Initial community commit

Src/external_dependencies/openmpt-trunk/libopenmpt/libopenmpt_stream_callbacks_fd.h

@@ -0,0 +1,101 @@
+/*
+ * libopenmpt_stream_callbacks_fd.h
+ * --------------------------------
+ * Purpose: libopenmpt public c interface
+ * Notes  : (currently none)
+ * Authors: OpenMPT Devs
+ * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
+ */
+
+#ifndef LIBOPENMPT_STREAM_CALLBACKS_FD_H
+#define LIBOPENMPT_STREAM_CALLBACKS_FD_H
+
+#include "libopenmpt.h"
+
+#ifdef _MSC_VER
+#include <io.h>
+#endif
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#ifndef _MSC_VER
+#include <unistd.h>
+#endif
+
+/*! \addtogroup libopenmpt_c
+ * @{
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* This stuff has to be in a header file because of possibly different MSVC CRTs which cause problems for fd crossing CRT boundaries. */
+
+static size_t openmpt_stream_fd_read_func( void * stream, void * dst, size_t bytes ) {
+	int fd = 0;
+	#if defined(_MSC_VER)
+		size_t retval = 0;
+		int to_read = 0;
+		int ret_read = 0;
+	#else
+		ssize_t retval = 0;
+	#endif
+	fd = (int)(uintptr_t)stream;
+	if ( fd < 0 ) {
+		return 0;
+	}
+	#if defined(_MSC_VER)
+		retval = 0;
+		while ( bytes > 0 ) {
+			to_read = 0;
+			if ( bytes < (size_t)INT_MAX ) {
+				to_read = (int)bytes;
+			} else {
+				to_read = INT_MAX;
+			}
+			ret_read = _read( fd, dst, to_read );
+			if ( ret_read <= 0 ) {
+				return retval;
+			}
+			bytes -= ret_read;
+			retval += ret_read;
+		}
+	#else
+		retval = read( fd, dst, bytes );
+	#endif
+	if ( retval <= 0 ) {
+		return 0;
+	}
+	return retval;
+}
+
+/*! \brief Provide openmpt_stream_callbacks for standard POSIX file descriptors
+ *
+ * Fills openmpt_stream_callbacks suitable for passing a POSIX filer descriptor as a stream parameter to functions doing file input/output.
+ *
+ * \remarks The stream argument must be passed as `(void*)(uintptr_t)(int)fd`.
+ * \sa \ref libopenmpt_c_fileio
+ * \sa openmpt_stream_callbacks
+ * \sa openmpt_could_open_probability2
+ * \sa openmpt_probe_file_header_from_stream
+ * \sa openmpt_module_create2
+ */
+static openmpt_stream_callbacks openmpt_stream_get_fd_callbacks(void) {
+	openmpt_stream_callbacks retval;
+	memset( &retval, 0, sizeof( openmpt_stream_callbacks ) );
+	retval.read = openmpt_stream_fd_read_func;
+	return retval;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+/*!
+ * @}
+ */
+
+#endif /* LIBOPENMPT_STREAM_CALLBACKS_FD_H */
+