/*

 * jdphuff.c

 *

 * Copyright (C) 1995-1997, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * This file contains Huffman entropy decoding routines for progressive JPEG.

 *

 * Much of the complexity here has to do with supporting input suspension.

 * If the data source module demands suspension, we want to be able to back

 * up to the start of the current MCU.  To do this, we copy state variables

 * into local working storage, and update them back to the permanent

 * storage only upon successful completion of an MCU.

 */

#define JPEG_INTERNALS

#include <limits.h>

#include "jinclude.h"

#include "jpeglib.h"

#include "jdhuff.h"   /* Declarations shared with jdhuff.c */

#ifdef D_PROGRESSIVE_SUPPORTED

/*

 * Expanded entropy decoder object for progressive Huffman decoding.

 *

 * The savable_state subrecord contains fields that change within an MCU,

 * but must not be updated permanently until we complete the MCU.

 */

typedef struct {

  unsigned int EOBRUN;      /* remaining EOBs in EOBRUN */

  int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */

} savable_state;

/* This macro is to work around compilers with missing or broken

 * structure assignment.  You'll need to fix this code if you have

 * such a compiler and you change MAX_COMPS_IN_SCAN.

 */

#ifndef NO_STRUCT_ASSIGN

#define ASSIGN_STATE(dest,src)  ((dest) = (src))

#else

#if MAX_COMPS_IN_SCAN == 4

#define ASSIGN_STATE(dest,src)  \

  ((dest).EOBRUN = (src).EOBRUN, \

   (dest).last_dc_val[0] = (src).last_dc_val[0], \

   (dest).last_dc_val[1] = (src).last_dc_val[1], \

   (dest).last_dc_val[2] = (src).last_dc_val[2], \

   (dest).last_dc_val[3] = (src).last_dc_val[3])

#endif

#endif

typedef struct {

  struct jpeg_entropy_decoder pub; /* public fields */

  /* These fields are loaded into local variables at start of each MCU.

   * In case of suspension, we exit WITHOUT updating them.

   */

  bitread_perm_state bitstate;  /* Bit buffer at start of MCU */

  savable_state saved;    /* Other state at start of MCU */

  /* These fields are NOT loaded into local working state. */

  unsigned int restarts_to_go;  /* MCUs left in this restart interval */

  /* Pointers to derived tables (these workspaces have image lifespan) */

  d_derived_tbl * derived_tbls[NUM_HUFF_TBLS];

  d_derived_tbl * ac_derived_tbl; /* active table during an AC scan */

} phuff_entropy_decoder;

typedef phuff_entropy_decoder * phuff_entropy_ptr;

/* Forward declarations */

METHODDEF(boolean) decode_mcu_DC_first JPP((j_decompress_ptr cinfo,

              JBLOCKROW *MCU_data));

METHODDEF(boolean) decode_mcu_AC_first JPP((j_decompress_ptr cinfo,

              JBLOCKROW *MCU_data));

METHODDEF(boolean) decode_mcu_DC_refine JPP((j_decompress_ptr cinfo,

               JBLOCKROW *MCU_data));

METHODDEF(boolean) decode_mcu_AC_refine JPP((j_decompress_ptr cinfo,

               JBLOCKROW *MCU_data));

/*

 * Initialize for a Huffman-compressed scan.

 */

METHODDEF(void)

start_pass_phuff_decoder (j_decompress_ptr cinfo)

{

  phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

  boolean is_DC_band, bad;

  int ci, coefi, tbl;

  int *coef_bit_ptr;

  jpeg_component_info * compptr;

  is_DC_band = (cinfo->Ss == 0);

  /* Validate scan parameters */

  bad = FALSE;

  if (is_DC_band) {

    if (cinfo->Se != 0)

      bad = TRUE;

  } else {

    /* need not check Ss/Se < 0 since they came from unsigned bytes */

    if (cinfo->Ss > cinfo->Se || cinfo->Se >= DCTSIZE2)

      bad = TRUE;

    /* AC scans may have only one component */

    if (cinfo->comps_in_scan != 1)

      bad = TRUE;

  }

  if (cinfo->Ah != 0) {

    /* Successive approximation refinement scan: must have Al = Ah-1. */

    if (cinfo->Al != cinfo->Ah-1)

      bad = TRUE;

  }

  if (cinfo->Al > 13)    /* need not check for < 0 */

    bad = TRUE;

  /* Arguably the maximum Al value should be less than 13 for 8-bit precision,

   * but the spec doesn't say so, and we try to be liberal about what we

   * accept.  Note: large Al values could result in out-of-range DC

   * coefficients during early scans, leading to bizarre displays due to

   * overflows in the IDCT math.  But we won't crash.

   */

  if (bad)

    ERREXIT4(cinfo, JERR_BAD_PROGRESSION,

       cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al);

  /* Update progression status, and verify that scan order is legal.

   * Note that inter-scan inconsistencies are treated as warnings

   * not fatal errors ... not clear if this is right way to behave.

   */

  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {

    int cindex = cinfo->cur_comp_info[ci]->component_index;

    coef_bit_ptr = & cinfo->coef_bits[cindex][0];

    if (!is_DC_band && coef_bit_ptr[0] < 0) /* AC without prior DC scan */

      WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, 0);

    for (coefi = cinfo->Ss; coefi <= cinfo->Se; coefi++) {

      int expected = (coef_bit_ptr[coefi] < 0) ? 0 : coef_bit_ptr[coefi];

      if (cinfo->Ah != expected)

  WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, coefi);

      coef_bit_ptr[coefi] = cinfo->Al;

    }

  }

  /* Select MCU decoding routine */

  if (cinfo->Ah == 0) {

    if (is_DC_band)

      entropy->pub.decode_mcu = decode_mcu_DC_first;

    else

      entropy->pub.decode_mcu = decode_mcu_AC_first;

  } else {

    if (is_DC_band)

      entropy->pub.decode_mcu = decode_mcu_DC_refine;

    else

      entropy->pub.decode_mcu = decode_mcu_AC_refine;

  }

  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {

    compptr = cinfo->cur_comp_info[ci];

    /* Make sure requested tables are present, and compute derived tables.

     * We may build same derived table more than once, but it's not expensive.

     */

    if (is_DC_band) {

      if (cinfo->Ah == 0) { /* DC refinement needs no table */

  tbl = compptr->dc_tbl_no;

  if (tbl < 0 || tbl >= NUM_HUFF_TBLS)

    ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);

  jpeg_make_d_derived_tbl(cinfo, TRUE, tbl,

        & entropy->derived_tbls[tbl]);

      }

    } else {

      tbl = compptr->ac_tbl_no;

      if (tbl < 0 || tbl >= NUM_HUFF_TBLS)

        ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);

      jpeg_make_d_derived_tbl(cinfo, FALSE, tbl,

            & entropy->derived_tbls[tbl]);

      /* remember the single active table */

      entropy->ac_derived_tbl = entropy->derived_tbls[tbl];

    }

    /* Initialize DC predictions to 0 */

    entropy->saved.last_dc_val[ci] = 0;

  }

  /* Initialize bitread state variables */

  entropy->bitstate.bits_left = 0;

  entropy->bitstate.get_buffer = 0; /* unnecessary, but keeps Purify quiet */

  entropy->pub.insufficient_data = FALSE;

  /* Initialize private state variables */

  entropy->saved.EOBRUN = 0;

  /* Initialize restart counter */

  entropy->restarts_to_go = cinfo->restart_interval;

}

/*

 * Figure F.12: extend sign bit.

 * On some machines, a shift and add will be faster than a table lookup.

 */

#define NEG_1 ((unsigned)-1)

#define AVOID_TABLES

#ifdef AVOID_TABLES

#define HUFF_EXTEND(x,s)  ((x) < (1<<((s)-1)) ? (int)((x) + (((NEG_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, -3, -7, -15, -31, -63, -127, -255, -511, -1023, -2047, -4095, -8191, -16383, -32767 };

#endif /* AVOID_TABLES */

/*

 * Check for a restart marker & resynchronize decoder.

 * Returns FALSE if must suspend.

 */

LOCAL(boolean)

process_restart (j_decompress_ptr cinfo)

{

  phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

  int ci;

  /* Throw away any unused bits remaining in bit buffer; */

  /* include any full bytes in next_marker's count of discarded bytes */

  cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8;

  entropy->bitstate.bits_left = 0;

  /* Advance past the RSTn marker */

  if (! (*cinfo->marker->read_restart_marker) (cinfo))

    return FALSE;

  /* Re-initialize DC predictions to 0 */

  for (ci = 0; ci < cinfo->comps_in_scan; ci++)

    entropy->saved.last_dc_val[ci] = 0;

  /* Re-init EOB run count, too */

  entropy->saved.EOBRUN = 0;

  /* Reset restart counter */

  entropy->restarts_to_go = cinfo->restart_interval;

  /* Reset out-of-data flag, unless read_restart_marker left us smack up

   * against a marker.  In that case we will end up treating the next data

   * segment as empty, and we can avoid producing bogus output pixels by

   * leaving the flag set.

   */

  if (cinfo->unread_marker == 0)

    entropy->pub.insufficient_data = FALSE;

  return TRUE;

}

/*

 * Huffman MCU decoding.

 * Each of these routines decodes and returns one MCU's worth of

 * Huffman-compressed coefficients. 

 * The coefficients are reordered from zigzag order into natural array order,

 * but are not dequantized.

 *

 * The i'th block of the MCU is stored into the block pointed to by

 * MCU_data[i].  WE ASSUME THIS AREA IS INITIALLY ZEROED BY THE CALLER.

 *

 * We return FALSE if data source requested suspension.  In that case no

 * changes have been made to permanent state.  (Exception: some output

 * coefficients may already have been assigned.  This is harmless for

 * spectral selection, since we'll just re-assign them on the next call.

 * Successive approximation AC refinement has to be more careful, however.)

 */

/*

 * MCU decoding for DC initial scan (either spectral selection,

 * or first pass of successive approximation).

 */

METHODDEF(boolean)

decode_mcu_DC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)

{   

  phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

  int Al = cinfo->Al;

  register int s, r;

  int blkn, ci;

  JBLOCKROW block;

  BITREAD_STATE_VARS;

  savable_state state;

  d_derived_tbl * tbl;

  jpeg_component_info * compptr;

  /* Process restart marker if needed; may have to suspend */

  if (cinfo->restart_interval) {

    if (entropy->restarts_to_go == 0)

      if (! process_restart(cinfo))

  return FALSE;

  }

  /* If we've run out of data, just leave the MCU set to zeroes.

   * This way, we return uniform gray for the remainder of the segment.

   */

  if (! entropy->pub.insufficient_data) {

    /* Load up working state */

    BITREAD_LOAD_STATE(cinfo,entropy->bitstate);

    ASSIGN_STATE(state, entropy->saved);

    /* Outer loop handles each block in the MCU */

    for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {

      block = MCU_data[blkn];

      ci = cinfo->MCU_membership[blkn];

      compptr = cinfo->cur_comp_info[ci];

      tbl = entropy->derived_tbls[compptr->dc_tbl_no];

      /* Decode a single block's worth of coefficients */

      /* Section F.2.2.1: decode the DC coefficient difference */

      HUFF_DECODE(s, br_state, tbl, return FALSE, label1);

      if (s) {

  CHECK_BIT_BUFFER(br_state, s, return FALSE);

  r = GET_BITS(s);

  s = HUFF_EXTEND(r, s);

      }

      /* Convert DC difference to actual value, update last_dc_val */

      if( (state.last_dc_val[ci] >= 0 && s > INT_MAX - state.last_dc_val[ci]) ||

          (state.last_dc_val[ci] < 0 && s < INT_MIN - state.last_dc_val[ci]) ) {

        ERREXIT(cinfo, JERR_BAD_DCT_COEF);

      }

      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) LEFT_SHIFT(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) */

  if( entropy->restarts_to_go == 0 )

      entropy->restarts_to_go = ~0U;

  else

      entropy->restarts_to_go--;

  return TRUE;

}

/*

 * MCU decoding for AC initial scan (either spectral selection,

 * or first pass of successive approximation).

 */

METHODDEF(boolean)

decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)

{   

  phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

  int Se = cinfo->Se;

  int Al = cinfo->Al;

  register int s, k, r;

  unsigned int EOBRUN;

  JBLOCKROW block;

  BITREAD_STATE_VARS;

  d_derived_tbl * tbl;

  /* Process restart marker if needed; may have to suspend */

  if (cinfo->restart_interval) {

    if (entropy->restarts_to_go == 0)

      if (! process_restart(cinfo))

  return FALSE;

  }

  /* If we've run out of data, just leave the MCU set to zeroes.

   * This way, we return uniform gray for the remainder of the segment.

   */

  if (! entropy->pub.insufficient_data) {

    /* Load up working state.

     * We can avoid loading/saving bitread state if in an EOB run.

     */

    EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */

    /* There is always only one block per MCU */

    if (EOBRUN > 0)    /* if it's a band of zeroes... */

      EOBRUN--;      /* ...process it now (we do nothing) */

    else {

      BITREAD_LOAD_STATE(cinfo,entropy->bitstate);

      block = MCU_data[0];

      tbl = entropy->ac_derived_tbl;

      for (k = cinfo->Ss; k <= Se; k++) {

  HUFF_DECODE(s, br_state, tbl, return FALSE, label2);

  r = s >> 4;

  s &= 15;

  if (s) {

    k += r;

    CHECK_BIT_BUFFER(br_state, s, return FALSE);

    r = GET_BITS(s);

    s = HUFF_EXTEND(r, s);

    /* Scale and output coefficient in natural (dezigzagged) order */

    (*block)[jpeg_natural_order[k]] = (JCOEF) LEFT_SHIFT(s, Al);

  } else {

    if (r == 15) { /* ZRL */

      k += 15;    /* skip 15 zeroes in band */

    } else {   /* EOBr, run length is 2^r + appended bits */

      EOBRUN = 1 << r;

      if (r) {   /* EOBr, r > 0 */

        CHECK_BIT_BUFFER(br_state, r, return FALSE);

        r = GET_BITS(r);

        EOBRUN += r;

      }

      EOBRUN--;   /* this band is processed at this moment */

      break;   /* force end-of-band */

    }

  }

      }

      BITREAD_SAVE_STATE(cinfo,entropy->bitstate);

    }

    /* Completed MCU, so update state */

    entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */

  }

  /* Account for restart interval (no-op if not using restarts) */

  if( entropy->restarts_to_go == 0 )

      entropy->restarts_to_go = ~0U;

  else

      entropy->restarts_to_go--;

  return TRUE;

}

/*

 * MCU decoding for DC successive approximation refinement scan.

 * Note: we assume such scans can be multi-component, although the spec

 * is not very clear on the point.

 */

METHODDEF(boolean)

decode_mcu_DC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)

{   

  phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

  int p1 = 1 << cinfo->Al;  /* 1 in the bit position being coded */

  int blkn;

  JBLOCKROW block;

  BITREAD_STATE_VARS;

  /* Process restart marker if needed; may have to suspend */

  if (cinfo->restart_interval) {

    if (entropy->restarts_to_go == 0)

      if (! process_restart(cinfo))

  return FALSE;

  }

  /* Not worth the cycles to check insufficient_data here,

   * since we will not change the data anyway if we read zeroes.

   */

  /* Load up working state */

  BITREAD_LOAD_STATE(cinfo,entropy->bitstate);

  /* Outer loop handles each block in the MCU */

  for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {

    block = MCU_data[blkn];

    /* Encoded data is simply the next bit of the two's-complement DC value */

    CHECK_BIT_BUFFER(br_state, 1, return FALSE);

    if (GET_BITS(1))

      (*block)[0] |= p1;

    /* Note: since we use |=, repeating the assignment later is safe */

  }

  /* Completed MCU, so update state */

  BITREAD_SAVE_STATE(cinfo,entropy->bitstate);

  /* Account for restart interval (no-op if not using restarts) */

  if( entropy->restarts_to_go == 0 )

      entropy->restarts_to_go = ~0U;

  else

      entropy->restarts_to_go--;

  return TRUE;

}

/*

 * MCU decoding for AC successive approximation refinement scan.

 */

METHODDEF(boolean)

decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)

{   

  phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

  int Se = cinfo->Se;

  int p1 = 1 << cinfo->Al;  /* 1 in the bit position being coded */

  int m1 = (NEG_1) << cinfo->Al; /* -1 in the bit position being coded */

  register int s, k, r;

  unsigned int EOBRUN;

  JBLOCKROW block;

  JCOEFPTR thiscoef;

  BITREAD_STATE_VARS;

  d_derived_tbl * tbl;

  int num_newnz;

  int newnz_pos[DCTSIZE2];

  /* Process restart marker if needed; may have to suspend */

  if (cinfo->restart_interval) {

    if (entropy->restarts_to_go == 0)

      if (! process_restart(cinfo))

  return FALSE;

  }

  /* If we've run out of data, don't modify the MCU.

   */

  if (! entropy->pub.insufficient_data) {

    /* Load up working state */

    BITREAD_LOAD_STATE(cinfo,entropy->bitstate);

    EOBRUN = entropy->saved.EOBRUN; /* only part of saved state we need */

    /* There is always only one block per MCU */

    block = MCU_data[0];

    tbl = entropy->ac_derived_tbl;

    /* If we are forced to suspend, we must undo the assignments to any newly

     * nonzero coefficients in the block, because otherwise we'd get confused

     * next time about which coefficients were already nonzero.

     * But we need not undo addition of bits to already-nonzero coefficients;

     * instead, we can test the current bit to see if we already did it.

     */

    num_newnz = 0;

    /* initialize coefficient loop counter to start of band */

    k = cinfo->Ss;

    if (EOBRUN == 0) {

      for (; k <= Se; k++) {

  HUFF_DECODE(s, br_state, tbl, goto undoit, label3);

  r = s >> 4;

  s &= 15;

  if (s) {

    if (s != 1)    /* size of new coef should always be 1 */

      WARNMS(cinfo, JWRN_HUFF_BAD_CODE);

    CHECK_BIT_BUFFER(br_state, 1, goto undoit);

    if (GET_BITS(1))

      s = p1;    /* newly nonzero coef is positive */

    else

      s = m1;   /* newly nonzero coef is negative */

  } else {

    if (r != 15) {

      EOBRUN = 1 << r;  /* EOBr, run length is 2^r + appended bits */

      if (r) {

        CHECK_BIT_BUFFER(br_state, r, goto undoit);

        r = GET_BITS(r);

        EOBRUN += r;

      }

      break;   /* rest of block is handled by EOB logic */

    }

    /* note s = 0 for processing ZRL */

  }

  /* Advance over already-nonzero coefs and r still-zero coefs,

   * appending correction bits to the nonzeroes.  A correction bit is 1

   * if the absolute value of the coefficient must be increased.

   */

  do {

    thiscoef = *block + jpeg_natural_order[k];

    if (*thiscoef != 0) {

      CHECK_BIT_BUFFER(br_state, 1, goto undoit);

      if (GET_BITS(1)) {

        if ((*thiscoef & p1) == 0) { /* do nothing if already set it */

    if (*thiscoef >= 0)

      *thiscoef += p1;

    else

      *thiscoef += m1;

        }

      }

    } else {

      if (--r < 0)

        break;   /* reached target zero coefficient */

    }

    k++;

  } while (k <= Se);

  if (s) {

    int pos = jpeg_natural_order[k];

    /* Output newly nonzero coefficient */

    (*block)[pos] = (JCOEF) s;

    /* Remember its position in case we have to suspend */

    newnz_pos[num_newnz++] = pos;

  }

      }

    }

    if (EOBRUN > 0) {

      /* Scan any remaining coefficient positions after the end-of-band

       * (the last newly nonzero coefficient, if any).  Append a correction

       * bit to each already-nonzero coefficient.  A correction bit is 1

       * if the absolute value of the coefficient must be increased.

       */

      for (; k <= Se; k++) {

  thiscoef = *block + jpeg_natural_order[k];

  if (*thiscoef != 0) {

    CHECK_BIT_BUFFER(br_state, 1, goto undoit);

    if (GET_BITS(1)) {

      if ((*thiscoef & p1) == 0) { /* do nothing if already changed it */

        if (*thiscoef >= 0)

    *thiscoef += p1;

        else

    *thiscoef += m1;

      }

    }

  }

      }

      /* Count one block completed in EOB run */

      EOBRUN--;

    }

    /* Completed MCU, so update state */

    BITREAD_SAVE_STATE(cinfo,entropy->bitstate);

    entropy->saved.EOBRUN = EOBRUN; /* only part of saved state we need */

  }

  /* Account for restart interval (no-op if not using restarts) */

  if( entropy->restarts_to_go == 0 )

      entropy->restarts_to_go = ~0U;

  else

      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)

{

  phuff_entropy_ptr entropy;

  int *coef_bit_ptr;

  int ci, i;

  entropy = (phuff_entropy_ptr)

    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

        SIZEOF(phuff_entropy_decoder));

  cinfo->entropy = (struct jpeg_entropy_decoder *) entropy;

  entropy->pub.start_pass = start_pass_phuff_decoder;

  /* Mark derived tables unallocated */

  for (i = 0; i < NUM_HUFF_TBLS; i++) {

    entropy->derived_tbls[i] = NULL;

  }

  /* Create progression status table */

  cinfo->coef_bits = (int (*)[DCTSIZE2])

    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

        cinfo->num_components*DCTSIZE2*SIZEOF(int));

  coef_bit_ptr = & cinfo->coef_bits[0][0];

  for (ci = 0; ci < cinfo->num_components; ci++) 

    for (i = 0; i < DCTSIZE2; i++)

      *coef_bit_ptr++ = -1;

}

#endif /* D_PROGRESSIVE_SUPPORTED */