3rdparty/libjpeg/jdpostct.c

/*
 * 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);
    }
  }
}
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	{
75	my_post_ptr post = (my_post_ptr) cinfo->post;
76
77	switch (pass_mode) {
78	case JBUF_PASS_THRU:
79	if (cinfo->quantize_colors) {
80	/* Single-pass processing with color quantization. */
81	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	if (post->buffer == NULL) {
87	post->buffer = (*cinfo->mem->access_virt_sarray)
88	((j_common_ptr) cinfo, post->whole_image,
89	(JDIMENSION) 0, post->strip_height, TRUE);
90	}
91	} else {
92	/* For single-pass processing without color quantization,
93	* I have no work to do; just call the upsampler directly.
94	*/
95	post->pub.post_process_data = cinfo->upsample->upsample;
96	}
97	break;
98	#ifdef QUANT_2PASS_SUPPORTED
99	case JBUF_SAVE_AND_PASS:
100	/* First pass of 2-pass quantization */
101	if (post->whole_image == NULL)
102	ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
103	post->pub.post_process_data = post_process_prepass;
104	break;
105	case JBUF_CRANK_DEST:
106	/* Second pass of 2-pass quantization */
107	if (post->whole_image == NULL)
108	ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
109	post->pub.post_process_data = post_process_2pass;
110	break;
111	#endif /* QUANT_2PASS_SUPPORTED */
112	default:
113	ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
114	break;
115	}
116	post->starting_row = post->next_row = 0;
117	}
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	{
132	my_post_ptr post = (my_post_ptr) cinfo->post;
133	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	max_rows = out_rows_avail - *out_row_ctr;
138	if (max_rows > post->strip_height)
139	max_rows = post->strip_height;
140	num_rows = 0;
141	(*cinfo->upsample->upsample) (cinfo,
142	input_buf, in_row_group_ctr, in_row_groups_avail,
143	post->buffer, &num_rows, max_rows);
144	/* Quantize and emit data. */
145	(*cinfo->cquantize->color_quantize) (cinfo,
146	post->buffer, output_buf + *out_row_ctr, (int) num_rows);
147	*out_row_ctr += num_rows;
148	}
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	{
164	my_post_ptr post = (my_post_ptr) cinfo->post;
165	JDIMENSION old_next_row, num_rows;
166
167	/* Reposition virtual buffer if at start of strip. */
168	if (post->next_row == 0) {
169	post->buffer = (*cinfo->mem->access_virt_sarray)
170	((j_common_ptr) cinfo, post->whole_image,
171	post->starting_row, post->strip_height, TRUE);
172	}
173
174	/* Upsample some data (up to a strip height's worth). */
175	old_next_row = post->next_row;
176	(*cinfo->upsample->upsample) (cinfo,
177	input_buf, in_row_group_ctr, in_row_groups_avail,
178	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	if (post->next_row > old_next_row) {
183	num_rows = post->next_row - old_next_row;
184	(*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row,
185	(JSAMPARRAY) NULL, (int) num_rows);
186	*out_row_ctr += num_rows;
187	}
188
189	/* Advance if we filled the strip. */
190	if (post->next_row >= post->strip_height) {
191	post->starting_row += post->strip_height;
192	post->next_row = 0;
193	}
194	}
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	{
208	my_post_ptr post = (my_post_ptr) cinfo->post;
209	JDIMENSION num_rows, max_rows;
210
211	/* Reposition virtual buffer if at start of strip. */
212	if (post->next_row == 0) {
213	post->buffer = (*cinfo->mem->access_virt_sarray)
214	((j_common_ptr) cinfo, post->whole_image,
215	post->starting_row, post->strip_height, FALSE);
216	}
217
218	/* Determine number of rows to emit. */
219	num_rows = post->strip_height - post->next_row; /* available in strip */
220	max_rows = out_rows_avail - out_row_ctr; / available in output area */
221	if (num_rows > max_rows)
222	num_rows = max_rows;
223	/* We have to check bottom of image here, can't depend on upsampler. */
224	max_rows = cinfo->output_height - post->starting_row;
225	if (num_rows > max_rows)
226	num_rows = max_rows;
227
228	/* Quantize and emit data. */
229	(*cinfo->cquantize->color_quantize) (cinfo,
230	post->buffer + post->next_row, output_buf + *out_row_ctr,
231	(int) num_rows);
232	*out_row_ctr += num_rows;
233
234	/* Advance if we filled the strip. */
235	post->next_row += num_rows;
236	if (post->next_row >= post->strip_height) {
237	post->starting_row += post->strip_height;
238	post->next_row = 0;
239	}
240	}
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	{
252	my_post_ptr post;
253
254	post = (my_post_ptr)
255	(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
256	SIZEOF(my_post_controller));
257	cinfo->post = (struct jpeg_d_post_controller *) post;
258	post->pub.start_pass = start_pass_dpost;
259	post->whole_image = NULL; /* flag for no virtual arrays */
260	post->buffer = NULL; /* flag for no strip buffer */
261
262	/* Create the quantization buffer, if needed */
263	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	post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor;
269	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	#ifdef QUANT_2PASS_SUPPORTED
273	post->whole_image = (*cinfo->mem->request_virt_sarray)
274	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
275	cinfo->output_width * cinfo->out_color_components,
276	(JDIMENSION) jround_up((long) cinfo->output_height,
277	(long) post->strip_height),
278	post->strip_height);
279	#else
280	ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
281	#endif /* QUANT_2PASS_SUPPORTED */
282	} else {
283	/* One-pass color quantization: just make a strip buffer. */
284	post->buffer = (*cinfo->mem->alloc_sarray)
285	((j_common_ptr) cinfo, JPOOL_IMAGE,
286	cinfo->output_width * cinfo->out_color_components,
287	post->strip_height);
288	}
289	}
290	}