Courgette: Add static method QuickDetect() to optimize program detection.

courgette/program_detector.cc

Index: courgette/program_detector.cc
diff --git a/courgette/program_detector.cc b/courgette/program_detector.cc
index 60b295fef7a82825c7e2f097c22c9fd55b87446c..e659522265b18728365a71e253eb1ed02bbc4368 100644
--- a/courgette/program_detector.cc
+++ b/courgette/program_detector.cc
@@ -23,22 +23,26 @@ std::unique_ptr<Disassembler> DetectDisassembler(const void* buffer,
                                                  size_t length) {
   std::unique_ptr<Disassembler> disassembler;
 
-  disassembler.reset(new DisassemblerWin32X86(buffer, length));
-  if (disassembler->ParseHeader())
-    return disassembler;
-
-  disassembler.reset(new DisassemblerWin32X64(buffer, length));
-  if (disassembler->ParseHeader())
-    return disassembler;
-
-  disassembler.reset(new DisassemblerElf32X86(buffer, length));
-  if (disassembler->ParseHeader())
-    return disassembler;
-
-  disassembler.reset(new DisassemblerElf32ARM(buffer, length));
-  if (disassembler->ParseHeader())
-    return disassembler;
-
+  if (DisassemblerWin32X86::QuickDetects(buffer, length)) {

[huangs, 2016/06/10 21:10:22]

NIT: Rename to QuickDetect() (verb).

[etiennep, 2016/06/13 17:50:22]

Done.

+    disassembler.reset(new DisassemblerWin32X86(buffer, length));
+    if (disassembler->ParseHeader())
+      return disassembler;
+  }
+  if (DisassemblerWin32X64::QuickDetects(buffer, length)) {
+    disassembler.reset(new DisassemblerWin32X64(buffer, length));
+    if (disassembler->ParseHeader())
+      return disassembler;
+  }
+  if (DisassemblerElf32X86::QuickDetects(buffer, length)) {
+    disassembler.reset(new DisassemblerElf32X86(buffer, length));
+    if (disassembler->ParseHeader())
+      return disassembler;
+  }
+  if (DisassemblerElf32ARM::QuickDetects(buffer, length)) {
+    disassembler.reset(new DisassemblerElf32ARM(buffer, length));
+    if (disassembler->ParseHeader())
+      return disassembler;
+  }
   return nullptr;
 }