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661 lines
24 KiB
661 lines
24 KiB
/* |
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* jdinput.c |
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* |
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* Copyright (C) 1991-1997, Thomas G. Lane. |
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* Modified 2002-2009 by Guido Vollbeding. |
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* This file is part of the Independent JPEG Group's software. |
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* For conditions of distribution and use, see the accompanying README file. |
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* |
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* This file contains input control logic for the JPEG decompressor. |
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* These routines are concerned with controlling the decompressor's input |
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* processing (marker reading and coefficient decoding). The actual input |
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* reading is done in jdmarker.c, jdhuff.c, and jdarith.c. |
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*/ |
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#define JPEG_INTERNALS |
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#include "jinclude.h" |
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#include "jpeglib.h" |
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/* Private state */ |
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typedef struct { |
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struct jpeg_input_controller pub; /* public fields */ |
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int inheaders; /* Nonzero until first SOS is reached */ |
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} my_input_controller; |
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typedef my_input_controller * my_inputctl_ptr; |
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/* Forward declarations */ |
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METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo)); |
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/* |
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* Routines to calculate various quantities related to the size of the image. |
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*/ |
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/* |
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* Compute output image dimensions and related values. |
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* NOTE: this is exported for possible use by application. |
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* Hence it mustn't do anything that can't be done twice. |
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*/ |
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GLOBAL(void) |
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jpeg_core_output_dimensions (j_decompress_ptr cinfo) |
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/* Do computations that are needed before master selection phase. |
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* This function is used for transcoding and full decompression. |
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*/ |
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{ |
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#ifdef IDCT_SCALING_SUPPORTED |
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int ci; |
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jpeg_component_info *compptr; |
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/* Compute actual output image dimensions and DCT scaling choices. */ |
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if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) { |
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/* Provide 1/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 1; |
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cinfo->min_DCT_v_scaled_size = 1; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) { |
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/* Provide 2/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 2; |
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cinfo->min_DCT_v_scaled_size = 2; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 3) { |
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/* Provide 3/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 3L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 3L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 3; |
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cinfo->min_DCT_v_scaled_size = 3; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) { |
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/* Provide 4/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 4; |
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cinfo->min_DCT_v_scaled_size = 4; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 5) { |
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/* Provide 5/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 5L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 5L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 5; |
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cinfo->min_DCT_v_scaled_size = 5; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 6) { |
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/* Provide 6/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 6L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 6L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 6; |
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cinfo->min_DCT_v_scaled_size = 6; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 7) { |
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/* Provide 7/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 7L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 7L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 7; |
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cinfo->min_DCT_v_scaled_size = 7; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) { |
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/* Provide 8/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 8; |
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cinfo->min_DCT_v_scaled_size = 8; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 9) { |
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/* Provide 9/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 9L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 9L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 9; |
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cinfo->min_DCT_v_scaled_size = 9; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 10) { |
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/* Provide 10/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 10L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 10L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 10; |
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cinfo->min_DCT_v_scaled_size = 10; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 11) { |
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/* Provide 11/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 11L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 11L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 11; |
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cinfo->min_DCT_v_scaled_size = 11; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 12) { |
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/* Provide 12/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 12L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 12L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 12; |
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cinfo->min_DCT_v_scaled_size = 12; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 13) { |
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/* Provide 13/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 13L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 13L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 13; |
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cinfo->min_DCT_v_scaled_size = 13; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 14) { |
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/* Provide 14/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 14L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 14L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 14; |
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cinfo->min_DCT_v_scaled_size = 14; |
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} else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 15) { |
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/* Provide 15/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 15L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 15L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 15; |
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cinfo->min_DCT_v_scaled_size = 15; |
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} else { |
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/* Provide 16/block_size scaling */ |
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cinfo->output_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * 16L, (long) cinfo->block_size); |
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cinfo->output_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * 16L, (long) cinfo->block_size); |
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cinfo->min_DCT_h_scaled_size = 16; |
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cinfo->min_DCT_v_scaled_size = 16; |
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} |
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/* Recompute dimensions of components */ |
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for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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ci++, compptr++) { |
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compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size; |
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compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size; |
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} |
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#else /* !IDCT_SCALING_SUPPORTED */ |
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/* Hardwire it to "no scaling" */ |
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cinfo->output_width = cinfo->image_width; |
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cinfo->output_height = cinfo->image_height; |
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/* jdinput.c has already initialized DCT_scaled_size, |
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* and has computed unscaled downsampled_width and downsampled_height. |
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*/ |
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#endif /* IDCT_SCALING_SUPPORTED */ |
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} |
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LOCAL(void) |
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initial_setup (j_decompress_ptr cinfo) |
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/* Called once, when first SOS marker is reached */ |
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{ |
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int ci; |
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jpeg_component_info *compptr; |
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/* Make sure image isn't bigger than I can handle */ |
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if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION || |
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(long) cinfo->image_width > (long) JPEG_MAX_DIMENSION) |
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ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION); |
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/* For now, precision must match compiled-in value... */ |
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if (cinfo->data_precision != BITS_IN_JSAMPLE) |
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ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); |
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/* Check that number of components won't exceed internal array sizes */ |
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if (cinfo->num_components > MAX_COMPONENTS) |
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ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, |
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MAX_COMPONENTS); |
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/* Compute maximum sampling factors; check factor validity */ |
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cinfo->max_h_samp_factor = 1; |
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cinfo->max_v_samp_factor = 1; |
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for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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ci++, compptr++) { |
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if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR || |
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compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR) |
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ERREXIT(cinfo, JERR_BAD_SAMPLING); |
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cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, |
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compptr->h_samp_factor); |
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cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, |
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compptr->v_samp_factor); |
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} |
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/* Derive block_size, natural_order, and lim_Se */ |
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if (cinfo->is_baseline || (cinfo->progressive_mode && |
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cinfo->comps_in_scan)) { /* no pseudo SOS marker */ |
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cinfo->block_size = DCTSIZE; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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} else |
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switch (cinfo->Se) { |
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case (1*1-1): |
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cinfo->block_size = 1; |
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cinfo->natural_order = jpeg_natural_order; /* not needed */ |
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cinfo->lim_Se = cinfo->Se; |
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break; |
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case (2*2-1): |
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cinfo->block_size = 2; |
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cinfo->natural_order = jpeg_natural_order2; |
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cinfo->lim_Se = cinfo->Se; |
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break; |
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case (3*3-1): |
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cinfo->block_size = 3; |
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cinfo->natural_order = jpeg_natural_order3; |
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cinfo->lim_Se = cinfo->Se; |
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break; |
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case (4*4-1): |
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cinfo->block_size = 4; |
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cinfo->natural_order = jpeg_natural_order4; |
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cinfo->lim_Se = cinfo->Se; |
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break; |
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case (5*5-1): |
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cinfo->block_size = 5; |
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cinfo->natural_order = jpeg_natural_order5; |
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cinfo->lim_Se = cinfo->Se; |
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break; |
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case (6*6-1): |
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cinfo->block_size = 6; |
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cinfo->natural_order = jpeg_natural_order6; |
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cinfo->lim_Se = cinfo->Se; |
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break; |
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case (7*7-1): |
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cinfo->block_size = 7; |
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cinfo->natural_order = jpeg_natural_order7; |
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cinfo->lim_Se = cinfo->Se; |
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break; |
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case (8*8-1): |
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cinfo->block_size = 8; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (9*9-1): |
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cinfo->block_size = 9; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (10*10-1): |
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cinfo->block_size = 10; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (11*11-1): |
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cinfo->block_size = 11; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (12*12-1): |
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cinfo->block_size = 12; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (13*13-1): |
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cinfo->block_size = 13; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (14*14-1): |
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cinfo->block_size = 14; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (15*15-1): |
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cinfo->block_size = 15; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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case (16*16-1): |
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cinfo->block_size = 16; |
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cinfo->natural_order = jpeg_natural_order; |
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cinfo->lim_Se = DCTSIZE2-1; |
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break; |
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default: |
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ERREXIT4(cinfo, JERR_BAD_PROGRESSION, |
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cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al); |
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break; |
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} |
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/* We initialize DCT_scaled_size and min_DCT_scaled_size to block_size. |
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* In the full decompressor, |
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* this will be overridden by jpeg_calc_output_dimensions in jdmaster.c; |
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* but in the transcoder, |
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* jpeg_calc_output_dimensions is not used, so we must do it here. |
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*/ |
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cinfo->min_DCT_h_scaled_size = cinfo->block_size; |
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cinfo->min_DCT_v_scaled_size = cinfo->block_size; |
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/* Compute dimensions of components */ |
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for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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ci++, compptr++) { |
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compptr->DCT_h_scaled_size = cinfo->block_size; |
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compptr->DCT_v_scaled_size = cinfo->block_size; |
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/* Size in DCT blocks */ |
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compptr->width_in_blocks = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor, |
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(long) (cinfo->max_h_samp_factor * cinfo->block_size)); |
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compptr->height_in_blocks = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor, |
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(long) (cinfo->max_v_samp_factor * cinfo->block_size)); |
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/* downsampled_width and downsampled_height will also be overridden by |
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* jdmaster.c if we are doing full decompression. The transcoder library |
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* doesn't use these values, but the calling application might. |
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*/ |
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/* Size in samples */ |
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compptr->downsampled_width = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor, |
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(long) cinfo->max_h_samp_factor); |
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compptr->downsampled_height = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor, |
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(long) cinfo->max_v_samp_factor); |
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/* Mark component needed, until color conversion says otherwise */ |
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compptr->component_needed = TRUE; |
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/* Mark no quantization table yet saved for component */ |
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compptr->quant_table = NULL; |
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} |
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/* Compute number of fully interleaved MCU rows. */ |
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cinfo->total_iMCU_rows = (JDIMENSION) |
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jdiv_round_up((long) cinfo->image_height, |
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(long) (cinfo->max_v_samp_factor * cinfo->block_size)); |
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|
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/* Decide whether file contains multiple scans */ |
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if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode) |
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cinfo->inputctl->has_multiple_scans = TRUE; |
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else |
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cinfo->inputctl->has_multiple_scans = FALSE; |
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} |
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LOCAL(void) |
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per_scan_setup (j_decompress_ptr cinfo) |
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/* Do computations that are needed before processing a JPEG scan */ |
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/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */ |
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{ |
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int ci, mcublks, tmp; |
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jpeg_component_info *compptr; |
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if (cinfo->comps_in_scan == 1) { |
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|
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/* Noninterleaved (single-component) scan */ |
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compptr = cinfo->cur_comp_info[0]; |
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|
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/* Overall image size in MCUs */ |
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cinfo->MCUs_per_row = compptr->width_in_blocks; |
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cinfo->MCU_rows_in_scan = compptr->height_in_blocks; |
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|
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/* For noninterleaved scan, always one block per MCU */ |
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compptr->MCU_width = 1; |
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compptr->MCU_height = 1; |
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compptr->MCU_blocks = 1; |
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compptr->MCU_sample_width = compptr->DCT_h_scaled_size; |
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compptr->last_col_width = 1; |
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/* For noninterleaved scans, it is convenient to define last_row_height |
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* as the number of block rows present in the last iMCU row. |
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*/ |
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tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor); |
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if (tmp == 0) tmp = compptr->v_samp_factor; |
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compptr->last_row_height = tmp; |
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|
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/* Prepare array describing MCU composition */ |
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cinfo->blocks_in_MCU = 1; |
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cinfo->MCU_membership[0] = 0; |
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} else { |
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/* Interleaved (multi-component) scan */ |
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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; |
|
}
|
|
|