Add initial support of ELF files

1 files changed, 55 insertions, 0 deletions

diff --git a/elf_image.h b/elf_image.h
new file mode 100644
index 0000000..b7c7123
--- /dev/null
+++ b/elf_image.h
@@ -0,0 +1,55 @@
+#pragma once
+
+/* SPDX-License-Identifier: Unlicense
+ */
+
+#include "elf_format.h"
+#include "data_buffer.h"
+
+#include <cstdlib>
+
+namespace ELF {
+
+struct ProgramHeader32Table {
+    const ProgramHeader32 *headers{};
+    size_t size{};
+    static ProgramHeader32Table FromBytes(const DataView &, DataEncoding);
+};
+
+struct Segment {
+    Segment *next{};
+    const DataView view{};
+};
+
+class Image {
+    const DataBuffer _data;
+    char *const _error;
+    const Header32 _h;
+    const ProgramHeader32Table _pht;
+public:
+    explicit Image(DataBuffer&&);
+    ~Image();
+    constexpr bool IsValid() const { return _error == nullptr; }
+    constexpr const DataBuffer &Data() const { return _data; };
+    constexpr const DataView ProgramView() const
+    {
+        if (!IsValid()) {
+            return DataView{};
+        }
+        for (size_t i = 0; i < _pht.size; i++) {
+            const auto ph = _pht.headers[i];
+            const bool is_code = (ph.flags & (kPHFlagX | kPHFlagW | kPHFlagR)) ==
+                (kPHFlagX | kPHFlagR);
+            const bool is_load = ParsePHType(ph.type) == PHType::kLoad;
+            const bool contains_entry = _h.entry >= ph.vaddr && _h.entry < ph.vaddr + ph.memsz;
+            if (is_load && is_code && ph.vaddr == 0 && contains_entry)
+            {
+                return _data.View(ph.offset, ph.filesz);
+            }
+        }
+        return DataView{};
+    };
+    constexpr const char *Error() const { return _error; }
+};
+
+}