Gents,
Part 2 of the changes fed back from my experiments with making
Ghotscript work with lcms v2.
As far as I can see, there exists no way within the current API to
avoid the memory functions using malloc and free (unless you are
implementing a plugin, which we are not).
Lcms v2 appears to have gained some changes in this area over v1 that
are, I think, intended to allow different plugins to use different
families of allocation functions.
As far as I can see this code still ends up redirecting through a set
of static variables that hold function pointers. As such attempting
to use a single library instantiation simultaneously from multiple
different plugins will fail?
This is, currently at least, not a problem for us, however as we
statically link against a library and are hence sure that we will be
the only callers at a time.
The attached patch is a simple change that follows the approach we
took for lcms v1. If we define 'CMS_USER_ALLOC' when the lib is
built, we get to define cms{Malloc,Realloc,Free}DefaultFn, and the
library will link and use those.
This is working locally, and seems a relatively non-invasive change
to your library.
Thinking about again however, while writing this email, I wonder if a
better solution would not be to simply expose
_cmsRegisterMemHandlerPlugin (or something like it) to the outside
world. This would enable non-plugin callers to provide their own
malloc/realloc/free functions.
It would leave the library depending on malloc/realloc/free, but
they'd never be called. I suspect this is unlikely to ever be a
serious issue.
Thanks for your time and effort in creating a great library.
Robin
--
diff --git a/include/lcms2.h b/include/lcms2.h
index 16c1b46..6bb6055 100644
--- a/include/lcms2.h
+++ b/include/lcms2.h
@@ -52,6 +52,11 @@
// require "KEYWORD" on undefined identifiers, keep it comented out unless
needed
// #define CMS_STRICT_CGATS 1
+// Uncomment this line if you plan to provide the default cms malloc/realloc/
+// free functions outside of lcms.
+
+// #define CMS_USER_ALLOC 1
+
// ********** End of configuration toggles ******************************
// Needed for streams
@@ -1728,6 +1733,21 @@ CMSAPI cmsBool CMSEXPORT
cmsDesaturateLab(cmsCIELab* Lab,
double amax, double amin,
double bmax, double bmin);
+// Default memory handling
----------------------------------------------------------------------------------------
+
+#ifdef CMS_USER_ALLOC
+
+// If CMS_USER_ALLOC is defined, then the libraries environment will provide
+// the following 3 functions.
+
+void* cmsMallocDefaultFn(cmsContext ContextID, cmsUInt32Number size);
+
+void cmsFreeDefaultFn(cmsContext ContextID, void *Ptr);
+
+void* cmsReallocDefaultFn(cmsContext ContextID, void* Ptr, cmsUInt32Number
size);
+
+#endif
+
#ifndef CMS_USE_CPP_API
# ifdef __cplusplus
}
diff --git a/src/cmserr.c b/src/cmserr.c
index caa17e5..552af36 100644
--- a/src/cmserr.c
+++ b/src/cmserr.c
@@ -78,6 +78,15 @@ cmsBool _cmsRegisterMemHandlerPlugin(cmsPluginBase*
Plugin);
//
*********************************************************************************
+#ifdef CMS_USER_ALLOC
+
+// The following 3 functions will be provided by the libraries environment
+#define _cmsMallocDefaultFn cmsMallocDefaultFn
+#define _cmsFreeDefaultFn cmsFreeDefaultFn
+#define _cmsReallocDefaultFn cmsReallocDefaultFn
+
+#else
+
// This is the default memory allocation function. It does a very coarse
// check of amout of memory, just to prevent exploits
static
@@ -90,18 +99,6 @@ void* _cmsMallocDefaultFn(cmsContext ContextID,
cmsUInt32Number size)
cmsUNUSED_PARAMETER(ContextID);
}
-// Generic allocate & zero
-static
-void* _cmsMallocZeroDefaultFn(cmsContext ContextID, cmsUInt32Number size)
-{
- void *pt = _cmsMalloc(ContextID, size);
- if (pt == NULL) return NULL;
-
- memset(pt, 0, size);
- return pt;
-}
-
-
// The default free function. The only check proformed is against NULL pointers
static
void _cmsFreeDefaultFn(cmsContext ContextID, void *Ptr)
@@ -126,6 +123,19 @@ void* _cmsReallocDefaultFn(cmsContext ContextID, void*
Ptr, cmsUInt32Number size
cmsUNUSED_PARAMETER(ContextID);
}
+#endif
+
+
+// Generic allocate & zero
+static
+void* _cmsMallocZeroDefaultFn(cmsContext ContextID, cmsUInt32Number size)
+{
+ void *pt = _cmsMalloc(ContextID, size);
+ if (pt == NULL) return NULL;
+
+ memset(pt, 0, size);
+ return pt;
+}
// The default calloc function. Allocates an array of num elements, each one
of size bytes
------------------------------------------------------------------------------
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