--- /dev/null
+/*
+ * jdinput.c
+ *
+ * Copyright (C) 1991-1997, 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 input control logic for the JPEG decompressor.
+ * These routines are concerned with controlling the decompressor's input
+ * processing (marker reading and coefficient decoding). The actual input
+ * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Private state */
+
+typedef struct {
+ struct jpeg_input_controller pub; /* public fields */
+
+ boolean inheaders; /* TRUE until first SOS is reached */
+} my_input_controller;
+
+typedef my_input_controller * my_inputctl_ptr;
+
+
+/* Forward declarations */
+METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));
+
+
+/*
+ * Routines to calculate various quantities related to the size of the image.
+ */
+
+LOCAL(void)
+initial_setup (j_decompress_ptr cinfo)
+/* Called once, when first SOS marker is reached */
+{
+ int ci;
+ jpeg_component_info *compptr;
+
+ /* Make sure image isn't bigger than I can handle */
+ if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
+ (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
+ ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
+
+ /* For now, precision must match compiled-in value... */
+ if (cinfo->data_precision != BITS_IN_JSAMPLE)
+ ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
+
+ /* Check that number of components won't exceed internal array sizes */
+ if (cinfo->num_components > MAX_COMPONENTS)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
+ MAX_COMPONENTS);
+
+ /* Compute maximum sampling factors; check factor validity */
+ cinfo->max_h_samp_factor = 1;
+ cinfo->max_v_samp_factor = 1;
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
+ compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
+ ERREXIT(cinfo, JERR_BAD_SAMPLING);
+ cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
+ compptr->h_samp_factor);
+ cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
+ compptr->v_samp_factor);
+ }
+
+ /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
+ * In the full decompressor, this will be overridden by jdmaster.c;
+ * but in the transcoder, jdmaster.c is not used, so we must do it here.
+ */
+ cinfo->min_DCT_scaled_size = DCTSIZE;
+
+ /* Compute dimensions of components */
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ compptr->DCT_scaled_size = DCTSIZE;
+ /* Size in DCT blocks */
+ compptr->width_in_blocks = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+ (long) (cinfo->max_h_samp_factor * DCTSIZE));
+ compptr->height_in_blocks = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+ (long) (cinfo->max_v_samp_factor * DCTSIZE));
+ /* downsampled_width and downsampled_height will also be overridden by
+ * jdmaster.c if we are doing full decompression. The transcoder library
+ * doesn't use these values, but the calling application might.
+ */
+ /* Size in samples */
+ compptr->downsampled_width = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+ (long) cinfo->max_h_samp_factor);
+ compptr->downsampled_height = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+ (long) cinfo->max_v_samp_factor);
+ /* Mark component needed, until color conversion says otherwise */
+ compptr->component_needed = TRUE;
+ /* Mark no quantization table yet saved for component */
+ compptr->quant_table = NULL;
+ }
+
+ /* Compute number of fully interleaved MCU rows. */
+ cinfo->total_iMCU_rows = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height,
+ (long) (cinfo->max_v_samp_factor*DCTSIZE));
+
+ /* Decide whether file contains multiple scans */
+ if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
+ cinfo->inputctl->has_multiple_scans = TRUE;
+ else
+ cinfo->inputctl->has_multiple_scans = FALSE;
+}
+
+
+LOCAL(void)
+per_scan_setup (j_decompress_ptr cinfo)
+/* Do computations that are needed before processing a JPEG scan */
+/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
+{
+ int ci, mcublks, tmp;
+ jpeg_component_info *compptr;
+
+ if (cinfo->comps_in_scan == 1) {
+
+ /* Noninterleaved (single-component) scan */
+ compptr = cinfo->cur_comp_info[0];
+
+ /* Overall image size in MCUs */
+ cinfo->MCUs_per_row = compptr->width_in_blocks;
+ cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
+
+ /* For noninterleaved scan, always one block per MCU */
+ compptr->MCU_width = 1;
+ compptr->MCU_height = 1;
+ compptr->MCU_blocks = 1;
+ compptr->MCU_sample_width = compptr->DCT_scaled_size;
+ compptr->last_col_width = 1;
+ /* For noninterleaved scans, it is convenient to define last_row_height
+ * as the number of block rows present in the last iMCU row.
+ */
+ tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
+ if (tmp == 0) tmp = compptr->v_samp_factor;
+ compptr->last_row_height = tmp;
+
+ /* Prepare array describing MCU composition */
+ cinfo->blocks_in_MCU = 1;
+ cinfo->MCU_membership[0] = 0;
+
+ } else {
+
+ /* Interleaved (multi-component) scan */
+ if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
+ ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
+ MAX_COMPS_IN_SCAN);
+
+ /* Overall image size in MCUs */
+ cinfo->MCUs_per_row = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_width,
+ (long) (cinfo->max_h_samp_factor*DCTSIZE));
+ cinfo->MCU_rows_in_scan = (JDIMENSION)
+ jdiv_round_up((long) cinfo->image_height,
+ (long) (cinfo->max_v_samp_factor*DCTSIZE));
+
+ cinfo->blocks_in_MCU = 0;
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* Sampling factors give # of blocks of component in each MCU */
+ compptr->MCU_width = compptr->h_samp_factor;
+ compptr->MCU_height = compptr->v_samp_factor;
+ compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
+ compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_scaled_size;
+ /* Figure number of non-dummy blocks in last MCU column & row */
+ tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
+ if (tmp == 0) tmp = compptr->MCU_width;
+ compptr->last_col_width = tmp;
+ tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
+ if (tmp == 0) tmp = compptr->MCU_height;
+ compptr->last_row_height = tmp;
+ /* Prepare array describing MCU composition */
+ mcublks = compptr->MCU_blocks;
+ if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
+ ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
+ while (mcublks-- > 0) {
+ cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
+ }
+ }
+
+ }
+}
+
+
+/*
+ * Save away a copy of the Q-table referenced by each component present
+ * in the current scan, unless already saved during a prior scan.
+ *
+ * In a multiple-scan JPEG file, the encoder could assign different components
+ * the same Q-table slot number, but change table definitions between scans
+ * so that each component uses a different Q-table. (The IJG encoder is not
+ * currently capable of doing this, but other encoders might.) Since we want
+ * to be able to dequantize all the components at the end of the file, this
+ * means that we have to save away the table actually used for each component.
+ * We do this by copying the table at the start of the first scan containing
+ * the component.
+ * The JPEG spec prohibits the encoder from changing the contents of a Q-table
+ * slot between scans of a component using that slot. If the encoder does so
+ * anyway, this decoder will simply use the Q-table values that were current
+ * at the start of the first scan for the component.
+ *
+ * The decompressor output side looks only at the saved quant tables,
+ * not at the current Q-table slots.
+ */
+
+LOCAL(void)
+latch_quant_tables (j_decompress_ptr cinfo)
+{
+ int ci, qtblno;
+ jpeg_component_info *compptr;
+ JQUANT_TBL * qtbl;
+
+ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
+ compptr = cinfo->cur_comp_info[ci];
+ /* No work if we already saved Q-table for this component */
+ if (compptr->quant_table != NULL)
+ continue;
+ /* Make sure specified quantization table is present */
+ qtblno = compptr->quant_tbl_no;
+ if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
+ cinfo->quant_tbl_ptrs[qtblno] == NULL)
+ ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
+ /* OK, save away the quantization table */
+ qtbl = (JQUANT_TBL *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(JQUANT_TBL));
+ MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
+ compptr->quant_table = qtbl;
+ }
+}
+
+
+/*
+ * Initialize the input modules to read a scan of compressed data.
+ * The first call to this is done by jdmaster.c after initializing
+ * the entire decompressor (during jpeg_start_decompress).
+ * Subsequent calls come from consume_markers, below.
+ */
+
+METHODDEF(void)
+start_input_pass (j_decompress_ptr cinfo)
+{
+ per_scan_setup(cinfo);
+ latch_quant_tables(cinfo);
+ (*cinfo->entropy->start_pass) (cinfo);
+ (*cinfo->coef->start_input_pass) (cinfo);
+ cinfo->inputctl->consume_input = cinfo->coef->consume_data;
+}
+
+
+/*
+ * Finish up after inputting a compressed-data scan.
+ * This is called by the coefficient controller after it's read all
+ * the expected data of the scan.
+ */
+
+METHODDEF(void)
+finish_input_pass (j_decompress_ptr cinfo)
+{
+ cinfo->inputctl->consume_input = consume_markers;
+}
+
+
+/*
+ * Read JPEG markers before, between, or after compressed-data scans.
+ * Change state as necessary when a new scan is reached.
+ * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
+ *
+ * The consume_input method pointer points either here or to the
+ * coefficient controller's consume_data routine, depending on whether
+ * we are reading a compressed data segment or inter-segment markers.
+ */
+
+METHODDEF(int)
+consume_markers (j_decompress_ptr cinfo)
+{
+ my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
+ int val;
+
+ if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
+ return JPEG_REACHED_EOI;
+
+ val = (*cinfo->marker->read_markers) (cinfo);
+
+ switch (val) {
+ case JPEG_REACHED_SOS: /* Found SOS */
+ if (inputctl->inheaders) { /* 1st SOS */
+ initial_setup(cinfo);
+ inputctl->inheaders = FALSE;
+ /* Note: start_input_pass must be called by jdmaster.c
+ * before any more input can be consumed. jdapimin.c is
+ * responsible for enforcing this sequencing.
+ */
+ } else { /* 2nd or later SOS marker */
+ if (! inputctl->pub.has_multiple_scans)
+ ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
+ start_input_pass(cinfo);
+ }
+ break;
+ case JPEG_REACHED_EOI: /* Found EOI */
+ inputctl->pub.eoi_reached = TRUE;
+ if (inputctl->inheaders) { /* Tables-only datastream, apparently */
+ if (cinfo->marker->saw_SOF)
+ ERREXIT(cinfo, JERR_SOF_NO_SOS);
+ } else {
+ /* Prevent infinite loop in coef ctlr's decompress_data routine
+ * if user set output_scan_number larger than number of scans.
+ */
+ if (cinfo->output_scan_number > cinfo->input_scan_number)
+ cinfo->output_scan_number = cinfo->input_scan_number;
+ }
+ break;
+ case JPEG_SUSPENDED:
+ break;
+ }
+
+ return val;
+}
+
+
+/*
+ * Reset state to begin a fresh datastream.
+ */
+
+METHODDEF(void)
+reset_input_controller (j_decompress_ptr cinfo)
+{
+ my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
+
+ inputctl->pub.consume_input = consume_markers;
+ inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
+ inputctl->pub.eoi_reached = FALSE;
+ inputctl->inheaders = TRUE;
+ /* Reset other modules */
+ (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
+ (*cinfo->marker->reset_marker_reader) (cinfo);
+ /* Reset progression state -- would be cleaner if entropy decoder did this */
+ cinfo->coef_bits = NULL;
+}
+
+
+/*
+ * Initialize the input controller module.
+ * This is called only once, when the decompression object is created.
+ */
+
+GLOBAL(void)
+jinit_input_controller (j_decompress_ptr cinfo)
+{
+ my_inputctl_ptr inputctl;
+
+ /* Create subobject in permanent pool */
+ inputctl = (my_inputctl_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ SIZEOF(my_input_controller));
+ cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
+ /* Initialize method pointers */
+ inputctl->pub.consume_input = consume_markers;
+ inputctl->pub.reset_input_controller = reset_input_controller;
+ inputctl->pub.start_input_pass = start_input_pass;
+ inputctl->pub.finish_input_pass = finish_input_pass;
+ /* Initialize state: can't use reset_input_controller since we don't
+ * want to try to reset other modules yet.
+ */
+ inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
+ inputctl->pub.eoi_reached = FALSE;
+ inputctl->inheaders = TRUE;
+}
projects / opencv / blobdiff