nuclear@26: /*
nuclear@26:  * jcphuff.c
nuclear@26:  *
nuclear@26:  * Copyright (C) 1995-1997, Thomas G. Lane.
nuclear@26:  * This file is part of the Independent JPEG Group's software.
nuclear@26:  * For conditions of distribution and use, see the accompanying README file.
nuclear@26:  *
nuclear@26:  * This file contains Huffman entropy encoding routines for progressive JPEG.
nuclear@26:  *
nuclear@26:  * We do not support output suspension in this module, since the library
nuclear@26:  * currently does not allow multiple-scan files to be written with output
nuclear@26:  * suspension.
nuclear@26:  */
nuclear@26: 
nuclear@26: #define JPEG_INTERNALS
nuclear@26: #include "jinclude.h"
nuclear@26: #include "jpeglib.h"
nuclear@26: #include "jchuff.h"		/* Declarations shared with jchuff.c */
nuclear@26: 
nuclear@26: #ifdef C_PROGRESSIVE_SUPPORTED
nuclear@26: 
nuclear@26: /* Expanded entropy encoder object for progressive Huffman encoding. */
nuclear@26: 
nuclear@26: typedef struct {
nuclear@26:   struct jpeg_entropy_encoder pub; /* public fields */
nuclear@26: 
nuclear@26:   /* Mode flag: TRUE for optimization, FALSE for actual data output */
nuclear@26:   boolean gather_statistics;
nuclear@26: 
nuclear@26:   /* Bit-level coding status.
nuclear@26:    * next_output_byte/free_in_buffer are local copies of cinfo->dest fields.
nuclear@26:    */
nuclear@26:   JOCTET * next_output_byte;	/* => next byte to write in buffer */
nuclear@26:   size_t free_in_buffer;	/* # of byte spaces remaining in buffer */
nuclear@26:   INT32 put_buffer;		/* current bit-accumulation buffer */
nuclear@26:   int put_bits;			/* # of bits now in it */
nuclear@26:   j_compress_ptr cinfo;		/* link to cinfo (needed for dump_buffer) */
nuclear@26: 
nuclear@26:   /* Coding status for DC components */
nuclear@26:   int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
nuclear@26: 
nuclear@26:   /* Coding status for AC components */
nuclear@26:   int ac_tbl_no;		/* the table number of the single component */
nuclear@26:   unsigned int EOBRUN;		/* run length of EOBs */
nuclear@26:   unsigned int BE;		/* # of buffered correction bits before MCU */
nuclear@26:   char * bit_buffer;		/* buffer for correction bits (1 per char) */
nuclear@26:   /* packing correction bits tightly would save some space but cost time... */
nuclear@26: 
nuclear@26:   unsigned int restarts_to_go;	/* MCUs left in this restart interval */
nuclear@26:   int next_restart_num;		/* next restart number to write (0-7) */
nuclear@26: 
nuclear@26:   /* Pointers to derived tables (these workspaces have image lifespan).
nuclear@26:    * Since any one scan codes only DC or only AC, we only need one set
nuclear@26:    * of tables, not one for DC and one for AC.
nuclear@26:    */
nuclear@26:   c_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
nuclear@26: 
nuclear@26:   /* Statistics tables for optimization; again, one set is enough */
nuclear@26:   long * count_ptrs[NUM_HUFF_TBLS];
nuclear@26: } phuff_entropy_encoder;
nuclear@26: 
nuclear@26: typedef phuff_entropy_encoder * phuff_entropy_ptr;
nuclear@26: 
nuclear@26: /* MAX_CORR_BITS is the number of bits the AC refinement correction-bit
nuclear@26:  * buffer can hold.  Larger sizes may slightly improve compression, but
nuclear@26:  * 1000 is already well into the realm of overkill.
nuclear@26:  * The minimum safe size is 64 bits.
nuclear@26:  */
nuclear@26: 
nuclear@26: #define MAX_CORR_BITS  1000	/* Max # of correction bits I can buffer */
nuclear@26: 
nuclear@26: /* IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than INT32.
nuclear@26:  * We assume that int right shift is unsigned if INT32 right shift is,
nuclear@26:  * which should be safe.
nuclear@26:  */
nuclear@26: 
nuclear@26: #ifdef RIGHT_SHIFT_IS_UNSIGNED
nuclear@26: #define ISHIFT_TEMPS	int ishift_temp;
nuclear@26: #define IRIGHT_SHIFT(x,shft)  \
nuclear@26: 	((ishift_temp = (x)) < 0 ? \
nuclear@26: 	 (ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \
nuclear@26: 	 (ishift_temp >> (shft)))
nuclear@26: #else
nuclear@26: #define ISHIFT_TEMPS
nuclear@26: #define IRIGHT_SHIFT(x,shft)	((x) >> (shft))
nuclear@26: #endif
nuclear@26: 
nuclear@26: /* Forward declarations */
nuclear@26: METHODDEF(boolean) encode_mcu_DC_first JPP((j_compress_ptr cinfo,
nuclear@26: 					    JBLOCKROW *MCU_data));
nuclear@26: METHODDEF(boolean) encode_mcu_AC_first JPP((j_compress_ptr cinfo,
nuclear@26: 					    JBLOCKROW *MCU_data));
nuclear@26: METHODDEF(boolean) encode_mcu_DC_refine JPP((j_compress_ptr cinfo,
nuclear@26: 					     JBLOCKROW *MCU_data));
nuclear@26: METHODDEF(boolean) encode_mcu_AC_refine JPP((j_compress_ptr cinfo,
nuclear@26: 					     JBLOCKROW *MCU_data));
nuclear@26: METHODDEF(void) finish_pass_phuff JPP((j_compress_ptr cinfo));
nuclear@26: METHODDEF(void) finish_pass_gather_phuff JPP((j_compress_ptr cinfo));
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Initialize for a Huffman-compressed scan using progressive JPEG.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: start_pass_phuff (j_compress_ptr cinfo, boolean gather_statistics)
nuclear@26: {  
nuclear@26:   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
nuclear@26:   boolean is_DC_band;
nuclear@26:   int ci, tbl;
nuclear@26:   jpeg_component_info * compptr;
nuclear@26: 
nuclear@26:   entropy->cinfo = cinfo;
nuclear@26:   entropy->gather_statistics = gather_statistics;
nuclear@26: 
nuclear@26:   is_DC_band = (cinfo->Ss == 0);
nuclear@26: 
nuclear@26:   /* We assume jcmaster.c already validated the scan parameters. */
nuclear@26: 
nuclear@26:   /* Select execution routines */
nuclear@26:   if (cinfo->Ah == 0) {
nuclear@26:     if (is_DC_band)
nuclear@26:       entropy->pub.encode_mcu = encode_mcu_DC_first;
nuclear@26:     else
nuclear@26:       entropy->pub.encode_mcu = encode_mcu_AC_first;
nuclear@26:   } else {
nuclear@26:     if (is_DC_band)
nuclear@26:       entropy->pub.encode_mcu = encode_mcu_DC_refine;
nuclear@26:     else {
nuclear@26:       entropy->pub.encode_mcu = encode_mcu_AC_refine;
nuclear@26:       /* AC refinement needs a correction bit buffer */
nuclear@26:       if (entropy->bit_buffer == NULL)
nuclear@26: 	entropy->bit_buffer = (char *)
nuclear@26: 	  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 				      MAX_CORR_BITS * SIZEOF(char));
nuclear@26:     }
nuclear@26:   }
nuclear@26:   if (gather_statistics)
nuclear@26:     entropy->pub.finish_pass = finish_pass_gather_phuff;
nuclear@26:   else
nuclear@26:     entropy->pub.finish_pass = finish_pass_phuff;
nuclear@26: 
nuclear@26:   /* Only DC coefficients may be interleaved, so cinfo->comps_in_scan = 1
nuclear@26:    * for AC coefficients.
nuclear@26:    */
nuclear@26:   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
nuclear@26:     compptr = cinfo->cur_comp_info[ci];
nuclear@26:     /* Initialize DC predictions to 0 */
nuclear@26:     entropy->last_dc_val[ci] = 0;
nuclear@26:     /* Get table index */
nuclear@26:     if (is_DC_band) {
nuclear@26:       if (cinfo->Ah != 0)	/* DC refinement needs no table */
nuclear@26: 	continue;
nuclear@26:       tbl = compptr->dc_tbl_no;
nuclear@26:     } else {
nuclear@26:       entropy->ac_tbl_no = tbl = compptr->ac_tbl_no;
nuclear@26:     }
nuclear@26:     if (gather_statistics) {
nuclear@26:       /* Check for invalid table index */
nuclear@26:       /* (make_c_derived_tbl does this in the other path) */
nuclear@26:       if (tbl < 0 || tbl >= NUM_HUFF_TBLS)
nuclear@26:         ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);
nuclear@26:       /* Allocate and zero the statistics tables */
nuclear@26:       /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
nuclear@26:       if (entropy->count_ptrs[tbl] == NULL)
nuclear@26: 	entropy->count_ptrs[tbl] = (long *)
nuclear@26: 	  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 				      257 * SIZEOF(long));
nuclear@26:       MEMZERO(entropy->count_ptrs[tbl], 257 * SIZEOF(long));
nuclear@26:     } else {
nuclear@26:       /* Compute derived values for Huffman table */
nuclear@26:       /* We may do this more than once for a table, but it's not expensive */
nuclear@26:       jpeg_make_c_derived_tbl(cinfo, is_DC_band, tbl,
nuclear@26: 			      & entropy->derived_tbls[tbl]);
nuclear@26:     }
nuclear@26:   }
nuclear@26: 
nuclear@26:   /* Initialize AC stuff */
nuclear@26:   entropy->EOBRUN = 0;
nuclear@26:   entropy->BE = 0;
nuclear@26: 
nuclear@26:   /* Initialize bit buffer to empty */
nuclear@26:   entropy->put_buffer = 0;
nuclear@26:   entropy->put_bits = 0;
nuclear@26: 
nuclear@26:   /* Initialize restart stuff */
nuclear@26:   entropy->restarts_to_go = cinfo->restart_interval;
nuclear@26:   entropy->next_restart_num = 0;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /* Outputting bytes to the file.
nuclear@26:  * NB: these must be called only when actually outputting,
nuclear@26:  * that is, entropy->gather_statistics == FALSE.
nuclear@26:  */
nuclear@26: 
nuclear@26: /* Emit a byte */
nuclear@26: #define emit_byte(entropy,val)  \
nuclear@26: 	{ *(entropy)->next_output_byte++ = (JOCTET) (val);  \
nuclear@26: 	  if (--(entropy)->free_in_buffer == 0)  \
nuclear@26: 	    dump_buffer(entropy); }
nuclear@26: 
nuclear@26: 
nuclear@26: LOCAL(void)
nuclear@26: dump_buffer (phuff_entropy_ptr entropy)
nuclear@26: /* Empty the output buffer; we do not support suspension in this module. */
nuclear@26: {
nuclear@26:   struct jpeg_destination_mgr * dest = entropy->cinfo->dest;
nuclear@26: 
nuclear@26:   if (! (*dest->empty_output_buffer) (entropy->cinfo))
nuclear@26:     ERREXIT(entropy->cinfo, JERR_CANT_SUSPEND);
nuclear@26:   /* After a successful buffer dump, must reset buffer pointers */
nuclear@26:   entropy->next_output_byte = dest->next_output_byte;
nuclear@26:   entropy->free_in_buffer = dest->free_in_buffer;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /* Outputting bits to the file */
nuclear@26: 
nuclear@26: /* Only the right 24 bits of put_buffer are used; the valid bits are
nuclear@26:  * left-justified in this part.  At most 16 bits can be passed to emit_bits
nuclear@26:  * in one call, and we never retain more than 7 bits in put_buffer
nuclear@26:  * between calls, so 24 bits are sufficient.
nuclear@26:  */
nuclear@26: 
nuclear@26: INLINE
nuclear@26: LOCAL(void)
nuclear@26: emit_bits (phuff_entropy_ptr entropy, unsigned int code, int size)
nuclear@26: /* Emit some bits, unless we are in gather mode */
nuclear@26: {
nuclear@26:   /* This routine is heavily used, so it's worth coding tightly. */
nuclear@26:   register INT32 put_buffer = (INT32) code;
nuclear@26:   register int put_bits = entropy->put_bits;
nuclear@26: 
nuclear@26:   /* if size is 0, caller used an invalid Huffman table entry */
nuclear@26:   if (size == 0)
nuclear@26:     ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
nuclear@26: 
nuclear@26:   if (entropy->gather_statistics)
nuclear@26:     return;			/* do nothing if we're only getting stats */
nuclear@26: 
nuclear@26:   put_buffer &= (((INT32) 1)<<size) - 1; /* mask off any extra bits in code */
nuclear@26:   
nuclear@26:   put_bits += size;		/* new number of bits in buffer */
nuclear@26:   
nuclear@26:   put_buffer <<= 24 - put_bits; /* align incoming bits */
nuclear@26: 
nuclear@26:   put_buffer |= entropy->put_buffer; /* and merge with old buffer contents */
nuclear@26: 
nuclear@26:   while (put_bits >= 8) {
nuclear@26:     int c = (int) ((put_buffer >> 16) & 0xFF);
nuclear@26:     
nuclear@26:     emit_byte(entropy, c);
nuclear@26:     if (c == 0xFF) {		/* need to stuff a zero byte? */
nuclear@26:       emit_byte(entropy, 0);
nuclear@26:     }
nuclear@26:     put_buffer <<= 8;
nuclear@26:     put_bits -= 8;
nuclear@26:   }
nuclear@26: 
nuclear@26:   entropy->put_buffer = put_buffer; /* update variables */
nuclear@26:   entropy->put_bits = put_bits;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: LOCAL(void)
nuclear@26: flush_bits (phuff_entropy_ptr entropy)
nuclear@26: {
nuclear@26:   emit_bits(entropy, 0x7F, 7); /* fill any partial byte with ones */
nuclear@26:   entropy->put_buffer = 0;     /* and reset bit-buffer to empty */
nuclear@26:   entropy->put_bits = 0;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Emit (or just count) a Huffman symbol.
nuclear@26:  */
nuclear@26: 
nuclear@26: INLINE
nuclear@26: LOCAL(void)
nuclear@26: emit_symbol (phuff_entropy_ptr entropy, int tbl_no, int symbol)
nuclear@26: {
nuclear@26:   if (entropy->gather_statistics)
nuclear@26:     entropy->count_ptrs[tbl_no][symbol]++;
nuclear@26:   else {
nuclear@26:     c_derived_tbl * tbl = entropy->derived_tbls[tbl_no];
nuclear@26:     emit_bits(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Emit bits from a correction bit buffer.
nuclear@26:  */
nuclear@26: 
nuclear@26: LOCAL(void)
nuclear@26: emit_buffered_bits (phuff_entropy_ptr entropy, char * bufstart,
nuclear@26: 		    unsigned int nbits)
nuclear@26: {
nuclear@26:   if (entropy->gather_statistics)
nuclear@26:     return;			/* no real work */
nuclear@26: 
nuclear@26:   while (nbits > 0) {
nuclear@26:     emit_bits(entropy, (unsigned int) (*bufstart), 1);
nuclear@26:     bufstart++;
nuclear@26:     nbits--;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Emit any pending EOBRUN symbol.
nuclear@26:  */
nuclear@26: 
nuclear@26: LOCAL(void)
nuclear@26: emit_eobrun (phuff_entropy_ptr entropy)
nuclear@26: {
nuclear@26:   register int temp, nbits;
nuclear@26: 
nuclear@26:   if (entropy->EOBRUN > 0) {	/* if there is any pending EOBRUN */
nuclear@26:     temp = entropy->EOBRUN;
nuclear@26:     nbits = 0;
nuclear@26:     while ((temp >>= 1))
nuclear@26:       nbits++;
nuclear@26:     /* safety check: shouldn't happen given limited correction-bit buffer */
nuclear@26:     if (nbits > 14)
nuclear@26:       ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);
nuclear@26: 
nuclear@26:     emit_symbol(entropy, entropy->ac_tbl_no, nbits << 4);
nuclear@26:     if (nbits)
nuclear@26:       emit_bits(entropy, entropy->EOBRUN, nbits);
nuclear@26: 
nuclear@26:     entropy->EOBRUN = 0;
nuclear@26: 
nuclear@26:     /* Emit any buffered correction bits */
nuclear@26:     emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE);
nuclear@26:     entropy->BE = 0;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Emit a restart marker & resynchronize predictions.
nuclear@26:  */
nuclear@26: 
nuclear@26: LOCAL(void)
nuclear@26: emit_restart (phuff_entropy_ptr entropy, int restart_num)
nuclear@26: {
nuclear@26:   int ci;
nuclear@26: 
nuclear@26:   emit_eobrun(entropy);
nuclear@26: 
nuclear@26:   if (! entropy->gather_statistics) {
nuclear@26:     flush_bits(entropy);
nuclear@26:     emit_byte(entropy, 0xFF);
nuclear@26:     emit_byte(entropy, JPEG_RST0 + restart_num);
nuclear@26:   }
nuclear@26: 
nuclear@26:   if (entropy->cinfo->Ss == 0) {
nuclear@26:     /* Re-initialize DC predictions to 0 */
nuclear@26:     for (ci = 0; ci < entropy->cinfo->comps_in_scan; ci++)
nuclear@26:       entropy->last_dc_val[ci] = 0;
nuclear@26:   } else {
nuclear@26:     /* Re-initialize all AC-related fields to 0 */
nuclear@26:     entropy->EOBRUN = 0;
nuclear@26:     entropy->BE = 0;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * MCU encoding for DC initial scan (either spectral selection,
nuclear@26:  * or first pass of successive approximation).
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(boolean)
nuclear@26: encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
nuclear@26: {
nuclear@26:   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
nuclear@26:   register int temp, temp2;
nuclear@26:   register int nbits;
nuclear@26:   int blkn, ci;
nuclear@26:   int Al = cinfo->Al;
nuclear@26:   JBLOCKROW block;
nuclear@26:   jpeg_component_info * compptr;
nuclear@26:   ISHIFT_TEMPS
nuclear@26: 
nuclear@26:   entropy->next_output_byte = cinfo->dest->next_output_byte;
nuclear@26:   entropy->free_in_buffer = cinfo->dest->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Emit restart marker if needed */
nuclear@26:   if (cinfo->restart_interval)
nuclear@26:     if (entropy->restarts_to_go == 0)
nuclear@26:       emit_restart(entropy, entropy->next_restart_num);
nuclear@26: 
nuclear@26:   /* Encode the MCU data blocks */
nuclear@26:   for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
nuclear@26:     block = MCU_data[blkn];
nuclear@26:     ci = cinfo->MCU_membership[blkn];
nuclear@26:     compptr = cinfo->cur_comp_info[ci];
nuclear@26: 
nuclear@26:     /* Compute the DC value after the required point transform by Al.
nuclear@26:      * This is simply an arithmetic right shift.
nuclear@26:      */
nuclear@26:     temp2 = IRIGHT_SHIFT((int) ((*block)[0]), Al);
nuclear@26: 
nuclear@26:     /* DC differences are figured on the point-transformed values. */
nuclear@26:     temp = temp2 - entropy->last_dc_val[ci];
nuclear@26:     entropy->last_dc_val[ci] = temp2;
nuclear@26: 
nuclear@26:     /* Encode the DC coefficient difference per section G.1.2.1 */
nuclear@26:     temp2 = temp;
nuclear@26:     if (temp < 0) {
nuclear@26:       temp = -temp;		/* temp is abs value of input */
nuclear@26:       /* For a negative input, want temp2 = bitwise complement of abs(input) */
nuclear@26:       /* This code assumes we are on a two's complement machine */
nuclear@26:       temp2--;
nuclear@26:     }
nuclear@26:     
nuclear@26:     /* Find the number of bits needed for the magnitude of the coefficient */
nuclear@26:     nbits = 0;
nuclear@26:     while (temp) {
nuclear@26:       nbits++;
nuclear@26:       temp >>= 1;
nuclear@26:     }
nuclear@26:     /* Check for out-of-range coefficient values.
nuclear@26:      * Since we're encoding a difference, the range limit is twice as much.
nuclear@26:      */
nuclear@26:     if (nbits > MAX_COEF_BITS+1)
nuclear@26:       ERREXIT(cinfo, JERR_BAD_DCT_COEF);
nuclear@26:     
nuclear@26:     /* Count/emit the Huffman-coded symbol for the number of bits */
nuclear@26:     emit_symbol(entropy, compptr->dc_tbl_no, nbits);
nuclear@26:     
nuclear@26:     /* Emit that number of bits of the value, if positive, */
nuclear@26:     /* or the complement of its magnitude, if negative. */
nuclear@26:     if (nbits)			/* emit_bits rejects calls with size 0 */
nuclear@26:       emit_bits(entropy, (unsigned int) temp2, nbits);
nuclear@26:   }
nuclear@26: 
nuclear@26:   cinfo->dest->next_output_byte = entropy->next_output_byte;
nuclear@26:   cinfo->dest->free_in_buffer = entropy->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Update restart-interval state too */
nuclear@26:   if (cinfo->restart_interval) {
nuclear@26:     if (entropy->restarts_to_go == 0) {
nuclear@26:       entropy->restarts_to_go = cinfo->restart_interval;
nuclear@26:       entropy->next_restart_num++;
nuclear@26:       entropy->next_restart_num &= 7;
nuclear@26:     }
nuclear@26:     entropy->restarts_to_go--;
nuclear@26:   }
nuclear@26: 
nuclear@26:   return TRUE;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * MCU encoding for AC initial scan (either spectral selection,
nuclear@26:  * or first pass of successive approximation).
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(boolean)
nuclear@26: encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
nuclear@26: {
nuclear@26:   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
nuclear@26:   register int temp, temp2;
nuclear@26:   register int nbits;
nuclear@26:   register int r, k;
nuclear@26:   int Se = cinfo->Se;
nuclear@26:   int Al = cinfo->Al;
nuclear@26:   JBLOCKROW block;
nuclear@26: 
nuclear@26:   entropy->next_output_byte = cinfo->dest->next_output_byte;
nuclear@26:   entropy->free_in_buffer = cinfo->dest->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Emit restart marker if needed */
nuclear@26:   if (cinfo->restart_interval)
nuclear@26:     if (entropy->restarts_to_go == 0)
nuclear@26:       emit_restart(entropy, entropy->next_restart_num);
nuclear@26: 
nuclear@26:   /* Encode the MCU data block */
nuclear@26:   block = MCU_data[0];
nuclear@26: 
nuclear@26:   /* Encode the AC coefficients per section G.1.2.2, fig. G.3 */
nuclear@26:   
nuclear@26:   r = 0;			/* r = run length of zeros */
nuclear@26:    
nuclear@26:   for (k = cinfo->Ss; k <= Se; k++) {
nuclear@26:     if ((temp = (*block)[jpeg_natural_order[k]]) == 0) {
nuclear@26:       r++;
nuclear@26:       continue;
nuclear@26:     }
nuclear@26:     /* We must apply the point transform by Al.  For AC coefficients this
nuclear@26:      * is an integer division with rounding towards 0.  To do this portably
nuclear@26:      * in C, we shift after obtaining the absolute value; so the code is
nuclear@26:      * interwoven with finding the abs value (temp) and output bits (temp2).
nuclear@26:      */
nuclear@26:     if (temp < 0) {
nuclear@26:       temp = -temp;		/* temp is abs value of input */
nuclear@26:       temp >>= Al;		/* apply the point transform */
nuclear@26:       /* For a negative coef, want temp2 = bitwise complement of abs(coef) */
nuclear@26:       temp2 = ~temp;
nuclear@26:     } else {
nuclear@26:       temp >>= Al;		/* apply the point transform */
nuclear@26:       temp2 = temp;
nuclear@26:     }
nuclear@26:     /* Watch out for case that nonzero coef is zero after point transform */
nuclear@26:     if (temp == 0) {
nuclear@26:       r++;
nuclear@26:       continue;
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* Emit any pending EOBRUN */
nuclear@26:     if (entropy->EOBRUN > 0)
nuclear@26:       emit_eobrun(entropy);
nuclear@26:     /* if run length > 15, must emit special run-length-16 codes (0xF0) */
nuclear@26:     while (r > 15) {
nuclear@26:       emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
nuclear@26:       r -= 16;
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* Find the number of bits needed for the magnitude of the coefficient */
nuclear@26:     nbits = 1;			/* there must be at least one 1 bit */
nuclear@26:     while ((temp >>= 1))
nuclear@26:       nbits++;
nuclear@26:     /* Check for out-of-range coefficient values */
nuclear@26:     if (nbits > MAX_COEF_BITS)
nuclear@26:       ERREXIT(cinfo, JERR_BAD_DCT_COEF);
nuclear@26: 
nuclear@26:     /* Count/emit Huffman symbol for run length / number of bits */
nuclear@26:     emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + nbits);
nuclear@26: 
nuclear@26:     /* Emit that number of bits of the value, if positive, */
nuclear@26:     /* or the complement of its magnitude, if negative. */
nuclear@26:     emit_bits(entropy, (unsigned int) temp2, nbits);
nuclear@26: 
nuclear@26:     r = 0;			/* reset zero run length */
nuclear@26:   }
nuclear@26: 
nuclear@26:   if (r > 0) {			/* If there are trailing zeroes, */
nuclear@26:     entropy->EOBRUN++;		/* count an EOB */
nuclear@26:     if (entropy->EOBRUN == 0x7FFF)
nuclear@26:       emit_eobrun(entropy);	/* force it out to avoid overflow */
nuclear@26:   }
nuclear@26: 
nuclear@26:   cinfo->dest->next_output_byte = entropy->next_output_byte;
nuclear@26:   cinfo->dest->free_in_buffer = entropy->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Update restart-interval state too */
nuclear@26:   if (cinfo->restart_interval) {
nuclear@26:     if (entropy->restarts_to_go == 0) {
nuclear@26:       entropy->restarts_to_go = cinfo->restart_interval;
nuclear@26:       entropy->next_restart_num++;
nuclear@26:       entropy->next_restart_num &= 7;
nuclear@26:     }
nuclear@26:     entropy->restarts_to_go--;
nuclear@26:   }
nuclear@26: 
nuclear@26:   return TRUE;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * MCU encoding for DC successive approximation refinement scan.
nuclear@26:  * Note: we assume such scans can be multi-component, although the spec
nuclear@26:  * is not very clear on the point.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(boolean)
nuclear@26: encode_mcu_DC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
nuclear@26: {
nuclear@26:   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
nuclear@26:   register int temp;
nuclear@26:   int blkn;
nuclear@26:   int Al = cinfo->Al;
nuclear@26:   JBLOCKROW block;
nuclear@26: 
nuclear@26:   entropy->next_output_byte = cinfo->dest->next_output_byte;
nuclear@26:   entropy->free_in_buffer = cinfo->dest->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Emit restart marker if needed */
nuclear@26:   if (cinfo->restart_interval)
nuclear@26:     if (entropy->restarts_to_go == 0)
nuclear@26:       emit_restart(entropy, entropy->next_restart_num);
nuclear@26: 
nuclear@26:   /* Encode the MCU data blocks */
nuclear@26:   for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
nuclear@26:     block = MCU_data[blkn];
nuclear@26: 
nuclear@26:     /* We simply emit the Al'th bit of the DC coefficient value. */
nuclear@26:     temp = (*block)[0];
nuclear@26:     emit_bits(entropy, (unsigned int) (temp >> Al), 1);
nuclear@26:   }
nuclear@26: 
nuclear@26:   cinfo->dest->next_output_byte = entropy->next_output_byte;
nuclear@26:   cinfo->dest->free_in_buffer = entropy->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Update restart-interval state too */
nuclear@26:   if (cinfo->restart_interval) {
nuclear@26:     if (entropy->restarts_to_go == 0) {
nuclear@26:       entropy->restarts_to_go = cinfo->restart_interval;
nuclear@26:       entropy->next_restart_num++;
nuclear@26:       entropy->next_restart_num &= 7;
nuclear@26:     }
nuclear@26:     entropy->restarts_to_go--;
nuclear@26:   }
nuclear@26: 
nuclear@26:   return TRUE;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * MCU encoding for AC successive approximation refinement scan.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(boolean)
nuclear@26: encode_mcu_AC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
nuclear@26: {
nuclear@26:   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
nuclear@26:   register int temp;
nuclear@26:   register int r, k;
nuclear@26:   int EOB;
nuclear@26:   char *BR_buffer;
nuclear@26:   unsigned int BR;
nuclear@26:   int Se = cinfo->Se;
nuclear@26:   int Al = cinfo->Al;
nuclear@26:   JBLOCKROW block;
nuclear@26:   int absvalues[DCTSIZE2];
nuclear@26: 
nuclear@26:   entropy->next_output_byte = cinfo->dest->next_output_byte;
nuclear@26:   entropy->free_in_buffer = cinfo->dest->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Emit restart marker if needed */
nuclear@26:   if (cinfo->restart_interval)
nuclear@26:     if (entropy->restarts_to_go == 0)
nuclear@26:       emit_restart(entropy, entropy->next_restart_num);
nuclear@26: 
nuclear@26:   /* Encode the MCU data block */
nuclear@26:   block = MCU_data[0];
nuclear@26: 
nuclear@26:   /* It is convenient to make a pre-pass to determine the transformed
nuclear@26:    * coefficients' absolute values and the EOB position.
nuclear@26:    */
nuclear@26:   EOB = 0;
nuclear@26:   for (k = cinfo->Ss; k <= Se; k++) {
nuclear@26:     temp = (*block)[jpeg_natural_order[k]];
nuclear@26:     /* We must apply the point transform by Al.  For AC coefficients this
nuclear@26:      * is an integer division with rounding towards 0.  To do this portably
nuclear@26:      * in C, we shift after obtaining the absolute value.
nuclear@26:      */
nuclear@26:     if (temp < 0)
nuclear@26:       temp = -temp;		/* temp is abs value of input */
nuclear@26:     temp >>= Al;		/* apply the point transform */
nuclear@26:     absvalues[k] = temp;	/* save abs value for main pass */
nuclear@26:     if (temp == 1)
nuclear@26:       EOB = k;			/* EOB = index of last newly-nonzero coef */
nuclear@26:   }
nuclear@26: 
nuclear@26:   /* Encode the AC coefficients per section G.1.2.3, fig. G.7 */
nuclear@26:   
nuclear@26:   r = 0;			/* r = run length of zeros */
nuclear@26:   BR = 0;			/* BR = count of buffered bits added now */
nuclear@26:   BR_buffer = entropy->bit_buffer + entropy->BE; /* Append bits to buffer */
nuclear@26: 
nuclear@26:   for (k = cinfo->Ss; k <= Se; k++) {
nuclear@26:     if ((temp = absvalues[k]) == 0) {
nuclear@26:       r++;
nuclear@26:       continue;
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* Emit any required ZRLs, but not if they can be folded into EOB */
nuclear@26:     while (r > 15 && k <= EOB) {
nuclear@26:       /* emit any pending EOBRUN and the BE correction bits */
nuclear@26:       emit_eobrun(entropy);
nuclear@26:       /* Emit ZRL */
nuclear@26:       emit_symbol(entropy, entropy->ac_tbl_no, 0xF0);
nuclear@26:       r -= 16;
nuclear@26:       /* Emit buffered correction bits that must be associated with ZRL */
nuclear@26:       emit_buffered_bits(entropy, BR_buffer, BR);
nuclear@26:       BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
nuclear@26:       BR = 0;
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* If the coef was previously nonzero, it only needs a correction bit.
nuclear@26:      * NOTE: a straight translation of the spec's figure G.7 would suggest
nuclear@26:      * that we also need to test r > 15.  But if r > 15, we can only get here
nuclear@26:      * if k > EOB, which implies that this coefficient is not 1.
nuclear@26:      */
nuclear@26:     if (temp > 1) {
nuclear@26:       /* The correction bit is the next bit of the absolute value. */
nuclear@26:       BR_buffer[BR++] = (char) (temp & 1);
nuclear@26:       continue;
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* Emit any pending EOBRUN and the BE correction bits */
nuclear@26:     emit_eobrun(entropy);
nuclear@26: 
nuclear@26:     /* Count/emit Huffman symbol for run length / number of bits */
nuclear@26:     emit_symbol(entropy, entropy->ac_tbl_no, (r << 4) + 1);
nuclear@26: 
nuclear@26:     /* Emit output bit for newly-nonzero coef */
nuclear@26:     temp = ((*block)[jpeg_natural_order[k]] < 0) ? 0 : 1;
nuclear@26:     emit_bits(entropy, (unsigned int) temp, 1);
nuclear@26: 
nuclear@26:     /* Emit buffered correction bits that must be associated with this code */
nuclear@26:     emit_buffered_bits(entropy, BR_buffer, BR);
nuclear@26:     BR_buffer = entropy->bit_buffer; /* BE bits are gone now */
nuclear@26:     BR = 0;
nuclear@26:     r = 0;			/* reset zero run length */
nuclear@26:   }
nuclear@26: 
nuclear@26:   if (r > 0 || BR > 0) {	/* If there are trailing zeroes, */
nuclear@26:     entropy->EOBRUN++;		/* count an EOB */
nuclear@26:     entropy->BE += BR;		/* concat my correction bits to older ones */
nuclear@26:     /* We force out the EOB if we risk either:
nuclear@26:      * 1. overflow of the EOB counter;
nuclear@26:      * 2. overflow of the correction bit buffer during the next MCU.
nuclear@26:      */
nuclear@26:     if (entropy->EOBRUN == 0x7FFF || entropy->BE > (MAX_CORR_BITS-DCTSIZE2+1))
nuclear@26:       emit_eobrun(entropy);
nuclear@26:   }
nuclear@26: 
nuclear@26:   cinfo->dest->next_output_byte = entropy->next_output_byte;
nuclear@26:   cinfo->dest->free_in_buffer = entropy->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Update restart-interval state too */
nuclear@26:   if (cinfo->restart_interval) {
nuclear@26:     if (entropy->restarts_to_go == 0) {
nuclear@26:       entropy->restarts_to_go = cinfo->restart_interval;
nuclear@26:       entropy->next_restart_num++;
nuclear@26:       entropy->next_restart_num &= 7;
nuclear@26:     }
nuclear@26:     entropy->restarts_to_go--;
nuclear@26:   }
nuclear@26: 
nuclear@26:   return TRUE;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Finish up at the end of a Huffman-compressed progressive scan.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: finish_pass_phuff (j_compress_ptr cinfo)
nuclear@26: {   
nuclear@26:   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
nuclear@26: 
nuclear@26:   entropy->next_output_byte = cinfo->dest->next_output_byte;
nuclear@26:   entropy->free_in_buffer = cinfo->dest->free_in_buffer;
nuclear@26: 
nuclear@26:   /* Flush out any buffered data */
nuclear@26:   emit_eobrun(entropy);
nuclear@26:   flush_bits(entropy);
nuclear@26: 
nuclear@26:   cinfo->dest->next_output_byte = entropy->next_output_byte;
nuclear@26:   cinfo->dest->free_in_buffer = entropy->free_in_buffer;
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Finish up a statistics-gathering pass and create the new Huffman tables.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: finish_pass_gather_phuff (j_compress_ptr cinfo)
nuclear@26: {
nuclear@26:   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
nuclear@26:   boolean is_DC_band;
nuclear@26:   int ci, tbl;
nuclear@26:   jpeg_component_info * compptr;
nuclear@26:   JHUFF_TBL **htblptr;
nuclear@26:   boolean did[NUM_HUFF_TBLS];
nuclear@26: 
nuclear@26:   /* Flush out buffered data (all we care about is counting the EOB symbol) */
nuclear@26:   emit_eobrun(entropy);
nuclear@26: 
nuclear@26:   is_DC_band = (cinfo->Ss == 0);
nuclear@26: 
nuclear@26:   /* It's important not to apply jpeg_gen_optimal_table more than once
nuclear@26:    * per table, because it clobbers the input frequency counts!
nuclear@26:    */
nuclear@26:   MEMZERO(did, SIZEOF(did));
nuclear@26: 
nuclear@26:   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
nuclear@26:     compptr = cinfo->cur_comp_info[ci];
nuclear@26:     if (is_DC_band) {
nuclear@26:       if (cinfo->Ah != 0)	/* DC refinement needs no table */
nuclear@26: 	continue;
nuclear@26:       tbl = compptr->dc_tbl_no;
nuclear@26:     } else {
nuclear@26:       tbl = compptr->ac_tbl_no;
nuclear@26:     }
nuclear@26:     if (! did[tbl]) {
nuclear@26:       if (is_DC_band)
nuclear@26:         htblptr = & cinfo->dc_huff_tbl_ptrs[tbl];
nuclear@26:       else
nuclear@26:         htblptr = & cinfo->ac_huff_tbl_ptrs[tbl];
nuclear@26:       if (*htblptr == NULL)
nuclear@26:         *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
nuclear@26:       jpeg_gen_optimal_table(cinfo, *htblptr, entropy->count_ptrs[tbl]);
nuclear@26:       did[tbl] = TRUE;
nuclear@26:     }
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Module initialization routine for progressive Huffman entropy encoding.
nuclear@26:  */
nuclear@26: 
nuclear@26: GLOBAL(void)
nuclear@26: jinit_phuff_encoder (j_compress_ptr cinfo)
nuclear@26: {
nuclear@26:   phuff_entropy_ptr entropy;
nuclear@26:   int i;
nuclear@26: 
nuclear@26:   entropy = (phuff_entropy_ptr)
nuclear@26:     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 				SIZEOF(phuff_entropy_encoder));
nuclear@26:   cinfo->entropy = (struct jpeg_entropy_encoder *) entropy;
nuclear@26:   entropy->pub.start_pass = start_pass_phuff;
nuclear@26: 
nuclear@26:   /* Mark tables unallocated */
nuclear@26:   for (i = 0; i < NUM_HUFF_TBLS; i++) {
nuclear@26:     entropy->derived_tbls[i] = NULL;
nuclear@26:     entropy->count_ptrs[i] = NULL;
nuclear@26:   }
nuclear@26:   entropy->bit_buffer = NULL;	/* needed only in AC refinement scan */
nuclear@26: }
nuclear@26: 
nuclear@26: #endif /* C_PROGRESSIVE_SUPPORTED */