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      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() */
     26 extern void * malloc JPP((size_t size));
     27 extern 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 
     35 GLOBAL(void *)
     36 jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)
     37 {
     38   return (void *) malloc(sizeofobject);
     39 }
     40 
     41 GLOBAL(void)
     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 *)
     56 jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
     57 {
     58   return (void FAR *) malloc(sizeofobject);
     59 }
     60 
     61 GLOBAL(void)
     62 jpeg_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 
     79 GLOBAL(long)
     80 jpeg_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 
     94 METHODDEF(void)
     95 read_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 
    103 METHODDEF(void)
    104 write_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 
    112 METHODDEF(void)
    113 close_backing_store (j_common_ptr cinfo, backing_store_ptr info)
    114 {
    115   munmap(info->addr, info->size);
    116   close(info->temp_file);
    117 }
    118 
    119 LOCAL(int)
    120 get_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 
    143 GLOBAL(void)
    144 jpeg_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 
    159 GLOBAL(long)
    160 jpeg_mem_init (j_common_ptr cinfo)
    161 {
    162   return DEFAULT_MAX_MEM;	/* default for max_memory_to_use */
    163 }
    164 
    165 GLOBAL(void)
    166 jpeg_mem_term (j_common_ptr cinfo)
    167 {
    168   /* no work */
    169 }
    170