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-rw-r--r--libjpegtwrp/jdphuff.c770
1 files changed, 0 insertions, 770 deletions
diff --git a/libjpegtwrp/jdphuff.c b/libjpegtwrp/jdphuff.c
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index 2f856e07b..000000000
--- a/libjpegtwrp/jdphuff.c
+++ /dev/null
@@ -1,770 +0,0 @@
-/*
- * jdphuff.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 decoding routines for progressive JPEG.
- *
- * Much of the complexity here has to do with supporting input suspension.
- * If the data source module demands suspension, we want to be able to back
- * up to the start of the current MCU. To do this, we copy state variables
- * into local working storage, and update them back to the permanent
- * storage only upon successful completion of an MCU.
- */
-
-#define JPEG_INTERNALS
-#include "jinclude.h"
-#include "jpeglib.h"
-#include "jdhuff.h" /* Declarations shared with jdhuff.c */
-
-
-#ifdef D_PROGRESSIVE_SUPPORTED
-
-/*
- * Expanded entropy decoder object for progressive Huffman decoding.
- *
- * The savable_state subrecord contains fields that change within an MCU,
- * but must not be updated permanently until we complete the MCU.
- */
-
-typedef struct {
- unsigned int EOBRUN; /* remaining EOBs in EOBRUN */
- int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
-} savable_state;
-
-/* This macro is to work around compilers with missing or broken
- * structure assignment. You'll need to fix this code if you have
- * such a compiler and you change MAX_COMPS_IN_SCAN.
- */
-
-#ifndef NO_STRUCT_ASSIGN
-#define ASSIGN_STATE(dest,src) ((dest) = (src))
-#else
-#if MAX_COMPS_IN_SCAN == 4
-#define ASSIGN_STATE(dest,src) \
- ((dest).EOBRUN = (src).EOBRUN, \
- (dest).last_dc_val[0] = (src).last_dc_val[0], \
- (dest).last_dc_val[1] = (src).last_dc_val[1], \
- (dest).last_dc_val[2] = (src).last_dc_val[2], \
- (dest).last_dc_val[3] = (src).last_dc_val[3])
-#endif
-#endif
-
-
-typedef struct {
- struct jpeg_entropy_decoder pub; /* public fields */
-
- /* These fields are loaded into local variables at start of each MCU.
- * In case of suspension, we exit WITHOUT updating them.
- */
- bitread_perm_state bitstate; /* Bit buffer at start of MCU */
- savable_state saved; /* Other state at start of MCU */
-
- /* These fields are NOT loaded into local working state. */
- unsigned int restarts_to_go; /* MCUs left in this restart interval */
-
- /* Pointers to derived tables (these workspaces have image lifespan) */
- d_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
-
- d_derived_tbl * ac_derived_tbl; /* active table during an AC scan */
-} phuff_entropy_decoder;
-
-typedef phuff_entropy_decoder * phuff_entropy_ptr;
-
-/* Forward declarations */
-METHODDEF(boolean) decode_mcu_DC_first JPP((j_decompress_ptr cinfo,
- JBLOCKROW *MCU_data));
-METHODDEF(boolean) decode_mcu_AC_first JPP((j_decompress_ptr cinfo,
- JBLOCKROW *MCU_data));
-METHODDEF(boolean) decode_mcu_DC_refine JPP((j_decompress_ptr cinfo,
- JBLOCKROW *MCU_data));
-METHODDEF(boolean) decode_mcu_AC_refine JPP((j_decompress_ptr cinfo,
- JBLOCKROW *MCU_data));
-
-/*
- * Initialize for a Huffman-compressed scan.
- */
-
-METHODDEF(void)
-start_pass_phuff_decoder (j_decompress_ptr cinfo)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- boolean is_DC_band, bad;
- int ci, coefi, tbl;
- int *coef_bit_ptr;
- jpeg_component_info * compptr;
-
- is_DC_band = (cinfo->Ss == 0);
-
- /* Validate scan parameters */
- bad = FALSE;
- if (is_DC_band) {
- if (cinfo->Se != 0)
- bad = TRUE;
- } else {
- /* need not check Ss/Se < 0 since they came from unsigned bytes */
- if (cinfo->Ss > cinfo->Se || cinfo->Se >= DCTSIZE2)
- bad = TRUE;
- /* AC scans may have only one component */
- if (cinfo->comps_in_scan != 1)
- bad = TRUE;
- }
- if (cinfo->Ah != 0) {
- /* Successive approximation refinement scan: must have Al = Ah-1. */
- if (cinfo->Al != cinfo->Ah-1)
- bad = TRUE;
- }
- if (cinfo->Al > 13) /* need not check for < 0 */
- bad = TRUE;
- /* Arguably the maximum Al value should be less than 13 for 8-bit precision,
- * but the spec doesn't say so, and we try to be liberal about what we
- * accept. Note: large Al values could result in out-of-range DC
- * coefficients during early scans, leading to bizarre displays due to
- * overflows in the IDCT math. But we won't crash.
- */
- if (bad)
- ERREXIT4(cinfo, JERR_BAD_PROGRESSION,
- cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al);
- /* Update progression status, and verify that scan order is legal.
- * Note that inter-scan inconsistencies are treated as warnings
- * not fatal errors ... not clear if this is right way to behave.
- */
- for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
- int cindex = cinfo->cur_comp_info[ci]->component_index;
- coef_bit_ptr = & cinfo->coef_bits[cindex][0];
- if (!is_DC_band && coef_bit_ptr[0] < 0) /* AC without prior DC scan */
- WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, 0);
- for (coefi = cinfo->Ss; coefi <= cinfo->Se; coefi++) {
- int expected = (coef_bit_ptr[coefi] < 0) ? 0 : coef_bit_ptr[coefi];
- if (cinfo->Ah != expected)
- WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, coefi);
- coef_bit_ptr[coefi] = cinfo->Al;
- }
- }
-
- /* Select MCU decoding routine */
- if (cinfo->Ah == 0) {
- if (is_DC_band)
- entropy->pub.decode_mcu = decode_mcu_DC_first;
- else
- entropy->pub.decode_mcu = decode_mcu_AC_first;
- } else {
- if (is_DC_band)
- entropy->pub.decode_mcu = decode_mcu_DC_refine;
- else
- entropy->pub.decode_mcu = decode_mcu_AC_refine;
- }
-
- for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
- compptr = cinfo->cur_comp_info[ci];
- /* Make sure requested tables are present, and compute derived tables.
- * We may build same derived table more than once, but it's not expensive.
- */
- if (is_DC_band) {
- if (cinfo->Ah == 0) { /* DC refinement needs no table */
- tbl = compptr->dc_tbl_no;
- jpeg_make_d_derived_tbl(cinfo, TRUE, tbl,
- & entropy->derived_tbls[tbl]);
- }
- } else {
- tbl = compptr->ac_tbl_no;
- jpeg_make_d_derived_tbl(cinfo, FALSE, tbl,
- & entropy->derived_tbls[tbl]);
- /* remember the single active table */
- entropy->ac_derived_tbl = entropy->derived_tbls[tbl];
- }
- /* Initialize DC predictions to 0 */
- entropy->saved.last_dc_val[ci] = 0;
- }
-
- /* Initialize bitread state variables */
- entropy->bitstate.bits_left = 0;
- entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */
- entropy->pub.insufficient_data = FALSE;
-
- /* Initialize private state variables */
- entropy->saved.EOBRUN = 0;
-
- /* Initialize restart counter */
- entropy->restarts_to_go = cinfo->restart_interval;
-}
-
-
-/*
- * Figure F.12: extend sign bit.
- * On some machines, a shift and add will be faster than a table lookup.
- */
-
-#ifdef AVOID_TABLES
-
-#define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x))
-
-#else
-
-#define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x))
-
-static const int extend_test[16] = /* entry n is 2**(n-1) */
- { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
- 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 };
-
-static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */
- { 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1,
- ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1,
- ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1,
- ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1 };
-
-#endif /* AVOID_TABLES */
-
-
-/*
- * Check for a restart marker & resynchronize decoder.
- * Returns FALSE if must suspend.
- */
-
-LOCAL(boolean)
-process_restart (j_decompress_ptr cinfo)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- int ci;
-
- /* Throw away any unused bits remaining in bit buffer; */
- /* include any full bytes in next_marker's count of discarded bytes */
- cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8;
- entropy->bitstate.bits_left = 0;
-
- /* Advance past the RSTn marker */
- if (! (*cinfo->marker->read_restart_marker) (cinfo))
- return FALSE;
-
- /* Re-initialize DC predictions to 0 */
- for (ci = 0; ci < cinfo->comps_in_scan; ci++)
- entropy->saved.last_dc_val[ci] = 0;
- /* Re-init EOB run count, too */
- entropy->saved.EOBRUN = 0;
-
- /* Reset restart counter */
- entropy->restarts_to_go = cinfo->restart_interval;
-
- /* Reset out-of-data flag, unless read_restart_marker left us smack up
- * against a marker. In that case we will end up treating the next data
- * segment as empty, and we can avoid producing bogus output pixels by
- * leaving the flag set.
- */
- if (cinfo->unread_marker == 0)
- entropy->pub.insufficient_data = FALSE;
-
- return TRUE;
-}
-
-
-/*
- * Huffman MCU decoding.
- * Each of these routines decodes and returns one MCU's worth of
- * Huffman-compressed coefficients.
- * The coefficients are reordered from zigzag order into natural array order,
- * but are not dequantized.
- *
- * The i'th block of the MCU is stored into the block pointed to by
- * MCU_data[i]. WE ASSUME THIS AREA IS INITIALLY ZEROED BY THE CALLER.
- *
- * We return FALSE if data source requested suspension. In that case no
- * changes have been made to permanent state. (Exception: some output
- * coefficients may already have been assigned. This is harmless for
- * spectral selection, since we'll just re-assign them on the next call.
- * Successive approximation AC refinement has to be more careful, however.)
- */
-
-/*
- * MCU decoding for DC initial scan (either spectral selection,
- * or first pass of successive approximation).
- */
-
-METHODDEF(boolean)
-decode_mcu_DC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- int Al = cinfo->Al;
- register int s, r;
- int blkn, ci;
- JBLOCKROW block;
- BITREAD_STATE_VARS;
- savable_state state;
- d_derived_tbl * tbl;
- jpeg_component_info * compptr;
-
- /* Process restart marker if needed; may have to suspend */
- if (cinfo->restart_interval) {
- if (entropy->restarts_to_go == 0)
- if (! process_restart(cinfo))
- return FALSE;
- }
-
- /* If we've run out of data, just leave the MCU set to zeroes.
- * This way, we return uniform gray for the remainder of the segment.
- */
- if (! entropy->pub.insufficient_data) {
-
- /* Load up working state */
- BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
- ASSIGN_STATE(state, entropy->saved);
-
- /* Outer loop handles each block in the MCU */
-
- for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
- block = MCU_data[blkn];
- ci = cinfo->MCU_membership[blkn];
- compptr = cinfo->cur_comp_info[ci];
- tbl = entropy->derived_tbls[compptr->dc_tbl_no];
-
- /* Decode a single block's worth of coefficients */
-
- /* Section F.2.2.1: decode the DC coefficient difference */
- HUFF_DECODE(s, br_state, tbl, return FALSE, label1);
- if (s) {
- CHECK_BIT_BUFFER(br_state, s, return FALSE);
- r = GET_BITS(s);
- s = HUFF_EXTEND(r, s);
- }
-
- /* Convert DC difference to actual value, update last_dc_val */
- s += state.last_dc_val[ci];
- state.last_dc_val[ci] = s;
- /* Scale and output the coefficient (assumes jpeg_natural_order[0]=0) */
- (*block)[0] = (JCOEF) (s << Al);
- }
-
- /* Completed MCU, so update state */
- BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
- ASSIGN_STATE(entropy->saved, state);
- }
-
- /* Account for restart interval (no-op if not using restarts) */
- entropy->restarts_to_go--;
-
- return TRUE;
-}
-
-
-/*
- * MCU decoding for AC initial scan (either spectral selection,
- * or first pass of successive approximation).
- */
-
-METHODDEF(boolean)
-decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- int Se = cinfo->Se;
- int Al = cinfo->Al;
- register int s, k, r;
- unsigned int EOBRUN;
- JBLOCKROW block;
- BITREAD_STATE_VARS;
- d_derived_tbl * tbl;
-
- /* Process restart marker if needed; may have to suspend */
- if (cinfo->restart_interval) {
- if (entropy->restarts_to_go == 0)
- if (! process_restart(cinfo))
- return FALSE;
- }
-
- /* If we've run out of data, just leave the MCU set to zeroes.
- * This way, we return uniform gray for the remainder of the segment.
- */
- if (! entropy->pub.insufficient_data) {
-
- /* Load up working state.
- * We can avoid loading/saving bitread state if in an EOB run.
- */
- EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */
-
- /* There is always only one block per MCU */
-
- if (EOBRUN > 0) /* if it's a band of zeroes... */
- EOBRUN--; /* ...process it now (we do nothing) */
- else {
- BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
- block = MCU_data[0];
- tbl = entropy->ac_derived_tbl;
-
- for (k = cinfo->Ss; k <= Se; k++) {
- HUFF_DECODE(s, br_state, tbl, return FALSE, label2);
- r = s >> 4;
- s &= 15;
- if (s) {
- k += r;
- CHECK_BIT_BUFFER(br_state, s, return FALSE);
- r = GET_BITS(s);
- s = HUFF_EXTEND(r, s);
- /* Scale and output coefficient in natural (dezigzagged) order */
- (*block)[jpeg_natural_order[k]] = (JCOEF) (s << Al);
- } else {
- if (r == 15) { /* ZRL */
- k += 15; /* skip 15 zeroes in band */
- } else { /* EOBr, run length is 2^r + appended bits */
- EOBRUN = 1 << r;
- if (r) { /* EOBr, r > 0 */
- CHECK_BIT_BUFFER(br_state, r, return FALSE);
- r = GET_BITS(r);
- EOBRUN += r;
- }
- EOBRUN--; /* this band is processed at this moment */
- break; /* force end-of-band */
- }
- }
- }
-
- BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
- }
-
- /* Completed MCU, so update state */
- entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */
- }
-
- /* Account for restart interval (no-op if not using restarts) */
- entropy->restarts_to_go--;
-
- return TRUE;
-}
-
-
-/*
- * MCU decoding 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)
-decode_mcu_DC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- int p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */
- int blkn;
- JBLOCKROW block;
- BITREAD_STATE_VARS;
-
- /* Process restart marker if needed; may have to suspend */
- if (cinfo->restart_interval) {
- if (entropy->restarts_to_go == 0)
- if (! process_restart(cinfo))
- return FALSE;
- }
-
- /* Not worth the cycles to check insufficient_data here,
- * since we will not change the data anyway if we read zeroes.
- */
-
- /* Load up working state */
- BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
-
- /* Outer loop handles each block in the MCU */
-
- for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
- block = MCU_data[blkn];
-
- /* Encoded data is simply the next bit of the two's-complement DC value */
- CHECK_BIT_BUFFER(br_state, 1, return FALSE);
- if (GET_BITS(1))
- (*block)[0] |= p1;
- /* Note: since we use |=, repeating the assignment later is safe */
- }
-
- /* Completed MCU, so update state */
- BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
-
- /* Account for restart interval (no-op if not using restarts) */
- entropy->restarts_to_go--;
-
- return TRUE;
-}
-
-
-/*
- * MCU decoding for AC successive approximation refinement scan.
- */
-
-METHODDEF(boolean)
-decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- int Se = cinfo->Se;
- int p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */
- int m1 = (-1) << cinfo->Al; /* -1 in the bit position being coded */
- register int s, k, r;
- unsigned int EOBRUN;
- JBLOCKROW block;
- JCOEFPTR thiscoef;
- BITREAD_STATE_VARS;
- d_derived_tbl * tbl;
- int num_newnz;
- int newnz_pos[DCTSIZE2];
-
- /* Process restart marker if needed; may have to suspend */
- if (cinfo->restart_interval) {
- if (entropy->restarts_to_go == 0)
- if (! process_restart(cinfo))
- return FALSE;
- }
-
- /* If we've run out of data, don't modify the MCU.
- */
- if (! entropy->pub.insufficient_data) {
-
- /* Load up working state */
- BITREAD_LOAD_STATE(cinfo,entropy->bitstate);
- EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */
-
- /* There is always only one block per MCU */
- block = MCU_data[0];
- tbl = entropy->ac_derived_tbl;
-
- /* If we are forced to suspend, we must undo the assignments to any newly
- * nonzero coefficients in the block, because otherwise we'd get confused
- * next time about which coefficients were already nonzero.
- * But we need not undo addition of bits to already-nonzero coefficients;
- * instead, we can test the current bit to see if we already did it.
- */
- num_newnz = 0;
-
- /* initialize coefficient loop counter to start of band */
- k = cinfo->Ss;
-
- if (EOBRUN == 0) {
- for (; k <= Se; k++) {
- HUFF_DECODE(s, br_state, tbl, goto undoit, label3);
- r = s >> 4;
- s &= 15;
- if (s) {
- if (s != 1) /* size of new coef should always be 1 */
- WARNMS(cinfo, JWRN_HUFF_BAD_CODE);
- CHECK_BIT_BUFFER(br_state, 1, goto undoit);
- if (GET_BITS(1))
- s = p1; /* newly nonzero coef is positive */
- else
- s = m1; /* newly nonzero coef is negative */
- } else {
- if (r != 15) {
- EOBRUN = 1 << r; /* EOBr, run length is 2^r + appended bits */
- if (r) {
- CHECK_BIT_BUFFER(br_state, r, goto undoit);
- r = GET_BITS(r);
- EOBRUN += r;
- }
- break; /* rest of block is handled by EOB logic */
- }
- /* note s = 0 for processing ZRL */
- }
- /* Advance over already-nonzero coefs and r still-zero coefs,
- * appending correction bits to the nonzeroes. A correction bit is 1
- * if the absolute value of the coefficient must be increased.
- */
- do {
- thiscoef = *block + jpeg_natural_order[k];
- if (*thiscoef != 0) {
- CHECK_BIT_BUFFER(br_state, 1, goto undoit);
- if (GET_BITS(1)) {
- if ((*thiscoef & p1) == 0) { /* do nothing if already set it */
- if (*thiscoef >= 0)
- *thiscoef += p1;
- else
- *thiscoef += m1;
- }
- }
- } else {
- if (--r < 0)
- break; /* reached target zero coefficient */
- }
- k++;
- } while (k <= Se);
- if (s) {
- int pos = jpeg_natural_order[k];
- /* Output newly nonzero coefficient */
- (*block)[pos] = (JCOEF) s;
- /* Remember its position in case we have to suspend */
- newnz_pos[num_newnz++] = pos;
- }
- }
- }
-
- if (EOBRUN > 0) {
- /* Scan any remaining coefficient positions after the end-of-band
- * (the last newly nonzero coefficient, if any). Append a correction
- * bit to each already-nonzero coefficient. A correction bit is 1
- * if the absolute value of the coefficient must be increased.
- */
- for (; k <= Se; k++) {
- thiscoef = *block + jpeg_natural_order[k];
- if (*thiscoef != 0) {
- CHECK_BIT_BUFFER(br_state, 1, goto undoit);
- if (GET_BITS(1)) {
- if ((*thiscoef & p1) == 0) { /* do nothing if already changed it */
- if (*thiscoef >= 0)
- *thiscoef += p1;
- else
- *thiscoef += m1;
- }
- }
- }
- }
- /* Count one block completed in EOB run */
- EOBRUN--;
- }
-
- /* Completed MCU, so update state */
- BITREAD_SAVE_STATE(cinfo,entropy->bitstate);
- entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */
- }
-
- /* Account for restart interval (no-op if not using restarts) */
- entropy->restarts_to_go--;
-
- return TRUE;
-
-undoit:
- /* Re-zero any output coefficients that we made newly nonzero */
- while (num_newnz > 0)
- (*block)[newnz_pos[--num_newnz]] = 0;
-
- return FALSE;
-}
-
-/*
- * Save the current Huffman decoder position and the bit buffer
- * into bitstream_offset and get_buffer, respectively.
- */
-GLOBAL(void)
-jpeg_get_huffman_decoder_configuration_progressive(j_decompress_ptr cinfo,
- huffman_offset_data *offset)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
-
- if (cinfo->restart_interval) {
- // We are at the end of a data segment
- if (entropy->restarts_to_go == 0)
- if (! process_restart(cinfo))
- return;
- }
-
- // Save restarts_to_go and next_restart_num.
- offset->restarts_to_go = (unsigned short) entropy->restarts_to_go;
- offset->next_restart_num = cinfo->marker->next_restart_num;
-
- offset->bitstream_offset =
- (jget_input_stream_position(cinfo) << LOG_TWO_BIT_BUF_SIZE)
- + entropy->bitstate.bits_left;
-
- offset->get_buffer = entropy->bitstate.get_buffer;
-}
-
-/*
- * Save the current Huffman deocde position and the DC coefficients
- * for each component into bitstream_offset and dc_info[], respectively.
- */
-METHODDEF(void)
-get_huffman_decoder_configuration(j_decompress_ptr cinfo,
- huffman_offset_data *offset)
-{
- int i;
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- jpeg_get_huffman_decoder_configuration_progressive(cinfo, offset);
- offset->EOBRUN = entropy->saved.EOBRUN;
- for (i = 0; i < cinfo->comps_in_scan; i++)
- offset->prev_dc[i] = entropy->saved.last_dc_val[i];
-}
-
-/*
- * Configure the Huffman decoder reader position and bit buffer.
- */
-GLOBAL(void)
-jpeg_configure_huffman_decoder_progressive(j_decompress_ptr cinfo,
- huffman_offset_data offset)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
-
- // Restore restarts_to_go and next_restart_num
- cinfo->unread_marker = 0;
- entropy->restarts_to_go = offset.restarts_to_go;
- cinfo->marker->next_restart_num = offset.next_restart_num;
-
- unsigned int bitstream_offset = offset.bitstream_offset;
- int blkn, i;
-
- unsigned int byte_offset = bitstream_offset >> LOG_TWO_BIT_BUF_SIZE;
- unsigned int bit_in_bit_buffer =
- bitstream_offset & ((1 << LOG_TWO_BIT_BUF_SIZE) - 1);
-
- jset_input_stream_position_bit(cinfo, byte_offset,
- bit_in_bit_buffer, offset.get_buffer);
-}
-
-/*
- * Configure the Huffman decoder to decode the image
- * starting from (iMCU_row_offset, iMCU_col_offset).
- */
-METHODDEF(void)
-configure_huffman_decoder(j_decompress_ptr cinfo, huffman_offset_data offset)
-{
- int i;
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- jpeg_configure_huffman_decoder_progressive(cinfo, offset);
- entropy->saved.EOBRUN = offset.EOBRUN;
- for (i = 0; i < cinfo->comps_in_scan; i++)
- entropy->saved.last_dc_val[i] = offset.prev_dc[i];
-}
-
-GLOBAL(void)
-jpeg_configure_huffman_index_scan(j_decompress_ptr cinfo,
- huffman_index *index, int scan_no, int offset)
-{
- phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
- if (scan_no >= index->scan_count) {
- index->scan = realloc(index->scan,
- (scan_no + 1) * sizeof(huffman_scan_header));
- index->mem_used += (scan_no - index->scan_count + 1)
- * (sizeof(huffman_scan_header) + cinfo->total_iMCU_rows
- * sizeof(huffman_offset_data*));
- index->scan_count = scan_no + 1;
- }
- index->scan[scan_no].offset = (huffman_offset_data**)malloc(
- cinfo->total_iMCU_rows * sizeof(huffman_offset_data*));
- index->scan[scan_no].bitstream_offset = offset;
-}
-
-/*
- * Module initialization routine for progressive Huffman entropy decoding.
- */
-GLOBAL(void)
-jinit_phuff_decoder (j_decompress_ptr cinfo)
-{
- phuff_entropy_ptr entropy;
- int *coef_bit_ptr;
- int ci, i;
-
- entropy = (phuff_entropy_ptr)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(phuff_entropy_decoder));
- cinfo->entropy = (struct jpeg_entropy_decoder *) entropy;
- entropy->pub.start_pass = start_pass_phuff_decoder;
- entropy->pub.configure_huffman_decoder = configure_huffman_decoder;
- entropy->pub.get_huffman_decoder_configuration =
- get_huffman_decoder_configuration;
-
- /* Mark derived tables unallocated */
- for (i = 0; i < NUM_HUFF_TBLS; i++) {
- entropy->derived_tbls[i] = NULL;
- }
-
- /* Create progression status table */
- cinfo->coef_bits = (int (*)[DCTSIZE2])
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- cinfo->num_components*DCTSIZE2*SIZEOF(int));
- coef_bit_ptr = & cinfo->coef_bits[0][0];
- for (ci = 0; ci < cinfo->num_components; ci++)
- for (i = 0; i < DCTSIZE2; i++)
- *coef_bit_ptr++ = -1;
-}
-
-#endif /* D_PROGRESSIVE_SUPPORTED */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 18:20:51 +0100