text: /*
   * jdphuff.c
   *
   * Copyright (C) 1995-1998, 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 "jinclude8.h"
  #include "jpeglib8.h"
  #include "jlossy8.h"        /* Private declarations for lossy subsystem */
  #include "jdhuff8.h"        /* Declarations shared with jd*huff.c */
  
  
  #ifdef D_PROGRESSIVE_SUPPORTED
  
  /*
   * Private 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 {
    huffd_common_fields;      /* Fields shared with other entropy decoders */
  
    /* These fields are loaded into local variables at start of each MCU.
     * In case of suspension, we exit WITHOUT updating them.
     */
    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)
  {
    j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
    phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
    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)
        lossyd->entropy_decode_mcu = decode_mcu_DC_first;
      else
        lossyd->entropy_decode_mcu = decode_mcu_AC_first;
    } else {
      if (is_DC_band)
        lossyd->entropy_decode_mcu = decode_mcu_DC_refine;
      else
        lossyd->entropy_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->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, ((-1u)<<1) + 1, ((-1u)<<2) + 1, ((-1u)<<3) + 1, ((-1u)<<4) + 1,
      ((-1u)<<5) + 1, ((-1u)<<6) + 1, ((-1u)<<7) + 1, ((-1u)<<8) + 1,
      ((-1u)<<9) + 1, ((-1u)<<10) + 1, ((-1u)<<11) + 1, ((-1u)<<12) + 1,
      ((-1u)<<13) + 1, ((-1u)<<14) + 1, ((-1u)<<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)
  {
    j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
    phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
    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 += (unsigned int)(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->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)
  {   
    j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
    phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
    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->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->data_units_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)
  {   
    j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
    phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
    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->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 = (unsigned int)(1 << r);
          if (r) {        /* EOBr, r > 0 */
            CHECK_BIT_BUFFER(br_state, r, return FALSE);
            r = GET_BITS(r);
            EOBRUN += (unsigned int)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)
  {   
    j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
    phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
    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->data_units_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] |= (JCOEF)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)
  {   
    j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
    phuff_entropy_ptr entropy = (phuff_entropy_ptr) lossyd->entropy_private;
    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->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 = (unsigned int)(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 += (unsigned int)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;
  }
  
  
  /*
   * Module initialization routine for progressive Huffman entropy decoding.
   */
  
  GLOBAL(void)
  jinit_phuff_decoder (j_decompress_ptr cinfo)
  {
    j_lossy_d_ptr lossyd = (j_lossy_d_ptr) cinfo->codec;
    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));
    lossyd->entropy_private = (void *) entropy;
    lossyd->entropy_start_pass = start_pass_phuff_decoder;
  
    /* 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,
                  (size_t)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 */
  