media/libjpeg/jmemnobs.c

   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
  20 #define JPEG_INTERNALS
  21 #include "jinclude.h"
  22 #include "jpeglib.h"
  23 #include "jmemsys.h"            /* import the system-dependent declarations */
  24
  25
  26 /*
  27  * Memory allocation and freeing are controlled by the regular library
  28  * routines malloc() and free().
  29  */
  30
  31 GLOBAL(void *)
  32 jpeg_get_small(j_common_ptr cinfo, size_t sizeofobject)
  33 {
  34   return (void *)malloc(sizeofobject);
  35 }
  36
  37 GLOBAL(void)
  38 jpeg_free_small(j_common_ptr cinfo, void *object, size_t sizeofobject)
  39 {
  40   free(object);
  41 }
  42
  43
  44 /*
  45  * "Large" objects are treated the same as "small" ones.
  46  */
  47
  48 GLOBAL(void *)
  49 jpeg_get_large(j_common_ptr cinfo, size_t sizeofobject)
  50 {
  51   return (void *)malloc(sizeofobject);
  52 }
  53
  54 GLOBAL(void)
  55 jpeg_free_large(j_common_ptr cinfo, void *object, size_t sizeofobject)
  56 {
  57   free(object);
  58 }
  59
  60
  61 /*
  62  * This routine computes the total memory space available for allocation.
  63  */
  64
  65 GLOBAL(size_t)
  66 jpeg_mem_available(j_common_ptr cinfo, size_t min_bytes_needed,
  67                    size_t max_bytes_needed, size_t already_allocated)
  68 {
  69   if (cinfo->mem->max_memory_to_use) {
  70     if ((size_t)cinfo->mem->max_memory_to_use > already_allocated)
  71       return cinfo->mem->max_memory_to_use - already_allocated;
  72     else
  73       return 0;
  74   } else {
  75     /* Here we always say, "we got all you want bud!" */
  76     return max_bytes_needed;
  77   }
  78 }
  79
  80
  81 /*
  82  * Backing store (temporary file) management.
  83  * Since jpeg_mem_available always promised the moon,
  84  * this should never be called and we can just error out.
  85  */
  86
  87 GLOBAL(void)
  88 jpeg_open_backing_store(j_common_ptr cinfo, backing_store_ptr info,
  89                         long total_bytes_needed)
  90 {
  91   ERREXIT(cinfo, JERR_NO_BACKING_STORE);
  92 }
  93
  94
  95 /*
  96  * These routines take care of any system-dependent initialization and
  97  * cleanup required.  Here, there isn't any.
  98  */
  99
 100 GLOBAL(long)
 101 jpeg_mem_init(j_common_ptr cinfo)
 102 {
 103   return 0;                     /* just set max_memory_to_use to 0 */
 104 }
 105
 106 GLOBAL(void)
 107 jpeg_mem_term(j_common_ptr cinfo)
 108 {
 109   /* no work */
 110 }