nuclear@2: /*
nuclear@2:  * jdpostct.c
nuclear@2:  *
nuclear@2:  * Copyright (C) 1994-1996, Thomas G. Lane.
nuclear@2:  * This file is part of the Independent JPEG Group's software.
nuclear@2:  * For conditions of distribution and use, see the accompanying README file.
nuclear@2:  *
nuclear@2:  * This file contains the decompression postprocessing controller.
nuclear@2:  * This controller manages the upsampling, color conversion, and color
nuclear@2:  * quantization/reduction steps; specifically, it controls the buffering
nuclear@2:  * between upsample/color conversion and color quantization/reduction.
nuclear@2:  *
nuclear@2:  * If no color quantization/reduction is required, then this module has no
nuclear@2:  * work to do, and it just hands off to the upsample/color conversion code.
nuclear@2:  * An integrated upsample/convert/quantize process would replace this module
nuclear@2:  * entirely.
nuclear@2:  */
nuclear@2: 
nuclear@2: #define JPEG_INTERNALS
nuclear@2: #include "jinclude.h"
nuclear@2: #include "jpeglib.h"
nuclear@2: 
nuclear@2: 
nuclear@2: /* Private buffer controller object */
nuclear@2: 
nuclear@2: typedef struct {
nuclear@2:   struct jpeg_d_post_controller pub; /* public fields */
nuclear@2: 
nuclear@2:   /* Color quantization source buffer: this holds output data from
nuclear@2:    * the upsample/color conversion step to be passed to the quantizer.
nuclear@2:    * For two-pass color quantization, we need a full-image buffer;
nuclear@2:    * for one-pass operation, a strip buffer is sufficient.
nuclear@2:    */
nuclear@2:   jvirt_sarray_ptr whole_image;	/* virtual array, or NULL if one-pass */
nuclear@2:   JSAMPARRAY buffer;		/* strip buffer, or current strip of virtual */
nuclear@2:   JDIMENSION strip_height;	/* buffer size in rows */
nuclear@2:   /* for two-pass mode only: */
nuclear@2:   JDIMENSION starting_row;	/* row # of first row in current strip */
nuclear@2:   JDIMENSION next_row;		/* index of next row to fill/empty in strip */
nuclear@2: } my_post_controller;
nuclear@2: 
nuclear@2: typedef my_post_controller * my_post_ptr;
nuclear@2: 
nuclear@2: 
nuclear@2: /* Forward declarations */
nuclear@2: METHODDEF(void) post_process_1pass
nuclear@2: 	JPP((j_decompress_ptr cinfo,
nuclear@2: 	     JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
nuclear@2: 	     JDIMENSION in_row_groups_avail,
nuclear@2: 	     JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
nuclear@2: 	     JDIMENSION out_rows_avail));
nuclear@2: #ifdef QUANT_2PASS_SUPPORTED
nuclear@2: METHODDEF(void) post_process_prepass
nuclear@2: 	JPP((j_decompress_ptr cinfo,
nuclear@2: 	     JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
nuclear@2: 	     JDIMENSION in_row_groups_avail,
nuclear@2: 	     JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
nuclear@2: 	     JDIMENSION out_rows_avail));
nuclear@2: METHODDEF(void) post_process_2pass
nuclear@2: 	JPP((j_decompress_ptr cinfo,
nuclear@2: 	     JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
nuclear@2: 	     JDIMENSION in_row_groups_avail,
nuclear@2: 	     JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
nuclear@2: 	     JDIMENSION out_rows_avail));
nuclear@2: #endif
nuclear@2: 
nuclear@2: 
nuclear@2: /*
nuclear@2:  * Initialize for a processing pass.
nuclear@2:  */
nuclear@2: 
nuclear@2: METHODDEF(void)
nuclear@2: start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
nuclear@2: {
nuclear@2:   my_post_ptr post = (my_post_ptr) cinfo->post;
nuclear@2: 
nuclear@2:   switch (pass_mode) {
nuclear@2:   case JBUF_PASS_THRU:
nuclear@2:     if (cinfo->quantize_colors) {
nuclear@2:       /* Single-pass processing with color quantization. */
nuclear@2:       post->pub.post_process_data = post_process_1pass;
nuclear@2:       /* We could be doing buffered-image output before starting a 2-pass
nuclear@2:        * color quantization; in that case, jinit_d_post_controller did not
nuclear@2:        * allocate a strip buffer.  Use the virtual-array buffer as workspace.
nuclear@2:        */
nuclear@2:       if (post->buffer == NULL) {
nuclear@2: 	post->buffer = (*cinfo->mem->access_virt_sarray)
nuclear@2: 	  ((j_common_ptr) cinfo, post->whole_image,
nuclear@2: 	   (JDIMENSION) 0, post->strip_height, TRUE);
nuclear@2:       }
nuclear@2:     } else {
nuclear@2:       /* For single-pass processing without color quantization,
nuclear@2:        * I have no work to do; just call the upsampler directly.
nuclear@2:        */
nuclear@2:       post->pub.post_process_data = cinfo->upsample->upsample;
nuclear@2:     }
nuclear@2:     break;
nuclear@2: #ifdef QUANT_2PASS_SUPPORTED
nuclear@2:   case JBUF_SAVE_AND_PASS:
nuclear@2:     /* First pass of 2-pass quantization */
nuclear@2:     if (post->whole_image == NULL)
nuclear@2:       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2:     post->pub.post_process_data = post_process_prepass;
nuclear@2:     break;
nuclear@2:   case JBUF_CRANK_DEST:
nuclear@2:     /* Second pass of 2-pass quantization */
nuclear@2:     if (post->whole_image == NULL)
nuclear@2:       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2:     post->pub.post_process_data = post_process_2pass;
nuclear@2:     break;
nuclear@2: #endif /* QUANT_2PASS_SUPPORTED */
nuclear@2:   default:
nuclear@2:     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2:     break;
nuclear@2:   }
nuclear@2:   post->starting_row = post->next_row = 0;
nuclear@2: }
nuclear@2: 
nuclear@2: 
nuclear@2: /*
nuclear@2:  * Process some data in the one-pass (strip buffer) case.
nuclear@2:  * This is used for color precision reduction as well as one-pass quantization.
nuclear@2:  */
nuclear@2: 
nuclear@2: METHODDEF(void)
nuclear@2: post_process_1pass (j_decompress_ptr cinfo,
nuclear@2: 		    JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
nuclear@2: 		    JDIMENSION in_row_groups_avail,
nuclear@2: 		    JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
nuclear@2: 		    JDIMENSION out_rows_avail)
nuclear@2: {
nuclear@2:   my_post_ptr post = (my_post_ptr) cinfo->post;
nuclear@2:   JDIMENSION num_rows, max_rows;
nuclear@2: 
nuclear@2:   /* Fill the buffer, but not more than what we can dump out in one go. */
nuclear@2:   /* Note we rely on the upsampler to detect bottom of image. */
nuclear@2:   max_rows = out_rows_avail - *out_row_ctr;
nuclear@2:   if (max_rows > post->strip_height)
nuclear@2:     max_rows = post->strip_height;
nuclear@2:   num_rows = 0;
nuclear@2:   (*cinfo->upsample->upsample) (cinfo,
nuclear@2: 		input_buf, in_row_group_ctr, in_row_groups_avail,
nuclear@2: 		post->buffer, &num_rows, max_rows);
nuclear@2:   /* Quantize and emit data. */
nuclear@2:   (*cinfo->cquantize->color_quantize) (cinfo,
nuclear@2: 		post->buffer, output_buf + *out_row_ctr, (int) num_rows);
nuclear@2:   *out_row_ctr += num_rows;
nuclear@2: }
nuclear@2: 
nuclear@2: 
nuclear@2: #ifdef QUANT_2PASS_SUPPORTED
nuclear@2: 
nuclear@2: /*
nuclear@2:  * Process some data in the first pass of 2-pass quantization.
nuclear@2:  */
nuclear@2: 
nuclear@2: METHODDEF(void)
nuclear@2: post_process_prepass (j_decompress_ptr cinfo,
nuclear@2: 		      JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
nuclear@2: 		      JDIMENSION in_row_groups_avail,
nuclear@2: 		      JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
nuclear@2: 		      JDIMENSION out_rows_avail)
nuclear@2: {
nuclear@2:   my_post_ptr post = (my_post_ptr) cinfo->post;
nuclear@2:   JDIMENSION old_next_row, num_rows;
nuclear@2: 
nuclear@2:   /* Reposition virtual buffer if at start of strip. */
nuclear@2:   if (post->next_row == 0) {
nuclear@2:     post->buffer = (*cinfo->mem->access_virt_sarray)
nuclear@2: 	((j_common_ptr) cinfo, post->whole_image,
nuclear@2: 	 post->starting_row, post->strip_height, TRUE);
nuclear@2:   }
nuclear@2: 
nuclear@2:   /* Upsample some data (up to a strip height's worth). */
nuclear@2:   old_next_row = post->next_row;
nuclear@2:   (*cinfo->upsample->upsample) (cinfo,
nuclear@2: 		input_buf, in_row_group_ctr, in_row_groups_avail,
nuclear@2: 		post->buffer, &post->next_row, post->strip_height);
nuclear@2: 
nuclear@2:   /* Allow quantizer to scan new data.  No data is emitted, */
nuclear@2:   /* but we advance out_row_ctr so outer loop can tell when we're done. */
nuclear@2:   if (post->next_row > old_next_row) {
nuclear@2:     num_rows = post->next_row - old_next_row;
nuclear@2:     (*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row,
nuclear@2: 					 (JSAMPARRAY) NULL, (int) num_rows);
nuclear@2:     *out_row_ctr += num_rows;
nuclear@2:   }
nuclear@2: 
nuclear@2:   /* Advance if we filled the strip. */
nuclear@2:   if (post->next_row >= post->strip_height) {
nuclear@2:     post->starting_row += post->strip_height;
nuclear@2:     post->next_row = 0;
nuclear@2:   }
nuclear@2: }
nuclear@2: 
nuclear@2: 
nuclear@2: /*
nuclear@2:  * Process some data in the second pass of 2-pass quantization.
nuclear@2:  */
nuclear@2: 
nuclear@2: METHODDEF(void)
nuclear@2: post_process_2pass (j_decompress_ptr cinfo,
nuclear@2: 		    JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
nuclear@2: 		    JDIMENSION in_row_groups_avail,
nuclear@2: 		    JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
nuclear@2: 		    JDIMENSION out_rows_avail)
nuclear@2: {
nuclear@2:   my_post_ptr post = (my_post_ptr) cinfo->post;
nuclear@2:   JDIMENSION num_rows, max_rows;
nuclear@2: 
nuclear@2:   /* Reposition virtual buffer if at start of strip. */
nuclear@2:   if (post->next_row == 0) {
nuclear@2:     post->buffer = (*cinfo->mem->access_virt_sarray)
nuclear@2: 	((j_common_ptr) cinfo, post->whole_image,
nuclear@2: 	 post->starting_row, post->strip_height, FALSE);
nuclear@2:   }
nuclear@2: 
nuclear@2:   /* Determine number of rows to emit. */
nuclear@2:   num_rows = post->strip_height - post->next_row; /* available in strip */
nuclear@2:   max_rows = out_rows_avail - *out_row_ctr; /* available in output area */
nuclear@2:   if (num_rows > max_rows)
nuclear@2:     num_rows = max_rows;
nuclear@2:   /* We have to check bottom of image here, can't depend on upsampler. */
nuclear@2:   max_rows = cinfo->output_height - post->starting_row;
nuclear@2:   if (num_rows > max_rows)
nuclear@2:     num_rows = max_rows;
nuclear@2: 
nuclear@2:   /* Quantize and emit data. */
nuclear@2:   (*cinfo->cquantize->color_quantize) (cinfo,
nuclear@2: 		post->buffer + post->next_row, output_buf + *out_row_ctr,
nuclear@2: 		(int) num_rows);
nuclear@2:   *out_row_ctr += num_rows;
nuclear@2: 
nuclear@2:   /* Advance if we filled the strip. */
nuclear@2:   post->next_row += num_rows;
nuclear@2:   if (post->next_row >= post->strip_height) {
nuclear@2:     post->starting_row += post->strip_height;
nuclear@2:     post->next_row = 0;
nuclear@2:   }
nuclear@2: }
nuclear@2: 
nuclear@2: #endif /* QUANT_2PASS_SUPPORTED */
nuclear@2: 
nuclear@2: 
nuclear@2: /*
nuclear@2:  * Initialize postprocessing controller.
nuclear@2:  */
nuclear@2: 
nuclear@2: GLOBAL(void)
nuclear@2: jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
nuclear@2: {
nuclear@2:   my_post_ptr post;
nuclear@2: 
nuclear@2:   post = (my_post_ptr)
nuclear@2:     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@2: 				SIZEOF(my_post_controller));
nuclear@2:   cinfo->post = (struct jpeg_d_post_controller *) post;
nuclear@2:   post->pub.start_pass = start_pass_dpost;
nuclear@2:   post->whole_image = NULL;	/* flag for no virtual arrays */
nuclear@2:   post->buffer = NULL;		/* flag for no strip buffer */
nuclear@2: 
nuclear@2:   /* Create the quantization buffer, if needed */
nuclear@2:   if (cinfo->quantize_colors) {
nuclear@2:     /* The buffer strip height is max_v_samp_factor, which is typically
nuclear@2:      * an efficient number of rows for upsampling to return.
nuclear@2:      * (In the presence of output rescaling, we might want to be smarter?)
nuclear@2:      */
nuclear@2:     post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor;
nuclear@2:     if (need_full_buffer) {
nuclear@2:       /* Two-pass color quantization: need full-image storage. */
nuclear@2:       /* We round up the number of rows to a multiple of the strip height. */
nuclear@2: #ifdef QUANT_2PASS_SUPPORTED
nuclear@2:       post->whole_image = (*cinfo->mem->request_virt_sarray)
nuclear@2: 	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
nuclear@2: 	 cinfo->output_width * cinfo->out_color_components,
nuclear@2: 	 (JDIMENSION) jround_up((long) cinfo->output_height,
nuclear@2: 				(long) post->strip_height),
nuclear@2: 	 post->strip_height);
nuclear@2: #else
nuclear@2:       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2: #endif /* QUANT_2PASS_SUPPORTED */
nuclear@2:     } else {
nuclear@2:       /* One-pass color quantization: just make a strip buffer. */
nuclear@2:       post->buffer = (*cinfo->mem->alloc_sarray)
nuclear@2: 	((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@2: 	 cinfo->output_width * cinfo->out_color_components,
nuclear@2: 	 post->strip_height);
nuclear@2:     }
nuclear@2:   }
nuclear@2: }