1 /*

2 * jcinit.c

3 *

4 * Copyright (C) 1991-1997, Thomas G. Lane.

5 * This file is part of the Independent JPEG Group's software.

6 * For conditions of distribution and use, see the accompanying README file.

7 *

8 * This file contains initialization logic for the JPEG compressor.

9 * This routine is in charge of selecting the modules to be executed and

10 * making an initialization call to each one.

11 *

12 * Logically, this code belongs in jcmaster.c. It's split out because

13 * linking this routine implies linking the entire compression library.

14 * For a transcoding-only application, we want to be able to use jcmaster.c

15 * without linking in the whole library.

16 */

17

18 #define JPEG_INTERNALS

19 #include "jinclude.h"

20 #include "jpeglib.h"

21

22

23 /*

24 * Master selection of compression modules.

25 * This is done once at the start of processing an image. We determine

26 * which modules will be used and give them appropriate initialization calls.

27 */

28

29 GLOBAL(void)

30 jinit_compress_master (j_compress_ptr cinfo)

31 {

32 /* Initialize master control (includes parameter checking/processing) */

33 jinit_c_master_control(cinfo, FALSE /* full compression */);

34

35 /* Preprocessing */

36 if (! cinfo->raw_data_in) {

37 jinit_color_converter(cinfo);

38 jinit_downsampler(cinfo);

39 jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);

40 }

41 /* Forward DCT */

42 jinit_forward_dct(cinfo);

43 /* Entropy encoding: either Huffman or arithmetic coding. */

44 if (cinfo->arith_code) {

45 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);

46 } else {

47 if (cinfo->progressive_mode) {

48 #ifdef C_PROGRESSIVE_SUPPORTED

49 jinit_phuff_encoder(cinfo);

50 #else

51 ERREXIT(cinfo, JERR_NOT_COMPILED);

52 #endif

53 } else

54 jinit_huff_encoder(cinfo);

55 }

56

57 /* Need a full-image coefficient buffer in any multi-pass mode. */

58 jinit_c_coef_controller(cinfo,

59 (boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));

60 jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);

61

62 jinit_marker_writer(cinfo);

63

64 /* We can now tell the memory manager to allocate virtual arrays. */

65 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);

66

67 /* Write the datastream header (SOI) immediately.

68 * Frame and scan headers are postponed till later.

69 * This lets application insert special markers after the SOI.

70 */

71 (*cinfo->marker->write_file_header) (cinfo);

72 }