Add ability to emulate malloc() and free() to prevent nasty hard to find link errors from C library routines that need malloc

5 files changed, 43 insertions, 2 deletions

diff --git a/gfxconf.example.h b/gfxconf.example.h
index 36b4cda4..c0b1cf6c 100644
--- a/gfxconf.example.h
+++ b/gfxconf.example.h
@@ -53,6 +53,7 @@
 //    #define GFX_OS_PRE_INIT_FUNCTION                 myHardwareInitRoutine
 //    #define GFX_OS_EXTRA_INIT_FUNCTION               myOSInitRoutine
 //    #define GFX_OS_EXTRA_DEINIT_FUNCTION             myOSDeInitRoutine
+//    #define GFX_EMULATE_MALLOC                       FALSE
 
 
 ///////////////////////////////////////////////////////////////////////////
diff --git a/src/gos/gos.h b/src/gos/gos.h
index 445e4b3a..172a813e 100644
--- a/src/gos/gos.h
+++ b/src/gos/gos.h
@@ -176,6 +176,23 @@
 	void gfxFree(void *ptr);
 
 	/**
+	 * @brief	Use gfxAlloc and gfxFree to implement malloc() and free()
+	 *
+	 * @notes	Sometimes your application will include functions that
+	 * 			want to internally use malloc() and free(). As the default
+	 * 			implementations of these in your C library are almost
+	 * 			invariably incorrect for an embedded platform, this option
+	 * 			allows you to emulate those calls with gfxAlloc() and gfxFree().
+	 *			An example is the C library routine rand() which on many
+	 *			implementations internally uses malloc().
+	 *
+	 * @api
+	 */
+	#ifndef GFX_EMULATE_MALLOC
+		#define GFX_EMULATE_MALLOC			FALSE
+	#endif
+
+	/**
 	 * @brief	Yield the current thread
 	 * @details	Give up the rest of the current time slice for this thread in order to give other threads
 	 * 			a chance to run.
diff --git a/src/gos/gos_options.h b/src/gos/gos_options.h
index 8a724e12..78b8781b 100644
--- a/src/gos/gos_options.h
+++ b/src/gos/gos_options.h
@@ -174,9 +174,10 @@
  		#define GFX_FREERTOS_USE_TRACE	FALSE
  	#endif
  	/**
- 	 * @brief	How much RAM should uGFX use for the heap
+ 	 * @brief	How much RAM should uGFX use for the heap when using its own internal heap allocator
  	 * @details	Defaults to 0.
- 	 * @note	Only used when the generic ugfx heap code is used (GFX_USE_OS_RAW32, GFX_USE_OS_ARDUINO, GFX_US_OS_KEIL, GFX_USE_OS_CMSIS)
+ 	 * @note	Only used when the internal ugfx heap allocator is used
+ 	 * 				(GFX_USE_OS_RAW32, GFX_USE_OS_ARDUINO, GFX_US_OS_KEIL, GFX_USE_OS_CMSIS)
  	 * @note	If 0 then the standard C runtime malloc(), free() and realloc()
  	 * 			are used.
  	 * @note	If it is non-zero then this is the number of bytes of RAM
diff --git a/src/gos/gos_rules.h b/src/gos/gos_rules.h
index 0f0f6596..de30befe 100644
--- a/src/gos/gos_rules.h
+++ b/src/gos/gos_rules.h
@@ -32,5 +32,16 @@
  	#error "GOS: GFX_FREERTOS_USE_TRACE is only available for the FreeRTOS port."
 #endif
 
+#if GFX_EMULATE_MALLOC
+	#if GFX_USE_OS_WIN32 || GFX_USE_OS_LINUX || GFX_USE_OS_OSX || GFX_USE_OS_ECOS || \
+			(GFX_OS_HEAP_SIZE == 0 && (GFX_USE_OS_RAW32 || GFX_USE_OS_ARDUINO || GFX_USE_OS_CMSIS || GFX_USE_OS_KEIL))
+		#if GFX_DISPLAY_RULE_WARNINGS
+			#warning "GOS: Cannot emulate malloc as gfxAlloc() internally uses malloc on this platform"
+		#endif
+		#undef GFX_EMULATE_MALLOC
+		#define GFX_EMULATE_MALLOC	FALSE
+	#endif
+#endif
+
 #endif /* _GOS_RULES_H */
 /** @} */
diff --git a/src/gos/gos_x_heap.c b/src/gos/gos_x_heap.c
index cd78f403..7e79d1c6 100644
--- a/src/gos/gos_x_heap.c
+++ b/src/gos/gos_x_heap.c
@@ -194,3 +194,14 @@
 #endif
 
 #endif /* GOS_NEED_X_HEAP */
+
+#if GFX_EMULATE_MALLOC
+	#include <stdlib.h>
+
+	void* malloc(size_t size) {
+		return gfxAlloc(size);
+	}
+	void free(void *ptr) {
+		gfxFree(ptr);
+	}
+#endif