Provide memory manager overriding api

jcapimin.c

@@ -30,13 +30,15 @@
  * The error manager must already be set up (in case memory manager fails).
  */
 
-GLOBAL(void)
-jpeg_CreateCompress(j_compress_ptr cinfo, int version, size_t structsize)
+LOCAL(void)
+jpeg_create_compress_internal(j_compress_ptr cinfo, int version, size_t structsize, boolean withmem)
 {
   int i;
 
+  if (!withmem) {
+    cinfo->mem = NULL;            /* so jpeg_destroy knows mem mgr not called */
+  }
   /* Guard against version mismatches between library and caller. */
-  cinfo->mem = NULL;            /* so jpeg_destroy knows mem mgr not called */
   if (version != JPEG_LIB_VERSION)
     ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
   if (structsize != sizeof(struct jpeg_compress_struct))
@@ -52,14 +54,18 @@ jpeg_CreateCompress(j_compress_ptr cinfo, int version, size_t structsize)
   {
     struct jpeg_error_mgr *err = cinfo->err;
     void *client_data = cinfo->client_data; /* ignore Purify complaint here */
+    struct jpeg_memory_mgr *mem = cinfo->mem;
     MEMZERO(cinfo, sizeof(struct jpeg_compress_struct));
     cinfo->err = err;
     cinfo->client_data = client_data;
+    cinfo->mem = mem;
   }
   cinfo->is_decompressor = FALSE;
 
-  /* Initialize a memory manager instance for this object */
-  jinit_memory_mgr((j_common_ptr)cinfo);
+  if (cinfo->mem == NULL) {
+    /* Initialize a memory manager instance for this object */
+    jinit_memory_mgr((j_common_ptr)cinfo);
+  }
 
   /* Zero out pointers to permanent structures. */
   cinfo->progress = NULL;
@@ -94,6 +100,18 @@ jpeg_CreateCompress(j_compress_ptr cinfo, int version, size_t structsize)
   cinfo->global_state = CSTATE_START;
 }
 
+GLOBAL(void)
+jpeg_CreateCompressWithMem(j_compress_ptr cinfo, int version, size_t structsize)
+{
+  jpeg_create_compress_internal(cinfo, version, structsize, TRUE);
+}
+
+GLOBAL(void)
+jpeg_CreateCompress(j_compress_ptr cinfo, int version, size_t structsize)
+{
+  jpeg_create_compress_internal(cinfo, version, structsize, FALSE);
+}
+
 
 /*
  * Destruction of a JPEG compression object

jdapimin.c

@@ -30,13 +30,15 @@
  * The error manager must already be set up (in case memory manager fails).
  */
 
-GLOBAL(void)
-jpeg_CreateDecompress(j_decompress_ptr cinfo, int version, size_t structsize)
+LOCAL(void)
+jpeg_create_decompress_internal(j_decompress_ptr cinfo, int version, size_t structsize, boolean withmem)
 {
   int i;
 
+  if (!withmem) {
+    cinfo->mem = NULL;            /* so jpeg_destroy knows mem mgr not called */
+  }
   /* Guard against version mismatches between library and caller. */
-  cinfo->mem = NULL;            /* so jpeg_destroy knows mem mgr not called */
   if (version != JPEG_LIB_VERSION)
     ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
   if (structsize != sizeof(struct jpeg_decompress_struct))
@@ -52,14 +54,18 @@ jpeg_CreateDecompress(j_decompress_ptr cinfo, int version, size_t structsize)
   {
     struct jpeg_error_mgr *err = cinfo->err;
     void *client_data = cinfo->client_data; /* ignore Purify complaint here */
+    struct jpeg_memory_mgr *mem = cinfo->mem;
     MEMZERO(cinfo, sizeof(struct jpeg_decompress_struct));
     cinfo->err = err;
     cinfo->client_data = client_data;
+    cinfo->mem = mem;
   }
   cinfo->is_decompressor = TRUE;
 
-  /* Initialize a memory manager instance for this object */
-  jinit_memory_mgr((j_common_ptr)cinfo);
+  if (cinfo->mem == NULL) {
+    /* Initialize a memory manager instance for this object */
+    jinit_memory_mgr((j_common_ptr)cinfo);
+  }
 
   /* Zero out pointers to permanent structures. */
   cinfo->progress = NULL;
@@ -94,6 +100,18 @@ jpeg_CreateDecompress(j_decompress_ptr cinfo, int version, size_t structsize)
   MEMZERO(cinfo->master, sizeof(my_decomp_master));
 }
 
+GLOBAL(void)
+jpeg_CreateDecompressWithMem(j_decompress_ptr cinfo, int version, size_t structsize)
+{
+    jpeg_create_decompress_internal(cinfo, version, structsize, TRUE);
+}
+
+GLOBAL(void)
+jpeg_CreateDecompress(j_decompress_ptr cinfo, int version, size_t structsize)
+{
+    jpeg_create_decompress_internal(cinfo, version, structsize, FALSE);
+}
+
 
 /*
  * Destruction of a JPEG decompression object

jpeglib.h

@@ -903,10 +903,21 @@ EXTERN(struct jpeg_error_mgr *) jpeg_std_error(struct jpeg_error_mgr *err);
 #define jpeg_create_decompress(cinfo) \
   jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
                         (size_t)sizeof(struct jpeg_decompress_struct))
+#define jpeg_create_compress_with_mem(cinfo) \
+  jpeg_CreateCompressWithMem((cinfo), JPEG_LIB_VERSION, \
+                             (size_t)sizeof(struct jpeg_compress_struct))
+#define jpeg_create_decompress_with_mem(cinfo) \
+  jpeg_CreateDecompressWithMem((cinfo), JPEG_LIB_VERSION, \
+                               (size_t)sizeof(struct jpeg_decompress_struct))
+
 EXTERN(void) jpeg_CreateCompress(j_compress_ptr cinfo, int version,
                                  size_t structsize);
 EXTERN(void) jpeg_CreateDecompress(j_decompress_ptr cinfo, int version,
                                    size_t structsize);
+EXTERN(void) jpeg_CreateCompressWithMem(j_compress_ptr cinfo, int version,
+                                        size_t structsize);
+EXTERN(void) jpeg_CreateDecompressWithMem(j_decompress_ptr cinfo, int version,
+                                          size_t structsize);
 /* Destruction of JPEG compression objects */
 EXTERN(void) jpeg_destroy_compress(j_compress_ptr cinfo);
 EXTERN(void) jpeg_destroy_decompress(j_decompress_ptr cinfo);

libjpeg.txt

@@ -52,6 +52,7 @@ Advanced features:
         Really raw data: DCT coefficients
         Progress monitoring
         Memory management
+        Custom memory management
         Memory usage
         Library compile-time options
         Portability considerations
@@ -3000,6 +3001,23 @@ malloc()s and free()s virtual arrays, and an error occurs if the required
 memory exceeds the limit specified in cinfo->mem->max_memory_to_use.
 
 
+Custom memory management
+------------------------
+
+The default memory manager can be replaced with a custom one for special cases
+where the default memory manager is not sufficient. This is done by filling out
+the jpeg_memory_manager structure before calling one of the jpeg_create_
+functions. When the jpeg_create_ function is called it needs to be one of the
+_with_mem versions (jpeg_create_compress_with_mem or
+jpeg_create_decompress_with_mem).  If one of the jpeg_create_ functions that
+does not have _with_mem is called the custom memory manager will be replaced
+with the standard one, so it is important to call the _with_mem versions.
+
+The custom memory manager must fill out the jpeg_memory_manager structure with
+functions for all of the callbacks in the jpeg_memory_mgr structure, as these
+will all be called by libjpeg.
+
+
 Memory usage
 ------------
 
@@ -3045,7 +3063,6 @@ requested.
 If you need more detailed information about memory usage in a particular
 situation, you can enable the MEM_STATS code in jmemmgr.c.
 
-
 Library compile-time options
 ----------------------------
 

win/jpeg62-memsrcdst.def

@@ -106,3 +106,5 @@ EXPORTS
   jpeg_crop_scanline @ 105 ;
   jpeg_read_icc_profile @ 106 ;
   jpeg_write_icc_profile @ 107 ;
+  jpeg_CreateCompressWithMem @ 108 ;
+  jpeg_CreateDecompressWithMem @ 109 ;

win/jpeg62.def

@@ -104,3 +104,5 @@ EXPORTS
   jpeg_crop_scanline @ 103 ;
   jpeg_read_icc_profile @ 104 ;
   jpeg_write_icc_profile @ 105 ;
+  jpeg_CreateCompressWithMem @ 106 ;
+  jpeg_CreateDecompressWithMem @ 107 ;

win/jpeg7-memsrcdst.def

@@ -108,3 +108,5 @@ EXPORTS
   jpeg_crop_scanline @ 107 ;
   jpeg_read_icc_profile @ 108 ;
   jpeg_write_icc_profile @ 109 ;
+  jpeg_CreateCompressWithMem @ 110 ;
+  jpeg_CreateDecompressWithMem @ 111 ;

win/jpeg7.def

@@ -106,3 +106,5 @@ EXPORTS
   jpeg_crop_scanline @ 105 ;
   jpeg_read_icc_profile @ 106 ;
   jpeg_write_icc_profile @ 107 ;
+  jpeg_CreateCompressWithMem @ 108 ;
+  jpeg_CreateDecompressWithMem @ 109 ;

win/jpeg8.def

@@ -109,3 +109,5 @@ EXPORTS
   jpeg_crop_scanline @ 108 ;
   jpeg_read_icc_profile @ 109 ;
   jpeg_write_icc_profile @ 110 ;
+  jpeg_CreateCompressWithMem @ 111 ;
+  jpeg_CreateDecompressWithMem @ 112 ;