Add bzip2 stream compression support

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

3 files changed, 93 insertions, 0 deletions

diff --git a/lib/fstream/uncompress/autodetect.c b/lib/fstream/uncompress/autodetect.c
index b788518..61628f8 100644
--- a/lib/fstream/uncompress/autodetect.c
+++ b/lib/fstream/uncompress/autodetect.c
@@ -14,6 +14,7 @@ static const struct {
 	{ FSTREAM_COMPRESSOR_GZIP, (const sqfs_u8 *)"\x1F\x8B\x08", 3 },
 	{ FSTREAM_COMPRESSOR_XZ, (const sqfs_u8 *)("\xFD" "7zXZ"), 6 },
 	{ FSTREAM_COMPRESSOR_ZSTD, (const sqfs_u8 *)"\x28\xB5\x2F\xFD", 4 },
+	{ FSTREAM_COMPRESSOR_BZIP2, (const sqfs_u8 *)"BZh", 3 },
 };
 
 int istream_detect_compressor(istream_t *strm,
diff --git a/lib/fstream/uncompress/bzip2.c b/lib/fstream/uncompress/bzip2.c
new file mode 100644
index 0000000..b5fae5c
--- /dev/null
+++ b/lib/fstream/uncompress/bzip2.c
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * bzip2.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "../internal.h"
+
+#include <bzlib.h>
+
+typedef struct {
+	istream_comp_t base;
+
+	bz_stream strm;
+} istream_bzip2_t;
+
+static int precache(istream_t *base)
+{
+	istream_bzip2_t *bzip2 = (istream_bzip2_t *)base;
+	istream_t *wrapped = ((istream_comp_t *)base)->wrapped;
+	int ret;
+
+	for (;;) {
+		ret = istream_precache(wrapped);
+		if (ret != 0)
+			return ret;
+
+		bzip2->strm.next_in = (char *)wrapped->buffer;
+		bzip2->strm.avail_in = wrapped->buffer_used;
+
+		bzip2->strm.next_out = (char *)base->buffer + base->buffer_used;
+		bzip2->strm.avail_out = BUFSZ - base->buffer_used;
+
+		if (bzip2->strm.avail_out < 1)
+			break;
+
+		ret = BZ2_bzDecompress(&bzip2->strm);
+
+		if (ret < 0) {
+			fprintf(stderr, "%s: internal error in bzip2 "
+				"decompressor.\n",
+				wrapped->get_filename(wrapped));
+			return -1;
+		}
+
+		base->buffer_used = BUFSZ - bzip2->strm.avail_out;
+		wrapped->buffer_offset = wrapped->buffer_used -
+					 bzip2->strm.avail_in;
+
+		if (ret == BZ_STREAM_END) {
+			base->eof = true;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static void cleanup(istream_comp_t *base)
+{
+	istream_bzip2_t *bzip2 = (istream_bzip2_t *)base;
+
+	BZ2_bzDecompressEnd(&bzip2->strm);
+}
+
+istream_comp_t *istream_bzip2_create(const char *filename)
+{
+	istream_bzip2_t *bzip2 = calloc(1, sizeof(*bzip2));
+	istream_comp_t *base = (istream_comp_t *)bzip2;
+
+	if (bzip2 == NULL) {
+		fprintf(stderr, "%s: creating bzip2 compressor: %s.\n",
+			filename, strerror(errno));
+		return NULL;
+	}
+
+	if (BZ2_bzDecompressInit(&bzip2->strm, 0, 0) != BZ_OK) {
+		fprintf(stderr, "%s: error initializing bzip2 decompressor.\n",
+			filename);
+		free(bzip2);
+		return NULL;
+	}
+
+	((istream_t *)base)->precache = precache;
+	base->cleanup = cleanup;
+	return base;
+}
diff --git a/lib/fstream/uncompress/istream_compressor.c b/lib/fstream/uncompress/istream_compressor.c
index 2262c9b..bc8ef39 100644
--- a/lib/fstream/uncompress/istream_compressor.c
+++ b/lib/fstream/uncompress/istream_compressor.c
@@ -44,6 +44,11 @@ istream_t *istream_compressor_create(istream_t *strm, int comp_id)
 		comp = istream_zstd_create(strm->get_filename(strm));
 #endif
 		break;
+	case FSTREAM_COMPRESSOR_BZIP2:
+#ifdef WITH_BZIP2
+		comp = istream_bzip2_create(strm->get_filename(strm));
+#endif
+		break;
 	default:
 		break;
 	}