Home | History | Annotate | Download | only in libjpeg-turbo 
      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, 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 (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 }
    116