diff --git a/src/base/system.cpp b/src/base/system.cpp
index a65651211..3e70e8d68 100644
--- a/src/base/system.cpp
+++ b/src/base/system.cpp
@@ -208,21 +208,39 @@ void dbg_msg(const char *sys, const char *fmt, ...)
 
 /* */
 
-void mem_copy(void *dest, const void *source, unsigned size)
+void mem_copy(void *dest, const void *source, size_t size)
 {
 	memcpy(dest, source, size);
 }
 
-void mem_move(void *dest, const void *source, unsigned size)
+void mem_move(void *dest, const void *source, size_t size)
 {
 	memmove(dest, source, size);
 }
 
-void mem_zero(void *block, unsigned size)
+void mem_zero(void *block, size_t size)
 {
 	memset(block, 0, size);
 }
 
+int mem_comp(const void *a, const void *b, size_t size)
+{
+	return memcmp(a, b, size);
+}
+
+bool mem_has_null(const void *block, size_t size)
+{
+	const unsigned char *bytes = (const unsigned char *)block;
+	for(size_t i = 0; i < size; i++)
+	{
+		if(bytes[i] == 0)
+		{
+			return true;
+		}
+	}
+	return false;
+}
+
 IOHANDLE io_open_impl(const char *filename, int flags)
 {
 	dbg_assert(flags == (IOFLAG_READ | IOFLAG_SKIP_BOM) || flags == IOFLAG_READ || flags == IOFLAG_WRITE || flags == IOFLAG_APPEND, "flags must be read, read+skipbom, write or append");
@@ -3426,25 +3444,6 @@ void str_escape(char **dst, const char *src, const char *end)
 	**dst = 0;
 }
 
-int mem_comp(const void *a, const void *b, int size)
-{
-	return memcmp(a, b, size);
-}
-
-int mem_has_null(const void *block, unsigned size)
-{
-	const unsigned char *bytes = (const unsigned char *)block;
-	unsigned i;
-	for(i = 0; i < size; i++)
-	{
-		if(bytes[i] == 0)
-		{
-			return 1;
-		}
-	}
-	return 0;
-}
-
 void net_stats(NETSTATS *stats_inout)
 {
 	*stats_inout = network_stats;
diff --git a/src/base/system.h b/src/base/system.h
index 6ffcb1d6e..4b2a3ea7c 100644
--- a/src/base/system.h
+++ b/src/base/system.h
@@ -131,7 +131,7 @@ void dbg_msg(const char *sys, const char *fmt, ...)
  *
  * @see mem_move
  */
-void mem_copy(void *dest, const void *source, unsigned size);
+void mem_copy(void *dest, const void *source, size_t size);
 
 /**
  * Copies a a memory block.
@@ -146,7 +146,7 @@ void mem_copy(void *dest, const void *source, unsigned size);
  *
  * @see mem_copy
  */
-void mem_move(void *dest, const void *source, unsigned size);
+void mem_move(void *dest, const void *source, size_t size);
 
 /**
  * Sets a complete memory block to 0.
@@ -156,7 +156,7 @@ void mem_move(void *dest, const void *source, unsigned size);
  * @param block Pointer to the block to zero out.
  * @param size Size of the block.
  */
-void mem_zero(void *block, unsigned size);
+void mem_zero(void *block, size_t size);
 
 /**
  * Compares two blocks of memory
@@ -171,7 +171,7 @@ void mem_zero(void *block, unsigned size);
  * @return 0 - Block a is equal to block b.
  * @return > 0 - Block a is greater than block b.
  */
-int mem_comp(const void *a, const void *b, int size);
+int mem_comp(const void *a, const void *b, size_t size);
 
 /**
  * Checks whether a block of memory contains null bytes.
@@ -181,10 +181,9 @@ int mem_comp(const void *a, const void *b, int size);
  * @param block Pointer to the block to check for nulls.
  * @param size Size of the block.
  *
- * @return 1 - The block has a null byte.
- * @return 0 - The block does not have a null byte.
+ * @return true if the block has a null byte, false otherwise.
  */
-int mem_has_null(const void *block, unsigned size);
+bool mem_has_null(const void *block, size_t size);
 
 /**
  * @defgroup File-IO
diff --git a/src/engine/client/text.cpp b/src/engine/client/text.cpp
index 443e624d8..3c8e0df41 100644
--- a/src/engine/client/text.cpp
+++ b/src/engine/client/text.cpp
@@ -540,7 +540,7 @@ class CTextRender : public IEngineTextRender
 		if(Width > 0 && Height > 0)
 		{
 			// prepare glyph data
-			mem_zero(ms_aGlyphData, Width * Height);
+			mem_zero(ms_aGlyphData, (size_t)Width * Height);
 
 			for(py = 0; py < pBitmap->rows; py++)
 				for(px = 0; px < pBitmap->width; px++)
diff --git a/src/game/editor/io.cpp b/src/game/editor/io.cpp
index b5fd115a5..63eebb7a9 100644
--- a/src/game/editor/io.cpp
+++ b/src/game/editor/io.cpp
@@ -511,8 +511,9 @@ bool CEditorMap::Load(class IStorage *pStorage, const char *pFileName, int Stora
 
 					// copy image data
 					void *pData = DataFile.GetData(pItem->m_ImageData);
-					pImg->m_pData = malloc((size_t)pImg->m_Width * pImg->m_Height * 4);
-					mem_copy(pImg->m_pData, pData, pImg->m_Width * pImg->m_Height * 4);
+					const size_t DataSize = (size_t)pImg->m_Width * pImg->m_Height * 4;
+					pImg->m_pData = malloc(DataSize);
+					mem_copy(pImg->m_pData, pData, DataSize);
 					int TextureLoadFlag = m_pEditor->Graphics()->HasTextureArrays() ? IGraphics::TEXLOAD_TO_2D_ARRAY_TEXTURE : IGraphics::TEXLOAD_TO_3D_TEXTURE;
 					if(pImg->m_Width % 16 != 0 || pImg->m_Height % 16 != 0)
 						TextureLoadFlag = 0;
diff --git a/src/tools/map_optimize.cpp b/src/tools/map_optimize.cpp
index 9602703ca..c0ac1b8bf 100644
--- a/src/tools/map_optimize.cpp
+++ b/src/tools/map_optimize.cpp
@@ -250,7 +250,7 @@ int main(int argc, const char **argv)
 				}
 				else if(aImageFlags[ImageIndex] == 0)
 				{
-					mem_zero(pImgBuff, Width * Height * 4);
+					mem_zero(pImgBuff, (size_t)Width * Height * 4);
 				}
 				else
 				{