1 files changed, 75 insertions, 0 deletions
diff --git a/src/port/win32fseek.c b/src/port/win32fseek.c
new file mode 100644
index 0000000..985313c
--- /dev/null
+++ b/src/port/win32fseek.c
@@ -0,0 +1,75 @@
+/*-------------------------------------------------------------------------
+ *
+ * win32fseek.c
+ *	  Replacements for fseeko() and ftello().
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  src/port/win32fseek.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifdef FRONTEND
+#include "postgres_fe.h"
+#else
+#include "postgres.h"
+#endif
+
+#if defined(WIN32) && defined(_MSC_VER)
+
+/*
+ * _pgfseeko64
+ *
+ * Calling fseek() on a handle to a non-seeking device such as a pipe or
+ * a communications device is not supported, and fseek() may not return
+ * an error.  This wrapper relies on the file type to check which cases
+ * are supported.
+ */
+int
+_pgfseeko64(FILE *stream, pgoff_t offset, int origin)
+{
+	DWORD		fileType;
+	HANDLE		hFile = (HANDLE) _get_osfhandle(_fileno(stream));
+
+	fileType = pgwin32_get_file_type(hFile);
+	if (errno != 0)
+		return -1;
+
+	if (fileType == FILE_TYPE_DISK)
+		return _fseeki64(stream, offset, origin);
+	else if (fileType == FILE_TYPE_CHAR || fileType == FILE_TYPE_PIPE)
+		errno = ESPIPE;
+	else
+		errno = EINVAL;
+
+	return -1;
+}
+
+/*
+ * _pgftello64
+ *
+ * Same as _pgfseeko64().
+ */
+pgoff_t
+_pgftello64(FILE *stream)
+{
+	DWORD		fileType;
+	HANDLE		hFile = (HANDLE) _get_osfhandle(_fileno(stream));
+
+	fileType = pgwin32_get_file_type(hFile);
+	if (errno != 0)
+		return -1;
+
+	if (fileType == FILE_TYPE_DISK)
+		return _ftelli64(stream);
+	else if (fileType == FILE_TYPE_CHAR || fileType == FILE_TYPE_PIPE)
+		errno = ESPIPE;
+	else
+		errno = EINVAL;
+
+	return -1;
+}
+
+#endif							/* defined(WIN32) && defined(_MSC_VER) */