8 files changed, 221 insertions, 26 deletions
diff --git a/include/cru/common/Exception.h b/include/cru/common/Exception.h
index 365d2064..6f458d35 100644
--- a/include/cru/common/Exception.h
+++ b/include/cru/common/Exception.h
@@ -29,4 +29,21 @@ class CRU_BASE_API TextEncodeException : public Exception {
  public:
   using Exception::Exception;
 };
+
+class ErrnoException : public Exception {
+ public:
+  ErrnoException() : ErrnoException(String{}) {}
+  explicit ErrnoException(const String& message);
+  ErrnoException(const String& message, int errno_code);
+
+  CRU_DELETE_COPY(ErrnoException)
+  CRU_DELETE_MOVE(ErrnoException)
+
+  ~ErrnoException() override = default;
+
+  int GetErrnoCode() const { return errno_code_; }
+
+ private:
+  int errno_code_;
+};
 }  // namespace cru
diff --git a/include/cru/common/io/CFileStream.h b/include/cru/common/io/CFileStream.h
new file mode 100644
index 00000000..65de2ac7
--- /dev/null
+++ b/include/cru/common/io/CFileStream.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include "Stream.h"
+
+#include <cstdio>
+
+namespace cru::io {
+class CRU_BASE_API CFileStream : public Stream {
+ public:
+  CFileStream(const char* path, const char* mode);
+  explicit CFileStream(std::FILE* file, bool readable = true,
+                       bool writable = true, bool auto_close = true);
+
+  CRU_DELETE_COPY(CFileStream)
+  CRU_DELETE_MOVE(CFileStream)
+
+  ~CFileStream() override;
+
+ public:
+  bool CanSeek() override;
+  Index Seek(Index offset, SeekOrigin origin = SeekOrigin::Current) override;
+  Index Tell() override;
+  void Rewind() override;
+
+  bool CanRead() override;
+  Index Read(std::byte* buffer, Index offset, Index size) override;
+
+  bool CanWrite() override;
+  Index Write(const std::byte* buffer, Index offset, Index size) override;
+
+  void Flush() override;
+
+  void Close() override;
+
+  std::FILE* GetHandle() const;
+
+ private:
+  void CheckClosed();
+
+ private:
+  std::FILE* file_;
+  bool readable_;
+  bool writable_;
+  bool auto_close_;
+};
+}  // namespace cru::io
diff --git a/include/cru/common/io/Stream.h b/include/cru/common/io/Stream.h
index 66be4468..f833b0b9 100644
--- a/include/cru/common/io/Stream.h
+++ b/include/cru/common/io/Stream.h
@@ -2,12 +2,23 @@
 
 #include "../Base.h"
 
+#include "../Exception.h"
 #include "../String.h"
 
 #include <cstddef>
 #include <vector>
 
 namespace cru::io {
+class CRU_BASE_API StreamAlreadyClosedException : public Exception {
+ public:
+  using Exception::Exception;
+
+  CRU_DEFAULT_COPY(StreamAlreadyClosedException)
+  CRU_DEFAULT_MOVE(StreamAlreadyClosedException)
+
+  CRU_DEFAULT_DESTRUCTOR(StreamAlreadyClosedException)
+};
+
 class CRU_BASE_API Stream : public Object {
  public:
   enum class SeekOrigin { Current, Begin, End };
diff --git a/include/cru/common/platform/unix/ErrnoException.h b/include/cru/common/platform/unix/ErrnoException.h
index 00e1864b..97edcc78 100644
--- a/include/cru/common/platform/unix/ErrnoException.h
+++ b/include/cru/common/platform/unix/ErrnoException.h
@@ -7,22 +7,8 @@
 #include "../Exception.h"
 
 namespace cru::platform::unix {
-class ErrnoException : public PlatformException {
- public:
-  ErrnoException() : ErrnoException(String{}) {}
-  explicit ErrnoException(const String& message);
-  ErrnoException(const String& message, int errno_code);
-
-  CRU_DELETE_COPY(ErrnoException)
-  CRU_DELETE_MOVE(ErrnoException)
-
-  ~ErrnoException() override = default;
-
-  int GetErrnoCode() const { return errno_code_; }
-
- private:
-  int errno_code_;
-};
+// Moved to Exception.h
+using ErrnoException = cru::ErrnoException;
 }  // namespace cru::platform::unix
 
 #endif
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index fb2dd471..2c7f28e0 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -6,6 +6,7 @@ add_library(CruBase
 	String.cpp
 	StringToNumberConverter.cpp
 	StringUtil.cpp
+	io/CFileStream.cpp
 	io/Stream.cpp
 	io/Resource.cpp
 	io/MemoryStream.cpp
diff --git a/src/common/Exception.cpp b/src/common/Exception.cpp
index 86816720..b0053bac 100644
--- a/src/common/Exception.cpp
+++ b/src/common/Exception.cpp
@@ -1,5 +1,9 @@
 #include "cru/common/Exception.h"
 
+#include "cru/common/Format.h"
+
+#include <cerrno>
+
 namespace cru {
 Exception::Exception() {}
 
@@ -14,4 +18,11 @@ const char* Exception::what() const noexcept {
 
   return utf8_message_.c_str();
 }
+
+ErrnoException::ErrnoException(const String& message)
+    : ErrnoException(message, errno) {}
+
+ErrnoException::ErrnoException(const String& message, int errno_code)
+    : Exception(Format(u"{}. Errno is {}.", message, errno_code)),
+      errno_code_(errno_code) {}
 }  // namespace cru
diff --git a/src/common/io/CFileStream.cpp b/src/common/io/CFileStream.cpp
new file mode 100644
index 00000000..de195538
--- /dev/null
+++ b/src/common/io/CFileStream.cpp
@@ -0,0 +1,132 @@
+#include "cru/common/io/CFileStream.h"
+#include "cru/common/Exception.h"
+#include "cru/common/io/Stream.h"
+
+#include <cstdio>
+
+namespace cru::io {
+static bool ModeCanRead(const char* mode) {
+  for (const char* p = mode; *p != '\0'; p++) {
+    if (*p == 'r' || *p == '+') {
+      return true;
+    }
+  }
+  return false;
+}
+
+static bool ModeCanWrite(const char* mode) {
+  for (const char* p = mode; *p != '\0'; p++) {
+    if (*p == 'w' || *p == 'a' || *p == '+') {
+      return true;
+    }
+  }
+  return false;
+}
+
+CFileStream::CFileStream(const char* path, const char* mode)
+    : file_(std::fopen(path, mode)),
+      readable_(ModeCanRead(mode)),
+      writable_(ModeCanWrite(mode)),
+      auto_close_(true) {
+  if (file_ == nullptr) {
+    throw ErrnoException(u"Cannot open file.");
+  }
+}
+
+CFileStream::CFileStream(std::FILE* file, bool readable, bool writable,
+                         bool auto_close)
+    : file_(file),
+      readable_(readable),
+      writable_(writable),
+      auto_close_(auto_close) {
+  if (file_ == nullptr) {
+    throw Exception(u"File is NULL.");
+  }
+}
+
+CFileStream::~CFileStream() {
+  if (auto_close_ && file_ != nullptr) {
+    std::fclose(file_);
+  }
+}
+
+bool CFileStream::CanSeek() {
+  CheckClosed();
+  return true;
+}
+
+static int ConvertOriginFlag(Stream::SeekOrigin origin) {
+  switch (origin) {
+    case Stream::SeekOrigin::Begin:
+      return SEEK_SET;
+    case Stream::SeekOrigin::Current:
+      return SEEK_CUR;
+    case Stream::SeekOrigin::End:
+      return SEEK_END;
+    default:
+      throw Exception(u"Unknown seek origin.");
+  }
+}
+
+Index CFileStream::Seek(Index offset, SeekOrigin origin) {
+  CheckClosed();
+  if (std::fseek(file_, offset, ConvertOriginFlag(origin))) {
+    throw ErrnoException(u"Seek failed.");
+  }
+  return Tell();
+}
+
+Index CFileStream::Tell() {
+  CheckClosed();
+  long position = std::ftell(file_);
+  if (position == -1) {
+    throw ErrnoException(u"Tell failed.");
+  }
+  return position;
+}
+
+void CFileStream::Rewind() {
+  CheckClosed();
+  std::rewind(file_);
+}
+
+bool CFileStream::CanRead() {
+  CheckClosed();
+  return readable_;
+}
+
+Index CFileStream::Read(std::byte* buffer, Index offset, Index size) {
+  CheckClosed();
+  auto count = std::fread(buffer + offset, 1, size, file_);
+  return count;
+}
+
+bool CFileStream::CanWrite() {
+  CheckClosed();
+  return writable_;
+}
+
+Index CFileStream::Write(const std::byte* buffer, Index offset, Index size) {
+  CheckClosed();
+  auto count = std::fwrite(buffer + offset, 1, size, file_);
+  return count;
+}
+
+void CFileStream::Flush() {
+  CheckClosed();
+  std::fflush(file_);
+}
+
+void CFileStream::Close() {
+  if (file_ != nullptr) {
+    std::fclose(file_);
+    file_ = nullptr;
+  }
+}
+
+void CFileStream::CheckClosed() {
+  if (file_ == nullptr) {
+    throw StreamAlreadyClosedException(u"File is closed.");
+  }
+}
+}  // namespace cru::io
diff --git a/src/common/platform/unix/ErrnoException.cpp b/src/common/platform/unix/ErrnoException.cpp
index f2171943..06c42ff6 100644
--- a/src/common/platform/unix/ErrnoException.cpp
+++ b/src/common/platform/unix/ErrnoException.cpp
@@ -1,14 +1,5 @@
 #include "cru/common/platform/unix/ErrnoException.h"
 
-#include "cru/common/Format.h"
-
-#include <errno.h>
-
 namespace cru::platform::unix {
-ErrnoException::ErrnoException(const String& message)
-    : ErrnoException(message, errno) {}
-
-ErrnoException::ErrnoException(const String& message, int errno_code)
-    : PlatformException(Format(u"{}. Errno is {}.", message, errno_code)),
-      errno_code_(errno_code) {}
+// Moved to Exception.cpp
 }  // namespace cru::platform::unix