#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* jdhuff.c | |
* | |
* Copyright (C) 1991-1997, 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. | |
* | |
* 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 jdphuff.c */ | |
#ifdef _FX_MANAGED_CODE_ | |
#define savable_state savable_state_d | |
#endif | |
/* | |
* Expanded entropy decoder object for 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 { | |
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).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 * dc_derived_tbls[NUM_HUFF_TBLS]; | |
d_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS]; | |
/* Precalculated info set up by start_pass for use in decode_mcu: */ | |
/* Pointers to derived tables to be used for each block within an MCU */ | |
d_derived_tbl * dc_cur_tbls[D_MAX_BLOCKS_IN_MCU]; | |
d_derived_tbl * ac_cur_tbls[D_MAX_BLOCKS_IN_MCU]; | |
/* Whether we care about the DC and AC coefficient values for each block */ | |
boolean dc_needed[D_MAX_BLOCKS_IN_MCU]; | |
boolean ac_needed[D_MAX_BLOCKS_IN_MCU]; | |
} huff_entropy_decoder; | |
typedef huff_entropy_decoder * huff_entropy_ptr; | |
/* | |
* Initialize for a Huffman-compressed scan. | |
*/ | |
METHODDEF(void) | |
start_pass_huff_decoder (j_decompress_ptr cinfo) | |
{ | |
huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | |
int ci, blkn, dctbl, actbl; | |
jpeg_component_info * compptr; | |
/* Check that the scan parameters Ss, Se, Ah/Al are OK for sequential JPEG. | |
* This ought to be an error condition, but we make it a warning because | |
* there are some baseline files out there with all zeroes in these bytes. | |
*/ | |
if (cinfo->Ss != 0 || cinfo->Se != DCTSIZE2-1 || | |
cinfo->Ah != 0 || cinfo->Al != 0) | |
WARNMS(cinfo, JWRN_NOT_SEQUENTIAL); | |
for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | |
compptr = cinfo->cur_comp_info[ci]; | |
dctbl = compptr->dc_tbl_no; | |
actbl = compptr->ac_tbl_no; | |
/* Compute derived values for Huffman tables */ | |
/* We may do this more than once for a table, but it's not expensive */ | |
jpeg_make_d_derived_tbl(cinfo, TRUE, dctbl, | |
& entropy->dc_derived_tbls[dctbl]); | |
jpeg_make_d_derived_tbl(cinfo, FALSE, actbl, | |
& entropy->ac_derived_tbls[actbl]); | |
/* Initialize DC predictions to 0 */ | |
entropy->saved.last_dc_val[ci] = 0; | |
} | |
/* Precalculate decoding info for each block in an MCU of this scan */ | |
for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { | |
ci = cinfo->MCU_membership[blkn]; | |
compptr = cinfo->cur_comp_info[ci]; | |
/* Precalculate which table to use for each block */ | |
entropy->dc_cur_tbls[blkn] = entropy->dc_derived_tbls[compptr->dc_tbl_no]; | |
entropy->ac_cur_tbls[blkn] = entropy->ac_derived_tbls[compptr->ac_tbl_no]; | |
/* Decide whether we really care about the coefficient values */ | |
if (compptr->component_needed) { | |
entropy->dc_needed[blkn] = TRUE; | |
/* we don't need the ACs if producing a 1/8th-size image */ | |
entropy->ac_needed[blkn] = (compptr->DCT_scaled_size > 1); | |
} else { | |
entropy->dc_needed[blkn] = entropy->ac_needed[blkn] = FALSE; | |
} | |
} | |
/* 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 restart counter */ | |
entropy->restarts_to_go = cinfo->restart_interval; | |
} | |
/* | |
* Compute the derived values for a Huffman table. | |
* This routine also performs some validation checks on the table. | |
* | |
* Note this is also used by jdphuff.c. | |
*/ | |
GLOBAL(void) | |
jpeg_make_d_derived_tbl (j_decompress_ptr cinfo, boolean isDC, int tblno, | |
d_derived_tbl ** pdtbl) | |
{ | |
JHUFF_TBL *htbl; | |
d_derived_tbl *dtbl; | |
int p, i, l, _si, numsymbols; | |
int lookbits, ctr; | |
char huffsize[257]; | |
unsigned int huffcode[257]; | |
unsigned int code; | |
/* Note that huffsize[] and huffcode[] are filled in code-length order, | |
* paralleling the order of the symbols themselves in htbl->huffval[]. | |
*/ | |
/* Find the input Huffman table */ | |
if (tblno < 0 || tblno >= NUM_HUFF_TBLS) | |
ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); | |
htbl = | |
isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno]; | |
if (htbl == NULL) | |
ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); | |
/* Allocate a workspace if we haven't already done so. */ | |
if (*pdtbl == NULL) | |
*pdtbl = (d_derived_tbl *) | |
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
SIZEOF(d_derived_tbl)); | |
dtbl = *pdtbl; | |
dtbl->pub = htbl; /* fill in back link */ | |
/* Figure C.1: make table of Huffman code length for each symbol */ | |
p = 0; | |
for (l = 1; l <= 16; l++) { | |
i = (int) htbl->bits[l]; | |
if (i < 0 || p + i > 256) /* protect against table overrun */ | |
ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); | |
while (i--) | |
huffsize[p++] = (char) l; | |
} | |
huffsize[p] = 0; | |
numsymbols = p; | |
/* Figure C.2: generate the codes themselves */ | |
/* We also validate that the counts represent a legal Huffman code tree. */ | |
code = 0; | |
_si = huffsize[0]; | |
p = 0; | |
while (huffsize[p]) { | |
while (((int) huffsize[p]) == _si) { | |
huffcode[p++] = code; | |
code++; | |
} | |
/* code is now 1 more than the last code used for codelength si; but | |
* it must still fit in si bits, since no code is allowed to be all ones. | |
*/ | |
if (((INT32) code) >= (((INT32) 1) << _si)) | |
ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); | |
code <<= 1; | |
_si++; | |
} | |
/* Figure F.15: generate decoding tables for bit-sequential decoding */ | |
p = 0; | |
for (l = 1; l <= 16; l++) { | |
if (htbl->bits[l]) { | |
/* valoffset[l] = huffval[] index of 1st symbol of code length l, | |
* minus the minimum code of length l | |
*/ | |
dtbl->valoffset[l] = (INT32) p - (INT32) huffcode[p]; | |
p += htbl->bits[l]; | |
dtbl->maxcode[l] = huffcode[p-1]; /* maximum code of length l */ | |
} else { | |
dtbl->maxcode[l] = -1; /* -1 if no codes of this length */ | |
} | |
} | |
dtbl->maxcode[17] = 0xFFFFFL; /* ensures jpeg_huff_decode terminates */ | |
/* Compute lookahead tables to speed up decoding. | |
* First we set all the table entries to 0, indicating "too long"; | |
* then we iterate through the Huffman codes that are short enough and | |
* fill in all the entries that correspond to bit sequences starting | |
* with that code. | |
*/ | |
MEMZERO(dtbl->look_nbits, SIZEOF(dtbl->look_nbits)); | |
p = 0; | |
for (l = 1; l <= HUFF_LOOKAHEAD; l++) { | |
for (i = 1; i <= (int) htbl->bits[l]; i++, p++) { | |
/* l = current code's length, p = its index in huffcode[] & huffval[]. */ | |
/* Generate left-justified code followed by all possible bit sequences */ | |
lookbits = huffcode[p] << (HUFF_LOOKAHEAD-l); | |
for (ctr = 1 << (HUFF_LOOKAHEAD-l); ctr > 0; ctr--) { | |
dtbl->look_nbits[lookbits] = l; | |
dtbl->look_sym[lookbits] = htbl->huffval[p]; | |
lookbits++; | |
} | |
} | |
} | |
/* Validate symbols as being reasonable. | |
* For AC tables, we make no check, but accept all byte values 0..255. | |
* For DC tables, we require the symbols to be in range 0..15. | |
* (Tighter bounds could be applied depending on the data depth and mode, | |
* but this is sufficient to ensure safe decoding.) | |
*/ | |
if (isDC) { | |
for (i = 0; i < numsymbols; i++) { | |
int sym = htbl->huffval[i]; | |
if (sym < 0 || sym > 15) | |
ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); | |
} | |
} | |
} | |
/* | |
* Out-of-line code for bit fetching (shared with jdphuff.c). | |
* See jdhuff.h for info about usage. | |
* Note: current values of get_buffer and bits_left are passed as parameters, | |
* but are returned in the corresponding fields of the state struct. | |
* | |
* On most machines MIN_GET_BITS should be 25 to allow the full 32-bit width | |
* of get_buffer to be used. (On machines with wider words, an even larger | |
* buffer could be used.) However, on some machines 32-bit shifts are | |
* quite slow and take time proportional to the number of places shifted. | |
* (This is true with most PC compilers, for instance.) In this case it may | |
* be a win to set MIN_GET_BITS to the minimum value of 15. This reduces the | |
* average shift distance at the cost of more calls to jpeg_fill_bit_buffer. | |
*/ | |
#ifdef SLOW_SHIFT_32 | |
#define MIN_GET_BITS 15 /* minimum allowable value */ | |
#else | |
#define MIN_GET_BITS (BIT_BUF_SIZE-7) | |
#endif | |
GLOBAL(boolean) | |
jpeg_fill_bit_buffer (bitread_working_state * state, | |
register bit_buf_type get_buffer, register int bits_left, | |
int nbits) | |
/* Load up the bit buffer to a depth of at least nbits */ | |
{ | |
/* Copy heavily used state fields into locals (hopefully registers) */ | |
register const JOCTET * next_input_byte = state->next_input_byte; | |
register size_t bytes_in_buffer = state->bytes_in_buffer; | |
j_decompress_ptr cinfo = state->cinfo; | |
/* Attempt to load at least MIN_GET_BITS bits into get_buffer. */ | |
/* (It is assumed that no request will be for more than that many bits.) */ | |
/* We fail to do so only if we hit a marker or are forced to suspend. */ | |
if (cinfo->unread_marker == 0) { /* cannot advance past a marker */ | |
while (bits_left < MIN_GET_BITS) { | |
register int c; | |
/* Attempt to read a byte */ | |
if (bytes_in_buffer == 0) { | |
if (! (*cinfo->src->fill_input_buffer) (cinfo)) | |
return FALSE; | |
next_input_byte = cinfo->src->next_input_byte; | |
bytes_in_buffer = cinfo->src->bytes_in_buffer; | |
} | |
bytes_in_buffer--; | |
c = GETJOCTET(*next_input_byte++); | |
/* If it's 0xFF, check and discard stuffed zero byte */ | |
if (c == 0xFF) { | |
/* Loop here to discard any padding FF's on terminating marker, | |
* so that we can save a valid unread_marker value. NOTE: we will | |
* accept multiple FF's followed by a 0 as meaning a single FF data | |
* byte. This data pattern is not valid according to the standard. | |
*/ | |
do { | |
if (bytes_in_buffer == 0) { | |
if (! (*cinfo->src->fill_input_buffer) (cinfo)) | |
return FALSE; | |
next_input_byte = cinfo->src->next_input_byte; | |
bytes_in_buffer = cinfo->src->bytes_in_buffer; | |
} | |
bytes_in_buffer--; | |
c = GETJOCTET(*next_input_byte++); | |
} while (c == 0xFF); | |
if (c == 0) { | |
/* Found FF/00, which represents an FF data byte */ | |
c = 0xFF; | |
} else { | |
/* Oops, it's actually a marker indicating end of compressed data. | |
* Save the marker code for later use. | |
* Fine point: it might appear that we should save the marker into | |
* bitread working state, not straight into permanent state. But | |
* once we have hit a marker, we cannot need to suspend within the | |
* current MCU, because we will read no more bytes from the data | |
* source. So it is OK to update permanent state right away. | |
*/ | |
cinfo->unread_marker = c; | |
/* See if we need to insert some fake zero bits. */ | |
goto no_more_bytes; | |
} | |
} | |
/* OK, load c into get_buffer */ | |
get_buffer = (get_buffer << 8) | c; | |
bits_left += 8; | |
} /* end while */ | |
} else { | |
no_more_bytes: | |
/* We get here if we've read the marker that terminates the compressed | |
* data segment. There should be enough bits in the buffer register | |
* to satisfy the request; if so, no problem. | |
*/ | |
if (nbits > bits_left) { | |
/* Uh-oh. Report corrupted data to user and stuff zeroes into | |
* the data stream, so that we can produce some kind of image. | |
* We use a nonvolatile flag to ensure that only one warning message | |
* appears per data segment. | |
*/ | |
if (! cinfo->entropy->insufficient_data) { | |
WARNMS(cinfo, JWRN_HIT_MARKER); | |
cinfo->entropy->insufficient_data = TRUE; | |
} | |
/* Fill the buffer with zero bits */ | |
get_buffer <<= MIN_GET_BITS - bits_left; | |
bits_left = MIN_GET_BITS; | |
} | |
} | |
/* Unload the local registers */ | |
state->next_input_byte = next_input_byte; | |
state->bytes_in_buffer = bytes_in_buffer; | |
state->get_buffer = get_buffer; | |
state->bits_left = bits_left; | |
return TRUE; | |
} | |
/* | |
* Out-of-line code for Huffman code decoding. | |
* See jdhuff.h for info about usage. | |
*/ | |
GLOBAL(int) | |
jpeg_huff_decode (bitread_working_state * state, | |
register bit_buf_type get_buffer, register int bits_left, | |
d_derived_tbl * htbl, int min_bits) | |
{ | |
register int l = min_bits; | |
register INT32 code; | |
/* HUFF_DECODE has determined that the code is at least min_bits */ | |
/* bits long, so fetch that many bits in one swoop. */ | |
CHECK_BIT_BUFFER(*state, l, return -1); | |
code = GET_BITS(l); | |
/* Collect the rest of the Huffman code one bit at a time. */ | |
/* This is per Figure F.16 in the JPEG spec. */ | |
while (code > htbl->maxcode[l]) { | |
code <<= 1; | |
CHECK_BIT_BUFFER(*state, 1, return -1); | |
code |= GET_BITS(1); | |
l++; | |
} | |
/* Unload the local registers */ | |
state->get_buffer = get_buffer; | |
state->bits_left = bits_left; | |
/* With garbage input we may reach the sentinel value l = 17. */ | |
if (l > 16) { | |
WARNMS(state->cinfo, JWRN_HUFF_BAD_CODE); | |
return 0; /* fake a zero as the safest result */ | |
} | |
return htbl->pub->huffval[ (int) (code + htbl->valoffset[l]) ]; | |
} | |
/* | |
* 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) | |
{ | |
huff_entropy_ptr entropy = (huff_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; | |
/* 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; | |
} | |
/* | |
* Decode and return 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 HAS BEEN ZEROED BY THE CALLER. | |
* (Wholesale zeroing is usually a little faster than retail...) | |
* | |
* Returns 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 | |
* this module, since we'll just re-assign them on the next call.) | |
*/ | |
METHODDEF(boolean) | |
decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) | |
{ | |
huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; | |
int blkn; | |
BITREAD_STATE_VARS; | |
savable_state state; | |
/* 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++) { | |
JBLOCKROW block = MCU_data[blkn]; | |
d_derived_tbl * dctbl = entropy->dc_cur_tbls[blkn]; | |
d_derived_tbl * actbl = entropy->ac_cur_tbls[blkn]; | |
register int s, k, r; | |
/* Decode a single block's worth of coefficients */ | |
/* Section F.2.2.1: decode the DC coefficient difference */ | |
HUFF_DECODE(s, br_state, dctbl, return FALSE, label1); | |
if (s) { | |
CHECK_BIT_BUFFER(br_state, s, return FALSE); | |
r = GET_BITS(s); | |
s = HUFF_EXTEND(r, s); | |
} | |
if (entropy->dc_needed[blkn]) { | |
/* Convert DC difference to actual value, update last_dc_val */ | |
int ci = cinfo->MCU_membership[blkn]; | |
s += state.last_dc_val[ci]; | |
state.last_dc_val[ci] = s; | |
/* Output the DC coefficient (assumes jpeg_natural_order[0] = 0) */ | |
(*block)[0] = (JCOEF) s; | |
} | |
if (entropy->ac_needed[blkn]) { | |
/* Section F.2.2.2: decode the AC coefficients */ | |
/* Since zeroes are skipped, output area must be cleared beforehand */ | |
for (k = 1; k < DCTSIZE2; k++) { | |
HUFF_DECODE(s, br_state, actbl, 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); | |
/* Output coefficient in natural (dezigzagged) order. | |
* Note: the extra entries in jpeg_natural_order[] will save us | |
* if k >= DCTSIZE2, which could happen if the data is corrupted. | |
*/ | |
(*block)[jpeg_natural_order[k]] = (JCOEF) s; | |
} else { | |
if (r != 15) | |
break; | |
k += 15; | |
} | |
} | |
} else { | |
/* Section F.2.2.2: decode the AC coefficients */ | |
/* In this path we just discard the values */ | |
for (k = 1; k < DCTSIZE2; k++) { | |
HUFF_DECODE(s, br_state, actbl, return FALSE, label3); | |
r = s >> 4; | |
s &= 15; | |
if (s) { | |
k += r; | |
CHECK_BIT_BUFFER(br_state, s, return FALSE); | |
DROP_BITS(s); | |
} else { | |
if (r != 15) | |
break; | |
k += 15; | |
} | |
} | |
} | |
} | |
/* 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; | |
} | |
/* | |
* Module initialization routine for Huffman entropy decoding. | |
*/ | |
GLOBAL(void) | |
jinit_huff_decoder (j_decompress_ptr cinfo) | |
{ | |
huff_entropy_ptr entropy; | |
int i; | |
entropy = (huff_entropy_ptr) | |
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
SIZEOF(huff_entropy_decoder)); | |
cinfo->entropy = (struct jpeg_entropy_decoder *) entropy; | |
entropy->pub.start_pass = start_pass_huff_decoder; | |
entropy->pub.decode_mcu = decode_mcu; | |
/* Mark tables unallocated */ | |
for (i = 0; i < NUM_HUFF_TBLS; i++) { | |
entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL; | |
} | |
} | |
#endif //_FX_JPEG_TURBO_ |