Add Windows implementation for sqfs_file_t

This commit moves the generic unix implementation into a "unix"
subdirectory and adds a "win32" subdirectory with a winapi based
implementation.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

3 files changed, 177 insertions, 1 deletions

diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index 3742f7f..821f22a 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -10,7 +10,7 @@ LIBSQFS_HEARDS = include/sqfs/meta_writer.h \
 		include/sqfs/xattr_reader.h include/sqfs/xattr_writer.h
 
 libsquashfs_la_SOURCES = $(LIBSQFS_HEARDS) lib/sqfs/id_table.c lib/sqfs/super.c
-libsquashfs_la_SOURCES += lib/sqfs/readdir.c lib/sqfs/io_file.c lib/sqfs/xattr.c
+libsquashfs_la_SOURCES += lib/sqfs/readdir.c lib/sqfs/xattr.c
 libsquashfs_la_SOURCES += lib/sqfs/write_table.c lib/sqfs/meta_writer.c
 libsquashfs_la_SOURCES += lib/sqfs/read_super.c lib/sqfs/meta_reader.c
 libsquashfs_la_SOURCES += lib/sqfs/read_inode.c lib/sqfs/write_inode.c
@@ -30,6 +30,12 @@ libsquashfs_la_CFLAGS += $(ZSTD_CFLAGS) $(PTHREAD_CFLAGS)
 libsquashfs_la_LIBADD = $(XZ_LIBS) $(ZLIB_LIBS) $(LZO_LIBS) $(LZ4_LIBS)
 libsquashfs_la_LIBADD += $(ZSTD_LIBS) $(PTHREAD_LIBS) libutil.la
 
+if WINDOWS
+libsquashfs_la_SOURCES += lib/sqfs/win32/io_file.c
+else
+libsquashfs_la_SOURCES += lib/sqfs/unix/io_file.c
+endif
+
 if HAVE_PTHREAD
 libsquashfs_la_SOURCES += lib/sqfs/data_writer/pthread.c
 libsquashfs_la_CPPFLAGS += -DWITH_PTHREAD
diff --git a/lib/sqfs/io_file.c b/lib/sqfs/unix/io_file.c
index f93af4d..f93af4d 100644
--- a/lib/sqfs/io_file.c
+++ b/lib/sqfs/unix/io_file.c
diff --git a/lib/sqfs/win32/io_file.c b/lib/sqfs/win32/io_file.c
new file mode 100644
index 0000000..c3de1fd
--- /dev/null
+++ b/lib/sqfs/win32/io_file.c
@@ -0,0 +1,170 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * io_file.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "sqfs/io.h"
+#include "sqfs/error.h"
+
+#include <stdlib.h>
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+
+typedef struct {
+	sqfs_file_t base;
+
+	sqfs_u64 size;
+	HANDLE fd;
+} sqfs_file_stdio_t;
+
+
+static void stdio_destroy(sqfs_file_t *base)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+
+	CloseHandle(file->fd);
+	free(file);
+}
+
+static int stdio_read_at(sqfs_file_t *base, sqfs_u64 offset,
+			 void *buffer, size_t size)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+	DWORD actually_read;
+	LARGE_INTEGER pos;
+
+	if (offset >= file->size)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	if (size == 0)
+		return 0;
+
+	if ((offset + size - 1) >= file->size)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	pos.QuadPart = offset;
+
+	if (!SetFilePointerEx(file->fd, pos, NULL, FILE_BEGIN))
+		return SQFS_ERROR_IO;
+
+	while (size > 0) {
+		if (!ReadFile(file->fd, buffer, size, &actually_read, NULL))
+			return SQFS_ERROR_IO;
+
+		size -= actually_read;
+		buffer = (char *)buffer + actually_read;
+	}
+
+	return 0;
+}
+
+static int stdio_write_at(sqfs_file_t *base, sqfs_u64 offset,
+			  const void *buffer, size_t size)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+	DWORD actually_read;
+	LARGE_INTEGER pos;
+
+	if (size == 0)
+		return 0;
+
+	pos.QuadPart = offset;
+
+	if (!SetFilePointerEx(file->fd, pos, NULL, FILE_BEGIN))
+		return SQFS_ERROR_IO;
+
+	while (size > 0) {
+		if (!WriteFile(file->fd, buffer, size, &actually_read, NULL))
+			return SQFS_ERROR_IO;
+
+		size -= actually_read;
+		buffer = (char *)buffer + actually_read;
+		offset += actually_read;
+
+		if (offset > file->size)
+			file->size = offset;
+	}
+
+	return 0;
+}
+
+static sqfs_u64 stdio_get_size(const sqfs_file_t *base)
+{
+	const sqfs_file_stdio_t *file = (const sqfs_file_stdio_t *)base;
+
+	return file->size;
+}
+
+static int stdio_truncate(sqfs_file_t *base, sqfs_u64 size)
+{
+	sqfs_file_stdio_t *file = (sqfs_file_stdio_t *)base;
+	LARGE_INTEGER pos;
+
+	pos.QuadPart = size;
+
+	if (!SetFilePointerEx(file->fd, pos, NULL, FILE_BEGIN))
+		return SQFS_ERROR_IO;
+
+	if (!SetEndOfFile(file->fd))
+		return SQFS_ERROR_IO;
+
+	file->size = size;
+	return 0;
+}
+
+
+sqfs_file_t *sqfs_open_file(const char *filename, sqfs_u32 flags)
+{
+	int access_flags, creation_mode;
+	sqfs_file_stdio_t *file;
+	LARGE_INTEGER size;
+	sqfs_file_t *base;
+
+	if (flags & ~SQFS_FILE_OPEN_ALL_FLAGS)
+		return NULL;
+
+	file = calloc(1, sizeof(*file));
+	base = (sqfs_file_t *)file;
+	if (file == NULL)
+		return NULL;
+
+	if (flags & SQFS_FILE_OPEN_READ_ONLY) {
+		access_flags = GENERIC_READ;
+		creation_mode = OPEN_EXISTING;
+	} else {
+		access_flags = GENERIC_READ | GENERIC_WRITE;
+
+		if (flags & SQFS_FILE_OPEN_OVERWRITE) {
+			creation_mode = TRUNCATE_EXISTING;
+		} else {
+			creation_mode = CREATE_NEW;
+		}
+	}
+
+	file->fd = CreateFile(filename, access_flags, 0, NULL, creation_mode,
+			      FILE_ATTRIBUTE_NORMAL, NULL);
+
+	if (file->fd == INVALID_HANDLE_VALUE) {
+		free(file);
+		return NULL;
+	}
+
+	if (!GetFileSizeEx(file->fd, &size)) {
+		free(file);
+		return NULL;
+	}
+
+	file->size = size.QuadPart;
+	base->destroy = stdio_destroy;
+	base->read_at = stdio_read_at;
+	base->write_at = stdio_write_at;
+	base->get_size = stdio_get_size;
+	base->truncate = stdio_truncate;
+	return base;
+}