Rename lzma compressor to xz, zlib compressor to gzip

Stick to the terminology that SquashFS uses. SquashFS uses "lzma" to
refere to lzma1, "xz" to refere to lzma2 and confusingly "gzip" to
refere to raw zlib deflate. We can avoid a lot of confusion by
_consistently_ using the same terminology.

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

1 files changed, 107 insertions, 0 deletions

diff --git a/lib/comp/gzip.c b/lib/comp/gzip.c
new file mode 100644
index 0000000..ea634b8
--- /dev/null
+++ b/lib/comp/gzip.c
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <zlib.h>
+
+#include "internal.h"
+
+typedef struct {
+	compressor_t base;
+
+	z_stream strm;
+	bool compress;
+
+	size_t block_size;
+} gzip_compressor_t;
+
+static void gzip_destroy(compressor_t *base)
+{
+	gzip_compressor_t *gzip = (gzip_compressor_t *)base;
+
+	if (gzip->compress) {
+		deflateEnd(&gzip->strm);
+	} else {
+		inflateEnd(&gzip->strm);
+	}
+
+	free(gzip);
+}
+
+static ssize_t gzip_do_block(compressor_t *base, const uint8_t *in,
+			     size_t size, uint8_t *out, size_t outsize)
+{
+	gzip_compressor_t *gzip = (gzip_compressor_t *)base;
+	size_t written;
+	int ret;
+
+	if (gzip->compress) {
+		ret = deflateReset(&gzip->strm);
+	} else {
+		ret = inflateReset(&gzip->strm);
+	}
+
+	if (ret != Z_OK) {
+		fputs("resetting zlib stream failed\n", stderr);
+		return -1;
+	}
+
+	gzip->strm.next_in = (void *)in;
+	gzip->strm.avail_in = size;
+	gzip->strm.next_out = out;
+	gzip->strm.avail_out = outsize;
+
+	if (gzip->compress) {
+		ret = deflate(&gzip->strm, Z_FINISH);
+	} else {
+		ret = inflate(&gzip->strm, Z_FINISH);
+	}
+
+	if (ret == Z_STREAM_END) {
+		written = gzip->strm.total_out;
+
+		if (gzip->compress && written >= size)
+			return 0;
+
+		return (ssize_t)written;
+	}
+
+	if (ret != Z_OK) {
+		fputs("gzip block processing failed\n", stderr);
+		return -1;
+	}
+
+	return 0;
+}
+
+compressor_t *create_gzip_compressor(bool compress, size_t block_size)
+{
+	gzip_compressor_t *gzip = calloc(1, sizeof(*gzip));
+	compressor_t *base = (compressor_t *)gzip;
+	int ret;
+
+	if (gzip == NULL) {
+		perror("creating gzip compressor");
+		return NULL;
+	}
+
+	gzip->compress = compress;
+	gzip->block_size = block_size;
+	base->do_block = gzip_do_block;
+	base->destroy = gzip_destroy;
+
+	if (compress) {
+		ret = deflateInit(&gzip->strm, Z_BEST_COMPRESSION);
+	} else {
+		ret = inflateInit(&gzip->strm);
+	}
+
+	if (ret != Z_OK) {
+		fputs("internal error creating zlib stream\n", stderr);
+		free(gzip);
+		return NULL;
+	}
+
+	return base;
+}