1 files changed, 169 insertions, 0 deletions
diff --git a/lib/sqfs/src/unix/istream.c b/lib/sqfs/src/unix/istream.c
new file mode 100644
index 0000000..fd2f120
--- /dev/null
+++ b/lib/sqfs/src/unix/istream.c
@@ -0,0 +1,169 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * istream.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>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#define BUFSZ (131072)
+
+typedef struct {
+	sqfs_istream_t base;
+	char *path;
+	int fd;
+
+	bool eof;
+	size_t buffer_offset;
+	size_t buffer_used;
+	sqfs_u8 buffer[BUFSZ];
+} file_istream_t;
+
+static int precache(sqfs_istream_t *strm)
+{
+	file_istream_t *file = (file_istream_t *)strm;
+
+	if (file->eof)
+		return 0;
+
+	if (file->buffer_offset > 0 &&
+	    file->buffer_offset < file->buffer_used) {
+		memmove(file->buffer, file->buffer + file->buffer_offset,
+			file->buffer_used - file->buffer_offset);
+	}
+
+	file->buffer_used -= file->buffer_offset;
+	file->buffer_offset = 0;
+
+	while (file->buffer_used < BUFSZ) {
+		ssize_t ret = read(file->fd, file->buffer + file->buffer_used,
+				   BUFSZ - file->buffer_used);
+
+		if (ret == 0) {
+			file->eof = true;
+			break;
+		}
+
+		if (ret < 0) {
+			if (errno == EINTR)
+				continue;
+			return SQFS_ERROR_IO;
+		}
+
+		file->buffer_used += ret;
+	}
+
+	return 0;
+}
+
+static int file_get_buffered_data(sqfs_istream_t *strm, const sqfs_u8 **out,
+				  size_t *size, size_t want)
+{
+	file_istream_t *file = (file_istream_t *)strm;
+
+	if (want > BUFSZ)
+		want = BUFSZ;
+
+	if (file->buffer_used == 0 ||
+	    (file->buffer_used - file->buffer_offset) < want) {
+		int ret = precache(strm);
+		if (ret)
+			return ret;
+	}
+
+	*out = file->buffer + file->buffer_offset;
+	*size = file->buffer_used - file->buffer_offset;
+	return (file->eof && *size == 0) ? 1 : 0;
+}
+
+static void file_advance_buffer(sqfs_istream_t *strm, size_t count)
+{
+	file_istream_t *file = (file_istream_t *)strm;
+
+	assert(count <= file->buffer_used);
+
+	file->buffer_offset += count;
+
+	assert(file->buffer_offset <= file->buffer_used);
+}
+
+static const char *file_get_filename(sqfs_istream_t *strm)
+{
+	return ((file_istream_t *)strm)->path;
+}
+
+static void file_destroy(sqfs_object_t *obj)
+{
+	file_istream_t *file = (file_istream_t *)obj;
+
+	close(file->fd);
+	free(file->path);
+	free(file);
+}
+
+int sqfs_istream_open_handle(sqfs_istream_t **out, const char *path,
+			     sqfs_file_handle_t fd)
+{
+	file_istream_t *file = calloc(1, sizeof(*file));
+	sqfs_istream_t *strm = (sqfs_istream_t *)file;
+
+	if (file == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	sqfs_object_init(file, file_destroy, NULL);
+
+	file->path = strdup(path);
+	if (file->path == NULL) {
+		int temp = errno;
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_ALLOC;
+	}
+
+	file->fd = dup(fd);
+	if (file->fd < 0) {
+		int temp = errno;
+		free(file->path);
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_IO;
+	}
+	close(fd);
+
+	strm->get_buffered_data = file_get_buffered_data;
+	strm->advance_buffer = file_advance_buffer;
+	strm->get_filename = file_get_filename;
+
+	*out = strm;
+	return 0;
+}
+
+int sqfs_istream_open_file(sqfs_istream_t **out, const char *path)
+{
+	sqfs_file_handle_t fd;
+	int ret;
+
+	ret = sqfs_open_native_file(&fd, path, SQFS_FILE_OPEN_READ_ONLY);
+	if (ret)
+		return ret;
+
+	ret = sqfs_istream_open_handle(out, path, fd);
+	if (ret != 0) {
+		int temp = errno;
+		close(fd);
+		errno = temp;
+	}
+
+	return ret;
+}