1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libjpeg/jdmainct.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,515 @@
1.4 +/*
1.5 + * jdmainct.c
1.6 + *
1.7 + * This file was part of the Independent JPEG Group's software:
1.8 + * Copyright (C) 1994-1996, Thomas G. Lane.
1.9 + * libjpeg-turbo Modifications:
1.10 + * Copyright (C) 2010, D. R. Commander.
1.11 + * For conditions of distribution and use, see the accompanying README file.
1.12 + *
1.13 + * This file contains the main buffer controller for decompression.
1.14 + * The main buffer lies between the JPEG decompressor proper and the
1.15 + * post-processor; it holds downsampled data in the JPEG colorspace.
1.16 + *
1.17 + * Note that this code is bypassed in raw-data mode, since the application
1.18 + * supplies the equivalent of the main buffer in that case.
1.19 + */
1.20 +
1.21 +#define JPEG_INTERNALS
1.22 +#include "jinclude.h"
1.23 +#include "jpeglib.h"
1.24 +#include "jpegcomp.h"
1.25 +
1.26 +
1.27 +/*
1.28 + * In the current system design, the main buffer need never be a full-image
1.29 + * buffer; any full-height buffers will be found inside the coefficient or
1.30 + * postprocessing controllers. Nonetheless, the main controller is not
1.31 + * trivial. Its responsibility is to provide context rows for upsampling/
1.32 + * rescaling, and doing this in an efficient fashion is a bit tricky.
1.33 + *
1.34 + * Postprocessor input data is counted in "row groups". A row group
1.35 + * is defined to be (v_samp_factor * DCT_scaled_size / min_DCT_scaled_size)
1.36 + * sample rows of each component. (We require DCT_scaled_size values to be
1.37 + * chosen such that these numbers are integers. In practice DCT_scaled_size
1.38 + * values will likely be powers of two, so we actually have the stronger
1.39 + * condition that DCT_scaled_size / min_DCT_scaled_size is an integer.)
1.40 + * Upsampling will typically produce max_v_samp_factor pixel rows from each
1.41 + * row group (times any additional scale factor that the upsampler is
1.42 + * applying).
1.43 + *
1.44 + * The coefficient controller will deliver data to us one iMCU row at a time;
1.45 + * each iMCU row contains v_samp_factor * DCT_scaled_size sample rows, or
1.46 + * exactly min_DCT_scaled_size row groups. (This amount of data corresponds
1.47 + * to one row of MCUs when the image is fully interleaved.) Note that the
1.48 + * number of sample rows varies across components, but the number of row
1.49 + * groups does not. Some garbage sample rows may be included in the last iMCU
1.50 + * row at the bottom of the image.
1.51 + *
1.52 + * Depending on the vertical scaling algorithm used, the upsampler may need
1.53 + * access to the sample row(s) above and below its current input row group.
1.54 + * The upsampler is required to set need_context_rows TRUE at global selection
1.55 + * time if so. When need_context_rows is FALSE, this controller can simply
1.56 + * obtain one iMCU row at a time from the coefficient controller and dole it
1.57 + * out as row groups to the postprocessor.
1.58 + *
1.59 + * When need_context_rows is TRUE, this controller guarantees that the buffer
1.60 + * passed to postprocessing contains at least one row group's worth of samples
1.61 + * above and below the row group(s) being processed. Note that the context
1.62 + * rows "above" the first passed row group appear at negative row offsets in
1.63 + * the passed buffer. At the top and bottom of the image, the required
1.64 + * context rows are manufactured by duplicating the first or last real sample
1.65 + * row; this avoids having special cases in the upsampling inner loops.
1.66 + *
1.67 + * The amount of context is fixed at one row group just because that's a
1.68 + * convenient number for this controller to work with. The existing
1.69 + * upsamplers really only need one sample row of context. An upsampler
1.70 + * supporting arbitrary output rescaling might wish for more than one row
1.71 + * group of context when shrinking the image; tough, we don't handle that.
1.72 + * (This is justified by the assumption that downsizing will be handled mostly
1.73 + * by adjusting the DCT_scaled_size values, so that the actual scale factor at
1.74 + * the upsample step needn't be much less than one.)
1.75 + *
1.76 + * To provide the desired context, we have to retain the last two row groups
1.77 + * of one iMCU row while reading in the next iMCU row. (The last row group
1.78 + * can't be processed until we have another row group for its below-context,
1.79 + * and so we have to save the next-to-last group too for its above-context.)
1.80 + * We could do this most simply by copying data around in our buffer, but
1.81 + * that'd be very slow. We can avoid copying any data by creating a rather
1.82 + * strange pointer structure. Here's how it works. We allocate a workspace
1.83 + * consisting of M+2 row groups (where M = min_DCT_scaled_size is the number
1.84 + * of row groups per iMCU row). We create two sets of redundant pointers to
1.85 + * the workspace. Labeling the physical row groups 0 to M+1, the synthesized
1.86 + * pointer lists look like this:
1.87 + * M+1 M-1
1.88 + * master pointer --> 0 master pointer --> 0
1.89 + * 1 1
1.90 + * ... ...
1.91 + * M-3 M-3
1.92 + * M-2 M
1.93 + * M-1 M+1
1.94 + * M M-2
1.95 + * M+1 M-1
1.96 + * 0 0
1.97 + * We read alternate iMCU rows using each master pointer; thus the last two
1.98 + * row groups of the previous iMCU row remain un-overwritten in the workspace.
1.99 + * The pointer lists are set up so that the required context rows appear to
1.100 + * be adjacent to the proper places when we pass the pointer lists to the
1.101 + * upsampler.
1.102 + *
1.103 + * The above pictures describe the normal state of the pointer lists.
1.104 + * At top and bottom of the image, we diddle the pointer lists to duplicate
1.105 + * the first or last sample row as necessary (this is cheaper than copying
1.106 + * sample rows around).
1.107 + *
1.108 + * This scheme breaks down if M < 2, ie, min_DCT_scaled_size is 1. In that
1.109 + * situation each iMCU row provides only one row group so the buffering logic
1.110 + * must be different (eg, we must read two iMCU rows before we can emit the
1.111 + * first row group). For now, we simply do not support providing context
1.112 + * rows when min_DCT_scaled_size is 1. That combination seems unlikely to
1.113 + * be worth providing --- if someone wants a 1/8th-size preview, they probably
1.114 + * want it quick and dirty, so a context-free upsampler is sufficient.
1.115 + */
1.116 +
1.117 +
1.118 +/* Private buffer controller object */
1.119 +
1.120 +typedef struct {
1.121 + struct jpeg_d_main_controller pub; /* public fields */
1.122 +
1.123 + /* Pointer to allocated workspace (M or M+2 row groups). */
1.124 + JSAMPARRAY buffer[MAX_COMPONENTS];
1.125 +
1.126 + boolean buffer_full; /* Have we gotten an iMCU row from decoder? */
1.127 + JDIMENSION rowgroup_ctr; /* counts row groups output to postprocessor */
1.128 +
1.129 + /* Remaining fields are only used in the context case. */
1.130 +
1.131 + /* These are the master pointers to the funny-order pointer lists. */
1.132 + JSAMPIMAGE xbuffer[2]; /* pointers to weird pointer lists */
1.133 +
1.134 + int whichptr; /* indicates which pointer set is now in use */
1.135 + int context_state; /* process_data state machine status */
1.136 + JDIMENSION rowgroups_avail; /* row groups available to postprocessor */
1.137 + JDIMENSION iMCU_row_ctr; /* counts iMCU rows to detect image top/bot */
1.138 +} my_main_controller;
1.139 +
1.140 +typedef my_main_controller * my_main_ptr;
1.141 +
1.142 +/* context_state values: */
1.143 +#define CTX_PREPARE_FOR_IMCU 0 /* need to prepare for MCU row */
1.144 +#define CTX_PROCESS_IMCU 1 /* feeding iMCU to postprocessor */
1.145 +#define CTX_POSTPONED_ROW 2 /* feeding postponed row group */
1.146 +
1.147 +
1.148 +/* Forward declarations */
1.149 +METHODDEF(void) process_data_simple_main
1.150 + JPP((j_decompress_ptr cinfo, JSAMPARRAY output_buf,
1.151 + JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail));
1.152 +METHODDEF(void) process_data_context_main
1.153 + JPP((j_decompress_ptr cinfo, JSAMPARRAY output_buf,
1.154 + JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail));
1.155 +#ifdef QUANT_2PASS_SUPPORTED
1.156 +METHODDEF(void) process_data_crank_post
1.157 + JPP((j_decompress_ptr cinfo, JSAMPARRAY output_buf,
1.158 + JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail));
1.159 +#endif
1.160 +
1.161 +
1.162 +LOCAL(void)
1.163 +alloc_funny_pointers (j_decompress_ptr cinfo)
1.164 +/* Allocate space for the funny pointer lists.
1.165 + * This is done only once, not once per pass.
1.166 + */
1.167 +{
1.168 + my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
1.169 + int ci, rgroup;
1.170 + int M = cinfo->_min_DCT_scaled_size;
1.171 + jpeg_component_info *compptr;
1.172 + JSAMPARRAY xbuf;
1.173 +
1.174 + /* Get top-level space for component array pointers.
1.175 + * We alloc both arrays with one call to save a few cycles.
1.176 + */
1.177 + main_ptr->xbuffer[0] = (JSAMPIMAGE)
1.178 + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.179 + cinfo->num_components * 2 * SIZEOF(JSAMPARRAY));
1.180 + main_ptr->xbuffer[1] = main_ptr->xbuffer[0] + cinfo->num_components;
1.181 +
1.182 + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
1.183 + ci++, compptr++) {
1.184 + rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) /
1.185 + cinfo->_min_DCT_scaled_size; /* height of a row group of component */
1.186 + /* Get space for pointer lists --- M+4 row groups in each list.
1.187 + * We alloc both pointer lists with one call to save a few cycles.
1.188 + */
1.189 + xbuf = (JSAMPARRAY)
1.190 + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.191 + 2 * (rgroup * (M + 4)) * SIZEOF(JSAMPROW));
1.192 + xbuf += rgroup; /* want one row group at negative offsets */
1.193 + main_ptr->xbuffer[0][ci] = xbuf;
1.194 + xbuf += rgroup * (M + 4);
1.195 + main_ptr->xbuffer[1][ci] = xbuf;
1.196 + }
1.197 +}
1.198 +
1.199 +
1.200 +LOCAL(void)
1.201 +make_funny_pointers (j_decompress_ptr cinfo)
1.202 +/* Create the funny pointer lists discussed in the comments above.
1.203 + * The actual workspace is already allocated (in main_ptr->buffer),
1.204 + * and the space for the pointer lists is allocated too.
1.205 + * This routine just fills in the curiously ordered lists.
1.206 + * This will be repeated at the beginning of each pass.
1.207 + */
1.208 +{
1.209 + my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
1.210 + int ci, i, rgroup;
1.211 + int M = cinfo->_min_DCT_scaled_size;
1.212 + jpeg_component_info *compptr;
1.213 + JSAMPARRAY buf, xbuf0, xbuf1;
1.214 +
1.215 + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
1.216 + ci++, compptr++) {
1.217 + rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) /
1.218 + cinfo->_min_DCT_scaled_size; /* height of a row group of component */
1.219 + xbuf0 = main_ptr->xbuffer[0][ci];
1.220 + xbuf1 = main_ptr->xbuffer[1][ci];
1.221 + /* First copy the workspace pointers as-is */
1.222 + buf = main_ptr->buffer[ci];
1.223 + for (i = 0; i < rgroup * (M + 2); i++) {
1.224 + xbuf0[i] = xbuf1[i] = buf[i];
1.225 + }
1.226 + /* In the second list, put the last four row groups in swapped order */
1.227 + for (i = 0; i < rgroup * 2; i++) {
1.228 + xbuf1[rgroup*(M-2) + i] = buf[rgroup*M + i];
1.229 + xbuf1[rgroup*M + i] = buf[rgroup*(M-2) + i];
1.230 + }
1.231 + /* The wraparound pointers at top and bottom will be filled later
1.232 + * (see set_wraparound_pointers, below). Initially we want the "above"
1.233 + * pointers to duplicate the first actual data line. This only needs
1.234 + * to happen in xbuffer[0].
1.235 + */
1.236 + for (i = 0; i < rgroup; i++) {
1.237 + xbuf0[i - rgroup] = xbuf0[0];
1.238 + }
1.239 + }
1.240 +}
1.241 +
1.242 +
1.243 +LOCAL(void)
1.244 +set_wraparound_pointers (j_decompress_ptr cinfo)
1.245 +/* Set up the "wraparound" pointers at top and bottom of the pointer lists.
1.246 + * This changes the pointer list state from top-of-image to the normal state.
1.247 + */
1.248 +{
1.249 + my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
1.250 + int ci, i, rgroup;
1.251 + int M = cinfo->_min_DCT_scaled_size;
1.252 + jpeg_component_info *compptr;
1.253 + JSAMPARRAY xbuf0, xbuf1;
1.254 +
1.255 + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
1.256 + ci++, compptr++) {
1.257 + rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) /
1.258 + cinfo->_min_DCT_scaled_size; /* height of a row group of component */
1.259 + xbuf0 = main_ptr->xbuffer[0][ci];
1.260 + xbuf1 = main_ptr->xbuffer[1][ci];
1.261 + for (i = 0; i < rgroup; i++) {
1.262 + xbuf0[i - rgroup] = xbuf0[rgroup*(M+1) + i];
1.263 + xbuf1[i - rgroup] = xbuf1[rgroup*(M+1) + i];
1.264 + xbuf0[rgroup*(M+2) + i] = xbuf0[i];
1.265 + xbuf1[rgroup*(M+2) + i] = xbuf1[i];
1.266 + }
1.267 + }
1.268 +}
1.269 +
1.270 +
1.271 +LOCAL(void)
1.272 +set_bottom_pointers (j_decompress_ptr cinfo)
1.273 +/* Change the pointer lists to duplicate the last sample row at the bottom
1.274 + * of the image. whichptr indicates which xbuffer holds the final iMCU row.
1.275 + * Also sets rowgroups_avail to indicate number of nondummy row groups in row.
1.276 + */
1.277 +{
1.278 + my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
1.279 + int ci, i, rgroup, iMCUheight, rows_left;
1.280 + jpeg_component_info *compptr;
1.281 + JSAMPARRAY xbuf;
1.282 +
1.283 + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
1.284 + ci++, compptr++) {
1.285 + /* Count sample rows in one iMCU row and in one row group */
1.286 + iMCUheight = compptr->v_samp_factor * compptr->_DCT_scaled_size;
1.287 + rgroup = iMCUheight / cinfo->_min_DCT_scaled_size;
1.288 + /* Count nondummy sample rows remaining for this component */
1.289 + rows_left = (int) (compptr->downsampled_height % (JDIMENSION) iMCUheight);
1.290 + if (rows_left == 0) rows_left = iMCUheight;
1.291 + /* Count nondummy row groups. Should get same answer for each component,
1.292 + * so we need only do it once.
1.293 + */
1.294 + if (ci == 0) {
1.295 + main_ptr->rowgroups_avail = (JDIMENSION) ((rows_left-1) / rgroup + 1);
1.296 + }
1.297 + /* Duplicate the last real sample row rgroup*2 times; this pads out the
1.298 + * last partial rowgroup and ensures at least one full rowgroup of context.
1.299 + */
1.300 + xbuf = main_ptr->xbuffer[main_ptr->whichptr][ci];
1.301 + for (i = 0; i < rgroup * 2; i++) {
1.302 + xbuf[rows_left + i] = xbuf[rows_left-1];
1.303 + }
1.304 + }
1.305 +}
1.306 +
1.307 +
1.308 +/*
1.309 + * Initialize for a processing pass.
1.310 + */
1.311 +
1.312 +METHODDEF(void)
1.313 +start_pass_main (j_decompress_ptr cinfo, J_BUF_MODE pass_mode)
1.314 +{
1.315 + my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
1.316 +
1.317 + switch (pass_mode) {
1.318 + case JBUF_PASS_THRU:
1.319 + if (cinfo->upsample->need_context_rows) {
1.320 + main_ptr->pub.process_data = process_data_context_main;
1.321 + make_funny_pointers(cinfo); /* Create the xbuffer[] lists */
1.322 + main_ptr->whichptr = 0; /* Read first iMCU row into xbuffer[0] */
1.323 + main_ptr->context_state = CTX_PREPARE_FOR_IMCU;
1.324 + main_ptr->iMCU_row_ctr = 0;
1.325 + } else {
1.326 + /* Simple case with no context needed */
1.327 + main_ptr->pub.process_data = process_data_simple_main;
1.328 + }
1.329 + main_ptr->buffer_full = FALSE; /* Mark buffer empty */
1.330 + main_ptr->rowgroup_ctr = 0;
1.331 + break;
1.332 +#ifdef QUANT_2PASS_SUPPORTED
1.333 + case JBUF_CRANK_DEST:
1.334 + /* For last pass of 2-pass quantization, just crank the postprocessor */
1.335 + main_ptr->pub.process_data = process_data_crank_post;
1.336 + break;
1.337 +#endif
1.338 + default:
1.339 + ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
1.340 + break;
1.341 + }
1.342 +}
1.343 +
1.344 +
1.345 +/*
1.346 + * Process some data.
1.347 + * This handles the simple case where no context is required.
1.348 + */
1.349 +
1.350 +METHODDEF(void)
1.351 +process_data_simple_main (j_decompress_ptr cinfo,
1.352 + JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
1.353 + JDIMENSION out_rows_avail)
1.354 +{
1.355 + my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
1.356 + JDIMENSION rowgroups_avail;
1.357 +
1.358 + /* Read input data if we haven't filled the main buffer yet */
1.359 + if (! main_ptr->buffer_full) {
1.360 + if (! (*cinfo->coef->decompress_data) (cinfo, main_ptr->buffer))
1.361 + return; /* suspension forced, can do nothing more */
1.362 + main_ptr->buffer_full = TRUE; /* OK, we have an iMCU row to work with */
1.363 + }
1.364 +
1.365 + /* There are always min_DCT_scaled_size row groups in an iMCU row. */
1.366 + rowgroups_avail = (JDIMENSION) cinfo->_min_DCT_scaled_size;
1.367 + /* Note: at the bottom of the image, we may pass extra garbage row groups
1.368 + * to the postprocessor. The postprocessor has to check for bottom
1.369 + * of image anyway (at row resolution), so no point in us doing it too.
1.370 + */
1.371 +
1.372 + /* Feed the postprocessor */
1.373 + (*cinfo->post->post_process_data) (cinfo, main_ptr->buffer,
1.374 + &main_ptr->rowgroup_ctr, rowgroups_avail,
1.375 + output_buf, out_row_ctr, out_rows_avail);
1.376 +
1.377 + /* Has postprocessor consumed all the data yet? If so, mark buffer empty */
1.378 + if (main_ptr->rowgroup_ctr >= rowgroups_avail) {
1.379 + main_ptr->buffer_full = FALSE;
1.380 + main_ptr->rowgroup_ctr = 0;
1.381 + }
1.382 +}
1.383 +
1.384 +
1.385 +/*
1.386 + * Process some data.
1.387 + * This handles the case where context rows must be provided.
1.388 + */
1.389 +
1.390 +METHODDEF(void)
1.391 +process_data_context_main (j_decompress_ptr cinfo,
1.392 + JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
1.393 + JDIMENSION out_rows_avail)
1.394 +{
1.395 + my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
1.396 +
1.397 + /* Read input data if we haven't filled the main buffer yet */
1.398 + if (! main_ptr->buffer_full) {
1.399 + if (! (*cinfo->coef->decompress_data) (cinfo,
1.400 + main_ptr->xbuffer[main_ptr->whichptr]))
1.401 + return; /* suspension forced, can do nothing more */
1.402 + main_ptr->buffer_full = TRUE; /* OK, we have an iMCU row to work with */
1.403 + main_ptr->iMCU_row_ctr++; /* count rows received */
1.404 + }
1.405 +
1.406 + /* Postprocessor typically will not swallow all the input data it is handed
1.407 + * in one call (due to filling the output buffer first). Must be prepared
1.408 + * to exit and restart. This switch lets us keep track of how far we got.
1.409 + * Note that each case falls through to the next on successful completion.
1.410 + */
1.411 + switch (main_ptr->context_state) {
1.412 + case CTX_POSTPONED_ROW:
1.413 + /* Call postprocessor using previously set pointers for postponed row */
1.414 + (*cinfo->post->post_process_data) (cinfo, main_ptr->xbuffer[main_ptr->whichptr],
1.415 + &main_ptr->rowgroup_ctr, main_ptr->rowgroups_avail,
1.416 + output_buf, out_row_ctr, out_rows_avail);
1.417 + if (main_ptr->rowgroup_ctr < main_ptr->rowgroups_avail)
1.418 + return; /* Need to suspend */
1.419 + main_ptr->context_state = CTX_PREPARE_FOR_IMCU;
1.420 + if (*out_row_ctr >= out_rows_avail)
1.421 + return; /* Postprocessor exactly filled output buf */
1.422 + /*FALLTHROUGH*/
1.423 + case CTX_PREPARE_FOR_IMCU:
1.424 + /* Prepare to process first M-1 row groups of this iMCU row */
1.425 + main_ptr->rowgroup_ctr = 0;
1.426 + main_ptr->rowgroups_avail = (JDIMENSION) (cinfo->_min_DCT_scaled_size - 1);
1.427 + /* Check for bottom of image: if so, tweak pointers to "duplicate"
1.428 + * the last sample row, and adjust rowgroups_avail to ignore padding rows.
1.429 + */
1.430 + if (main_ptr->iMCU_row_ctr == cinfo->total_iMCU_rows)
1.431 + set_bottom_pointers(cinfo);
1.432 + main_ptr->context_state = CTX_PROCESS_IMCU;
1.433 + /*FALLTHROUGH*/
1.434 + case CTX_PROCESS_IMCU:
1.435 + /* Call postprocessor using previously set pointers */
1.436 + (*cinfo->post->post_process_data) (cinfo, main_ptr->xbuffer[main_ptr->whichptr],
1.437 + &main_ptr->rowgroup_ctr, main_ptr->rowgroups_avail,
1.438 + output_buf, out_row_ctr, out_rows_avail);
1.439 + if (main_ptr->rowgroup_ctr < main_ptr->rowgroups_avail)
1.440 + return; /* Need to suspend */
1.441 + /* After the first iMCU, change wraparound pointers to normal state */
1.442 + if (main_ptr->iMCU_row_ctr == 1)
1.443 + set_wraparound_pointers(cinfo);
1.444 + /* Prepare to load new iMCU row using other xbuffer list */
1.445 + main_ptr->whichptr ^= 1; /* 0=>1 or 1=>0 */
1.446 + main_ptr->buffer_full = FALSE;
1.447 + /* Still need to process last row group of this iMCU row, */
1.448 + /* which is saved at index M+1 of the other xbuffer */
1.449 + main_ptr->rowgroup_ctr = (JDIMENSION) (cinfo->_min_DCT_scaled_size + 1);
1.450 + main_ptr->rowgroups_avail = (JDIMENSION) (cinfo->_min_DCT_scaled_size + 2);
1.451 + main_ptr->context_state = CTX_POSTPONED_ROW;
1.452 + }
1.453 +}
1.454 +
1.455 +
1.456 +/*
1.457 + * Process some data.
1.458 + * Final pass of two-pass quantization: just call the postprocessor.
1.459 + * Source data will be the postprocessor controller's internal buffer.
1.460 + */
1.461 +
1.462 +#ifdef QUANT_2PASS_SUPPORTED
1.463 +
1.464 +METHODDEF(void)
1.465 +process_data_crank_post (j_decompress_ptr cinfo,
1.466 + JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
1.467 + JDIMENSION out_rows_avail)
1.468 +{
1.469 + (*cinfo->post->post_process_data) (cinfo, (JSAMPIMAGE) NULL,
1.470 + (JDIMENSION *) NULL, (JDIMENSION) 0,
1.471 + output_buf, out_row_ctr, out_rows_avail);
1.472 +}
1.473 +
1.474 +#endif /* QUANT_2PASS_SUPPORTED */
1.475 +
1.476 +
1.477 +/*
1.478 + * Initialize main buffer controller.
1.479 + */
1.480 +
1.481 +GLOBAL(void)
1.482 +jinit_d_main_controller (j_decompress_ptr cinfo, boolean need_full_buffer)
1.483 +{
1.484 + my_main_ptr main_ptr;
1.485 + int ci, rgroup, ngroups;
1.486 + jpeg_component_info *compptr;
1.487 +
1.488 + main_ptr = (my_main_ptr)
1.489 + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.490 + SIZEOF(my_main_controller));
1.491 + cinfo->main = (struct jpeg_d_main_controller *) main_ptr;
1.492 + main_ptr->pub.start_pass = start_pass_main;
1.493 +
1.494 + if (need_full_buffer) /* shouldn't happen */
1.495 + ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
1.496 +
1.497 + /* Allocate the workspace.
1.498 + * ngroups is the number of row groups we need.
1.499 + */
1.500 + if (cinfo->upsample->need_context_rows) {
1.501 + if (cinfo->_min_DCT_scaled_size < 2) /* unsupported, see comments above */
1.502 + ERREXIT(cinfo, JERR_NOTIMPL);
1.503 + alloc_funny_pointers(cinfo); /* Alloc space for xbuffer[] lists */
1.504 + ngroups = cinfo->_min_DCT_scaled_size + 2;
1.505 + } else {
1.506 + ngroups = cinfo->_min_DCT_scaled_size;
1.507 + }
1.508 +
1.509 + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
1.510 + ci++, compptr++) {
1.511 + rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) /
1.512 + cinfo->_min_DCT_scaled_size; /* height of a row group of component */
1.513 + main_ptr->buffer[ci] = (*cinfo->mem->alloc_sarray)
1.514 + ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.515 + compptr->width_in_blocks * compptr->_DCT_scaled_size,
1.516 + (JDIMENSION) (rgroup * ngroups));
1.517 + }
1.518 +}
