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Diffstat (limited to 'src/jpeg-8c/jdinput.c')
| -rw-r--r-- | src/jpeg-8c/jdinput.c | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/src/jpeg-8c/jdinput.c b/src/jpeg-8c/jdinput.c new file mode 100644 index 00000000..2c5c717b --- /dev/null +++ b/src/jpeg-8c/jdinput.c @@ -0,0 +1,661 @@ +/* + * jdinput.c + * + * Copyright (C) 1991-1997, Thomas G. Lane. + * Modified 2002-2009 by Guido Vollbeding. + * 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 jdarith.c. + */ + +#define JPEG_INTERNALS +#include "jinclude.h" +#include "jpeglib.h" + + +/* Private state */ + +typedef struct { + struct jpeg_input_controller pub; /* public fields */ + + int inheaders; /* Nonzero 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. + */ + + +/* + * Compute output image dimensions and related values. + * NOTE: this is exported for possible use by application. + * Hence it mustn't do anything that can't be done twice. + */ + +GLOBAL(void) +jpeg_core_output_dimensions (j_decompress_ptr cinfo) +/* Do computations that are needed before master selection phase. + * This function is used for transcoding and full decompression. + */ +{ +#ifdef IDCT_SCALING_SUPPORTED + int ci; + jpeg_component_info *compptr; + + /* Compute actual output image dimensions and DCT scaling choices. */ + if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) { + /* Provide 1/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 1; + cinfo->min_DCT_v_scaled_size = 1; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) { + /* Provide 2/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 2; + cinfo->min_DCT_v_scaled_size = 2; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 3) { + /* Provide 3/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 3L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 3L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 3; + cinfo->min_DCT_v_scaled_size = 3; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) { + /* Provide 4/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 4; + cinfo->min_DCT_v_scaled_size = 4; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 5) { + /* Provide 5/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 5L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 5L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 5; + cinfo->min_DCT_v_scaled_size = 5; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 6) { + /* Provide 6/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 6L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 6L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 6; + cinfo->min_DCT_v_scaled_size = 6; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 7) { + /* Provide 7/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 7L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 7L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 7; + cinfo->min_DCT_v_scaled_size = 7; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) { + /* Provide 8/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 8; + cinfo->min_DCT_v_scaled_size = 8; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 9) { + /* Provide 9/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 9L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 9L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 9; + cinfo->min_DCT_v_scaled_size = 9; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 10) { + /* Provide 10/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 10L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 10L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 10; + cinfo->min_DCT_v_scaled_size = 10; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 11) { + /* Provide 11/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 11L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 11L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 11; + cinfo->min_DCT_v_scaled_size = 11; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 12) { + /* Provide 12/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 12L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 12L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 12; + cinfo->min_DCT_v_scaled_size = 12; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 13) { + /* Provide 13/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 13L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 13L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 13; + cinfo->min_DCT_v_scaled_size = 13; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 14) { + /* Provide 14/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 14L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 14L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 14; + cinfo->min_DCT_v_scaled_size = 14; + } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 15) { + /* Provide 15/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 15L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 15L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 15; + cinfo->min_DCT_v_scaled_size = 15; + } else { + /* Provide 16/block_size scaling */ + cinfo->output_width = (JDIMENSION) + jdiv_round_up((long) cinfo->image_width * 16L, (long) cinfo->block_size); + cinfo->output_height = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * 16L, (long) cinfo->block_size); + cinfo->min_DCT_h_scaled_size = 16; + cinfo->min_DCT_v_scaled_size = 16; + } + + /* Recompute dimensions of components */ + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; + ci++, compptr++) { + compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size; + compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size; + } + +#else /* !IDCT_SCALING_SUPPORTED */ + + /* Hardwire it to "no scaling" */ + cinfo->output_width = cinfo->image_width; + cinfo->output_height = cinfo->image_height; + /* jdinput.c has already initialized DCT_scaled_size, + * and has computed unscaled downsampled_width and downsampled_height. + */ + +#endif /* IDCT_SCALING_SUPPORTED */ +} + + +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); + } + + /* Derive block_size, natural_order, and lim_Se */ + if (cinfo->is_baseline || (cinfo->progressive_mode && + cinfo->comps_in_scan)) { /* no pseudo SOS marker */ + cinfo->block_size = DCTSIZE; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + } else + switch (cinfo->Se) { + case (1*1-1): + cinfo->block_size = 1; + cinfo->natural_order = jpeg_natural_order; /* not needed */ + cinfo->lim_Se = cinfo->Se; + break; + case (2*2-1): + cinfo->block_size = 2; + cinfo->natural_order = jpeg_natural_order2; + cinfo->lim_Se = cinfo->Se; + break; + case (3*3-1): + cinfo->block_size = 3; + cinfo->natural_order = jpeg_natural_order3; + cinfo->lim_Se = cinfo->Se; + break; + case (4*4-1): + cinfo->block_size = 4; + cinfo->natural_order = jpeg_natural_order4; + cinfo->lim_Se = cinfo->Se; + break; + case (5*5-1): + cinfo->block_size = 5; + cinfo->natural_order = jpeg_natural_order5; + cinfo->lim_Se = cinfo->Se; + break; + case (6*6-1): + cinfo->block_size = 6; + cinfo->natural_order = jpeg_natural_order6; + cinfo->lim_Se = cinfo->Se; + break; + case (7*7-1): + cinfo->block_size = 7; + cinfo->natural_order = jpeg_natural_order7; + cinfo->lim_Se = cinfo->Se; + break; + case (8*8-1): + cinfo->block_size = 8; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (9*9-1): + cinfo->block_size = 9; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (10*10-1): + cinfo->block_size = 10; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (11*11-1): + cinfo->block_size = 11; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (12*12-1): + cinfo->block_size = 12; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (13*13-1): + cinfo->block_size = 13; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (14*14-1): + cinfo->block_size = 14; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (15*15-1): + cinfo->block_size = 15; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + case (16*16-1): + cinfo->block_size = 16; + cinfo->natural_order = jpeg_natural_order; + cinfo->lim_Se = DCTSIZE2-1; + break; + default: + ERREXIT4(cinfo, JERR_BAD_PROGRESSION, + cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al); + break; + } + + /* We initialize DCT_scaled_size and min_DCT_scaled_size to block_size. + * In the full decompressor, + * this will be overridden by jpeg_calc_output_dimensions in jdmaster.c; + * but in the transcoder, + * jpeg_calc_output_dimensions is not used, so we must do it here. + */ + cinfo->min_DCT_h_scaled_size = cinfo->block_size; + cinfo->min_DCT_v_scaled_size = cinfo->block_size; + + /* Compute dimensions of components */ + for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; + ci++, compptr++) { + compptr->DCT_h_scaled_size = cinfo->block_size; + compptr->DCT_v_scaled_size = cinfo->block_size; + /* 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 * cinfo->block_size)); + compptr->height_in_blocks = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor, + (long) (cinfo->max_v_samp_factor * cinfo->block_size)); + /* 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 * cinfo->block_size)); + + /* 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_h_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 * cinfo->block_size)); + cinfo->MCU_rows_in_scan = (JDIMENSION) + jdiv_round_up((long) cinfo->image_height, + (long) (cinfo->max_v_samp_factor * cinfo->block_size)); + + 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_h_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. + * + * Note: This function should NOT return a pseudo SOS marker (with zero + * component number) to the caller. A pseudo marker received by + * read_markers is processed and then skipped for other 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; + + for (;;) { /* Loop to pass pseudo SOS marker */ + val = (*cinfo->marker->read_markers) (cinfo); + + switch (val) { + case JPEG_REACHED_SOS: /* Found SOS */ + if (inputctl->inheaders) { /* 1st SOS */ + if (inputctl->inheaders == 1) + initial_setup(cinfo); + if (cinfo->comps_in_scan == 0) { /* pseudo SOS marker */ + inputctl->inheaders = 2; + break; + } + inputctl->inheaders = 0; + /* 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! */ + if (cinfo->comps_in_scan == 0) /* unexpected pseudo SOS marker */ + break; + start_input_pass(cinfo); + } + return val; + 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; + } + return val; + case JPEG_SUSPENDED: + return val; + default: + 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 = 1; + /* 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 = 1; +} |