1 files changed, 102 insertions, 0 deletions
diff --git a/lib/xfrm/compress.c b/lib/xfrm/compress.c
new file mode 100644
index 0000000..fbd6987
--- /dev/null
+++ b/lib/xfrm/compress.c
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * compress.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "xfrm/compress.h"
+#include "config.h"
+
+#include <string.h>
+
+static const struct {
+	int id;
+	const char *name;
+	const sqfs_u8 *magic;
+	size_t count;
+	xfrm_stream_t *(*mk_comp_stream)(const compressor_config_t *);
+	xfrm_stream_t *(*mk_decomp_stream)(void);
+} compressors[] = {
+#ifdef WITH_GZIP
+	{ XFRM_COMPRESSOR_GZIP, "gzip", (const sqfs_u8 *)"\x1F\x8B\x08", 3,
+	  compressor_stream_gzip_create, decompressor_stream_gzip_create },
+#endif
+#ifdef WITH_XZ
+	{ XFRM_COMPRESSOR_XZ, "xz", (const sqfs_u8 *)("\xFD" "7zXZ"), 6,
+	  compressor_stream_xz_create, decompressor_stream_xz_create },
+#endif
+#if defined(WITH_ZSTD) && defined(HAVE_ZSTD_STREAM)
+	{ XFRM_COMPRESSOR_ZSTD, "zstd",
+	  (const sqfs_u8 *)"\x28\xB5\x2F\xFD", 4,
+	  compressor_stream_zstd_create, decompressor_stream_zstd_create },
+#endif
+#ifdef WITH_BZIP2
+	{ XFRM_COMPRESSOR_BZIP2, "bzip2", (const sqfs_u8 *)"BZh", 3,
+	  compressor_stream_bzip2_create, decompressor_stream_bzip2_create },
+#endif
+};
+
+int xfrm_compressor_id_from_name(const char *name)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(compressors) / sizeof(compressors[0]); ++i) {
+		if (strcmp(name, compressors[i].name) == 0)
+			return compressors[i].id;
+	}
+
+	return -1;
+}
+
+int xfrm_compressor_id_from_magic(const void *data, size_t count)
+{
+	size_t i;
+	int ret;
+
+	for (i = 0; i < sizeof(compressors) / sizeof(compressors[0]); ++i) {
+		if (compressors[i].count > count)
+			continue;
+
+		ret = memcmp(compressors[i].magic, data, compressors[i].count);
+		if (ret == 0)
+			return compressors[i].id;
+	}
+
+	return -1;
+}
+
+const char *xfrm_compressor_name_from_id(int id)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(compressors) / sizeof(compressors[0]); ++i) {
+		if (compressors[i].id == id)
+			return compressors[i].name;
+	}
+
+	return NULL;
+}
+
+xfrm_stream_t *compressor_stream_create(int id, const compressor_config_t *cfg)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(compressors) / sizeof(compressors[0]); ++i) {
+		if (compressors[i].id == id)
+			return compressors[i].mk_comp_stream(cfg);
+	}
+
+	return NULL;
+}
+
+xfrm_stream_t *decompressor_stream_create(int id)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(compressors) / sizeof(compressors[0]); ++i) {
+		if (compressors[i].id == id)
+			return compressors[i].mk_decomp_stream();
+	}
+
+	return NULL;
+}