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1 /* | 1 /* |
2 * jdinput.c | 2 * jdinput.c |
3 * | 3 * |
4 * Copyright (C) 1991-1997, Thomas G. Lane. | 4 * Copyright (C) 1991-1997, Thomas G. Lane. |
5 * Modified 2002-2009 by Guido Vollbeding. | |
6 * Copyright (C) 2010, D. R. Commander. | 5 * Copyright (C) 2010, D. R. Commander. |
7 * This file is part of the Independent JPEG Group's software. | 6 * This file is part of the Independent JPEG Group's software. |
8 * For conditions of distribution and use, see the accompanying README file. | 7 * For conditions of distribution and use, see the accompanying README file. |
9 * | 8 * |
10 * This file contains input control logic for the JPEG decompressor. | 9 * This file contains input control logic for the JPEG decompressor. |
11 * These routines are concerned with controlling the decompressor's input | 10 * These routines are concerned with controlling the decompressor's input |
12 * processing (marker reading and coefficient decoding). The actual input | 11 * processing (marker reading and coefficient decoding). The actual input |
13 * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c. | 12 * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c. |
14 */ | 13 */ |
15 | 14 |
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31 | 30 |
32 | 31 |
33 /* Forward declarations */ | 32 /* Forward declarations */ |
34 METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo)); | 33 METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo)); |
35 | 34 |
36 | 35 |
37 /* | 36 /* |
38 * Routines to calculate various quantities related to the size of the image. | 37 * Routines to calculate various quantities related to the size of the image. |
39 */ | 38 */ |
40 | 39 |
41 | |
42 #if JPEG_LIB_VERSION >= 80 | |
43 /* | |
44 * Compute output image dimensions and related values. | |
45 * NOTE: this is exported for possible use by application. | |
46 * Hence it mustn't do anything that can't be done twice. | |
47 */ | |
48 | |
49 GLOBAL(void) | |
50 jpeg_core_output_dimensions (j_decompress_ptr cinfo) | |
51 /* Do computations that are needed before master selection phase. | |
52 * This function is used for transcoding and full decompression. | |
53 */ | |
54 { | |
55 #ifdef IDCT_SCALING_SUPPORTED | |
56 int ci; | |
57 jpeg_component_info *compptr; | |
58 | |
59 /* Compute actual output image dimensions and DCT scaling choices. */ | |
60 if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) { | |
61 /* Provide 1/block_size scaling */ | |
62 cinfo->output_width = (JDIMENSION) | |
63 jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size); | |
64 cinfo->output_height = (JDIMENSION) | |
65 jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size); | |
66 cinfo->min_DCT_h_scaled_size = 1; | |
67 cinfo->min_DCT_v_scaled_size = 1; | |
68 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) { | |
69 /* Provide 2/block_size scaling */ | |
70 cinfo->output_width = (JDIMENSION) | |
71 jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size); | |
72 cinfo->output_height = (JDIMENSION) | |
73 jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size); | |
74 cinfo->min_DCT_h_scaled_size = 2; | |
75 cinfo->min_DCT_v_scaled_size = 2; | |
76 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) { | |
77 /* Provide 4/block_size scaling */ | |
78 cinfo->output_width = (JDIMENSION) | |
79 jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size); | |
80 cinfo->output_height = (JDIMENSION) | |
81 jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size); | |
82 cinfo->min_DCT_h_scaled_size = 4; | |
83 cinfo->min_DCT_v_scaled_size = 4; | |
84 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) { | |
85 /* Provide 8/block_size scaling */ | |
86 cinfo->output_width = (JDIMENSION) | |
87 jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size); | |
88 cinfo->output_height = (JDIMENSION) | |
89 jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size); | |
90 cinfo->min_DCT_h_scaled_size = 8; | |
91 cinfo->min_DCT_v_scaled_size = 8; | |
92 } | |
93 /* Recompute dimensions of components */ | |
94 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; | |
95 ci++, compptr++) { | |
96 compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size; | |
97 compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size; | |
98 } | |
99 | |
100 #else /* !IDCT_SCALING_SUPPORTED */ | |
101 | |
102 /* Hardwire it to "no scaling" */ | |
103 cinfo->output_width = cinfo->image_width; | |
104 cinfo->output_height = cinfo->image_height; | |
105 /* jdinput.c has already initialized DCT_scaled_size, | |
106 * and has computed unscaled downsampled_width and downsampled_height. | |
107 */ | |
108 | |
109 #endif /* IDCT_SCALING_SUPPORTED */ | |
110 } | |
111 #endif | |
112 | |
113 | |
114 LOCAL(void) | 40 LOCAL(void) |
115 initial_setup (j_decompress_ptr cinfo) | 41 initial_setup (j_decompress_ptr cinfo) |
116 /* Called once, when first SOS marker is reached */ | 42 /* Called once, when first SOS marker is reached */ |
117 { | 43 { |
118 int ci; | 44 int ci; |
119 jpeg_component_info *compptr; | 45 jpeg_component_info *compptr; |
120 | 46 |
121 /* Make sure image isn't bigger than I can handle */ | 47 /* Make sure image isn't bigger than I can handle */ |
122 if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION || | 48 if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION || |
123 (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION) | 49 (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION) |
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462 inputctl->pub.reset_input_controller = reset_input_controller; | 388 inputctl->pub.reset_input_controller = reset_input_controller; |
463 inputctl->pub.start_input_pass = start_input_pass; | 389 inputctl->pub.start_input_pass = start_input_pass; |
464 inputctl->pub.finish_input_pass = finish_input_pass; | 390 inputctl->pub.finish_input_pass = finish_input_pass; |
465 /* Initialize state: can't use reset_input_controller since we don't | 391 /* Initialize state: can't use reset_input_controller since we don't |
466 * want to try to reset other modules yet. | 392 * want to try to reset other modules yet. |
467 */ | 393 */ |
468 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ | 394 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ |
469 inputctl->pub.eoi_reached = FALSE; | 395 inputctl->pub.eoi_reached = FALSE; |
470 inputctl->inheaders = TRUE; | 396 inputctl->inheaders = TRUE; |
471 } | 397 } |
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