Changeset 846 for trunk/src/3rdparty/libjpeg/jchuff.c

Timestamp:

May 5, 2011, 5:36:53 AM (14 years ago)

Author:

Dmitry A. Kuminov

Message:

trunk: Merged in qt 4.7.2 sources from branches/vendor/nokia/qt.

Location:

trunk

Files:

• . (modified) (1 prop)
• src/3rdparty/libjpeg/jchuff.c (modified) (29 diffs)

trunk/src/3rdparty/libjpeg/jchuff.c

@@ -3 +3 @@
  *
  * Copyright (C) 1991-1997, Thomas G. Lane.
+ * Modified 2006-2009 by Guido Vollbeding.
  * 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.
+ * Both sequential and progressive modes are supported in this single module.
  *
  * Much of the complexity here has to do with supporting output suspension.
@@ -13 +15 @@
  * variables into local working storage, and update them back to the
  * permanent JPEG objects only upon successful completion of an MCU.
+ *
+ * We do not support output suspension for the progressive JPEG mode, since
+ * the library currently does not allow multiple-scan files to be written
+ * with output suspension.
  */
 
@@ -18 +24 @@
 #include "jinclude.h"
 #include "jpeglib.h"
-#include "jchuff.h"             /* Declarations shared with jcphuff.c */
+
+
+/* The legal range of a DCT coefficient is
+ *  -1024 .. +1023  for 8-bit data;
+ * -16384 .. +16383 for 12-bit data.
+ * Hence the magnitude should always fit in 10 or 14 bits respectively.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+#define MAX_COEF_BITS 10
+#else
+#define MAX_COEF_BITS 14
+#endif
+
+/* Derived data constructed for each Huffman table */
+
+typedef struct {
+  unsigned int ehufco[256];     /* code for each symbol */
+  char ehufsi[256];             /* length of code for each symbol */
+  /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */
+} c_derived_tbl;
 
 
@@ -66 +92 @@
   c_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS];
 
-#ifdef ENTROPY_OPT_SUPPORTED    /* Statistics tables for optimization */
+  /* Statistics tables for optimization */
   long * dc_count_ptrs[NUM_HUFF_TBLS];
   long * ac_count_ptrs[NUM_HUFF_TBLS];
-#endif
+
+  /* Following fields used only in progressive mode */
+
+  /* Mode flag: TRUE for optimization, FALSE for actual data output */
+  boolean gather_statistics;
+
+  /* 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 */
+  j_compress_ptr cinfo;         /* link to cinfo (needed for dump_buffer) */
+
+  /* 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... */
 } huff_entropy_encoder;
 
 typedef huff_entropy_encoder * huff_entropy_ptr;
 
-/* Working state while writing an MCU.
+/* Working state while writing an MCU (sequential mode).
  * This struct contains all the fields that are needed by subroutines.
  */
@@ -85 +128 @@
 } working_state;
 
-
-/* Forward declarations */
-METHODDEF(boolean) encode_mcu_huff JPP((j_compress_ptr cinfo,
-                                        JBLOCKROW *MCU_data));
-METHODDEF(void) finish_pass_huff JPP((j_compress_ptr cinfo));
-#ifdef ENTROPY_OPT_SUPPORTED
-METHODDEF(boolean) encode_mcu_gather JPP((j_compress_ptr cinfo,
-                                          JBLOCKROW *MCU_data));
-METHODDEF(void) finish_pass_gather JPP((j_compress_ptr cinfo));
+/* 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
-
-
-/*
- * Initialize for a Huffman-compressed scan.
- * If gather_statistics is TRUE, we do not output anything during the scan,
- * just count the Huffman symbols used and generate Huffman code tables.
- */
-
-METHODDEF(void)
-start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics)
-{
-  huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy;
-  int ci, dctbl, actbl;
-  jpeg_component_info * compptr;
-
-  if (gather_statistics) {
-#ifdef ENTROPY_OPT_SUPPORTED
-    entropy->pub.encode_mcu = encode_mcu_gather;
-    entropy->pub.finish_pass = finish_pass_gather;
-#else
-    ERREXIT(cinfo, JERR_NOT_COMPILED);
-#endif
-  } else {
-    entropy->pub.encode_mcu = encode_mcu_huff;
-    entropy->pub.finish_pass = finish_pass_huff;
-  }
-
-  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
-    compptr = cinfo->cur_comp_info[ci];
-    dctbl = compptr->dc_tbl_no;
-    actbl = compptr->ac_tbl_no;
-    if (gather_statistics) {
-#ifdef ENTROPY_OPT_SUPPORTED
-      /* Check for invalid table indexes */
-      /* (make_c_derived_tbl does this in the other path) */
-      if (dctbl < 0 || dctbl >= NUM_HUFF_TBLS)
-        ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, dctbl);
-      if (actbl < 0 || actbl >= NUM_HUFF_TBLS)
-        ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, actbl);
-      /* Allocate and zero the statistics tables */
-      /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */
-      if (entropy->dc_count_ptrs[dctbl] == NULL)
-        entropy->dc_count_ptrs[dctbl] = (long *)
-          (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
-                                      257 * SIZEOF(long));
-      MEMZERO(entropy->dc_count_ptrs[dctbl], 257 * SIZEOF(long));
-      if (entropy->ac_count_ptrs[actbl] == NULL)
-        entropy->ac_count_ptrs[actbl] = (long *)
-          (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
-                                      257 * SIZEOF(long));
-      MEMZERO(entropy->ac_count_ptrs[actbl], 257 * SIZEOF(long));
-#endif
-    } else {
-      /* Compute derived values for Huffman tables */
-      /* We may do this more than once for a table, but it's not expensive */
-      jpeg_make_c_derived_tbl(cinfo, TRUE, dctbl,
-                              & entropy->dc_derived_tbls[dctbl]);
-      jpeg_make_c_derived_tbl(cinfo, FALSE, actbl,
-                              & entropy->ac_derived_tbls[actbl]);
-    }
-    /* Initialize DC predictions to 0 */
-    entropy->saved.last_dc_val[ci] = 0;
-  }
-
-  /* Initialize bit buffer to empty */
-  entropy->saved.put_buffer = 0;
-  entropy->saved.put_bits = 0;
-
-  /* Initialize restart stuff */
-  entropy->restarts_to_go = cinfo->restart_interval;
-  entropy->next_restart_num = 0;
-}
 
 
@@ -172 +156 @@
  * Compute the derived values for a Huffman table.
  * This routine also performs some validation checks on the table.
- *
- * Note this is also used by jcphuff.c.
- */
-
-GLOBAL(void)
+ */
+
+LOCAL(void)
 jpeg_make_c_derived_tbl (j_compress_ptr cinfo, boolean isDC, int tblno,
                          c_derived_tbl ** pdtbl)
@@ -265 +247 @@
 
 
-/* Outputting bytes to the file */
+/* Outputting bytes to the file.
+ * NB: these must be called only when actually outputting,
+ * that is, entropy->gather_statistics == FALSE.
+ */
 
 /* Emit a byte, taking 'action' if must suspend. */
-#define emit_byte(state,val,action)  \
+#define emit_byte_s(state,val,action)  \
         { *(state)->next_output_byte++ = (JOCTET) (val);  \
           if (--(state)->free_in_buffer == 0)  \
-            if (! dump_buffer(state))  \
+            if (! dump_buffer_s(state))  \
               { action; } }
 
+/* Emit a byte */
+#define emit_byte_e(entropy,val)  \
+        { *(entropy)->next_output_byte++ = (JOCTET) (val);  \
+          if (--(entropy)->free_in_buffer == 0)  \
+            dump_buffer_e(entropy); }
+
 
 LOCAL(boolean)
-dump_buffer (working_state * state)
+dump_buffer_s (working_state * state)
 /* Empty the output buffer; return TRUE if successful, FALSE if must suspend */
 {
@@ -290 +281 @@
 
 
+LOCAL(void)
+dump_buffer_e (huff_entropy_ptr entropy)
+/* Empty the output buffer; we do not support suspension in this case. */
+{
+  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 */
 
@@ -300 +305 @@
 INLINE
 LOCAL(boolean)
-emit_bits (working_state * state, unsigned int code, int size)
+emit_bits_s (working_state * state, unsigned int code, int size)
 /* Emit some bits; return TRUE if successful, FALSE if must suspend */
 {
@@ -322 +327 @@
     int c = (int) ((put_buffer >> 16) & 0xFF);
     
-    emit_byte(state, c, return FALSE);
+    emit_byte_s(state, c, return FALSE);
     if (c == 0xFF) {            /* need to stuff a zero byte? */
-      emit_byte(state, 0, return FALSE);
+      emit_byte_s(state, 0, return FALSE);
     }
     put_buffer <<= 8;
@@ -337 +342 @@
 
 
+INLINE
+LOCAL(void)
+emit_bits_e (huff_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->saved.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 */
+
+  /* and merge with old buffer contents */
+  put_buffer |= entropy->saved.put_buffer;
+
+  while (put_bits >= 8) {
+    int c = (int) ((put_buffer >> 16) & 0xFF);
+
+    emit_byte_e(entropy, c);
+    if (c == 0xFF) {            /* need to stuff a zero byte? */
+      emit_byte_e(entropy, 0);
+    }
+    put_buffer <<= 8;
+    put_bits -= 8;
+  }
+
+  entropy->saved.put_buffer = put_buffer; /* update variables */
+  entropy->saved.put_bits = put_bits;
+}
+
+
 LOCAL(boolean)
-flush_bits (working_state * state)
-{
-  if (! emit_bits(state, 0x7F, 7)) /* fill any partial byte with ones */
+flush_bits_s (working_state * state)
+{
+  if (! emit_bits_s(state, 0x7F, 7)) /* fill any partial byte with ones */
     return FALSE;
-  state->cur.put_buffer = 0;    /* and reset bit-buffer to empty */
+  state->cur.put_buffer = 0;         /* and reset bit-buffer to empty */
   state->cur.put_bits = 0;
+  return TRUE;
+}
+
+
+LOCAL(void)
+flush_bits_e (huff_entropy_ptr entropy)
+{
+  emit_bits_e(entropy, 0x7F, 7); /* fill any partial byte with ones */
+  entropy->saved.put_buffer = 0; /* and reset bit-buffer to empty */
+  entropy->saved.put_bits = 0;
+}
+
+
+/*
+ * Emit (or just count) a Huffman symbol.
+ */
+
+INLINE
+LOCAL(void)
+emit_dc_symbol (huff_entropy_ptr entropy, int tbl_no, int symbol)
+{
+  if (entropy->gather_statistics)
+    entropy->dc_count_ptrs[tbl_no][symbol]++;
+  else {
+    c_derived_tbl * tbl = entropy->dc_derived_tbls[tbl_no];
+    emit_bits_e(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
+  }
+}
+
+
+INLINE
+LOCAL(void)
+emit_ac_symbol (huff_entropy_ptr entropy, int tbl_no, int symbol)
+{
+  if (entropy->gather_statistics)
+    entropy->ac_count_ptrs[tbl_no][symbol]++;
+  else {
+    c_derived_tbl * tbl = entropy->ac_derived_tbls[tbl_no];
+    emit_bits_e(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
+  }
+}
+
+
+/*
+ * Emit bits from a correction bit buffer.
+ */
+
+LOCAL(void)
+emit_buffered_bits (huff_entropy_ptr entropy, char * bufstart,
+                    unsigned int nbits)
+{
+  if (entropy->gather_statistics)
+    return;                     /* no real work */
+
+  while (nbits > 0) {
+    emit_bits_e(entropy, (unsigned int) (*bufstart), 1);
+    bufstart++;
+    nbits--;
+  }
+}
+
+
+/*
+ * Emit any pending EOBRUN symbol.
+ */
+
+LOCAL(void)
+emit_eobrun (huff_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_ac_symbol(entropy, entropy->ac_tbl_no, nbits << 4);
+    if (nbits)
+      emit_bits_e(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(boolean)
+emit_restart_s (working_state * state, int restart_num)
+{
+  int ci;
+
+  if (! flush_bits_s(state))
+    return FALSE;
+
+  emit_byte_s(state, 0xFF, return FALSE);
+  emit_byte_s(state, JPEG_RST0 + restart_num, return FALSE);
+
+  /* Re-initialize DC predictions to 0 */
+  for (ci = 0; ci < state->cinfo->comps_in_scan; ci++)
+    state->cur.last_dc_val[ci] = 0;
+
+  /* The restart counter is not updated until we successfully write the MCU. */
+
+  return TRUE;
+}
+
+
+LOCAL(void)
+emit_restart_e (huff_entropy_ptr entropy, int restart_num)
+{
+  int ci;
+
+  emit_eobrun(entropy);
+
+  if (! entropy->gather_statistics) {
+    flush_bits_e(entropy);
+    emit_byte_e(entropy, 0xFF);
+    emit_byte_e(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->saved.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)
+{
+  huff_entropy_ptr entropy = (huff_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_e(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->saved.last_dc_val[ci];
+    entropy->saved.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_dc_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_e(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)
+{
+  huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy;
+  register int temp, temp2;
+  register int nbits;
+  register int r, k;
+  int Se, Al;
+  const int * natural_order;
+  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_e(entropy, entropy->next_restart_num);
+
+  Se = cinfo->Se;
+  Al = cinfo->Al;
+  natural_order = cinfo->natural_order;
+
+  /* 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)[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_ac_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_ac_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_e(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)
+{
+  huff_entropy_ptr entropy = (huff_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_e(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_e(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)
+{
+  huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy;
+  register int temp;
+  register int r, k;
+  int EOB;
+  char *BR_buffer;
+  unsigned int BR;
+  int Se, Al;
+  const int * natural_order;
+  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_e(entropy, entropy->next_restart_num);
+
+  Se = cinfo->Se;
+  Al = cinfo->Al;
+  natural_order = cinfo->natural_order;
+
+  /* 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)[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_ac_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_ac_symbol(entropy, entropy->ac_tbl_no, (r << 4) + 1);
+
+    /* Emit output bit for newly-nonzero coef */
+    temp = ((*block)[natural_order[k]] < 0) ? 0 : 1;
+    emit_bits_e(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;
 }
@@ -357 +920 @@
   register int nbits;
   register int k, r, i;
-  
+  int Se = state->cinfo->lim_Se;
+  const int * natural_order = state->cinfo->natural_order;
+
   /* Encode the DC coefficient difference per section F.1.2.1 */
-  
+
   temp = temp2 = block[0] - last_dc_val;
 
@@ -368 +933 @@
     temp2--;
   }
-  
+
   /* Find the number of bits needed for the magnitude of the coefficient */
   nbits = 0;
@@ -380 +945 @@
   if (nbits > MAX_COEF_BITS+1)
     ERREXIT(state->cinfo, JERR_BAD_DCT_COEF);
-  
+
   /* Emit the Huffman-coded symbol for the number of bits */
-  if (! emit_bits(state, dctbl->ehufco[nbits], dctbl->ehufsi[nbits]))
+  if (! emit_bits_s(state, dctbl->ehufco[nbits], dctbl->ehufsi[nbits]))
     return FALSE;
 
@@ -388 +953 @@
   /* or the complement of its magnitude, if negative. */
   if (nbits)                    /* emit_bits rejects calls with size 0 */
-    if (! emit_bits(state, (unsigned int) temp2, nbits))
+    if (! emit_bits_s(state, (unsigned int) temp2, nbits))
       return FALSE;
 
   /* Encode the AC coefficients per section F.1.2.2 */
-  
+
   r = 0;                        /* r = run length of zeros */
-  
-  for (k = 1; k < DCTSIZE2; k++) {
-    if ((temp = block[jpeg_natural_order[k]]) == 0) {
+
+  for (k = 1; k <= Se; k++) {
+    if ((temp = block[natural_order[k]]) == 0) {
       r++;
     } else {
       /* if run length > 15, must emit special run-length-16 codes (0xF0) */
       while (r > 15) {
-        if (! emit_bits(state, actbl->ehufco[0xF0], actbl->ehufsi[0xF0]))
+        if (! emit_bits_s(state, actbl->ehufco[0xF0], actbl->ehufsi[0xF0]))
           return FALSE;
         r -= 16;
@@ -412 +977 @@
         temp2--;
       }
-      
+
       /* Find the number of bits needed for the magnitude of the coefficient */
       nbits = 1;                /* there must be at least one 1 bit */
@@ -420 +985 @@
       if (nbits > MAX_COEF_BITS)
         ERREXIT(state->cinfo, JERR_BAD_DCT_COEF);
-      
+
       /* Emit Huffman symbol for run length / number of bits */
       i = (r << 4) + nbits;
-      if (! emit_bits(state, actbl->ehufco[i], actbl->ehufsi[i]))
+      if (! emit_bits_s(state, actbl->ehufco[i], actbl->ehufsi[i]))
         return FALSE;
 
       /* Emit that number of bits of the value, if positive, */
       /* or the complement of its magnitude, if negative. */
-      if (! emit_bits(state, (unsigned int) temp2, nbits))
+      if (! emit_bits_s(state, (unsigned int) temp2, nbits))
         return FALSE;
-      
+
       r = 0;
     }
@@ -437 +1002 @@
   /* If the last coef(s) were zero, emit an end-of-block code */
   if (r > 0)
-    if (! emit_bits(state, actbl->ehufco[0], actbl->ehufsi[0]))
+    if (! emit_bits_s(state, actbl->ehufco[0], actbl->ehufsi[0]))
       return FALSE;
-
-  return TRUE;
-}
-
-
-/*
- * Emit a restart marker & resynchronize predictions.
- */
-
-LOCAL(boolean)
-emit_restart (working_state * state, int restart_num)
-{
-  int ci;
-
-  if (! flush_bits(state))
-    return FALSE;
-
-  emit_byte(state, 0xFF, return FALSE);
-  emit_byte(state, JPEG_RST0 + restart_num, return FALSE);
-
-  /* Re-initialize DC predictions to 0 */
-  for (ci = 0; ci < state->cinfo->comps_in_scan; ci++)
-    state->cur.last_dc_val[ci] = 0;
-
-  /* The restart counter is not updated until we successfully write the MCU. */
 
   return TRUE;
@@ -490 +1030 @@
   if (cinfo->restart_interval) {
     if (entropy->restarts_to_go == 0)
-      if (! emit_restart(&state, entropy->next_restart_num))
+      if (! emit_restart_s(&state, entropy->next_restart_num))
         return FALSE;
   }
@@ -536 +1076 @@
   working_state state;
 
-  /* Load up working state ... flush_bits needs it */
-  state.next_output_byte = cinfo->dest->next_output_byte;
-  state.free_in_buffer = cinfo->dest->free_in_buffer;
-  ASSIGN_STATE(state.cur, entropy->saved);
-  state.cinfo = cinfo;
-
-  /* Flush out the last data */
-  if (! flush_bits(&state))
-    ERREXIT(cinfo, JERR_CANT_SUSPEND);
-
-  /* Update state */
-  cinfo->dest->next_output_byte = state.next_output_byte;
-  cinfo->dest->free_in_buffer = state.free_in_buffer;
-  ASSIGN_STATE(entropy->saved, state.cur);
+  if (cinfo->progressive_mode) {
+    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_e(entropy);
+
+    cinfo->dest->next_output_byte = entropy->next_output_byte;
+    cinfo->dest->free_in_buffer = entropy->free_in_buffer;
+  } else {
+    /* Load up working state ... flush_bits needs it */
+    state.next_output_byte = cinfo->dest->next_output_byte;
+    state.free_in_buffer = cinfo->dest->free_in_buffer;
+    ASSIGN_STATE(state.cur, entropy->saved);
+    state.cinfo = cinfo;
+
+    /* Flush out the last data */
+    if (! flush_bits_s(&state))
+      ERREXIT(cinfo, JERR_CANT_SUSPEND);
+
+    /* Update state */
+    cinfo->dest->next_output_byte = state.next_output_byte;
+    cinfo->dest->free_in_buffer = state.free_in_buffer;
+    ASSIGN_STATE(entropy->saved, state.cur);
+  }
 }
 
@@ -564 +1116 @@
  */
 
-#ifdef ENTROPY_OPT_SUPPORTED
-
 
 /* Process a single block's worth of coefficients */
@@ -576 +1126 @@
   register int nbits;
   register int k, r;
+  int Se = cinfo->lim_Se;
+  const int * natural_order = cinfo->natural_order;
   
   /* Encode the DC coefficient difference per section F.1.2.1 */
@@ -602 +1154 @@
   r = 0;                        /* r = run length of zeros */
   
-  for (k = 1; k < DCTSIZE2; k++) {
-    if ((temp = block[jpeg_natural_order[k]]) == 0) {
+  for (k = 1; k <= Se; k++) {
+    if ((temp = block[natural_order[k]]) == 0) {
       r++;
     } else {
@@ -676 +1228 @@
 /*
  * Generate the best Huffman code table for the given counts, fill htbl.
- * Note this is also used by jcphuff.c.
  *
  * The JPEG standard requires that no symbol be assigned a codeword of all
@@ -702 +1253 @@
  */
 
-GLOBAL(void)
+LOCAL(void)
 jpeg_gen_optimal_table (j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[])
 {
@@ -847 +1398 @@
 {
   huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy;
-  int ci, dctbl, actbl;
+  int ci, tbl;
   jpeg_component_info * compptr;
   JHUFF_TBL **htblptr;
@@ -856 +1407 @@
    * per table, because it clobbers the input frequency counts!
    */
+  if (cinfo->progressive_mode)
+    /* Flush out buffered data (all we care about is counting the EOB symbol) */
+    emit_eobrun(entropy);
+
   MEMZERO(did_dc, SIZEOF(did_dc));
   MEMZERO(did_ac, SIZEOF(did_ac));
@@ -861 +1416 @@
   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
     compptr = cinfo->cur_comp_info[ci];
-    dctbl = compptr->dc_tbl_no;
-    actbl = compptr->ac_tbl_no;
-    if (! did_dc[dctbl]) {
-      htblptr = & cinfo->dc_huff_tbl_ptrs[dctbl];
-      if (*htblptr == NULL)
-        *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
-      jpeg_gen_optimal_table(cinfo, *htblptr, entropy->dc_count_ptrs[dctbl]);
-      did_dc[dctbl] = TRUE;
-    }
-    if (! did_ac[actbl]) {
-      htblptr = & cinfo->ac_huff_tbl_ptrs[actbl];
-      if (*htblptr == NULL)
-        *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
-      jpeg_gen_optimal_table(cinfo, *htblptr, entropy->ac_count_ptrs[actbl]);
-      did_ac[actbl] = TRUE;
-    }
-  }
-}
-
-
-#endif /* ENTROPY_OPT_SUPPORTED */
+    /* DC needs no table for refinement scan */
+    if (cinfo->Ss == 0 && cinfo->Ah == 0) {
+      tbl = compptr->dc_tbl_no;
+      if (! did_dc[tbl]) {
+        htblptr = & cinfo->dc_huff_tbl_ptrs[tbl];
+        if (*htblptr == NULL)
+          *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
+        jpeg_gen_optimal_table(cinfo, *htblptr, entropy->dc_count_ptrs[tbl]);
+        did_dc[tbl] = TRUE;
+      }
+    }
+    /* AC needs no table when not present */
+    if (cinfo->Se) {
+      tbl = compptr->ac_tbl_no;
+      if (! did_ac[tbl]) {
+        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->ac_count_ptrs[tbl]);
+        did_ac[tbl] = TRUE;
+      }
+    }
+  }
+}
+
+
+/*
+ * Initialize for a Huffman-compressed scan.
+ * If gather_statistics is TRUE, we do not output anything during the scan,
+ * just count the Huffman symbols used and generate Huffman code tables.
+ */
+
+METHODDEF(void)
+start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics)
+{
+  huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy;
+  int ci, tbl;
+  jpeg_component_info * compptr;
+
+  if (gather_statistics)
+    entropy->pub.finish_pass = finish_pass_gather;
+  else
+    entropy->pub.finish_pass = finish_pass_huff;
+
+  if (cinfo->progressive_mode) {
+    entropy->cinfo = cinfo;
+    entropy->gather_statistics = gather_statistics;
+
+    /* We assume jcmaster.c already validated the scan parameters. */
+
+    /* Select execution routine */
+    if (cinfo->Ah == 0) {
+      if (cinfo->Ss == 0)
+        entropy->pub.encode_mcu = encode_mcu_DC_first;
+      else
+        entropy->pub.encode_mcu = encode_mcu_AC_first;
+    } else {
+      if (cinfo->Ss == 0)
+        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));
+      }
+    }
+
+    /* Initialize AC stuff */
+    entropy->ac_tbl_no = cinfo->cur_comp_info[0]->ac_tbl_no;
+    entropy->EOBRUN = 0;
+    entropy->BE = 0;
+  } else {
+    if (gather_statistics)
+      entropy->pub.encode_mcu = encode_mcu_gather;
+    else
+      entropy->pub.encode_mcu = encode_mcu_huff;
+  }
+
+  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+    compptr = cinfo->cur_comp_info[ci];
+    /* DC needs no table for refinement scan */
+    if (cinfo->Ss == 0 && cinfo->Ah == 0) {
+      tbl = compptr->dc_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->dc_count_ptrs[tbl] == NULL)
+          entropy->dc_count_ptrs[tbl] = (long *)
+            (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+                                        257 * SIZEOF(long));
+        MEMZERO(entropy->dc_count_ptrs[tbl], 257 * SIZEOF(long));
+      } else {
+        /* Compute derived values for Huffman tables */
+        /* We may do this more than once for a table, but it's not expensive */
+        jpeg_make_c_derived_tbl(cinfo, TRUE, tbl,
+                                & entropy->dc_derived_tbls[tbl]);
+      }
+      /* Initialize DC predictions to 0 */
+      entropy->saved.last_dc_val[ci] = 0;
+    }
+    /* AC needs no table when not present */
+    if (cinfo->Se) {
+      tbl = compptr->ac_tbl_no;
+      if (gather_statistics) {
+        if (tbl < 0 || tbl >= NUM_HUFF_TBLS)
+          ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tbl);
+        if (entropy->ac_count_ptrs[tbl] == NULL)
+          entropy->ac_count_ptrs[tbl] = (long *)
+            (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+                                        257 * SIZEOF(long));
+        MEMZERO(entropy->ac_count_ptrs[tbl], 257 * SIZEOF(long));
+      } else {
+        jpeg_make_c_derived_tbl(cinfo, FALSE, tbl,
+                                & entropy->ac_derived_tbls[tbl]);
+      }
+    }
+  }
+
+  /* Initialize bit buffer to empty */
+  entropy->saved.put_buffer = 0;
+  entropy->saved.put_bits = 0;
+
+  /* Initialize restart stuff */
+  entropy->restarts_to_go = cinfo->restart_interval;
+  entropy->next_restart_num = 0;
+}
 
 
@@ -903 +1569 @@
   for (i = 0; i < NUM_HUFF_TBLS; i++) {
     entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL;
-#ifdef ENTROPY_OPT_SUPPORTED
     entropy->dc_count_ptrs[i] = entropy->ac_count_ptrs[i] = NULL;
-#endif
-  }
-}
+  }
+
+  if (cinfo->progressive_mode)
+    entropy->bit_buffer = NULL; /* needed only in AC refinement scan */
+}