1/*
2 * Copyright (C) 2007-2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define JPEG_INTERNALS
18#include "jinclude.h"
19#include "jpeglib.h"
20#include "jmemsys.h"		/* import the system-dependent declarations */
21
22#include <unistd.h>
23#include <sys/mman.h>
24
25#ifndef HAVE_STDLIB_H		/* <stdlib.h> should declare malloc(),free() */
26extern void * malloc JPP((size_t size));
27extern void free JPP((void *ptr));
28#endif
29
30/*
31 * Memory allocation and freeing are controlled by the regular library
32 * routines malloc() and free().
33 */
34
35GLOBAL(void *)
36jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)
37{
38  return (void *) malloc(sizeofobject);
39}
40
41GLOBAL(void)
42jpeg_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
55GLOBAL(void FAR *)
56jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
57{
58  return (void FAR *) malloc(sizeofobject);
59}
60
61GLOBAL(void)
62jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject)
63{
64  free(object);
65}
66
67/*
68 * This routine computes the total memory space available for allocation.
69 * It's impossible to do this in a portable way; our current solution is
70 * to make the user tell us (with a default value set at compile time).
71 * If you can actually get the available space, it's a good idea to subtract
72 * a slop factor of 5% or so.
73 */
74
75#ifndef DEFAULT_MAX_MEM		/* so can override from makefile */
76#define DEFAULT_MAX_MEM		10000000L /* default: ten megabyte */
77#endif
78
79GLOBAL(long)
80jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,
81		    long max_bytes_needed, long already_allocated)
82{
83  return cinfo->mem->max_memory_to_use - already_allocated;
84}
85
86
87/*
88 * Backing store (temporary file) management.
89 * Backing store objects are only used when the value returned by
90 * jpeg_mem_available is less than the total space needed.  You can dispense
91 * with these routines if you have plenty of virtual memory; see jmemnobs.c.
92 */
93
94METHODDEF(void)
95read_backing_store (j_common_ptr cinfo, backing_store_ptr info,
96		    void FAR * buffer_address,
97		    long file_offset, long byte_count)
98{
99  memmove(buffer_address, info->addr + file_offset, byte_count);
100}
101
102
103METHODDEF(void)
104write_backing_store (j_common_ptr cinfo, backing_store_ptr info,
105		     void FAR * buffer_address,
106		     long file_offset, long byte_count)
107{
108  memmove(info->addr + file_offset, buffer_address, byte_count);
109}
110
111
112METHODDEF(void)
113close_backing_store (j_common_ptr cinfo, backing_store_ptr info)
114{
115  munmap(info->addr, info->size);
116  close(info->temp_file);
117}
118
119LOCAL(int)
120get_ashmem(backing_store_ptr info, long total_bytes_needed)
121{
122  char path[1024];
123  snprintf(path, 1023, "%d.tmp.ashmem", getpid());
124  int fd = ashmem_create_region(path, total_bytes_needed);
125  if (fd == -1) {
126      return -1;
127  }
128  int err = ashmem_set_prot_region(fd, PROT_READ | PROT_WRITE);
129  if (err) {
130      return -1;
131  }
132  info->addr = mmap(NULL, total_bytes_needed, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
133  info->size = total_bytes_needed;
134  info->temp_file = fd;
135  return fd;
136}
137
138/*
139 * Initial opening of a backing-store object.
140 * This version uses ashmem to get a shared memory of total-bytes_needed.
141 */
142
143GLOBAL(void)
144jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
145			 long total_bytes_needed)
146{
147  if (get_ashmem(info, total_bytes_needed) == -1)
148    ERREXITS(cinfo, JERR_TFILE_CREATE, "");
149  info->read_backing_store = read_backing_store;
150  info->write_backing_store = write_backing_store;
151  info->close_backing_store = close_backing_store;
152}
153
154/*
155 * These routines take care of any system-dependent initialization and
156 * cleanup required.
157 */
158
159GLOBAL(long)
160jpeg_mem_init (j_common_ptr cinfo)
161{
162  return DEFAULT_MAX_MEM;	/* default for max_memory_to_use */
163}
164
165GLOBAL(void)
166jpeg_mem_term (j_common_ptr cinfo)
167{
168  /* no work */
169}
170