    /*
     * jccoefct.c
     *
     * Copyright (C) 1994-1997, 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 the coefficient buffer controller for compression.
     * This controller is the top level of the JPEG compressor proper.
     * The coefficient buffer lies between forward-DCT and entropy encoding steps.
     */

    #define JPEG_INTERNALS
    #include "jinclude.h"
    #include "jpeglib.h"

    /* We use a full-image coefficient buffer when doing Huffman optimization,
     * and also for writing multiple-scan JPEG files.  In all cases, the DCT
     * step is run during the first pass, and subsequent passes need only read
     * the buffered coefficients.
     */
    #ifdef ENTROPY_OPT_SUPPORTED
    #define FULL_COEF_BUFFER_SUPPORTED
    #else
    #ifdef C_MULTISCAN_FILES_SUPPORTED
    #define FULL_COEF_BUFFER_SUPPORTED
    #endif
    #endif

    /* Private buffer controller object */

    typedef struct {
      struct jpeg_c_coef_controller pub; /* public fields */

      JDIMENSION iMCU_row_num;	/* iMCU row # within image */
      JDIMENSION mcu_ctr;		/* counts MCUs processed in current row */
      int MCU_vert_offset;		/* counts MCU rows within iMCU row */
      int MCU_rows_per_iMCU_row;	/* number of such rows needed */

      /* For single-pass compression, it's sufficient to buffer just one MCU
       * (although this may prove a bit slow in practice).  We allocate a
       * workspace of C_MAX_BLOCKS_IN_MCU coefficient blocks, and reuse it for each
       * MCU constructed and sent.  (On 80x86, the workspace is FAR even though
       * it's not really very big; this is to keep the module interfaces unchanged
       * when a large coefficient buffer is necessary.)
       * In multi-pass modes, this array points to the current MCU's blocks
       * within the virtual arrays.
       */
      JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];

      /* In multi-pass modes, we need a virtual block array for each component. */
      jvirt_barray_ptr whole_image[MAX_COMPONENTS];
    } my_coef_controller;

    typedef my_coef_controller * my_coef_ptr;

    /* Forward declarations */
    METHODDEF(int) compress_data
        JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
    #ifdef FULL_COEF_BUFFER_SUPPORTED
    METHODDEF(int) compress_first_pass
        JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
    METHODDEF(int) compress_output
        JPP((j_compress_ptr cinfo, JSAMPIMAGE input_buf));
    #endif

    LOCAL(void)
    start_iMCU_row (j_compress_ptr cinfo)
    /* Reset within-iMCU-row counters for a new row */
    {
      my_coef_ptr coef = (my_coef_ptr) cinfo->coef;

      /* In an interleaved scan, an MCU row is the same as an iMCU row.
       * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
       * But at the bottom of the image, process only what's left.
       */
      if (cinfo->comps_in_scan > 1) {
        coef->MCU_rows_per_iMCU_row = 1;
      } else {
        if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))
          coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
        else
          coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
      }

      coef->mcu_ctr = 0;
      coef->MCU_vert_offset = 0;
    }

    /*
     * Initialize for a processing pass.
     */

    METHODDEF(void)
    start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
    {
      my_coef_ptr coef = (my_coef_ptr) cinfo->coef;

      coef->iMCU_row_num = 0;
      start_iMCU_row(cinfo);

      switch (pass_mode) {
      case JBUF_PASS_THRU:
        if (coef->whole_image[0] != NULL)
          ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
        coef->pub.compress_data = compress_data;
        break;
    #ifdef FULL_COEF_BUFFER_SUPPORTED
      case JBUF_SAVE_AND_PASS:
        if (coef->whole_image[0] == NULL)
          ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
        coef->pub.compress_data = compress_first_pass;
        break;
      case JBUF_CRANK_DEST:
        if (coef->whole_image[0] == NULL)
          ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
        coef->pub.compress_data = compress_output;
        break;
    #endif
      default:
        ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
        break;
      }
    }

    /*
     * Process some data in the single-pass case.
     * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
     * per call, ie, v_samp_factor block rows for each component in the image.
     * Returns TRUE if the iMCU row is completed, FALSE if suspended.
     *
     * NB: input_buf contains a plane for each component in image,
     * which we index according to the component's SOF position.
     */

    METHODDEF(int)
    compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
    {
      my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
      JDIMENSION MCU_col_num;	/* index of current MCU within row */
      JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
      JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
      int blkn, bi, ci, yindex, yoffset, blockcnt;
      JDIMENSION ypos, xpos;
      jpeg_component_info *compptr;

      /* Loop to write as much as one whole iMCU row */
      for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
           yoffset++) {
        for (MCU_col_num = coef->mcu_ctr; MCU_col_num <= last_MCU_col;
    	 MCU_col_num++) {
          /* Determine where data comes from in input_buf and do the DCT thing.
           * Each call on forward_DCT processes a horizontal row of DCT blocks
           * as wide as an MCU; we rely on having allocated the MCU_buffer[] blocks
           * sequentially.  Dummy blocks at the right or bottom edge are filled in
           * specially.  The data in them does not matter for image reconstruction,
           * so we fill them with values that will encode to the smallest amount of
           * data, viz: all zeroes in the AC entries, DC entries equal to previous
           * block's DC value.  (Thanks to Thomas Kinsman for this idea.)
           */
          blkn = 0;
          for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
    	compptr = cinfo->cur_comp_info[ci];
    	blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width
    						: compptr->last_col_width;
    	xpos = MCU_col_num * compptr->MCU_sample_width;
    	ypos = yoffset * DCTSIZE; /* ypos == (yoffset+yindex) * DCTSIZE */
    	for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
    	  if (coef->iMCU_row_num < last_iMCU_row ||
    	      yoffset+yindex < compptr->last_row_height) {
    	    (*cinfo->fdct->forward_DCT) (cinfo, compptr,
    					 input_buf[compptr->component_index],
    					 coef->MCU_buffer[blkn],
    					 ypos, xpos, (JDIMENSION) blockcnt);
    	    if (blockcnt < compptr->MCU_width) {
    	      /* Create some dummy blocks at the right edge of the image. */
    	      jzero_far((void FAR *) coef->MCU_buffer[blkn + blockcnt],
    			(compptr->MCU_width - blockcnt) * SIZEOF(JBLOCK));
    	      for (bi = blockcnt; bi < compptr->MCU_width; bi++) {
    		coef->MCU_buffer[blkn+bi][0][0] = coef->MCU_buffer[blkn+bi-1][0][0];
    	      }
    	    }
    	  } else {
    	    /* Create a row of dummy blocks at the bottom of the image. */
    	    jzero_far((void FAR *) coef->MCU_buffer[blkn],
    		      compptr->MCU_width * SIZEOF(JBLOCK));
    	    for (bi = 0; bi < compptr->MCU_width; bi++) {
    	      coef->MCU_buffer[blkn+bi][0][0] = coef->MCU_buffer[blkn-1][0][0];
    	    }
    	  }
    	  blkn += compptr->MCU_width;
    	  ypos += DCTSIZE;
    	}
          }
          /* Try to write the MCU.  In event of a suspension failure, we will
           * re-DCT the MCU on restart (a bit inefficient, could be fixed...)
           */
          if (! (*cinfo->entropy->encode_mcu) (cinfo, coef->MCU_buffer)) {
    	/* Suspension forced; update state counters and exit */
    	coef->MCU_vert_offset = yoffset;
    	coef->mcu_ctr = MCU_col_num;
    	return FALSE;
          }
        }
        /* Completed an MCU row, but perhaps not an iMCU row */
        coef->mcu_ctr = 0;
      }
      /* Completed the iMCU row, advance counters for next one */
      coef->iMCU_row_num++;
      start_iMCU_row(cinfo);
      return TRUE;
    }

    #ifdef FULL_COEF_BUFFER_SUPPORTED

    /*
     * Process some data in the first pass of a multi-pass case.
     * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
     * per call, ie, v_samp_factor block rows for each component in the image.
     * This amount of data is read from the source buffer, DCT'd and quantized,
     * and saved into the virtual arrays.  We also generate suitable dummy blocks
     * as needed at the right and lower edges.  (The dummy blocks are constructed
     * in the virtual arrays, which have been padded appropriately.)  This makes
     * it possible for subsequent passes not to worry about real vs. dummy blocks.
     *
     * We must also emit the data to the entropy encoder.  This is conveniently
     * done by calling compress_output() after we've loaded the current strip
     * of the virtual arrays.
     *
     * NB: input_buf contains a plane for each component in image.  All
     * components are DCT'd and loaded into the virtual arrays in this pass.
     * However, it may be that only a subset of the components are emitted to
     * the entropy encoder during this first pass; be careful about looking
     * at the scan-dependent variables (MCU dimensions, etc).
     */

    METHODDEF(int)
    compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
    {
      my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
      JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
      JDIMENSION blocks_across, MCUs_across, MCUindex;
      int bi, ci, h_samp_factor, block_row, block_rows, ndummy;
      JCOEF lastDC;
      jpeg_component_info *compptr;
      JBLOCKARRAY buffer;
      JBLOCKROW thisblockrow, lastblockrow;

      for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
           ci++, compptr++) {
        /* Align the virtual buffer for this component. */
        buffer = (*cinfo->mem->access_virt_barray)
          ((j_common_ptr) cinfo, coef->whole_image[ci],
           coef->iMCU_row_num * compptr->v_samp_factor,
           (JDIMENSION) compptr->v_samp_factor, TRUE);
        /* Count non-dummy DCT block rows in this iMCU row. */
        if (coef->iMCU_row_num < last_iMCU_row)
          block_rows = compptr->v_samp_factor;
        else {
          /* NB: can't use last_row_height here, since may not be set! */
          block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
          if (block_rows == 0) block_rows = compptr->v_samp_factor;
        }
        blocks_across = compptr->width_in_blocks;
        h_samp_factor = compptr->h_samp_factor;
        /* Count number of dummy blocks to be added at the right margin. */
        ndummy = (int) (blocks_across % h_samp_factor);
        if (ndummy > 0)
          ndummy = h_samp_factor - ndummy;
        /* Perform DCT for all non-dummy blocks in this iMCU row.  Each call
         * on forward_DCT processes a complete horizontal row of DCT blocks.
         */
        for (block_row = 0; block_row < block_rows; block_row++) {
          thisblockrow = buffer[block_row];
          (*cinfo->fdct->forward_DCT) (cinfo, compptr,
    				   input_buf[ci], thisblockrow,
    				   (JDIMENSION) (block_row * DCTSIZE),
    				   (JDIMENSION) 0, blocks_across);
          if (ndummy > 0) {
    	/* Create dummy blocks at the right edge of the image. */
    	thisblockrow += blocks_across; /* => first dummy block */
    	jzero_far((void FAR *) thisblockrow, ndummy * SIZEOF(JBLOCK));
    	lastDC = thisblockrow[-1][0];
    	for (bi = 0; bi < ndummy; bi++) {
    	  thisblockrow[bi][0] = lastDC;
    	}
          }
        }
        /* If at end of image, create dummy block rows as needed.
         * The tricky part here is that within each MCU, we want the DC values
         * of the dummy blocks to match the last real block's DC value.
         * This squeezes a few more bytes out of the resulting file...
         */
        if (coef->iMCU_row_num == last_iMCU_row) {
          blocks_across += ndummy;	/* include lower right corner */
          MCUs_across = blocks_across / h_samp_factor;
          for (block_row = block_rows; block_row < compptr->v_samp_factor;
    	   block_row++) {
    	thisblockrow = buffer[block_row];
    	lastblockrow = buffer[block_row-1];
    	jzero_far((void FAR *) thisblockrow,
    		  (size_t) (blocks_across * SIZEOF(JBLOCK)));
    	for (MCUindex = 0; MCUindex < MCUs_across; MCUindex++) {
    	  lastDC = lastblockrow[h_samp_factor-1][0];
    	  for (bi = 0; bi < h_samp_factor; bi++) {
    	    thisblockrow[bi][0] = lastDC;
    	  }
    	  thisblockrow += h_samp_factor; /* advance to next MCU in row */
    	  lastblockrow += h_samp_factor;
    	}
          }
        }
      }
      /* NB: compress_output will increment iMCU_row_num if successful.
       * A suspension return will result in redoing all the work above next time.
       */

      /* Emit data to the entropy encoder, sharing code with subsequent passes */
      return compress_output(cinfo, input_buf);
    }

    /*
     * Process some data in subsequent passes of a multi-pass case.
     * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
     * per call, ie, v_samp_factor block rows for each component in the scan.
     * The data is obtained from the virtual arrays and fed to the entropy coder.
     * Returns TRUE if the iMCU row is completed, FALSE if suspended.
     *
     * NB: input_buf is ignored; it is likely to be a NULL pointer.
     */

    METHODDEF(int)
    compress_output (j_compress_ptr cinfo, JSAMPIMAGE )//input_buf)
    {
      my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
      JDIMENSION MCU_col_num;	/* index of current MCU within row */
      int blkn, ci, xindex, yindex, yoffset;
      JDIMENSION start_col;
      JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
      JBLOCKROW buffer_ptr;
      jpeg_component_info *compptr;

      /* Align the virtual buffers for the components used in this scan.
       * NB: during first pass, this is safe only because the buffers will
       * already be aligned properly, so jmemmgr.c won't need to do any I/O.
       */
      for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
        compptr = cinfo->cur_comp_info[ci];
        buffer[ci] = (*cinfo->mem->access_virt_barray)
          ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
           coef->iMCU_row_num * compptr->v_samp_factor,
           (JDIMENSION) compptr->v_samp_factor, FALSE);
      }

      /* Loop to process one whole iMCU row */
      for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
           yoffset++) {
        for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
    	 MCU_col_num++) {
          /* Construct list of pointers to DCT blocks belonging to this MCU */
          blkn = 0;			/* index of current DCT block within MCU */
          for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
    	compptr = cinfo->cur_comp_info[ci];
    	start_col = MCU_col_num * compptr->MCU_width;
    	for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
    	  buffer_ptr = buffer[ci][yindex+yoffset] + start_col;
    	  for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
    	    coef->MCU_buffer[blkn++] = buffer_ptr++;
    	  }
    	}
          }
          /* Try to write the MCU. */
          if (! (*cinfo->entropy->encode_mcu) (cinfo, coef->MCU_buffer)) {
    	/* Suspension forced; update state counters and exit */
    	coef->MCU_vert_offset = yoffset;
    	coef->mcu_ctr = MCU_col_num;
    	return FALSE;
          }
        }
        /* Completed an MCU row, but perhaps not an iMCU row */
        coef->mcu_ctr = 0;
      }
      /* Completed the iMCU row, advance counters for next one */
      coef->iMCU_row_num++;
      start_iMCU_row(cinfo);
      return TRUE;
    }

    #endif /* FULL_COEF_BUFFER_SUPPORTED */

    /*
     * Initialize coefficient buffer controller.
     */

    GLOBAL(void)
    jinit_c_coef_controller (j_compress_ptr cinfo, int need_full_buffer)
    {
      my_coef_ptr coef;

      coef = (my_coef_ptr)
        (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
    				SIZEOF(my_coef_controller));
      cinfo->coef = (struct jpeg_c_coef_controller *) coef;
      coef->pub.start_pass = start_pass_coef;

      /* Create the coefficient buffer. */
      if (need_full_buffer) {
    #ifdef FULL_COEF_BUFFER_SUPPORTED
        /* Allocate a full-image virtual array for each component, */
        /* padded to a multiple of samp_factor DCT blocks in each direction. */
        int ci;
        jpeg_component_info *compptr;

        for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
    	 ci++, compptr++) {
          coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
    	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
    	 (JDIMENSION) jround_up((long) compptr->width_in_blocks,
    				(long) compptr->h_samp_factor),
    	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
    				(long) compptr->v_samp_factor),
    	 (JDIMENSION) compptr->v_samp_factor);
        }
    #else
        ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
    #endif
      } else {
        /* We only need a single-MCU buffer. */
        JBLOCKROW buffer;
        int i;

        buffer = (JBLOCKROW)
          (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
    				  C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
        for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
          coef->MCU_buffer[i] = buffer + i;
        }
        coef->whole_image[0] = NULL; /* flag for no virtual arrays */
      }
    }