ptr cinfo,
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JBLOCKROW *MCU_data));
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METHODDEF void finish_pass_phuff JPP((j_compress_ptr cinfo));
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METHODDEF void finish_pass_gather_phuff JPP((j_compress_ptr cinfo));
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// * Initialize for a Huffman-compressed scan using progressive JPEG.
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METHODDEF void
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start_pass_phuff (j_compress_ptr cinfo, boolean gather_statistics)
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{
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phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
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boolean is_DC_band;
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int ci, tbl;
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jpeg_component_info * compptr;
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entropy->cinfo = cinfo;
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entropy->gather_statistics = gather_statistics;
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is_DC_band = (cinfo->Ss == 0);
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// We assume jcmaster.c already validated the scan parameters.
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// Select execution routines
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if (cinfo->Ah == 0) {
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if (is_DC_band)
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entropy->pub.encode_mcu = encode_mcu_DC_first;
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else
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entropy->pub.encode_mcu = encode_mcu_AC_first;
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} else {
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if (is_DC_band)
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entropy->pub.encode_mcu = encode_mcu_DC_refine;
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else {
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entropy->pub.encode_mcu = encode_mcu_AC_refine;
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// AC refinement needs a correction bit buffer
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if (entropy->bit_buffer == NULL)
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entropy->bit_buffer = (char *)
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
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MAX_CORR_BITS * SIZEOF(char));
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}
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}
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if (gather_statistics)
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entropy->pub.finish_pass = finish_pass_gather_phuff;
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else
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entropy->pub.finish_pass = finish_pass_phuff;
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// Only DC coefficients may be interleaved, so cinfo->comps_in_scan = 1
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// * for AC coefficients.
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for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
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compptr = cinfo->cur_comp_info[ci];
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// Initialize DC predictions to 0
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entropy->last_dc_val[ci] = 0;
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// Make sure requested tables are present
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// (In gather mode, tables need not be allocated yet)
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if (is_DC_band) {
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if (cinfo->Ah != 0) // DC refinement needs no table
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continue;
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tbl = compptr->dc_tbl_no;
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if (tbl < 0 || tbl >= NUM_HUFF_TBLS ||
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(cinfo->dc_huff_tbl_ptrs[tbl] == NULL && !gather_statistics))
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ERREXIT1(cinfo,JERR_NO_HUFF_TABLE, tbl);
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} else {
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entropy->ac_tbl_no = tbl = compptr->ac_tbl_no;
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if (tbl < 0 || tbl >= NUM_HUFF_TBLS ||
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(cinfo->ac_huff_tbl_ptrs[tbl] == NULL && !gather_statistics))
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ERREXIT1(cinfo,JERR_NO_HUFF_TABLE, tbl);
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}
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if (gather_statistics) {
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// Allocate and zero the statistics tables
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// Note that jpeg_gen_optimal_table expects 257 entries in each table!
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if (entropy->count_ptrs[tbl] == NULL)
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entropy->count_ptrs[tbl] = (LONG *)
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(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
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257 * SIZEOF(LONG));
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MEMZERO(entropy->count_ptrs[tbl], 257 * SIZEOF(LONG));
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} else {
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// Compute derived values for Huffman tables
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// We may do this more than once for a table, but it's not expensive
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if (is_DC_band)
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jpeg_make_c_derived_tbl(cinfo, cinfo->dc_huff_tbl_ptrs[tbl],
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& entropy->derived_tbls[tbl]);
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else
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jpeg_make_c_derived_tbl(cinfo, cinfo->ac_huff_tbl_ptrs[tbl],
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& entropy->derived_tbls[tbl]);
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}
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}
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// Initialize AC stuff
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entropy->EOBRUN = 0;
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entropy->BE = 0;
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// Initialize bit buffer to empty
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entropy->put_buffer = 0;
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entropy->put_bits = 0;
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// Initialize restart stuff
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entropy->restarts_to_go = cinfo->restart_interval;
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entropy->next_restart_num = 0;
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}
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// Outputting bytes to the file.
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// * NB: these must be called only when actually outputting,
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// * that is, entropy->gather_statistics == FALSE.
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// Emit a byte
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#define emit_byte(entropy,val) \
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{ *(entropy)->next_output_byte++ = (JOCTET) (val); \
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if (--(entropy)->free_in_buffer == 0) \
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dump_buffer(entropy); }
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LOCAL void
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dump_buffer (phuff_entropy_ptr entropy)
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// Empty the output buffer; we do not support suspension in this module.
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{
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struct jpeg_destination_mgr * dest = entropy->cinfo->dest;
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if (! (*dest->empty_output_buffer) (entropy->cinfo))
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ERREXIT(entropy->cinfo, JERR_CANT_SUSPEND);
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// After a successful buffer dump, must reset buffer pointers
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entropy->next_output_byte = dest->next_output_byte;
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entropy->free_in_buffer = dest->free_in_buffer;
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}
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// Outputting bits to the file
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// Only the right 24 bits of put_buffer are used; the valid bits are
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// * left-justified in this part. At most 16 bits can be passed to emit_bits
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// * in one call, and we never retain more than 7 bits in put_buffer
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// * between calls, so 24 bits are sufficient.
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INLINE
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LOCAL void
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emit_bits (phuff_entropy_ptr entropy, unsigned int code, int size)
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// Emit some bits, unless we are in gather mode
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{
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// This routine is heavily used, so it's worth coding tightly.
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register INT32 put_buffer = (INT32) code;
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register int put_bits = entropy->put_bits;
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// if size is 0, caller used an invalid Huffman table entry
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if (size == 0)
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ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
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if (entropy->gather_statistics)
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return; // do nothing if we're only getting stats
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put_buffer &= (((INT32) 1)<<size) - 1; // mask off any extra bits in code
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put_bits += size; // new number of bits in buffer
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put_buffer <<= 24 - put_bits; // align incoming bits
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put_buffer |= entropy->put_buffer; // and merge with old buffer contents
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while (put_bits >= 8) {
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int c = (int) ((put_buffer >> 16) & 0xFF);
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emit_byte(entropy, c);
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if (c == 0xFF) { // need to stuff a zero byte?
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emit_byte(entropy, 0);
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}
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put_buffer <<= 8;
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put_bits -= 8;
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}
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entropy->put_buffer = put_buffer; // update variables
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entropy->put_bits = put_bits;
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}
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LOCAL void
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flush_bits (phuff_entropy_ptr entropy)
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{
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emit_bits(entropy, 0x7F, 7); // fill any partial byte with ones
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entropy->put_buffer = 0; // and reset bit-buffer to empty
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entropy->put_bits = 0;
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}
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// * Emit (or just count) a Huffman symbol.
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INLINE
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LOCAL void
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emit_symbol (phuff_entropy_ptr entropy, int tbl_no, int symbol)
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{
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if (entropy->gather_statistics)
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entropy->count_ptrs[tbl_no][symbol]++;
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else {
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c_derived_tbl * tbl = entropy->derived_tbls[tbl_no];
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emit_bits(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
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}
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}
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// * Emit bits from a correction bit buffer.
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LOCAL void
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emit_buffered_bits (phuff_entropy_ptr entropy, char * bufstart,
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unsigned int nbits)
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{
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if (entropy->gather_statistics)
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return; // no real work
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while (nbits > 0) {
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emit_bits(entropy, (unsigned int) (*bufstart), 1);
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bufstart++;
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nbits--;
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}
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}
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// * Emit any pending EOBRUN symbol.
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LOCAL void
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emit_eobrun (phuff_entropy_ptr entropy)
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{
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register int temp, nbits;
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if (entropy->EOBRUN > 0) { // if there is any pending EOBRUN
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temp = entropy->EOBRUN;
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nbits = 0;
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while ((temp >>= 1))
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nbits++;
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emit_symbol(entropy, entropy->ac_tbl_no, nbits << 4);
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if (nbits)
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emit_bits(entropy, entropy->EOBRUN, nbits);
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entropy->EOBRUN = 0;
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// Emit any buffered correction bits
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emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE);
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entropy->BE = 0;
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}
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}
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// * Emit a restart marker & resynchronize predictions.
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LOCAL void
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emit_restart (phuff_entropy_ptr entropy, int restart_num)
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{
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int ci;
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emit_eobrun(entropy);
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if (! entropy->gather_statistics) {
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flush_bits(entropy);
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emit_byte(entropy, 0xFF);
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emit_byte(entropy, JPEG_RST0 + restart_num);
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}
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if (entropy->cinfo->Ss == 0) {
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// Re-initialize DC predictions to 0
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for (ci = 0; ci < entropy->cinfo->comps_in_scan; ci++)
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entropy->last_dc_val[ci] = 0;
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} else {
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// Re-initialize all AC-related fields to 0
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entropy->EOBRUN = 0;
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entropy->BE = 0;
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}
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}
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// * MCU encoding for DC initial scan (either spectral selection,
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// * or first pass of successive approximation).
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METHODDEF boolean
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encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
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{
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phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
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register int temp, temp2;
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register int nbits;
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int blkn, ci;
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int Al = cinfo->Al;
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JBLOCKROW block;
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jpeg_component_info * compptr;
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ISHIFT_TEMPS
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entropy->next_output_byte = cinfo->dest->next_output_byte;
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entropy->free_in_buffer = cinfo->dest->free_in_buffer;
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// Emit restart marker if needed
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if (cinfo->restart_interval)
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if (entropy->restarts_to_go == 0)
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emit_restart(entropy, entropy->next_restart_num);
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// Encode the MCU data blocks
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for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
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block = MCU_data[blkn];
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ci = cinfo->MCU_membership[blkn];
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compptr = cinfo->cur_comp_info[ci];
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// Compute the DC value after the required point transform by Al.
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// * This is simply an arithmetic right shift.
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temp2 = IRIGHT_SHIFT((int) ((*block)[0]), Al);
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// DC differences are figured on the point-transformed values.
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temp = temp2 - entropy->last_dc_val[ci];
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entropy->last_dc_val[ci] = temp2;
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// Encode the DC coefficient difference per section G.1.2.1
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temp2 = temp;
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if (temp < 0) {
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temp = -temp; // temp is abs value of input
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// For a negative input, want temp2 = bitwise complement of abs(input)
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// This code assumes we are on a two's complement machine
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temp2--;
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}
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// Find the number of bits needed for the magnitude of the coefficient
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nbits = 0;
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while (temp) {
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nbits++;
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temp >>= 1;
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}
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// Count/emit the Huffman-coded symbol for the number of bits
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emit_symbol(entropy, compptr->dc_tbl_no, nbits);
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// Emit that number of bits of the value, if positive,
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// or the complement of its magnitude, if negative.
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if (nbits) // emit_bits rejects calls with size 0
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emit_bits(entropy, (unsigned int) temp2, nbits);
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}
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cinfo->dest->next_output_byte = entropy->next_output_byte;
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cinfo->dest->free_in_buffer = entropy->free_in_buffer;
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// Update restart-interval state too
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if (cinfo->restart_interval) {
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if (entropy->restarts_to_go == 0) {
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entropy->restarts_to_go = cinfo->restart_interval;
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entropy->next_restart_num++;
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entropy->next_restart_num &= 7;
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}
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entropy->restarts_to_go--;
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}
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return TRUE;
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}
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// * MCU encoding for AC initial scan (either spectral selection,
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// * or first pass of successive approximation).
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METHODDEF boolean
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encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
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{
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phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
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register int temp, temp2;
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register int nbits;
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register int r, k;
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int Se = cinfo->Se;
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int Al = cinfo->Al;
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JBLOCKROW block;
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entropy->next_output_byte = cinfo->dest->next_output_byte;
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entropy->free_in_buffer = cinfo->dest->free_in_buffer;
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// Emit restart marker if needed
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if (cinfo->restart_interval)
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if (entropy->restarts_to_go == 0)
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emit_restart(entropy, entropy->next_restart_num);
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// Encode the MCU data block
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block = MCU_data[0];
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// Encode the AC coefficients per section G.1.2.2, fig. G.3
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r = 0; // r = run length of zeros
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for (k = cinfo->Ss; k <= Se; k++) {
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if ((temp = (*block)[jpeg_natural_order[k]]) == 0) {
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r++;
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continue;
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}
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// We must apply the point transform by Al. For AC coefficients this
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// * is an integer division with rounding towards 0. To do this portably
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// * in C, we shift after obtaining the absolute value; so the code is
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// * interwoven with finding the abs value (temp) and output bits (temp2).
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if (temp < 0) {
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temp = -temp; // temp is abs value of input
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temp >>= Al; // apply the point transform
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// For a negative coef, want temp2 = bitwise complement of abs(coef)
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temp2 = ~temp;
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} else {
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temp >>= Al; // apply the point transform
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temp2 = temp;
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}
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// Watch out for case that nonzero coef is zero after point transform
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if (temp == 0) {
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r++;
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continue;
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}
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// Emit any pending EOBRUN
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if (entropy->EOBRUN > 0)
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emit_eobrun(entropy);
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// if run length > 15, must emit special run-length-16 codes (0xF0)
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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++;
|
|
|
|
// 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
|