Implement istream decompression support

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

1 files changed, 93 insertions, 0 deletions

diff --git a/lib/fstream/uncompress/xz.c b/lib/fstream/uncompress/xz.c
new file mode 100644
index 0000000..0e48468
--- /dev/null
+++ b/lib/fstream/uncompress/xz.c
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * xz.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "../internal.h"
+
+#include <lzma.h>
+
+typedef struct {
+	istream_comp_t base;
+
+	lzma_stream strm;
+} istream_xz_t;
+
+static int precache(istream_t *base)
+{
+	istream_xz_t *xz = (istream_xz_t *)base;
+	istream_t *wrapped = ((istream_comp_t *)base)->wrapped;
+	lzma_ret ret_xz;
+	int ret;
+
+	for (;;) {
+		ret = istream_precache(wrapped);
+		if (ret != 0)
+			return ret;
+
+		xz->strm.avail_in = wrapped->buffer_used;
+		xz->strm.next_in = wrapped->buffer;
+
+		xz->strm.avail_out = BUFSZ - base->buffer_used;
+		xz->strm.next_out = base->buffer + base->buffer_used;
+
+		ret_xz = lzma_code(&xz->strm, LZMA_RUN);
+
+		base->buffer_used = BUFSZ - xz->strm.avail_out;
+		wrapped->buffer_offset = wrapped->buffer_used -
+					 xz->strm.avail_in;
+
+		if (ret_xz == LZMA_BUF_ERROR)
+			break;
+
+		if (ret_xz == LZMA_STREAM_END) {
+			base->eof = true;
+			break;
+		}
+
+		if (ret_xz != LZMA_OK) {
+			fprintf(stderr,
+				"%s: internal error in xz decoder.\n",
+				wrapped->get_filename(wrapped));
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static void cleanup(istream_comp_t *base)
+{
+	istream_xz_t *xz = (istream_xz_t *)base;
+
+	lzma_end(&xz->strm);
+}
+
+istream_comp_t *istream_xz_create(const char *filename)
+{
+	istream_xz_t *xz = calloc(1, sizeof(*xz));
+	istream_comp_t *base = (istream_comp_t *)xz;
+	sqfs_u64 memlimit = 65 * 1024 * 1024;
+	lzma_ret ret_xz;
+
+	if (xz == NULL) {
+		fprintf(stderr, "%s: creating xz decoder: %s.\n",
+			filename, strerror(errno));
+		return NULL;
+	}
+
+	ret_xz = lzma_stream_decoder(&xz->strm, memlimit, 0);
+
+	if (ret_xz != LZMA_OK) {
+		fprintf(stderr,
+			"%s: error initializing xz decoder.\n",
+			filename);
+		free(xz);
+		return NULL;
+	}
+
+	((istream_t *)base)->precache = precache;
+	base->cleanup = cleanup;
+	return base;
+}