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 #ifndef HAVE_STDLIB_H           /* <stdlib.h> should declare malloc(),free() */
  26 extern void *malloc(size_t size);
  27 extern void free(void *ptr);
  28 #endif
  29
  30
  31 /*
  32  * Memory allocation and freeing are controlled by the regular library
  33  * routines malloc() and free().
  34  */
  35
  36 GLOBAL(void *)
  37 jpeg_get_small(j_common_ptr cinfo, size_t sizeofobject)
  38 {
  39   return (void *)malloc(sizeofobject);
  40 }
  41
  42 GLOBAL(void)
  43 jpeg_free_small(j_common_ptr cinfo, void *object, size_t sizeofobject)
  44 {
  45   free(object);
  46 }
  47
  48
  49 /*
  50  * "Large" objects are treated the same as "small" ones.
  51  */
  52
  53 GLOBAL(void *)
  54 jpeg_get_large(j_common_ptr cinfo, size_t sizeofobject)
  55 {
  56   return (void *)malloc(sizeofobject);
  57 }
  58
  59 GLOBAL(void)
  60 jpeg_free_large(j_common_ptr cinfo, void *object, size_t sizeofobject)
  61 {
  62   free(object);
  63 }
  64
  65
  66 /*
  67  * This routine computes the total memory space available for allocation.
  68  */
  69
  70 GLOBAL(size_t)
  71 jpeg_mem_available(j_common_ptr cinfo, size_t min_bytes_needed,
  72                    size_t max_bytes_needed, size_t already_allocated)
  73 {
  74   if (cinfo->mem->max_memory_to_use) {
  75     if ((size_t)cinfo->mem->max_memory_to_use > already_allocated)
  76       return cinfo->mem->max_memory_to_use - already_allocated;
  77     else
  78       return 0;
  79   } else {
  80     /* Here we always say, "we got all you want bud!" */
  81     return max_bytes_needed;
  82   }
  83 }
  84
  85
  86 /*
  87  * Backing store (temporary file) management.
  88  * Since jpeg_mem_available always promised the moon,
  89  * this should never be called and we can just error out.
  90  */
  91
  92 GLOBAL(void)
  93 jpeg_open_backing_store(j_common_ptr cinfo, backing_store_ptr info,
  94                         long total_bytes_needed)
  95 {
  96   ERREXIT(cinfo, JERR_NO_BACKING_STORE);
  97 }
  98
  99
 100 /*
 101  * These routines take care of any system-dependent initialization and
 102  * cleanup required.  Here, there isn't any.
 103  */
 104
 105 GLOBAL(long)
 106 jpeg_mem_init(j_common_ptr cinfo)
 107 {
 108   return 0;                     /* just set max_memory_to_use to 0 */
 109 }
 110
 111 GLOBAL(void)
 112 jpeg_mem_term(j_common_ptr cinfo)
 113 {
 114   /* no work */
 115 }