--- /dev/null
+/*
+ * 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);
+ }
+ }
+}
projects / reactos.git / blobdiff