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6417 | ashmew2 | 1 | /* |
2 | * jcinit.c |
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3 | * |
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4 | * Copyright (C) 1991-1997, Thomas G. Lane. |
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5 | * This file is part of the Independent JPEG Group's software. |
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6 | * For conditions of distribution and use, see the accompanying README file. |
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7 | * |
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8 | * This file contains initialization logic for the JPEG compressor. |
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9 | * This routine is in charge of selecting the modules to be executed and |
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10 | * making an initialization call to each one. |
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11 | * |
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12 | * Logically, this code belongs in jcmaster.c. It's split out because |
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13 | * linking this routine implies linking the entire compression library. |
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14 | * For a transcoding-only application, we want to be able to use jcmaster.c |
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15 | * without linking in the whole library. |
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16 | */ |
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17 | |||
18 | #define JPEG_INTERNALS |
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19 | #include "jinclude.h" |
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20 | #include "jpeglib.h" |
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21 | |||
22 | |||
23 | /* |
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24 | * Master selection of compression modules. |
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25 | * This is done once at the start of processing an image. We determine |
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26 | * which modules will be used and give them appropriate initialization calls. |
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27 | */ |
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28 | |||
29 | GLOBAL(void) |
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30 | jinit_compress_master (j_compress_ptr cinfo) |
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31 | { |
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32 | /* Initialize master control (includes parameter checking/processing) */ |
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33 | jinit_c_master_control(cinfo, FALSE /* full compression */); |
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34 | |||
35 | /* Preprocessing */ |
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36 | if (! cinfo->raw_data_in) { |
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37 | jinit_color_converter(cinfo); |
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38 | jinit_downsampler(cinfo); |
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39 | jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */); |
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40 | } |
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41 | /* Forward DCT */ |
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42 | jinit_forward_dct(cinfo); |
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43 | /* Entropy encoding: either Huffman or arithmetic coding. */ |
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44 | if (cinfo->arith_code) { |
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45 | ERREXIT(cinfo, JERR_ARITH_NOTIMPL); |
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46 | } else { |
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47 | if (cinfo->progressive_mode) { |
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48 | #ifdef C_PROGRESSIVE_SUPPORTED |
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49 | jinit_phuff_encoder(cinfo); |
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50 | #else |
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51 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
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52 | #endif |
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53 | } else |
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54 | jinit_huff_encoder(cinfo); |
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55 | } |
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56 | |||
57 | /* Need a full-image coefficient buffer in any multi-pass mode. */ |
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58 | jinit_c_coef_controller(cinfo, |
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59 | (boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding)); |
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60 | jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */); |
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61 | |||
62 | jinit_marker_writer(cinfo); |
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63 | |||
64 | /* We can now tell the memory manager to allocate virtual arrays. */ |
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65 | (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); |
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66 | |||
67 | /* Write the datastream header (SOI) immediately. |
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68 | * Frame and scan headers are postponed till later. |
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69 | * This lets application insert special markers after the SOI. |
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70 | */ |
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71 | (*cinfo->marker->write_file_header) (cinfo); |
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72 | } |