BLI_Buffer: support over 2gb allocations

Also move comment to C-source and enumerate useful features.

source/blender/blenkernel/intern/mesh_mapping.c

@@ -97,7 +97,7 @@ UvVertMap *BKE_mesh_uv_vert_map_create(
 			float (*tf_uv)[2] = NULL;
 
 			if (use_winding) {
-				tf_uv = (float (*)[2])BLI_buffer_resize_data(&tf_uv_buf, vec2f, mp->totloop);
+				tf_uv = (float (*)[2])BLI_buffer_resize_data(&tf_uv_buf, vec2f, (size_t)mp->totloop);
 			}
 
 			nverts = mp->totloop;

source/blender/blenlib/BLI_buffer.h

@@ -23,27 +23,12 @@
 
 /** \file BLI_buffer.h
  *  \ingroup bli
- *
- * \note this more or less fills same purpose as BLI_array, but makes
- * it much easier to resize the array outside of the function it was
- * declared in since.
- *
- * Usage examples:
- * \code{.c}
- * BLI_buffer_declare_static(int, my_int_array, BLI_BUFFER_NOP, 32);
- *
- * BLI_buffer_append(my_int_array, int, 42);
- * assert(my_int_array.count == 1);
- * assert(BLI_buffer_at(my_int_array, int, 0) == 42);
- *
- * BLI_buffer_free(&my_int_array);
- * \endcode
  */
 
 typedef struct {
 	void *data;
-	const int elem_size;
-	int count, alloc_count;
+	const size_t elem_size;
+	size_t count, alloc_count;
 	int flag;
 } BLI_Buffer;
 
@@ -98,7 +83,7 @@ enum {
 } (void)0
 
 /* Never decreases the amount of memory allocated */
-void BLI_buffer_resize(BLI_Buffer *buffer, int new_count);
+void BLI_buffer_resize(BLI_Buffer *buffer, const size_t new_count);
 
 /* Does not free the buffer structure itself */
 void _bli_buffer_free(BLI_Buffer *buffer);

source/blender/blenlib/intern/buffer.c

@@ -20,30 +20,55 @@
 
 /** \file blender/blenlib/intern/buffer.c
  *  \ingroup bli
+ *
+ * Primitive generic buffer library.
+ *
+ * - Automatically grow as needed.
+ *   (currently never shrinks).
+ * - Can be passed between functions.
+ * - Supports using stack memory by default,
+ *   falling back to heap as needed.
+ *
+ * Usage examples:
+ * \code{.c}
+ * BLI_buffer_declare_static(int, my_int_array, BLI_BUFFER_NOP, 32);
+ *
+ * BLI_buffer_append(my_int_array, int, 42);
+ * assert(my_int_array.count == 1);
+ * assert(BLI_buffer_at(my_int_array, int, 0) == 42);
+ *
+ * BLI_buffer_free(&my_int_array);
+ * \endcode
+ *
+ * \note this more or less fills same purpose as #BLI_array,
+ * but supports resizing the array outside of the function
+ * it was declared in.
  */
 
+#include <string.h>
+
 #include "MEM_guardedalloc.h"
 
 #include "BLI_buffer.h"
 #include "BLI_utildefines.h"
 
-#include <string.h>
+#include "BLI_strict_flags.h"
 
-static void *buffer_alloc(BLI_Buffer *buffer, int len)
+static void *buffer_alloc(BLI_Buffer *buffer, const size_t len)
 {
 	return ((buffer->flag & BLI_BUFFER_USE_CALLOC) ?
 	        MEM_callocN : MEM_mallocN)
 	        (buffer->elem_size * len, "BLI_Buffer.data");
 }
 
-static void *buffer_realloc(BLI_Buffer *buffer, int len)
+static void *buffer_realloc(BLI_Buffer *buffer, const size_t len)
 {
 	return ((buffer->flag & BLI_BUFFER_USE_CALLOC) ?
 	        MEM_recallocN_id : MEM_reallocN_id)
 	        (buffer->data, buffer->elem_size * len, "BLI_Buffer.data");
 }
 
-void BLI_buffer_resize(BLI_Buffer *buffer, int new_count)
+void BLI_buffer_resize(BLI_Buffer *buffer, const size_t new_count)
 {
 	if (UNLIKELY(new_count > buffer->alloc_count)) {
 		if (buffer->flag & BLI_BUFFER_USE_STATIC) {