jmemnobs.c 2.8 KB

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  1. /*
  2. * jmemnobs.c
  3. *
  4. * This file was part of the Independent JPEG Group's software:
  5. * Copyright (C) 1992-1996, Thomas G. Lane.
  6. * libjpeg-turbo Modifications:
  7. * Copyright (C) 2017-2018, D. R. Commander.
  8. * For conditions of distribution and use, see the accompanying README.ijg
  9. * file.
  10. *
  11. * This file provides a really simple implementation of the system-
  12. * dependent portion of the JPEG memory manager. This implementation
  13. * assumes that no backing-store files are needed: all required space
  14. * can be obtained from malloc().
  15. * This is very portable in the sense that it'll compile on almost anything,
  16. * but you'd better have lots of main memory (or virtual memory) if you want
  17. * to process big images.
  18. */
  19. #define JPEG_INTERNALS
  20. #include "jinclude.h"
  21. #include "jpeglib.h"
  22. #include "jmemsys.h" /* import the system-dependent declarations */
  23. #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc(),free() */
  24. extern void *malloc(size_t size);
  25. extern void free(void *ptr);
  26. #endif
  27. /*
  28. * Memory allocation and freeing are controlled by the regular library
  29. * routines malloc() and free().
  30. */
  31. GLOBAL(void *)
  32. jpeg_get_small(j_common_ptr cinfo, size_t sizeofobject)
  33. {
  34. return (void *)malloc(sizeofobject);
  35. }
  36. GLOBAL(void)
  37. jpeg_free_small(j_common_ptr cinfo, void *object, size_t sizeofobject)
  38. {
  39. free(object);
  40. }
  41. /*
  42. * "Large" objects are treated the same as "small" ones.
  43. */
  44. GLOBAL(void *)
  45. jpeg_get_large(j_common_ptr cinfo, size_t sizeofobject)
  46. {
  47. return (void *)malloc(sizeofobject);
  48. }
  49. GLOBAL(void)
  50. jpeg_free_large(j_common_ptr cinfo, void *object, size_t sizeofobject)
  51. {
  52. free(object);
  53. }
  54. /*
  55. * This routine computes the total memory space available for allocation.
  56. */
  57. GLOBAL(size_t)
  58. jpeg_mem_available(j_common_ptr cinfo, size_t min_bytes_needed,
  59. size_t max_bytes_needed, size_t already_allocated)
  60. {
  61. if (cinfo->mem->max_memory_to_use) {
  62. if ((size_t)cinfo->mem->max_memory_to_use > already_allocated)
  63. return cinfo->mem->max_memory_to_use - already_allocated;
  64. else
  65. return 0;
  66. } else {
  67. /* Here we always say, "we got all you want bud!" */
  68. return max_bytes_needed;
  69. }
  70. }
  71. /*
  72. * Backing store (temporary file) management.
  73. * Since jpeg_mem_available always promised the moon,
  74. * this should never be called and we can just error out.
  75. */
  76. GLOBAL(void)
  77. jpeg_open_backing_store(j_common_ptr cinfo, backing_store_ptr info,
  78. long total_bytes_needed)
  79. {
  80. ERREXIT(cinfo, JERR_NO_BACKING_STORE);
  81. }
  82. /*
  83. * These routines take care of any system-dependent initialization and
  84. * cleanup required. Here, there isn't any.
  85. */
  86. GLOBAL(long)
  87. jpeg_mem_init(j_common_ptr cinfo)
  88. {
  89. return 0; /* just set max_memory_to_use to 0 */
  90. }
  91. GLOBAL(void)
  92. jpeg_mem_term(j_common_ptr cinfo)
  93. {
  94. /* no work */
  95. }