From 30c065998bba8abdf1ac8d649a6714ab5dc0cf76 Mon Sep 17 00:00:00 2001
From: Nguyen Anh Quynh <aquynh@gmail.com>
Date: Sat, 7 Jun 2014 13:30:59 +0800
Subject: [PATCH] optimize memset() of MCInst_Init()

---
 MCInst.c                  | 18 +++++++++++++++---
 MCInst.h                  |  2 +-
 arch/ARM/ARMInstPrinter.c |  2 +-
 cs.c                      |  2 +-
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/MCInst.c b/MCInst.c
index 3a70af70c9..865f4aac7f 100644
--- a/MCInst.c
+++ b/MCInst.c
@@ -10,9 +10,21 @@
 
 #define MCINST_CACHE (ARR_SIZE(mcInst->Operands) - 1)
 
-void MCInst_Init(MCInst *inst)
-{
-	memset(inst, 0, sizeof(*inst));
+void MCInst_Init(cs_struct *handle, MCInst *inst)
+{
+	switch(handle->arch) {
+		default:
+			memset(inst, 0, sizeof(*inst));
+			break;
+		case CS_ARCH_X86:
+			inst->size = 0;
+			inst->flat_insn.x86.op_count = 0;
+			if (handle->detail) {
+				memset(inst->flat_insn.x86.prefix, 0, sizeof(inst->flat_insn.x86.prefix));
+				memset(inst->flat_insn.x86.operands, 0, sizeof(inst->flat_insn.x86.operands));
+			}
+			break;
+	}
 }
 
 void MCInst_clear(MCInst *inst)
diff --git a/MCInst.h b/MCInst.h
index bd9b760f4b..4222df0c2d 100644
--- a/MCInst.h
+++ b/MCInst.h
@@ -156,7 +156,7 @@ struct MCInst {
 	uint8_t x86_prefix[4];
 };
 
-void MCInst_Init(MCInst *inst);
+void MCInst_Init(cs_struct *handle, MCInst *inst);
 
 void MCInst_clear(MCInst *inst);
 
diff --git a/arch/ARM/ARMInstPrinter.c b/arch/ARM/ARMInstPrinter.c
index d70bb1bb06..cfd9f4ae9a 100644
--- a/arch/ARM/ARMInstPrinter.c
+++ b/arch/ARM/ARMInstPrinter.c
@@ -550,7 +550,7 @@ void ARM_printInst(MCInst *MI, SStream *O, void *Info)
 				   	 MCInst NewMI;
 				   	 MCOperand *NewReg;
 
-					 MCInst_Init(&NewMI);
+					 MCInst_Init(MI->csh, &NewMI);
 				   	 MCInst_setOpcode(&NewMI, Opcode);
 
 				   	 if (isStore)
diff --git a/cs.c b/cs.c
index 3a388e27ce..aa3a350dbb 100644
--- a/cs.c
+++ b/cs.c
@@ -450,7 +450,7 @@ size_t cs_disasm_ex(csh ud, const uint8_t *buffer, size_t size, uint64_t offset,
 	offset_org = offset;
 
 	while (size > 0) {
-		MCInst_Init(&mci);
+		MCInst_Init(handle, &mci);
 		mci.csh = handle;
 
 		r = handle->disasm(ud, buffer, size, &mci, &insn_size, offset, handle->getinsn_info);