#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* 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; | |
} | |
#endif //_FX_JPEG_TURBO_ |