intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 68 insertions, 0 deletions

diff --git a/util/system/src_root.h b/util/system/src_root.h
new file mode 100644
index 00000000000..4f2d9f5ee6c
--- /dev/null
+++ b/util/system/src_root.h
@@ -0,0 +1,68 @@
+#pragma once
+
+#include "compiler.h"
+#include "defaults.h"
+
+#include <type_traits>
+
+namespace NPrivate {
+    struct TStaticBuf {
+        constexpr TStaticBuf(const char* data, unsigned len) noexcept
+            : Data(data)
+            , Len(len)
+        {
+        }
+
+        template <class T>
+        constexpr T As() const noexcept {
+            return T(Data, Len);
+        }
+
+        template <class T>
+        constexpr operator T() const noexcept {
+            return this->As<T>();
+        }
+
+        const char* Data;
+        unsigned Len;
+    };
+
+#define STATIC_BUF(x) ::NPrivate::TStaticBuf(x, sizeof(x) - 1)
+
+    constexpr TStaticBuf ArcRoot = STATIC_BUF(Y_STRINGIZE(ARCADIA_ROOT));
+    constexpr TStaticBuf BuildRoot = STATIC_BUF(Y_STRINGIZE(ARCADIA_BUILD_ROOT));
+
+    constexpr Y_FORCE_INLINE bool IsProperPrefix(const TStaticBuf prefix, const TStaticBuf string) noexcept {
+        if (prefix.Len < string.Len) {
+            for (unsigned i = prefix.Len; i-- > 0;) {
+                if (prefix.Data[i] != string.Data[i]) {
+                    return false;
+                }
+            }
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    constexpr unsigned RootPrefixLength(const TStaticBuf& f) noexcept {
+        if (IsProperPrefix(ArcRoot, f)) {
+            return ArcRoot.Len + 1;
+        }
+        if (IsProperPrefix(BuildRoot, f)) {
+            return BuildRoot.Len + 1;
+        }
+        return 0;
+    }
+
+    constexpr Y_FORCE_INLINE TStaticBuf StripRoot(const TStaticBuf& f, unsigned prefixLength) noexcept {
+        return TStaticBuf(f.Data + prefixLength, f.Len - prefixLength);
+    }
+
+    //$(SRC_ROOT)/prj/blah.cpp -> prj/blah.cpp
+    constexpr Y_FORCE_INLINE TStaticBuf StripRoot(const TStaticBuf& f) noexcept {
+        return StripRoot(f, RootPrefixLength(f));
+    }
+}
+
+#define __SOURCE_FILE_IMPL__ ::NPrivate::StripRoot(STATIC_BUF(__FILE__), std::integral_constant<unsigned, ::NPrivate::RootPrefixLength(STATIC_BUF(__FILE__))>::value)