1 /*
2 * jmemnobs.c
3 *
4 * Copyright (C) 1992-1996, Thomas G. Lane.
5 * Modified 2019 by Guido Vollbeding.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
8 *
9 * This file provides a really simple implementation of the system-
10 * dependent portion of the JPEG memory manager. This implementation
11 * assumes that no backing-store files are needed: all required space
12 * can be obtained from malloc().
13 * This is very portable in the sense that it'll compile on almost anything,
14 * but you'd better have lots of main memory (or virtual memory) if you want
15 * to process big images.
16 * Note that the max_memory_to_use option is respected by this implementation.
17 */
18
19 #define JPEG_INTERNALS
20 #include "jinclude.h"
21 #include "jpeglib.h"
22 #include "jmemsys.h" /* import the system-dependent declarations */
23
24 #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare malloc(),free() */
25 extern void * malloc JPP((size_t size));
26 extern void free JPP((void *ptr));
27 #endif
28
29
30 /*
31 * Memory allocation and freeing are controlled by the regular library
32 * routines malloc() and free().
33 */
34
35 GLOBAL(void *)
jpeg_get_small(j_common_ptr cinfo,size_t sizeofobject)36 jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)
37 {
38 return (void *) malloc(sizeofobject);
39 }
40
41 GLOBAL(void)
jpeg_free_small(j_common_ptr cinfo,void * object,size_t sizeofobject)42 jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject)
43 {
44 free(object);
45 }
46
47
48 /*
49 * "Large" objects are treated the same as "small" ones.
50 * NB: although we include FAR keywords in the routine declarations,
51 * this file won't actually work in 80x86 small/medium model; at least,
52 * you probably won't be able to process useful-size images in only 64KB.
53 */
54
55 GLOBAL(void FAR *)
jpeg_get_large(j_common_ptr cinfo,size_t sizeofobject)56 jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
57 {
58 return (void FAR *) malloc(sizeofobject);
59 }
60
61 GLOBAL(void)
jpeg_free_large(j_common_ptr cinfo,void FAR * object,size_t sizeofobject)62 jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject)
63 {
64 free(object);
65 }
66
67
68 /*
69 * This routine computes the total memory space available for allocation.
70 */
71
72 GLOBAL(long)
jpeg_mem_available(j_common_ptr cinfo,long min_bytes_needed,long max_bytes_needed,long already_allocated)73 jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,
74 long max_bytes_needed, long already_allocated)
75 {
76 if (cinfo->mem->max_memory_to_use)
77 return cinfo->mem->max_memory_to_use - already_allocated;
78
79 /* Here we say, "we got all you want bud!" */
80 return max_bytes_needed;
81 }
82
83
84 /*
85 * Backing store (temporary file) management.
86 * Since jpeg_mem_available always promised the moon,
87 * this should never be called and we can just error out.
88 */
89
90 GLOBAL(void)
jpeg_open_backing_store(j_common_ptr cinfo,backing_store_ptr info,long total_bytes_needed)91 jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
92 long total_bytes_needed)
93 {
94 ERREXIT(cinfo, JERR_NO_BACKING_STORE);
95 }
96
97
98 /*
99 * These routines take care of any system-dependent initialization and
100 * cleanup required. Here, there isn't any.
101 */
102
103 GLOBAL(long)
jpeg_mem_init(j_common_ptr cinfo)104 jpeg_mem_init (j_common_ptr cinfo)
105 {
106 return 0; /* just set max_memory_to_use to 0 */
107 }
108
109 GLOBAL(void)
jpeg_mem_term(j_common_ptr cinfo)110 jpeg_mem_term (j_common_ptr cinfo)
111 {
112 /* no work */
113 }
114