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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 
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 *)
jpeg_get_small(j_common_ptr cinfo,size_t sizeofobject)37 jpeg_get_small(j_common_ptr cinfo, size_t sizeofobject)
38 {
39   return (void *)malloc(sizeofobject);
40 }
41 
42 GLOBAL(void)
jpeg_free_small(j_common_ptr cinfo,void * object,size_t sizeofobject)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 *)
jpeg_get_large(j_common_ptr cinfo,size_t sizeofobject)54 jpeg_get_large(j_common_ptr cinfo, size_t sizeofobject)
55 {
56   return (void *)malloc(sizeofobject);
57 }
58 
59 GLOBAL(void)
jpeg_free_large(j_common_ptr cinfo,void * object,size_t sizeofobject)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)
jpeg_mem_available(j_common_ptr cinfo,size_t min_bytes_needed,size_t max_bytes_needed,size_t already_allocated)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)
jpeg_open_backing_store(j_common_ptr cinfo,backing_store_ptr info,long total_bytes_needed)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)
jpeg_mem_init(j_common_ptr cinfo)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)
jpeg_mem_term(j_common_ptr cinfo)112 jpeg_mem_term(j_common_ptr cinfo)
113 {
114   /* no work */
115 }
116