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 /*

  * jcphuff.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 encoding routines for progressive JPEG.

  *

  * We do not support output suspension in this module, since the library

  * currently does not allow multiple-scan files to be written with output

  * suspension.

  */

 #define JPEG_INTERNALS

 #include "jinclude.h"

 #include "jpeglib.h"

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

 #ifdef C_PROGRESSIVE_SUPPORTED

 /* Expanded entropy encoder object for progressive Huffman encoding. */

 typedef struct {

   struct jpeg_entropy_encoder pub; /* public fields */

   /* Mode flag: TRUE for optimization, FALSE for actual data output */

   boolean gather_statistics;

   /* Bit-level coding status.

    * next_output_byte/free_in_buffer are local copies of cinfo->dest fields.

    */

   JOCTET * next_output_byte;	/* => next byte to write in buffer */

   size_t free_in_buffer;	/* # of byte spaces remaining in buffer */

   INT32 put_buffer;		/* current bit-accumulation buffer */

   int put_bits;			/* # of bits now in it */

   j_compress_ptr cinfo;		/* link to cinfo (needed for dump_buffer) */

   /* Coding status for DC components */

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

   /* Coding status for AC components */

   int ac_tbl_no;		/* the table number of the single component */

   unsigned int EOBRUN;		/* run length of EOBs */

   unsigned int BE;		/* # of buffered correction bits before MCU */

   char * bit_buffer;		/* buffer for correction bits (1 per char) */

   /* packing correction bits tightly would save some space but cost time... */

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

   int next_restart_num;		/* next restart number to write (0-7) */

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

    * Since any one scan codes only DC or only AC, we only need one set

    * of tables, not one for DC and one for AC.

    */

   c_derived_tbl * derived_tbls[NUM_HUFF_TBLS];

   /* Statistics tables for optimization; again, one set is enough */

   long * count_ptrs[NUM_HUFF_TBLS];

 } phuff_entropy_encoder;

 typedef phuff_entropy_encoder * phuff_entropy_ptr;

 /* MAX_CORR_BITS is the number of bits the AC refinement correction-bit

  * buffer can hold.  Larger sizes may slightly improve compression, but

  * 1000 is already well into the realm of overkill.

  * The minimum safe size is 64 bits.

  */

 #define MAX_CORR_BITS  1000	/* Max # of correction bits I can buffer */

 /* IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than INT32.

  * We assume that int right shift is unsigned if INT32 right shift is,

  * which should be safe.

  */

 #ifdef RIGHT_SHIFT_IS_UNSIGNED

 #define ISHIFT_TEMPS	int ishift_temp;

 #define IRIGHT_SHIFT(x,shft)  \

 	((ishift_temp = (x)) < 0 ? \

 	 (ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \

 	 (ishift_temp >> (shft)))

 #else

 #define ISHIFT_TEMPS

 #define IRIGHT_SHIFT(x,shft)	((x) >> (shft))

 #endif

 /* Forward declarations */

 METHODDEF(boolean) encode_mcu_DC_first JPP((j_compress_ptr cinfo,

 					    JBLOCKROW *MCU_data));

 METHODDEF(boolean) encode_mcu_AC_first JPP((j_compress_ptr cinfo,

 					    JBLOCKROW *MCU_data));

 METHODDEF(boolean) encode_mcu_DC_refine JPP((j_compress_ptr cinfo,

 					     JBLOCKROW *MCU_data));

 METHODDEF(boolean) encode_mcu_AC_refine JPP((j_compress_ptr cinfo,

 					     JBLOCKROW *MCU_data));

 METHODDEF(void) finish_pass_phuff JPP((j_compress_ptr cinfo));

 METHODDEF(void) finish_pass_gather_phuff JPP((j_compress_ptr cinfo));

 /*

  * Initialize for a Huffman-compressed scan using progressive JPEG.

  */

 METHODDEF(void)

 start_pass_phuff (j_compress_ptr cinfo, boolean gather_statistics)

 {  

   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

   boolean is_DC_band;

   int ci, tbl;

   jpeg_component_info * compptr;

   entropy->cinfo = cinfo;

   entropy->gather_statistics = gather_statistics;

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

   /* We assume jcmaster.c already validated the scan parameters. */

   /* Select execution routines */

   if (cinfo->Ah == 0) {

     if (is_DC_band)

       entropy->pub.encode_mcu = encode_mcu_DC_first;

     else

       entropy->pub.encode_mcu = encode_mcu_AC_first;

   } else {

     if (is_DC_band)

       entropy->pub.encode_mcu = encode_mcu_DC_refine;

     else {

       entropy->pub.encode_mcu = encode_mcu_AC_refine;

       /* AC refinement needs a correction bit buffer */

       if (entropy->bit_buffer == NULL)

 	entropy->bit_buffer = (char *)

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

 				      MAX_CORR_BITS * SIZEOF(char));

     }

   }

   if (gather_statistics)

     entropy->pub.finish_pass = finish_pass_gather_phuff;

   else

     entropy->pub.finish_pass = finish_pass_phuff;

   /* Only DC coefficients may be interleaved, so cinfo->comps_in_scan = 1

    * for AC coefficients.

    */

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

     compptr = cinfo->cur_comp_info[ci];

     /* Initialize DC predictions to 0 */

     entropy->last_dc_val[ci] = 0;

     /* Get table index */

     if (is_DC_band) {

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

 	continue;

       tbl = compptr->dc_tbl_no;

     } else {

       entropy->ac_tbl_no = tbl = compptr->ac_tbl_no;

     }

     if (gather_statistics) {

       /* Check for invalid table index */

       /* (make_c_derived_tbl does this in the other path) */

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

         ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);

       /* Allocate and zero the statistics tables */

       /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */

       if (entropy->count_ptrs[tbl] == NULL)

 	entropy->count_ptrs[tbl] = (long *)

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

 				      257 * SIZEOF(long));

       MEMZERO(entropy->count_ptrs[tbl], 257 * SIZEOF(long));

     } else {

       /* Compute derived values for Huffman table */

       /* We may do this more than once for a table, but it's not expensive */

       jpeg_make_c_derived_tbl(cinfo, is_DC_band, tbl,

 			      & entropy->derived_tbls[tbl]);

     }

   }

   /* Initialize AC stuff */

   entropy->EOBRUN = 0;

   entropy->BE = 0;

   /* Initialize bit buffer to empty */

   entropy->put_buffer = 0;

   entropy->put_bits = 0;

   /* Initialize restart stuff */

   entropy->restarts_to_go = cinfo->restart_interval;

   entropy->next_restart_num = 0;

 }

 /* Outputting bytes to the file.

  * NB: these must be called only when actually outputting,

  * that is, entropy->gather_statistics == FALSE.

  */

 /* Emit a byte */

 #define emit_byte(entropy,val)  \

 	{ *(entropy)->next_output_byte++ = (JOCTET) (val);  \

 	  if (--(entropy)->free_in_buffer == 0)  \

 	    dump_buffer(entropy); }

 LOCAL(void)

 dump_buffer (phuff_entropy_ptr entropy)

 /* Empty the output buffer; we do not support suspension in this module. */

 {

   struct jpeg_destination_mgr * dest = entropy->cinfo->dest;

   if (! (*dest->empty_output_buffer) (entropy->cinfo))

     ERREXIT(entropy->cinfo, JERR_CANT_SUSPEND);

   /* After a successful buffer dump, must reset buffer pointers */

   entropy->next_output_byte = dest->next_output_byte;

   entropy->free_in_buffer = dest->free_in_buffer;

 }

 /* Outputting bits to the file */

 /* Only the right 24 bits of put_buffer are used; the valid bits are

  * left-justified in this part.  At most 16 bits can be passed to emit_bits

  * in one call, and we never retain more than 7 bits in put_buffer

  * between calls, so 24 bits are sufficient.

  */

 LOCAL(void)

 emit_bits (phuff_entropy_ptr entropy, unsigned int code, int size)

 /* Emit some bits, unless we are in gather mode */

 {

   /* This routine is heavily used, so it's worth coding tightly. */

   register INT32 put_buffer = (INT32) code;

   register int put_bits = entropy->put_bits;

   /* if size is 0, caller used an invalid Huffman table entry */

   if (size == 0)

     ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);

   if (entropy->gather_statistics)

     return;			/* do nothing if we're only getting stats */

   put_buffer &= (((INT32) 1)<<size) - 1; /* mask off any extra bits in code */

   put_bits += size;		/* new number of bits in buffer */

   put_buffer <<= 24 - put_bits; /* align incoming bits */

   put_buffer |= entropy->put_buffer; /* and merge with old buffer contents */

   while (put_bits >= 8) {

     int c = (int) ((put_buffer >> 16) & 0xFF);

     emit_byte(entropy, c);

     if (c == 0xFF) {		/* need to stuff a zero byte? */

       emit_byte(entropy, 0);

     }

     put_buffer <<= 8;

     put_bits -= 8;

   }

   entropy->put_buffer = put_buffer; /* update variables */

   entropy->put_bits = put_bits;

 }

 LOCAL(void)

 flush_bits (phuff_entropy_ptr entropy)

 {

   emit_bits(entropy, 0x7F, 7); /* fill any partial byte with ones */

   entropy->put_buffer = 0;     /* and reset bit-buffer to empty */

   entropy->put_bits = 0;

 }

 /*

  * Emit (or just count) a Huffman symbol.

  */

 LOCAL(void)

 emit_symbol (phuff_entropy_ptr entropy, int tbl_no, int symbol)

 {

   if (entropy->gather_statistics)

     entropy->count_ptrs[tbl_no][symbol]++;

   else {

     c_derived_tbl * tbl = entropy->derived_tbls[tbl_no];

     emit_bits(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);

   }

 }

 /*

  * Emit bits from a correction bit buffer.

  */

 LOCAL(void)

 emit_buffered_bits (phuff_entropy_ptr entropy, char * bufstart,

 		    unsigned int nbits)

 {

   if (entropy->gather_statistics)

     return;			/* no real work */

   while (nbits > 0) {

     emit_bits(entropy, (unsigned int) (*bufstart), 1);

     bufstart++;

     nbits--;

   }

 }

 /*

  * Emit any pending EOBRUN symbol.

  */

 LOCAL(void)

 emit_eobrun (phuff_entropy_ptr entropy)

 {

   register int temp, nbits;

   if (entropy->EOBRUN > 0) {	/* if there is any pending EOBRUN */

     temp = entropy->EOBRUN;

     nbits = 0;

     while ((temp >>= 1))

       nbits++;

     /* safety check: shouldn't happen given limited correction-bit buffer */

     if (nbits > 14)

       ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);

     emit_symbol(entropy, entropy->ac_tbl_no, nbits << 4);

     if (nbits)

       emit_bits(entropy, entropy->EOBRUN, nbits);

     entropy->EOBRUN = 0;

     /* Emit any buffered correction bits */

     emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE);

     entropy->BE = 0;

   }

 }

 /*

  * Emit a restart marker & resynchronize predictions.

  */

 LOCAL(void)

 emit_restart (phuff_entropy_ptr entropy, int restart_num)

 {

   int ci;

   emit_eobrun(entropy);

   if (! entropy->gather_statistics) {

     flush_bits(entropy);

     emit_byte(entropy, 0xFF);

     emit_byte(entropy, JPEG_RST0 + restart_num);

   }

   if (entropy->cinfo->Ss == 0) {

     /* Re-initialize DC predictions to 0 */

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

       entropy->last_dc_val[ci] = 0;

   } else {

     /* Re-initialize all AC-related fields to 0 */

     entropy->EOBRUN = 0;

     entropy->BE = 0;

   }

 }

 /*

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

  * or first pass of successive approximation).

  */

 METHODDEF(boolean)

 encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)

 {

   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

   register int temp, temp2;

   register int nbits;

   int blkn, ci;

   int Al = cinfo->Al;

   JBLOCKROW block;

   jpeg_component_info * compptr;

   ISHIFT_TEMPS

   entropy->next_output_byte = cinfo->dest->next_output_byte;

   entropy->free_in_buffer = cinfo->dest->free_in_buffer;

   /* Emit restart marker if needed */

   if (cinfo->restart_interval)

     if (entropy->restarts_to_go == 0)

       emit_restart(entropy, entropy->next_restart_num);

   /* Encode the MCU data blocks */

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

     block = MCU_data[blkn];

     ci = cinfo->MCU_membership[blkn];

     compptr = cinfo->cur_comp_info[ci];

     /* Compute the DC value after the required point transform by Al.

      * This is simply an arithmetic right shift.

      */

     temp2 = IRIGHT_SHIFT((int) ((*block)[0]), Al);

     /* DC differences are figured on the point-transformed values. */

     temp = temp2 - entropy->last_dc_val[ci];

     entropy->last_dc_val[ci] = temp2;

     /* Encode the DC coefficient difference per section G.1.2.1 */

     temp2 = temp;

     if (temp < 0) {

       temp = -temp;		/* temp is abs value of input */

       /* For a negative input, want temp2 = bitwise complement of abs(input) */

       /* This code assumes we are on a two's complement machine */

       temp2--;

     }

     /* Find the number of bits needed for the magnitude of the coefficient */

     nbits = 0;

     while (temp) {

       nbits++;

       temp >>= 1;

     }

     /* Check for out-of-range coefficient values.

      * Since we're encoding a difference, the range limit is twice as much.

      */

     if (nbits > MAX_COEF_BITS+1)

       ERREXIT(cinfo, JERR_BAD_DCT_COEF);

     /* Count/emit the Huffman-coded symbol for the number of bits */

     emit_symbol(entropy, compptr->dc_tbl_no, nbits);

     /* Emit that number of bits of the value, if positive, */

     /* or the complement of its magnitude, if negative. */

     if (nbits)			/* emit_bits rejects calls with size 0 */

       emit_bits(entropy, (unsigned int) temp2, nbits);

   }

   cinfo->dest->next_output_byte = entropy->next_output_byte;

   cinfo->dest->free_in_buffer = entropy->free_in_buffer;

   /* Update restart-interval state too */

   if (cinfo->restart_interval) {

     if (entropy->restarts_to_go == 0) {

       entropy->restarts_to_go = cinfo->restart_interval;

       entropy->next_restart_num++;

       entropy->next_restart_num &= 7;

     }

     entropy->restarts_to_go--;

   }

   return TRUE;

 }

 /*

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

  * or first pass of successive approximation).

  */

 METHODDEF(boolean)

 encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)

 {

   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

   register int temp, temp2;

   register int nbits;

   register int r, k;

   int Se = cinfo->Se;

   int Al = cinfo->Al;

   JBLOCKROW block;

   entropy->next_output_byte = cinfo->dest->next_output_byte;

   entropy->free_in_buffer = cinfo->dest->free_in_buffer;

   /* Emit restart marker if needed */

   if (cinfo->restart_interval)

     if (entropy->restarts_to_go == 0)

       emit_restart(entropy, entropy->next_restart_num);

   /* Encode the MCU data block */

   block = MCU_data[0];

   /* Encode the AC coefficients per section G.1.2.2, fig. G.3 */

   r = 0;			/* r = run length of zeros */

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

     if ((temp = (*block)[jpeg_natural_order[k]]) == 0) {

       r++;

       continue;

     }

     /* We must apply the point transform by Al.  For AC coefficients this

      * is an integer division with rounding towards 0.  To do this portably

      * in C, we shift after obtaining the absolute value; so the code is

      * interwoven with finding the abs value (temp) and output bits (temp2).

      */

     if (temp < 0) {

       temp = -temp;		/* temp is abs value of input */

       temp >>= Al;		/* apply the point transform */

       /* For a negative coef, want temp2 = bitwise complement of abs(coef) */

       temp2 = ~temp;

     } else {

       temp >>= Al;		/* apply the point transform */

       temp2 = temp;

     }

     /* Watch out for case that nonzero coef is zero after point transform */

     if (temp == 0) {

       r++;

       continue;

     }

     /* Emit any pending EOBRUN */

     if (entropy->EOBRUN > 0)

       emit_eobrun(entropy);

     /* if run length > 15, must emit special run-length-16 codes (0xF0) */

     while (r > 15) {

       emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);

       r -= 16;

     }

     /* Find the number of bits needed for the magnitude of the coefficient */

     nbits = 1;			/* there must be at least one 1 bit */

     while ((temp >>= 1))

       nbits++;

     /* Check for out-of-range coefficient values */

     if (nbits > MAX_COEF_BITS)

       ERREXIT(cinfo, JERR_BAD_DCT_COEF);

     /* Count/emit Huffman symbol for run length / number of bits */

     emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + nbits);

     /* Emit that number of bits of the value, if positive, */

     /* or the complement of its magnitude, if negative. */

     emit_bits(entropy, (unsigned int) temp2, nbits);

     r = 0;			/* reset zero run length */

   }

   if (r > 0) {			/* If there are trailing zeroes, */

     entropy->EOBRUN++;		/* count an EOB */

     if (entropy->EOBRUN == 0x7FFF)

       emit_eobrun(entropy);	/* force it out to avoid overflow */

   }

   cinfo->dest->next_output_byte = entropy->next_output_byte;

   cinfo->dest->free_in_buffer = entropy->free_in_buffer;

   /* Update restart-interval state too */

   if (cinfo->restart_interval) {

     if (entropy->restarts_to_go == 0) {

       entropy->restarts_to_go = cinfo->restart_interval;

       entropy->next_restart_num++;

       entropy->next_restart_num &= 7;

     }

     entropy->restarts_to_go--;

   }

   return TRUE;

 }

 /*

  * MCU encoding 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)

 encode_mcu_DC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)

 {

   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

   register int temp;

   int blkn;

   int Al = cinfo->Al;

   JBLOCKROW block;

   entropy->next_output_byte = cinfo->dest->next_output_byte;

   entropy->free_in_buffer = cinfo->dest->free_in_buffer;

   /* Emit restart marker if needed */

   if (cinfo->restart_interval)

     if (entropy->restarts_to_go == 0)

       emit_restart(entropy, entropy->next_restart_num);

   /* Encode the MCU data blocks */

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

     block = MCU_data[blkn];

     /* We simply emit the Al'th bit of the DC coefficient value. */

     temp = (*block)[0];

     emit_bits(entropy, (unsigned int) (temp >> Al), 1);

   }

   cinfo->dest->next_output_byte = entropy->next_output_byte;

   cinfo->dest->free_in_buffer = entropy->free_in_buffer;

   /* Update restart-interval state too */

   if (cinfo->restart_interval) {

     if (entropy->restarts_to_go == 0) {

       entropy->restarts_to_go = cinfo->restart_interval;

       entropy->next_restart_num++;

       entropy->next_restart_num &= 7;

     }

     entropy->restarts_to_go--;

   }

   return TRUE;

 }

 /*

  * MCU encoding for AC successive approximation refinement scan.

  */

 METHODDEF(boolean)

 encode_mcu_AC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)

 {

   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

   register int temp;

   register int r, k;

   int EOB;

   char *BR_buffer;

   unsigned int BR;

   int Se = cinfo->Se;

   int Al = cinfo->Al;

   JBLOCKROW block;

   int absvalues[DCTSIZE2];

   entropy->next_output_byte = cinfo->dest->next_output_byte;

   entropy->free_in_buffer = cinfo->dest->free_in_buffer;

   /* Emit restart marker if needed */

   if (cinfo->restart_interval)

     if (entropy->restarts_to_go == 0)

       emit_restart(entropy, entropy->next_restart_num);

   /* Encode the MCU data block */

   block = MCU_data[0];

   /* It is convenient to make a pre-pass to determine the transformed

    * coefficients' absolute values and the EOB position.

    */

   EOB = 0;

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

     temp = (*block)[jpeg_natural_order[k]];

     /* We must apply the point transform by Al.  For AC coefficients this

      * is an integer division with rounding towards 0.  To do this portably

      * in C, we shift after obtaining the absolute value.

      */

     if (temp < 0)

       temp = -temp;		/* temp is abs value of input */

     temp >>= Al;		/* apply the point transform */

     absvalues[k] = temp;	/* save abs value for main pass */

     if (temp == 1)

       EOB = k;			/* EOB = index of last newly-nonzero coef */

   }

   /* Encode the AC coefficients per section G.1.2.3, fig. G.7 */

   r = 0;			/* r = run length of zeros */

   BR = 0;			/* BR = count of buffered bits added now */

   BR_buffer = entropy->bit_buffer + entropy->BE; /* Append bits to buffer */

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

     if ((temp = absvalues[k]) == 0) {

       r++;

       continue;

     }

     /* Emit any required ZRLs, but not if they can be folded into EOB */

     while (r > 15 && k <= EOB) {

       /* emit any pending EOBRUN and the BE correction bits */

       emit_eobrun(entropy);

       /* Emit ZRL */

       emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);

       r -= 16;

       /* Emit buffered correction bits that must be associated with ZRL */

       emit_buffered_bits(entropy, BR_buffer, BR);

       BR_buffer = entropy->bit_buffer; /* BE bits are gone now */

       BR = 0;

     }

     /* If the coef was previously nonzero, it only needs a correction bit.

      * NOTE: a straight translation of the spec's figure G.7 would suggest

      * that we also need to test r > 15.  But if r > 15, we can only get here

      * if k > EOB, which implies that this coefficient is not 1.

      */

     if (temp > 1) {

       /* The correction bit is the next bit of the absolute value. */

       BR_buffer[BR++] = (char) (temp & 1);

       continue;

     }

     /* Emit any pending EOBRUN and the BE correction bits */

     emit_eobrun(entropy);

     /* Count/emit Huffman symbol for run length / number of bits */

     emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + 1);

     /* Emit output bit for newly-nonzero coef */

     temp = ((*block)[jpeg_natural_order[k]] < 0) ? 0 : 1;

     emit_bits(entropy, (unsigned int) temp, 1);

     /* Emit buffered correction bits that must be associated with this code */

     emit_buffered_bits(entropy, BR_buffer, BR);

     BR_buffer = entropy->bit_buffer; /* BE bits are gone now */

     BR = 0;

     r = 0;			/* reset zero run length */

   }

   if (r > 0 || BR > 0) {	/* If there are trailing zeroes, */

     entropy->EOBRUN++;		/* count an EOB */

     entropy->BE += BR;		/* concat my correction bits to older ones */

     /* We force out the EOB if we risk either:

      * 1. overflow of the EOB counter;

      * 2. overflow of the correction bit buffer during the next MCU.

      */

     if (entropy->EOBRUN == 0x7FFF || entropy->BE > (MAX_CORR_BITS-DCTSIZE2+1))

       emit_eobrun(entropy);

   }

   cinfo->dest->next_output_byte = entropy->next_output_byte;

   cinfo->dest->free_in_buffer = entropy->free_in_buffer;

   /* Update restart-interval state too */

   if (cinfo->restart_interval) {

     if (entropy->restarts_to_go == 0) {

       entropy->restarts_to_go = cinfo->restart_interval;

       entropy->next_restart_num++;

       entropy->next_restart_num &= 7;

     }

     entropy->restarts_to_go--;

   }

   return TRUE;

 }

 /*

  * Finish up at the end of a Huffman-compressed progressive scan.

  */

 METHODDEF(void)

 finish_pass_phuff (j_compress_ptr cinfo)

 {   

   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

   entropy->next_output_byte = cinfo->dest->next_output_byte;

   entropy->free_in_buffer = cinfo->dest->free_in_buffer;

   /* Flush out any buffered data */

   emit_eobrun(entropy);

   flush_bits(entropy);

   cinfo->dest->next_output_byte = entropy->next_output_byte;

   cinfo->dest->free_in_buffer = entropy->free_in_buffer;

 }

 /*

  * Finish up a statistics-gathering pass and create the new Huffman tables.

  */

 METHODDEF(void)

 finish_pass_gather_phuff (j_compress_ptr cinfo)

 {

   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;

   boolean is_DC_band;

   int ci, tbl;

   jpeg_component_info * compptr;

   JHUFF_TBL **htblptr;

   boolean did[NUM_HUFF_TBLS];

   /* Flush out buffered data (all we care about is counting the EOB symbol) */

   emit_eobrun(entropy);

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

   /* It's important not to apply jpeg_gen_optimal_table more than once

    * per table, because it clobbers the input frequency counts!

    */

   MEMZERO(did, SIZEOF(did));

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

     compptr = cinfo->cur_comp_info[ci];

     if (is_DC_band) {

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

 	continue;

       tbl = compptr->dc_tbl_no;

     } else {

       tbl = compptr->ac_tbl_no;

     }

     if (! did[tbl]) {

       if (is_DC_band)

         htblptr = & cinfo->dc_huff_tbl_ptrs[tbl];

       else

         htblptr = & cinfo->ac_huff_tbl_ptrs[tbl];

       if (*htblptr == NULL)

         *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);

       jpeg_gen_optimal_table(cinfo, *htblptr, entropy->count_ptrs[tbl]);

       did[tbl] = TRUE;

     }

   }

 }

 /*

  * Module initialization routine for progressive Huffman entropy encoding.

  */

 GLOBAL(void)

 jinit_phuff_encoder (j_compress_ptr cinfo)

 {

   phuff_entropy_ptr entropy;

   int i;

   entropy = (phuff_entropy_ptr)

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

 				SIZEOF(phuff_entropy_encoder));

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

   entropy->pub.start_pass = start_pass_phuff;

   /* Mark tables unallocated */

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

     entropy->derived_tbls[i] = NULL;

     entropy->count_ptrs[i] = NULL;

   }

   entropy->bit_buffer = NULL;	/* needed only in AC refinement scan */

 }

 #endif /* C_PROGRESSIVE_SUPPORTED */