jdhuff.c revision 9f5d49a1588e438ae7ceabd0c94172117e3303aa
19f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 29f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * jdhuff.c 39f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 49f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Copyright (C) 1991-1997, Thomas G. Lane. 59f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This file is part of the Independent JPEG Group's software. 69f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * For conditions of distribution and use, see the accompanying README file. 79f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 89f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This file contains Huffman entropy decoding routines. 99f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Much of the complexity here has to do with supporting input suspension. 119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * If the data source module demands suspension, we want to be able to back 129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * up to the start of the current MCU. To do this, we copy state variables 139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * into local working storage, and update them back to the permanent 149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * storage only upon successful completion of an MCU. 159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define JPEG_INTERNALS 189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#include "jinclude.h" 199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#include "jpeglib.h" 209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#include "jdhuff.h" /* Declarations shared with jdphuff.c */ 219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Expanded entropy decoder object for Huffman decoding. 259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * The savable_state subrecord contains fields that change within an MCU, 279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * but must not be updated permanently until we complete the MCU. 289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef struct { 319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */ 329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} savable_state; 339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* This macro is to work around compilers with missing or broken 359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * structure assignment. You'll need to fix this code if you have 369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * such a compiler and you change MAX_COMPS_IN_SCAN. 379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifndef NO_STRUCT_ASSIGN 409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define ASSIGN_STATE(dest,src) ((dest) = (src)) 419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#else 429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#if MAX_COMPS_IN_SCAN == 4 439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define ASSIGN_STATE(dest,src) \ 449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ((dest).last_dc_val[0] = (src).last_dc_val[0], \ 459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project (dest).last_dc_val[1] = (src).last_dc_val[1], \ 469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project (dest).last_dc_val[2] = (src).last_dc_val[2], \ 479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project (dest).last_dc_val[3] = (src).last_dc_val[3]) 489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef struct { 539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project struct jpeg_entropy_decoder pub; /* public fields */ 549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* These fields are loaded into local variables at start of each MCU. 569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * In case of suspension, we exit WITHOUT updating them. 579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project bitread_perm_state bitstate; /* Bit buffer at start of MCU */ 599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project savable_state saved; /* Other state at start of MCU */ 609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* These fields are NOT loaded into local working state. */ 629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project unsigned int restarts_to_go; /* MCUs left in this restart interval */ 639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Pointers to derived tables (these workspaces have image lifespan) */ 659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl * dc_derived_tbls[NUM_HUFF_TBLS]; 669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS]; 679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Precalculated info set up by start_pass for use in decode_mcu: */ 699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Pointers to derived tables to be used for each block within an MCU */ 719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl * dc_cur_tbls[D_MAX_BLOCKS_IN_MCU]; 729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl * ac_cur_tbls[D_MAX_BLOCKS_IN_MCU]; 739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Whether we care about the DC and AC coefficient values for each block */ 749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project boolean dc_needed[D_MAX_BLOCKS_IN_MCU]; 759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project boolean ac_needed[D_MAX_BLOCKS_IN_MCU]; 769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} huff_entropy_decoder; 779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projecttypedef huff_entropy_decoder * huff_entropy_ptr; 799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Initialize for a Huffman-compressed scan. 839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectMETHODDEF(void) 869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectstart_pass_huff_decoder (j_decompress_ptr cinfo) 879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; 899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int ci, blkn, dctbl, actbl; 909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project jpeg_component_info * compptr; 919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Check that the scan parameters Ss, Se, Ah/Al are OK for sequential JPEG. 939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This ought to be an error condition, but we make it a warning because 949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * there are some baseline files out there with all zeroes in these bytes. 959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (cinfo->Ss != 0 || cinfo->Se != DCTSIZE2-1 || 979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project cinfo->Ah != 0 || cinfo->Al != 0) 989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project WARNMS(cinfo, JWRN_NOT_SEQUENTIAL); 999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 1019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project compptr = cinfo->cur_comp_info[ci]; 1029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dctbl = compptr->dc_tbl_no; 1039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project actbl = compptr->ac_tbl_no; 1049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Compute derived values for Huffman tables */ 1059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* We may do this more than once for a table, but it's not expensive */ 1069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project jpeg_make_d_derived_tbl(cinfo, TRUE, dctbl, 1079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & entropy->dc_derived_tbls[dctbl]); 1089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project jpeg_make_d_derived_tbl(cinfo, FALSE, actbl, 1099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project & entropy->ac_derived_tbls[actbl]); 1109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Initialize DC predictions to 0 */ 1119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->saved.last_dc_val[ci] = 0; 1129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 1139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Precalculate decoding info for each block in an MCU of this scan */ 1159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { 1169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ci = cinfo->MCU_membership[blkn]; 1179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project compptr = cinfo->cur_comp_info[ci]; 1189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Precalculate which table to use for each block */ 1199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->dc_cur_tbls[blkn] = entropy->dc_derived_tbls[compptr->dc_tbl_no]; 1209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->ac_cur_tbls[blkn] = entropy->ac_derived_tbls[compptr->ac_tbl_no]; 1219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Decide whether we really care about the coefficient values */ 1229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (compptr->component_needed) { 1239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->dc_needed[blkn] = TRUE; 1249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* we don't need the ACs if producing a 1/8th-size image */ 1259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->ac_needed[blkn] = (compptr->DCT_scaled_size > 1); 1269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } else { 1279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->dc_needed[blkn] = entropy->ac_needed[blkn] = FALSE; 1289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 1299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 1309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Initialize bitread state variables */ 1329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->bitstate.bits_left = 0; 1339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */ 1349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->pub.insufficient_data = FALSE; 1359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Initialize restart counter */ 1379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->restarts_to_go = cinfo->restart_interval; 1389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 1399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 1429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Compute the derived values for a Huffman table. 1439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This routine also performs some validation checks on the table. 1449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 1459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Note this is also used by jdphuff.c. 1469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 1479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectGLOBAL(void) 1499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectjpeg_make_d_derived_tbl (j_decompress_ptr cinfo, boolean isDC, int tblno, 1509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl ** pdtbl) 1519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 1529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JHUFF_TBL *htbl; 1539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl *dtbl; 1549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int p, i, l, si, numsymbols; 1559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int lookbits, ctr; 1569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project char huffsize[257]; 1579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project unsigned int huffcode[257]; 1589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project unsigned int code; 1599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Note that huffsize[] and huffcode[] are filled in code-length order, 1619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * paralleling the order of the symbols themselves in htbl->huffval[]. 1629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 1639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Find the input Huffman table */ 1659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (tblno < 0 || tblno >= NUM_HUFF_TBLS) 1669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); 1679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project htbl = 1689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno]; 1699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (htbl == NULL) 1709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); 1719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Allocate a workspace if we haven't already done so. */ 1739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (*pdtbl == NULL) 1749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project *pdtbl = (d_derived_tbl *) 1759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 1769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project SIZEOF(d_derived_tbl)); 1779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl = *pdtbl; 1789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl->pub = htbl; /* fill in back link */ 1799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Figure C.1: make table of Huffman code length for each symbol */ 1819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project p = 0; 1839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (l = 1; l <= 16; l++) { 1849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project i = (int) htbl->bits[l]; 1859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (i < 0 || p + i > 256) /* protect against table overrun */ 1869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 1879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project while (i--) 1889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project huffsize[p++] = (char) l; 1899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 1909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project huffsize[p] = 0; 1919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project numsymbols = p; 1929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Figure C.2: generate the codes themselves */ 1949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* We also validate that the counts represent a legal Huffman code tree. */ 1959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 1969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project code = 0; 1979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project si = huffsize[0]; 1989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project p = 0; 1999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project while (huffsize[p]) { 2009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project while (((int) huffsize[p]) == si) { 2019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project huffcode[p++] = code; 2029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project code++; 2039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* code is now 1 more than the last code used for codelength si; but 2059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * it must still fit in si bits, since no code is allowed to be all ones. 2069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 2079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (((INT32) code) >= (((INT32) 1) << si)) 2089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 2099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project code <<= 1; 2109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project si++; 2119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Figure F.15: generate decoding tables for bit-sequential decoding */ 2149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project p = 0; 2169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (l = 1; l <= 16; l++) { 2179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (htbl->bits[l]) { 2189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* valoffset[l] = huffval[] index of 1st symbol of code length l, 2199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * minus the minimum code of length l 2209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 2219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl->valoffset[l] = (INT32) p - (INT32) huffcode[p]; 2229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project p += htbl->bits[l]; 2239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl->maxcode[l] = huffcode[p-1]; /* maximum code of length l */ 2249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } else { 2259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl->maxcode[l] = -1; /* -1 if no codes of this length */ 2269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl->maxcode[17] = 0xFFFFFL; /* ensures jpeg_huff_decode terminates */ 2299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Compute lookahead tables to speed up decoding. 2319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * First we set all the table entries to 0, indicating "too long"; 2329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * then we iterate through the Huffman codes that are short enough and 2339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * fill in all the entries that correspond to bit sequences starting 2349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * with that code. 2359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 2369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project MEMZERO(dtbl->look_nbits, SIZEOF(dtbl->look_nbits)); 2389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project p = 0; 2409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (l = 1; l <= HUFF_LOOKAHEAD; l++) { 2419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (i = 1; i <= (int) htbl->bits[l]; i++, p++) { 2429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* l = current code's length, p = its index in huffcode[] & huffval[]. */ 2439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Generate left-justified code followed by all possible bit sequences */ 2449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project lookbits = huffcode[p] << (HUFF_LOOKAHEAD-l); 2459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (ctr = 1 << (HUFF_LOOKAHEAD-l); ctr > 0; ctr--) { 2469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl->look_nbits[lookbits] = l; 2479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project dtbl->look_sym[lookbits] = htbl->huffval[p]; 2489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project lookbits++; 2499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Validate symbols as being reasonable. 2549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * For AC tables, we make no check, but accept all byte values 0..255. 2559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * For DC tables, we require the symbols to be in range 0..15. 2569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * (Tighter bounds could be applied depending on the data depth and mode, 2579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * but this is sufficient to ensure safe decoding.) 2589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 2599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (isDC) { 2609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (i = 0; i < numsymbols; i++) { 2619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int sym = htbl->huffval[i]; 2629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (sym < 0 || sym > 15) 2639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 2649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 2669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 2679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 2709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Out-of-line code for bit fetching (shared with jdphuff.c). 2719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * See jdhuff.h for info about usage. 2729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Note: current values of get_buffer and bits_left are passed as parameters, 2739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * but are returned in the corresponding fields of the state struct. 2749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 2759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * On most machines MIN_GET_BITS should be 25 to allow the full 32-bit width 2769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * of get_buffer to be used. (On machines with wider words, an even larger 2779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * buffer could be used.) However, on some machines 32-bit shifts are 2789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * quite slow and take time proportional to the number of places shifted. 2799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * (This is true with most PC compilers, for instance.) In this case it may 2809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * be a win to set MIN_GET_BITS to the minimum value of 15. This reduces the 2819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * average shift distance at the cost of more calls to jpeg_fill_bit_buffer. 2829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 2839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifdef SLOW_SHIFT_32 2859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define MIN_GET_BITS 15 /* minimum allowable value */ 2869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#else 2879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define MIN_GET_BITS (BIT_BUF_SIZE-7) 2889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif 2899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 2919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectGLOBAL(boolean) 2929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectjpeg_fill_bit_buffer (bitread_working_state * state, 2939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register bit_buf_type get_buffer, register int bits_left, 2949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int nbits) 2959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* Load up the bit buffer to a depth of at least nbits */ 2969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 2979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Copy heavily used state fields into locals (hopefully registers) */ 2989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register const JOCTET * next_input_byte = state->next_input_byte; 2999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register size_t bytes_in_buffer = state->bytes_in_buffer; 3009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project j_decompress_ptr cinfo = state->cinfo; 3019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Attempt to load at least MIN_GET_BITS bits into get_buffer. */ 3039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* (It is assumed that no request will be for more than that many bits.) */ 3049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* We fail to do so only if we hit a marker or are forced to suspend. */ 3059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (cinfo->unread_marker == 0) { /* cannot advance past a marker */ 3079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project while (bits_left < MIN_GET_BITS) { 3089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register int c; 3099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Attempt to read a byte */ 3119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (bytes_in_buffer == 0) { 3129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (! (*cinfo->src->fill_input_buffer) (cinfo)) 3139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return FALSE; 3149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project next_input_byte = cinfo->src->next_input_byte; 3159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project bytes_in_buffer = cinfo->src->bytes_in_buffer; 3169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 3179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project bytes_in_buffer--; 3189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project c = GETJOCTET(*next_input_byte++); 3199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* If it's 0xFF, check and discard stuffed zero byte */ 3219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (c == 0xFF) { 3229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Loop here to discard any padding FF's on terminating marker, 3239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * so that we can save a valid unread_marker value. NOTE: we will 3249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * accept multiple FF's followed by a 0 as meaning a single FF data 3259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * byte. This data pattern is not valid according to the standard. 3269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 3279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project do { 3289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (bytes_in_buffer == 0) { 3299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (! (*cinfo->src->fill_input_buffer) (cinfo)) 3309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return FALSE; 3319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project next_input_byte = cinfo->src->next_input_byte; 3329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project bytes_in_buffer = cinfo->src->bytes_in_buffer; 3339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 3349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project bytes_in_buffer--; 3359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project c = GETJOCTET(*next_input_byte++); 3369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } while (c == 0xFF); 3379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (c == 0) { 3399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Found FF/00, which represents an FF data byte */ 3409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project c = 0xFF; 3419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } else { 3429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Oops, it's actually a marker indicating end of compressed data. 3439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Save the marker code for later use. 3449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Fine point: it might appear that we should save the marker into 3459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * bitread working state, not straight into permanent state. But 3469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * once we have hit a marker, we cannot need to suspend within the 3479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * current MCU, because we will read no more bytes from the data 3489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * source. So it is OK to update permanent state right away. 3499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 3509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project cinfo->unread_marker = c; 3519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* See if we need to insert some fake zero bits. */ 3529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project goto no_more_bytes; 3539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 3549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 3559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* OK, load c into get_buffer */ 3579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project get_buffer = (get_buffer << 8) | c; 3589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project bits_left += 8; 3599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } /* end while */ 3609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } else { 3619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project no_more_bytes: 3629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* We get here if we've read the marker that terminates the compressed 3639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * data segment. There should be enough bits in the buffer register 3649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * to satisfy the request; if so, no problem. 3659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 3669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (nbits > bits_left) { 3679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Uh-oh. Report corrupted data to user and stuff zeroes into 3689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * the data stream, so that we can produce some kind of image. 3699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * We use a nonvolatile flag to ensure that only one warning message 3709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * appears per data segment. 3719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 3729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (! cinfo->entropy->insufficient_data) { 3739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project WARNMS(cinfo, JWRN_HIT_MARKER); 3749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project cinfo->entropy->insufficient_data = TRUE; 3759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 3769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Fill the buffer with zero bits */ 3779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project get_buffer <<= MIN_GET_BITS - bits_left; 3789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project bits_left = MIN_GET_BITS; 3799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 3809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 3819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Unload the local registers */ 3839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project state->next_input_byte = next_input_byte; 3849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project state->bytes_in_buffer = bytes_in_buffer; 3859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project state->get_buffer = get_buffer; 3869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project state->bits_left = bits_left; 3879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return TRUE; 3899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 3909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 3939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Out-of-line code for Huffman code decoding. 3949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * See jdhuff.h for info about usage. 3959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 3969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 3979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectGLOBAL(int) 3989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectjpeg_huff_decode (bitread_working_state * state, 3999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register bit_buf_type get_buffer, register int bits_left, 4009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl * htbl, int min_bits) 4019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 4029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register int l = min_bits; 4039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register INT32 code; 4049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* HUFF_DECODE has determined that the code is at least min_bits */ 4069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* bits long, so fetch that many bits in one swoop. */ 4079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project CHECK_BIT_BUFFER(*state, l, return -1); 4099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project code = GET_BITS(l); 4109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Collect the rest of the Huffman code one bit at a time. */ 4129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* This is per Figure F.16 in the JPEG spec. */ 4139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project while (code > htbl->maxcode[l]) { 4159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project code <<= 1; 4169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project CHECK_BIT_BUFFER(*state, 1, return -1); 4179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project code |= GET_BITS(1); 4189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project l++; 4199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 4209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Unload the local registers */ 4229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project state->get_buffer = get_buffer; 4239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project state->bits_left = bits_left; 4249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* With garbage input we may reach the sentinel value l = 17. */ 4269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (l > 16) { 4289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project WARNMS(state->cinfo, JWRN_HUFF_BAD_CODE); 4299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return 0; /* fake a zero as the safest result */ 4309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 4319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return htbl->pub->huffval[ (int) (code + htbl->valoffset[l]) ]; 4339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 4349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 4379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Figure F.12: extend sign bit. 4389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * On some machines, a shift and add will be faster than a table lookup. 4399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 4409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#ifdef AVOID_TABLES 4429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define HUFF_EXTEND(x,s) ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x)) 4449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#else 4469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x)) 4489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectstatic const int extend_test[16] = /* entry n is 2**(n-1) */ 4509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project { 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080, 4519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 }; 4529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectstatic const int extend_offset[16] = /* entry n is (-1 << n) + 1 */ 4549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project { 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1, 4559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1, 4569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1, 4579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1 }; 4589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project#endif /* AVOID_TABLES */ 4609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 4639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Check for a restart marker & resynchronize decoder. 4649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Returns FALSE if must suspend. 4659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 4669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectLOCAL(boolean) 4689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectprocess_restart (j_decompress_ptr cinfo) 4699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 4709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; 4719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int ci; 4729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Throw away any unused bits remaining in bit buffer; */ 4749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* include any full bytes in next_marker's count of discarded bytes */ 4759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8; 4769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->bitstate.bits_left = 0; 4779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Advance past the RSTn marker */ 4799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (! (*cinfo->marker->read_restart_marker) (cinfo)) 4809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return FALSE; 4819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Re-initialize DC predictions to 0 */ 4839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (ci = 0; ci < cinfo->comps_in_scan; ci++) 4849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->saved.last_dc_val[ci] = 0; 4859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Reset restart counter */ 4879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->restarts_to_go = cinfo->restart_interval; 4889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Reset out-of-data flag, unless read_restart_marker left us smack up 4909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * against a marker. In that case we will end up treating the next data 4919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * segment as empty, and we can avoid producing bogus output pixels by 4929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * leaving the flag set. 4939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 4949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (cinfo->unread_marker == 0) 4959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->pub.insufficient_data = FALSE; 4969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 4979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return TRUE; 4989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 4999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 5029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Decode and return one MCU's worth of Huffman-compressed coefficients. 5039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * The coefficients are reordered from zigzag order into natural array order, 5049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * but are not dequantized. 5059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 5069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * The i'th block of the MCU is stored into the block pointed to by 5079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * MCU_data[i]. WE ASSUME THIS AREA HAS BEEN ZEROED BY THE CALLER. 5089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * (Wholesale zeroing is usually a little faster than retail...) 5099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * 5109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Returns FALSE if data source requested suspension. In that case no 5119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * changes have been made to permanent state. (Exception: some output 5129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * coefficients may already have been assigned. This is harmless for 5139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * this module, since we'll just re-assign them on the next call.) 5149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 5159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectMETHODDEF(boolean) 5179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectdecode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data) 5189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 5199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; 5209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int blkn; 5219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project BITREAD_STATE_VARS; 5229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project savable_state state; 5239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Process restart marker if needed; may have to suspend */ 5259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (cinfo->restart_interval) { 5269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (entropy->restarts_to_go == 0) 5279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (! process_restart(cinfo)) 5289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return FALSE; 5299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 5309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* If we've run out of data, just leave the MCU set to zeroes. 5329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * This way, we return uniform gray for the remainder of the segment. 5339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 5349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (! entropy->pub.insufficient_data) { 5359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Load up working state */ 5379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project BITREAD_LOAD_STATE(cinfo,entropy->bitstate); 5389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ASSIGN_STATE(state, entropy->saved); 5399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Outer loop handles each block in the MCU */ 5419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { 5439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project JBLOCKROW block = MCU_data[blkn]; 5449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl * dctbl = entropy->dc_cur_tbls[blkn]; 5459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project d_derived_tbl * actbl = entropy->ac_cur_tbls[blkn]; 5469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project register int s, k, r; 5479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Decode a single block's worth of coefficients */ 5499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Section F.2.2.1: decode the DC coefficient difference */ 5519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project HUFF_DECODE(s, br_state, dctbl, return FALSE, label1); 5529f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (s) { 5539f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project CHECK_BIT_BUFFER(br_state, s, return FALSE); 5549f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project r = GET_BITS(s); 5559f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project s = HUFF_EXTEND(r, s); 5569f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 5579f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5589f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (entropy->dc_needed[blkn]) { 5599f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Convert DC difference to actual value, update last_dc_val */ 5609f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int ci = cinfo->MCU_membership[blkn]; 5619f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project s += state.last_dc_val[ci]; 5629f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project state.last_dc_val[ci] = s; 5639f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Output the DC coefficient (assumes jpeg_natural_order[0] = 0) */ 5649f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project (*block)[0] = (JCOEF) s; 5659f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 5669f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5679f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (entropy->ac_needed[blkn]) { 5689f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5699f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Section F.2.2.2: decode the AC coefficients */ 5709f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Since zeroes are skipped, output area must be cleared beforehand */ 5719f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (k = 1; k < DCTSIZE2; k++) { 5729f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project HUFF_DECODE(s, br_state, actbl, return FALSE, label2); 5739f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5749f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project r = s >> 4; 5759f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project s &= 15; 5769f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5779f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (s) { 5789f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project k += r; 5799f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project CHECK_BIT_BUFFER(br_state, s, return FALSE); 5809f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project r = GET_BITS(s); 5819f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project s = HUFF_EXTEND(r, s); 5829f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Output coefficient in natural (dezigzagged) order. 5839f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Note: the extra entries in jpeg_natural_order[] will save us 5849f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * if k >= DCTSIZE2, which could happen if the data is corrupted. 5859f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 5869f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project (*block)[jpeg_natural_order[k]] = (JCOEF) s; 5879f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } else { 5889f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (r != 15) 5899f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project break; 5909f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project k += 15; 5919f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 5929f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 5939f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5949f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } else { 5959f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 5969f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Section F.2.2.2: decode the AC coefficients */ 5979f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* In this path we just discard the values */ 5989f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (k = 1; k < DCTSIZE2; k++) { 5999f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project HUFF_DECODE(s, br_state, actbl, return FALSE, label3); 6009f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6019f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project r = s >> 4; 6029f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project s &= 15; 6039f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6049f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (s) { 6059f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project k += r; 6069f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project CHECK_BIT_BUFFER(br_state, s, return FALSE); 6079f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project DROP_BITS(s); 6089f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } else { 6099f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project if (r != 15) 6109f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project break; 6119f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project k += 15; 6129f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 6139f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 6149f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6159f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 6169f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 6179f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6189f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Completed MCU, so update state */ 6199f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project BITREAD_SAVE_STATE(cinfo,entropy->bitstate); 6209f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project ASSIGN_STATE(entropy->saved, state); 6219f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 6229f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6239f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Account for restart interval (no-op if not using restarts) */ 6249f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->restarts_to_go--; 6259f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6269f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project return TRUE; 6279f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 6289f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6299f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6309f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project/* 6319f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project * Module initialization routine for Huffman entropy decoding. 6329f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project */ 6339f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6349f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source ProjectGLOBAL(void) 6359f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Projectjinit_huff_decoder (j_decompress_ptr cinfo) 6369f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project{ 6379f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project huff_entropy_ptr entropy; 6389f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project int i; 6399f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6409f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy = (huff_entropy_ptr) 6419f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 6429f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project SIZEOF(huff_entropy_decoder)); 6439f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project cinfo->entropy = (struct jpeg_entropy_decoder *) entropy; 6449f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->pub.start_pass = start_pass_huff_decoder; 6459f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->pub.decode_mcu = decode_mcu; 6469f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project 6479f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project /* Mark tables unallocated */ 6489f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project for (i = 0; i < NUM_HUFF_TBLS; i++) { 6499f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL; 6509f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project } 6519f5d49a1588e438ae7ceabd0c94172117e3303aaThe Android Open Source Project} 652