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The Independent JPEG Group's JPEG software v6

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This commit is contained in:
Thomas G. Lane
1995-08-02 00:00:00 +00:00
committed by DRC
parent a8b67c4fbb
commit bc79e0680a
88 changed files with 9850 additions and 3723 deletions
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67
jchuff.c
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@@ -1,7 +1,7 @@
/*
* jchuff.c
*
* Copyright (C) 1991-1994, Thomas G. Lane.
* Copyright (C) 1991-1995, 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.
*
@@ -17,16 +17,9 @@
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jchuff.h" /* Declarations shared with jcphuff.c */
/* Derived data constructed for each Huffman table */
typedef struct {
unsigned int ehufco[256]; /* code for each symbol */
char ehufsi[256]; /* length of code for each symbol */
/* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */
} C_DERIVED_TBL;
/* Expanded entropy encoder object for Huffman encoding.
*
* The savable_state subrecord contains fields that change within an MCU,
@@ -69,8 +62,8 @@ typedef struct {
int next_restart_num; /* next restart number to write (0-7) */
/* Pointers to derived tables (these workspaces have image lifespan) */
C_DERIVED_TBL * dc_derived_tbls[NUM_HUFF_TBLS];
C_DERIVED_TBL * ac_derived_tbls[NUM_HUFF_TBLS];
c_derived_tbl * dc_derived_tbls[NUM_HUFF_TBLS];
c_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS];
#ifdef ENTROPY_OPT_SUPPORTED /* Statistics tables for optimization */
long * dc_count_ptrs[NUM_HUFF_TBLS];
@@ -101,8 +94,6 @@ METHODDEF boolean encode_mcu_gather JPP((j_compress_ptr cinfo,
JBLOCKROW *MCU_data));
METHODDEF void finish_pass_gather JPP((j_compress_ptr cinfo));
#endif
LOCAL void fix_huff_tbl JPP((j_compress_ptr cinfo, JHUFF_TBL * htbl,
C_DERIVED_TBL ** pdtbl));
/*
@@ -145,7 +136,7 @@ start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics)
if (gather_statistics) {
#ifdef ENTROPY_OPT_SUPPORTED
/* Allocate and zero the statistics tables */
/* Note that gen_huff_coding expects 257 entries in each table! */
/* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
if (entropy->dc_count_ptrs[dctbl] == NULL)
entropy->dc_count_ptrs[dctbl] = (long *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
@@ -160,10 +151,10 @@ start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics)
} else {
/* Compute derived values for Huffman tables */
/* We may do this more than once for a table, but it's not expensive */
fix_huff_tbl(cinfo, cinfo->dc_huff_tbl_ptrs[dctbl],
& entropy->dc_derived_tbls[dctbl]);
fix_huff_tbl(cinfo, cinfo->ac_huff_tbl_ptrs[actbl],
& entropy->ac_derived_tbls[actbl]);
jpeg_make_c_derived_tbl(cinfo, cinfo->dc_huff_tbl_ptrs[dctbl],
& entropy->dc_derived_tbls[dctbl]);
jpeg_make_c_derived_tbl(cinfo, cinfo->ac_huff_tbl_ptrs[actbl],
& entropy->ac_derived_tbls[actbl]);
}
/* Initialize DC predictions to 0 */
entropy->saved.last_dc_val[ci] = 0;
@@ -179,11 +170,16 @@ start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics)
}
LOCAL void
fix_huff_tbl (j_compress_ptr cinfo, JHUFF_TBL * htbl, C_DERIVED_TBL ** pdtbl)
/* Compute the derived values for a Huffman table */
/*
* Compute the derived values for a Huffman table.
* Note this is also used by jcphuff.c.
*/
GLOBAL void
jpeg_make_c_derived_tbl (j_compress_ptr cinfo, JHUFF_TBL * htbl,
c_derived_tbl ** pdtbl)
{
C_DERIVED_TBL *dtbl;
c_derived_tbl *dtbl;
int p, i, l, lastp, si;
char huffsize[257];
unsigned int huffcode[257];
@@ -191,9 +187,9 @@ fix_huff_tbl (j_compress_ptr cinfo, JHUFF_TBL * htbl, C_DERIVED_TBL ** pdtbl)
/* Allocate a workspace if we haven't already done so. */
if (*pdtbl == NULL)
*pdtbl = (C_DERIVED_TBL *)
*pdtbl = (c_derived_tbl *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(C_DERIVED_TBL));
SIZEOF(c_derived_tbl));
dtbl = *pdtbl;
/* Figure C.1: make table of Huffman code length for each symbol */
@@ -324,7 +320,7 @@ flush_bits (working_state * state)
LOCAL boolean
encode_one_block (working_state * state, JCOEFPTR block, int last_dc_val,
C_DERIVED_TBL *dctbl, C_DERIVED_TBL *actbl)
c_derived_tbl *dctbl, c_derived_tbl *actbl)
{
register int temp, temp2;
register int nbits;
@@ -363,7 +359,7 @@ encode_one_block (working_state * state, JCOEFPTR block, int last_dc_val,
r = 0; /* r = run length of zeros */
for (k = 1; k < DCTSIZE2; k++) {
if ((temp = block[k]) == 0) {
if ((temp = block[jpeg_natural_order[k]]) == 0) {
r++;
} else {
/* if run length > 15, must emit special run-length-16 codes (0xF0) */
@@ -569,7 +565,7 @@ htest_one_block (JCOEFPTR block, int last_dc_val,
r = 0; /* r = run length of zeros */
for (k = 1; k < DCTSIZE2; k++) {
if ((temp = block[k]) == 0) {
if ((temp = block[jpeg_natural_order[k]]) == 0) {
r++;
} else {
/* if run length > 15, must emit special run-length-16 codes (0xF0) */
@@ -637,10 +633,13 @@ encode_mcu_gather (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
}
/* Generate the optimal coding for the given counts, initialize htbl */
/*
* Generate the optimal coding for the given counts, fill htbl.
* Note this is also used by jcphuff.c.
*/
LOCAL void
gen_huff_coding (j_compress_ptr cinfo, JHUFF_TBL *htbl, long freq[])
GLOBAL void
jpeg_gen_optimal_table (j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[])
{
#define MAX_CLEN 32 /* assumed maximum initial code length */
UINT8 bits[MAX_CLEN+1]; /* bits[k] = # of symbols with code length k */
@@ -790,8 +789,8 @@ finish_pass_gather (j_compress_ptr cinfo)
boolean did_dc[NUM_HUFF_TBLS];
boolean did_ac[NUM_HUFF_TBLS];
/* It's important not to apply gen_huff_coding more than once per table,
* because it clobbers the input frequency counts!
/* It's important not to apply jpeg_gen_optimal_table more than once
* per table, because it clobbers the input frequency counts!
*/
MEMZERO(did_dc, SIZEOF(did_dc));
MEMZERO(did_ac, SIZEOF(did_ac));
@@ -804,14 +803,14 @@ finish_pass_gather (j_compress_ptr cinfo)
htblptr = & cinfo->dc_huff_tbl_ptrs[dctbl];
if (*htblptr == NULL)
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
gen_huff_coding(cinfo, *htblptr, entropy->dc_count_ptrs[dctbl]);
jpeg_gen_optimal_table(cinfo, *htblptr, entropy->dc_count_ptrs[dctbl]);
did_dc[dctbl] = TRUE;
}
if (! did_ac[actbl]) {
htblptr = & cinfo->ac_huff_tbl_ptrs[actbl];
if (*htblptr == NULL)
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
gen_huff_coding(cinfo, *htblptr, entropy->ac_count_ptrs[actbl]);
jpeg_gen_optimal_table(cinfo, *htblptr, entropy->ac_count_ptrs[actbl]);
did_ac[actbl] = TRUE;
}
}