/src/freeimage-svn/FreeImage/trunk/Source/LibJPEG/jdpostct.c

Source
/*
 * jdpostct.c
 *
 * Copyright (C) 1994-1996, 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 decompression postprocessing controller.
 * This controller manages the upsampling, color conversion, and color
 * quantization/reduction steps; specifically, it controls the buffering
 * between upsample/color conversion and color quantization/reduction.
 *
 * If no color quantization/reduction is required, then this module has no
 * work to do, and it just hands off to the upsample/color conversion code.
 * An integrated upsample/convert/quantize process would replace this module
 * entirely.
 */

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


/* Private buffer controller object */

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

  /* Color quantization source buffer: this holds output data from
   * the upsample/color conversion step to be passed to the quantizer.
   * For two-pass color quantization, we need a full-image buffer;
   * for one-pass operation, a strip buffer is sufficient.
   */
  jvirt_sarray_ptr whole_image; /* virtual array, or NULL if one-pass */
  JSAMPARRAY buffer;    /* strip buffer, or current strip of virtual */
  JDIMENSION strip_height;  /* buffer size in rows */
  /* for two-pass mode only: */
  JDIMENSION starting_row;  /* row # of first row in current strip */
  JDIMENSION next_row;    /* index of next row to fill/empty in strip */
} my_post_controller;

typedef my_post_controller * my_post_ptr;


/* Forward declarations */
METHODDEF(void) post_process_1pass
  JPP((j_decompress_ptr cinfo,
       JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
       JDIMENSION in_row_groups_avail,
       JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
       JDIMENSION out_rows_avail));
#ifdef QUANT_2PASS_SUPPORTED
METHODDEF(void) post_process_prepass
  JPP((j_decompress_ptr cinfo,
       JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
       JDIMENSION in_row_groups_avail,
       JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
       JDIMENSION out_rows_avail));
METHODDEF(void) post_process_2pass
  JPP((j_decompress_ptr cinfo,
       JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
       JDIMENSION in_row_groups_avail,
       JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
       JDIMENSION out_rows_avail));
#endif


/*
 * Initialize for a processing pass.
 */

METHODDEF(void)
start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
{
  my_post_ptr post = (my_post_ptr) cinfo->post;

  switch (pass_mode) {
  case JBUF_PASS_THRU:
    if (cinfo->quantize_colors) {
      /* Single-pass processing with color quantization. */
      post->pub.post_process_data = post_process_1pass;
      /* We could be doing buffered-image output before starting a 2-pass
       * color quantization; in that case, jinit_d_post_controller did not
       * allocate a strip buffer.  Use the virtual-array buffer as workspace.
       */
      if (post->buffer == NULL) {
  post->buffer = (*cinfo->mem->access_virt_sarray)
    ((j_common_ptr) cinfo, post->whole_image,
     (JDIMENSION) 0, post->strip_height, TRUE);
      }
    } else {
      /* For single-pass processing without color quantization,
       * I have no work to do; just call the upsampler directly.
       */
      post->pub.post_process_data = cinfo->upsample->upsample;
    }
    break;
#ifdef QUANT_2PASS_SUPPORTED
  case JBUF_SAVE_AND_PASS:
    /* First pass of 2-pass quantization */
    if (post->whole_image == NULL)
      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
    post->pub.post_process_data = post_process_prepass;
    break;
  case JBUF_CRANK_DEST:
    /* Second pass of 2-pass quantization */
    if (post->whole_image == NULL)
      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
    post->pub.post_process_data = post_process_2pass;
    break;
#endif /* QUANT_2PASS_SUPPORTED */
  default:
    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
    break;
  }
  post->starting_row = post->next_row = 0;
}


/*
 * Process some data in the one-pass (strip buffer) case.
 * This is used for color precision reduction as well as one-pass quantization.
 */

METHODDEF(void)
post_process_1pass (j_decompress_ptr cinfo,
        JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
        JDIMENSION in_row_groups_avail,
        JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
        JDIMENSION out_rows_avail)
{
  my_post_ptr post = (my_post_ptr) cinfo->post;
  JDIMENSION num_rows, max_rows;

  /* Fill the buffer, but not more than what we can dump out in one go. */
  /* Note we rely on the upsampler to detect bottom of image. */
  max_rows = out_rows_avail - *out_row_ctr;
  if (max_rows > post->strip_height)
    max_rows = post->strip_height;
  num_rows = 0;
  (*cinfo->upsample->upsample) (cinfo,
    input_buf, in_row_group_ctr, in_row_groups_avail,
    post->buffer, &num_rows, max_rows);
  /* Quantize and emit data. */
  (*cinfo->cquantize->color_quantize) (cinfo,
    post->buffer, output_buf + *out_row_ctr, (int) num_rows);
  *out_row_ctr += num_rows;
}


#ifdef QUANT_2PASS_SUPPORTED

/*
 * Process some data in the first pass of 2-pass quantization.
 */

METHODDEF(void)
post_process_prepass (j_decompress_ptr cinfo,
          JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
          JDIMENSION in_row_groups_avail,
          JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
          JDIMENSION out_rows_avail)
{
  my_post_ptr post = (my_post_ptr) cinfo->post;
  JDIMENSION old_next_row, num_rows;

  /* Reposition virtual buffer if at start of strip. */
  if (post->next_row == 0) {
    post->buffer = (*cinfo->mem->access_virt_sarray)
  ((j_common_ptr) cinfo, post->whole_image,
   post->starting_row, post->strip_height, TRUE);
  }

  /* Upsample some data (up to a strip height's worth). */
  old_next_row = post->next_row;
  (*cinfo->upsample->upsample) (cinfo,
    input_buf, in_row_group_ctr, in_row_groups_avail,
    post->buffer, &post->next_row, post->strip_height);

  /* Allow quantizer to scan new data.  No data is emitted, */
  /* but we advance out_row_ctr so outer loop can tell when we're done. */
  if (post->next_row > old_next_row) {
    num_rows = post->next_row - old_next_row;
    (*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row,
           (JSAMPARRAY) NULL, (int) num_rows);
    *out_row_ctr += num_rows;
  }

  /* Advance if we filled the strip. */
  if (post->next_row >= post->strip_height) {
    post->starting_row += post->strip_height;
    post->next_row = 0;
  }
}


/*
 * Process some data in the second pass of 2-pass quantization.
 */

METHODDEF(void)
post_process_2pass (j_decompress_ptr cinfo,
        JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
        JDIMENSION in_row_groups_avail,
        JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
        JDIMENSION out_rows_avail)
{
  my_post_ptr post = (my_post_ptr) cinfo->post;
  JDIMENSION num_rows, max_rows;

  /* Reposition virtual buffer if at start of strip. */
  if (post->next_row == 0) {
    post->buffer = (*cinfo->mem->access_virt_sarray)
  ((j_common_ptr) cinfo, post->whole_image,
   post->starting_row, post->strip_height, FALSE);
  }

  /* Determine number of rows to emit. */
  num_rows = post->strip_height - post->next_row; /* available in strip */
  max_rows = out_rows_avail - *out_row_ctr; /* available in output area */
  if (num_rows > max_rows)
    num_rows = max_rows;
  /* We have to check bottom of image here, can't depend on upsampler. */
  max_rows = cinfo->output_height - post->starting_row;
  if (num_rows > max_rows)
    num_rows = max_rows;

  /* Quantize and emit data. */
  (*cinfo->cquantize->color_quantize) (cinfo,
    post->buffer + post->next_row, output_buf + *out_row_ctr,
    (int) num_rows);
  *out_row_ctr += num_rows;

  /* Advance if we filled the strip. */
  post->next_row += num_rows;
  if (post->next_row >= post->strip_height) {
    post->starting_row += post->strip_height;
    post->next_row = 0;
  }
}

#endif /* QUANT_2PASS_SUPPORTED */


/*
 * Initialize postprocessing controller.
 */

GLOBAL(void)
jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
{
  my_post_ptr post;

  post = (my_post_ptr)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
        SIZEOF(my_post_controller));
  cinfo->post = (struct jpeg_d_post_controller *) post;
  post->pub.start_pass = start_pass_dpost;
  post->whole_image = NULL; /* flag for no virtual arrays */
  post->buffer = NULL;   /* flag for no strip buffer */

  /* Create the quantization buffer, if needed */
  if (cinfo->quantize_colors) {
    /* The buffer strip height is max_v_samp_factor, which is typically
     * an efficient number of rows for upsampling to return.
     * (In the presence of output rescaling, we might want to be smarter?)
     */
    post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor;
    if (need_full_buffer) {
      /* Two-pass color quantization: need full-image storage. */
      /* We round up the number of rows to a multiple of the strip height. */
#ifdef QUANT_2PASS_SUPPORTED
      post->whole_image = (*cinfo->mem->request_virt_sarray)
  ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
   cinfo->output_width * cinfo->out_color_components,
   (JDIMENSION) jround_up((long) cinfo->output_height,
        (long) post->strip_height),
   post->strip_height);
#else
      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
#endif /* QUANT_2PASS_SUPPORTED */
    } else {
      /* One-pass color quantization: just make a strip buffer. */
      post->buffer = (*cinfo->mem->alloc_sarray)
  ((j_common_ptr) cinfo, JPOOL_IMAGE,
   cinfo->output_width * cinfo->out_color_components,
   post->strip_height);
    }
  }
}

Coverage Report

Created: 2025-10-28 06:24

Line	Count	Source
1		/*
2		* jdpostct.c
3		*
4		* Copyright (C) 1994-1996, Thomas G. Lane.
5		* This file is part of the Independent JPEG Group's software.
6		* For conditions of distribution and use, see the accompanying README file.
7		*
8		* This file contains the decompression postprocessing controller.
9		* This controller manages the upsampling, color conversion, and color
10		* quantization/reduction steps; specifically, it controls the buffering
11		* between upsample/color conversion and color quantization/reduction.
12		*
13		* If no color quantization/reduction is required, then this module has no
14		* work to do, and it just hands off to the upsample/color conversion code.
15		* An integrated upsample/convert/quantize process would replace this module
16		* entirely.
17		*/
18
19		#define JPEG_INTERNALS
20		#include "jinclude.h"
21		#include "jpeglib.h"
22
23
24		/* Private buffer controller object */
25
26		typedef struct {
27		struct jpeg_d_post_controller pub; /* public fields */
28
29		/* Color quantization source buffer: this holds output data from
30		* the upsample/color conversion step to be passed to the quantizer.
31		* For two-pass color quantization, we need a full-image buffer;
32		* for one-pass operation, a strip buffer is sufficient.
33		*/
34		jvirt_sarray_ptr whole_image; /* virtual array, or NULL if one-pass */
35		JSAMPARRAY buffer; /* strip buffer, or current strip of virtual */
36		JDIMENSION strip_height; /* buffer size in rows */
37		/* for two-pass mode only: */
38		JDIMENSION starting_row; /* row # of first row in current strip */
39		JDIMENSION next_row; /* index of next row to fill/empty in strip */
40		} my_post_controller;
41
42		typedef my_post_controller * my_post_ptr;
43
44
45		/* Forward declarations */
46		METHODDEF(void) post_process_1pass
47		JPP((j_decompress_ptr cinfo,
48		JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
49		JDIMENSION in_row_groups_avail,
50		JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
51		JDIMENSION out_rows_avail));
52		#ifdef QUANT_2PASS_SUPPORTED
53		METHODDEF(void) post_process_prepass
54		JPP((j_decompress_ptr cinfo,
55		JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
56		JDIMENSION in_row_groups_avail,
57		JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
58		JDIMENSION out_rows_avail));
59		METHODDEF(void) post_process_2pass
60		JPP((j_decompress_ptr cinfo,
61		JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
62		JDIMENSION in_row_groups_avail,
63		JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
64		JDIMENSION out_rows_avail));
65		#endif
66
67
68		/*
69		* Initialize for a processing pass.
70		*/
71
72		METHODDEF(void)
73		start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
74	0	{
75	0	my_post_ptr post = (my_post_ptr) cinfo->post;
76
77	0	switch (pass_mode) {
78	0	case JBUF_PASS_THRU:
79	0	if (cinfo->quantize_colors) {
80		/* Single-pass processing with color quantization. */
81	0	post->pub.post_process_data = post_process_1pass;
82		/* We could be doing buffered-image output before starting a 2-pass
83		* color quantization; in that case, jinit_d_post_controller did not
84		* allocate a strip buffer. Use the virtual-array buffer as workspace.
85		*/
86	0	if (post->buffer == NULL) {
87	0	post->buffer = (*cinfo->mem->access_virt_sarray)
88	0	((j_common_ptr) cinfo, post->whole_image,
89	0	(JDIMENSION) 0, post->strip_height, TRUE);
90	0	}
91	0	} else {
92		/* For single-pass processing without color quantization,
93		* I have no work to do; just call the upsampler directly.
94		*/
95	0	post->pub.post_process_data = cinfo->upsample->upsample;
96	0	}
97	0	break;
98	0	#ifdef QUANT_2PASS_SUPPORTED
99	0	case JBUF_SAVE_AND_PASS:
100		/* First pass of 2-pass quantization */
101	0	if (post->whole_image == NULL)
102	0	ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
103	0	post->pub.post_process_data = post_process_prepass;
104	0	break;
105	0	case JBUF_CRANK_DEST:
106		/* Second pass of 2-pass quantization */
107	0	if (post->whole_image == NULL)
108	0	ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
109	0	post->pub.post_process_data = post_process_2pass;
110	0	break;
111	0	#endif /* QUANT_2PASS_SUPPORTED */
112	0	default:
113	0	ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
114	0	break;
115	0	}
116	0	post->starting_row = post->next_row = 0;
117	0	}
118
119
120		/*
121		* Process some data in the one-pass (strip buffer) case.
122		* This is used for color precision reduction as well as one-pass quantization.
123		*/
124
125		METHODDEF(void)
126		post_process_1pass (j_decompress_ptr cinfo,
127		JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
128		JDIMENSION in_row_groups_avail,
129		JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
130		JDIMENSION out_rows_avail)
131	0	{
132	0	my_post_ptr post = (my_post_ptr) cinfo->post;
133	0	JDIMENSION num_rows, max_rows;
134
135		/* Fill the buffer, but not more than what we can dump out in one go. */
136		/* Note we rely on the upsampler to detect bottom of image. */
137	0	max_rows = out_rows_avail - *out_row_ctr;
138	0	if (max_rows > post->strip_height)
139	0	max_rows = post->strip_height;
140	0	num_rows = 0;
141	0	(*cinfo->upsample->upsample) (cinfo,
142	0	input_buf, in_row_group_ctr, in_row_groups_avail,
143	0	post->buffer, &num_rows, max_rows);
144		/* Quantize and emit data. */
145	0	(*cinfo->cquantize->color_quantize) (cinfo,
146	0	post->buffer, output_buf + *out_row_ctr, (int) num_rows);
147	0	*out_row_ctr += num_rows;
148	0	}
149
150
151		#ifdef QUANT_2PASS_SUPPORTED
152
153		/*
154		* Process some data in the first pass of 2-pass quantization.
155		*/
156
157		METHODDEF(void)
158		post_process_prepass (j_decompress_ptr cinfo,
159		JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
160		JDIMENSION in_row_groups_avail,
161		JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
162		JDIMENSION out_rows_avail)
163	0	{
164	0	my_post_ptr post = (my_post_ptr) cinfo->post;
165	0	JDIMENSION old_next_row, num_rows;
166
167		/* Reposition virtual buffer if at start of strip. */
168	0	if (post->next_row == 0) {
169	0	post->buffer = (*cinfo->mem->access_virt_sarray)
170	0	((j_common_ptr) cinfo, post->whole_image,
171	0	post->starting_row, post->strip_height, TRUE);
172	0	}
173
174		/* Upsample some data (up to a strip height's worth). */
175	0	old_next_row = post->next_row;
176	0	(*cinfo->upsample->upsample) (cinfo,
177	0	input_buf, in_row_group_ctr, in_row_groups_avail,
178	0	post->buffer, &post->next_row, post->strip_height);
179
180		/* Allow quantizer to scan new data. No data is emitted, */
181		/* but we advance out_row_ctr so outer loop can tell when we're done. */
182	0	if (post->next_row > old_next_row) {
183	0	num_rows = post->next_row - old_next_row;
184	0	(*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row,
185	0	(JSAMPARRAY) NULL, (int) num_rows);
186	0	*out_row_ctr += num_rows;
187	0	}
188
189		/* Advance if we filled the strip. */
190	0	if (post->next_row >= post->strip_height) {
191	0	post->starting_row += post->strip_height;
192	0	post->next_row = 0;
193	0	}
194	0	}
195
196
197		/*
198		* Process some data in the second pass of 2-pass quantization.
199		*/
200
201		METHODDEF(void)
202		post_process_2pass (j_decompress_ptr cinfo,
203		JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
204		JDIMENSION in_row_groups_avail,
205		JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
206		JDIMENSION out_rows_avail)
207	0	{
208	0	my_post_ptr post = (my_post_ptr) cinfo->post;
209	0	JDIMENSION num_rows, max_rows;
210
211		/* Reposition virtual buffer if at start of strip. */
212	0	if (post->next_row == 0) {
213	0	post->buffer = (*cinfo->mem->access_virt_sarray)
214	0	((j_common_ptr) cinfo, post->whole_image,
215	0	post->starting_row, post->strip_height, FALSE);
216	0	}
217
218		/* Determine number of rows to emit. */
219	0	num_rows = post->strip_height - post->next_row; /* available in strip */
220	0	max_rows = out_rows_avail - out_row_ctr; / available in output area */
221	0	if (num_rows > max_rows)
222	0	num_rows = max_rows;
223		/* We have to check bottom of image here, can't depend on upsampler. */
224	0	max_rows = cinfo->output_height - post->starting_row;
225	0	if (num_rows > max_rows)
226	0	num_rows = max_rows;
227
228		/* Quantize and emit data. */
229	0	(*cinfo->cquantize->color_quantize) (cinfo,
230	0	post->buffer + post->next_row, output_buf + *out_row_ctr,
231	0	(int) num_rows);
232	0	*out_row_ctr += num_rows;
233
234		/* Advance if we filled the strip. */
235	0	post->next_row += num_rows;
236	0	if (post->next_row >= post->strip_height) {
237	0	post->starting_row += post->strip_height;
238	0	post->next_row = 0;
239	0	}
240	0	}
241
242		#endif /* QUANT_2PASS_SUPPORTED */
243
244
245		/*
246		* Initialize postprocessing controller.
247		*/
248
249		GLOBAL(void)
250		jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
251	0	{
252	0	my_post_ptr post;
253
254	0	post = (my_post_ptr)
255	0	(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
256	0	SIZEOF(my_post_controller));
257	0	cinfo->post = (struct jpeg_d_post_controller *) post;
258	0	post->pub.start_pass = start_pass_dpost;
259	0	post->whole_image = NULL; /* flag for no virtual arrays */
260	0	post->buffer = NULL; /* flag for no strip buffer */
261
262		/* Create the quantization buffer, if needed */
263	0	if (cinfo->quantize_colors) {
264		/* The buffer strip height is max_v_samp_factor, which is typically
265		* an efficient number of rows for upsampling to return.
266		* (In the presence of output rescaling, we might want to be smarter?)
267		*/
268	0	post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor;
269	0	if (need_full_buffer) {
270		/* Two-pass color quantization: need full-image storage. */
271		/* We round up the number of rows to a multiple of the strip height. */
272	0	#ifdef QUANT_2PASS_SUPPORTED
273	0	post->whole_image = (*cinfo->mem->request_virt_sarray)
274	0	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
275	0	cinfo->output_width * cinfo->out_color_components,
276	0	(JDIMENSION) jround_up((long) cinfo->output_height,
277	0	(long) post->strip_height),
278	0	post->strip_height);
279		#else
280		ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
281		#endif /* QUANT_2PASS_SUPPORTED */
282	0	} else {
283		/* One-pass color quantization: just make a strip buffer. */
284	0	post->buffer = (*cinfo->mem->alloc_sarray)
285	0	((j_common_ptr) cinfo, JPOOL_IMAGE,
286	0	cinfo->output_width * cinfo->out_color_components,
287	0	post->strip_height);
288	0	}
289	0	}
290	0	}