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jcinit.c
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/*
* jcinit.c
*
* Copyright (C) 1991-1997, Thomas G. Lane.
* Modified 2003-2017 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 initialization logic for the JPEG compressor.
* This routine is in charge of selecting the modules to be executed and
* making an initialization call to each one.
*
* Logically, this code belongs in jcmaster.c. It's split out because
* linking this routine implies linking the entire compression library.
* For a transcoding-only application, we want to be able to use jcmaster.c
* without linking in the whole library.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
/*
* Compute JPEG 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_calc_jpeg_dimensions (j_compress_ptr cinfo)
/* Do computations that are needed before master selection phase */
{
/* Sanity check on input image dimensions to prevent overflow in
* following calculations.
* We do check jpeg_width and jpeg_height in initial_setup in jcmaster.c,
* but image_width and image_height can come from arbitrary data,
* and we need some space for multiplication by block_size.
*/
if (((long) cinfo->image_width >> 24) || ((long) cinfo->image_height >> 24))
ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
#ifdef DCT_SCALING_SUPPORTED
/* Compute actual JPEG image dimensions and DCT scaling choices. */
if (cinfo->scale_num >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/1 scaling */
cinfo->jpeg_width = cinfo->image_width * cinfo->block_size;
cinfo->jpeg_height = cinfo->image_height * cinfo->block_size;
cinfo->min_DCT_h_scaled_size = 1;
cinfo->min_DCT_v_scaled_size = 1;
} else if (cinfo->scale_num * 2 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/2 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 2L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 2L);
cinfo->min_DCT_h_scaled_size = 2;
cinfo->min_DCT_v_scaled_size = 2;
} else if (cinfo->scale_num * 3 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/3 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 3L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 3L);
cinfo->min_DCT_h_scaled_size = 3;
cinfo->min_DCT_v_scaled_size = 3;
} else if (cinfo->scale_num * 4 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/4 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 4L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 4L);
cinfo->min_DCT_h_scaled_size = 4;
cinfo->min_DCT_v_scaled_size = 4;
} else if (cinfo->scale_num * 5 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/5 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 5L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 5L);
cinfo->min_DCT_h_scaled_size = 5;
cinfo->min_DCT_v_scaled_size = 5;
} else if (cinfo->scale_num * 6 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/6 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 6L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 6L);
cinfo->min_DCT_h_scaled_size = 6;
cinfo->min_DCT_v_scaled_size = 6;
} else if (cinfo->scale_num * 7 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/7 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 7L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 7L);
cinfo->min_DCT_h_scaled_size = 7;
cinfo->min_DCT_v_scaled_size = 7;
} else if (cinfo->scale_num * 8 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/8 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 8L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 8L);
cinfo->min_DCT_h_scaled_size = 8;
cinfo->min_DCT_v_scaled_size = 8;
} else if (cinfo->scale_num * 9 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/9 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 9L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 9L);
cinfo->min_DCT_h_scaled_size = 9;
cinfo->min_DCT_v_scaled_size = 9;
} else if (cinfo->scale_num * 10 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/10 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 10L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 10L);
cinfo->min_DCT_h_scaled_size = 10;
cinfo->min_DCT_v_scaled_size = 10;
} else if (cinfo->scale_num * 11 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/11 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 11L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 11L);
cinfo->min_DCT_h_scaled_size = 11;
cinfo->min_DCT_v_scaled_size = 11;
} else if (cinfo->scale_num * 12 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/12 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 12L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 12L);
cinfo->min_DCT_h_scaled_size = 12;
cinfo->min_DCT_v_scaled_size = 12;
} else if (cinfo->scale_num * 13 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/13 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 13L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 13L);
cinfo->min_DCT_h_scaled_size = 13;
cinfo->min_DCT_v_scaled_size = 13;
} else if (cinfo->scale_num * 14 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/14 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 14L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 14L);
cinfo->min_DCT_h_scaled_size = 14;
cinfo->min_DCT_v_scaled_size = 14;
} else if (cinfo->scale_num * 15 >= cinfo->scale_denom * cinfo->block_size) {
/* Provide block_size/15 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 15L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 15L);
cinfo->min_DCT_h_scaled_size = 15;
cinfo->min_DCT_v_scaled_size = 15;
} else {
/* Provide block_size/16 scaling */
cinfo->jpeg_width = (JDIMENSION)
jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 16L);
cinfo->jpeg_height = (JDIMENSION)
jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 16L);
cinfo->min_DCT_h_scaled_size = 16;
cinfo->min_DCT_v_scaled_size = 16;
}
#else /* !DCT_SCALING_SUPPORTED */
/* Hardwire it to "no scaling" */
cinfo->jpeg_width = cinfo->image_width;
cinfo->jpeg_height = cinfo->image_height;
cinfo->min_DCT_h_scaled_size = DCTSIZE;
cinfo->min_DCT_v_scaled_size = DCTSIZE;
#endif /* DCT_SCALING_SUPPORTED */
}
/*
* Master selection of compression modules.
* This is done once at the start of processing an image. We determine
* which modules will be used and give them appropriate initialization calls.
*/
GLOBAL(void)
jinit_compress_master (j_compress_ptr cinfo)
{
long samplesperrow;
JDIMENSION jd_samplesperrow;
/* For now, precision must match compiled-in value... */
if (cinfo->data_precision != BITS_IN_JSAMPLE)
ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
/* Sanity check on input image dimensions */
if (cinfo->image_height <= 0 || cinfo->image_width <= 0 ||
cinfo->input_components <= 0)
ERREXIT(cinfo, JERR_EMPTY_IMAGE);
/* Width of an input scanline must be representable as JDIMENSION. */
samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
jd_samplesperrow = (JDIMENSION) samplesperrow;
if ((long) jd_samplesperrow != samplesperrow)
ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
/* Compute JPEG image dimensions and related values. */
jpeg_calc_jpeg_dimensions(cinfo);
/* Initialize master control (includes parameter checking/processing) */
jinit_c_master_control(cinfo, FALSE /* full compression */);
/* Preprocessing */
if (! cinfo->raw_data_in) {
jinit_color_converter(cinfo);
jinit_downsampler(cinfo);
jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
}
/* Forward DCT */
jinit_forward_dct(cinfo);
/* Entropy encoding: either Huffman or arithmetic coding. */
if (cinfo->arith_code)
jinit_arith_encoder(cinfo);
else {
jinit_huff_encoder(cinfo);
}
/* Need a full-image coefficient buffer in any multi-pass mode. */
jinit_c_coef_controller(cinfo,
(boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
jinit_marker_writer(cinfo);
/* We can now tell the memory manager to allocate virtual arrays. */
(*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
/* Write the datastream header (SOI) immediately.
* Frame and scan headers are postponed till later.
* This lets application insert special markers after the SOI.
*/
(*cinfo->marker->write_file_header) (cinfo);
}