jcomapi.c 3.2 KB

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  1. /*
  2. * jcomapi.c
  3. *
  4. * This file was part of the Independent JPEG Group's software:
  5. * Copyright (C) 1994-1997, Thomas G. Lane.
  6. * It was modified by The libjpeg-turbo Project to include only code relevant
  7. * to libjpeg-turbo.
  8. * For conditions of distribution and use, see the accompanying README.ijg
  9. * file.
  10. *
  11. * This file contains application interface routines that are used for both
  12. * compression and decompression.
  13. */
  14. #define JPEG_INTERNALS
  15. #include "jinclude.h"
  16. #include "jpeglib.h"
  17. /*
  18. * Abort processing of a JPEG compression or decompression operation,
  19. * but don't destroy the object itself.
  20. *
  21. * For this, we merely clean up all the nonpermanent memory pools.
  22. * Note that temp files (virtual arrays) are not allowed to belong to
  23. * the permanent pool, so we will be able to close all temp files here.
  24. * Closing a data source or destination, if necessary, is the application's
  25. * responsibility.
  26. */
  27. GLOBAL(void)
  28. jpeg_abort(j_common_ptr cinfo)
  29. {
  30. int pool;
  31. /* Do nothing if called on a not-initialized or destroyed JPEG object. */
  32. if (cinfo->mem == NULL)
  33. return;
  34. /* Releasing pools in reverse order might help avoid fragmentation
  35. * with some (brain-damaged) malloc libraries.
  36. */
  37. for (pool = JPOOL_NUMPOOLS - 1; pool > JPOOL_PERMANENT; pool--) {
  38. (*cinfo->mem->free_pool) (cinfo, pool);
  39. }
  40. /* Reset overall state for possible reuse of object */
  41. if (cinfo->is_decompressor) {
  42. cinfo->global_state = DSTATE_START;
  43. /* Try to keep application from accessing now-deleted marker list.
  44. * A bit kludgy to do it here, but this is the most central place.
  45. */
  46. ((j_decompress_ptr)cinfo)->marker_list = NULL;
  47. } else {
  48. cinfo->global_state = CSTATE_START;
  49. }
  50. }
  51. /*
  52. * Destruction of a JPEG object.
  53. *
  54. * Everything gets deallocated except the master jpeg_compress_struct itself
  55. * and the error manager struct. Both of these are supplied by the application
  56. * and must be freed, if necessary, by the application. (Often they are on
  57. * the stack and so don't need to be freed anyway.)
  58. * Closing a data source or destination, if necessary, is the application's
  59. * responsibility.
  60. */
  61. GLOBAL(void)
  62. jpeg_destroy(j_common_ptr cinfo)
  63. {
  64. /* We need only tell the memory manager to release everything. */
  65. /* NB: mem pointer is NULL if memory mgr failed to initialize. */
  66. if (cinfo->mem != NULL)
  67. (*cinfo->mem->self_destruct) (cinfo);
  68. cinfo->mem = NULL; /* be safe if jpeg_destroy is called twice */
  69. cinfo->global_state = 0; /* mark it destroyed */
  70. }
  71. /*
  72. * Convenience routines for allocating quantization and Huffman tables.
  73. * (Would jutils.c be a more reasonable place to put these?)
  74. */
  75. GLOBAL(JQUANT_TBL *)
  76. jpeg_alloc_quant_table(j_common_ptr cinfo)
  77. {
  78. JQUANT_TBL *tbl;
  79. tbl = (JQUANT_TBL *)
  80. (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, sizeof(JQUANT_TBL));
  81. tbl->sent_table = FALSE; /* make sure this is false in any new table */
  82. return tbl;
  83. }
  84. GLOBAL(JHUFF_TBL *)
  85. jpeg_alloc_huff_table(j_common_ptr cinfo)
  86. {
  87. JHUFF_TBL *tbl;
  88. tbl = (JHUFF_TBL *)
  89. (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, sizeof(JHUFF_TBL));
  90. tbl->sent_table = FALSE; /* make sure this is false in any new table */
  91. return tbl;
  92. }