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-rw-r--r--lib/comp/xz.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/lib/comp/xz.c b/lib/comp/xz.c
new file mode 100644
index 0000000..98d740c
--- /dev/null
+++ b/lib/comp/xz.c
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <lzma.h>
+
+#include "internal.h"
+
+typedef struct {
+ compressor_t base;
+ size_t block_size;
+} xz_compressor_t;
+
+static ssize_t xz_comp_block(compressor_t *base, const uint8_t *in,
+ size_t size, uint8_t *out, size_t outsize)
+{
+ xz_compressor_t *xz = (xz_compressor_t *)base;
+ lzma_filter filters[5];
+ lzma_options_lzma opt;
+ size_t written = 0;
+ lzma_ret ret;
+
+ if (lzma_lzma_preset(&opt, LZMA_PRESET_DEFAULT)) {
+ fputs("error initializing xz options\n", stderr);
+ return -1;
+ }
+
+ opt.dict_size = xz->block_size;
+
+ filters[0].id = LZMA_FILTER_LZMA2;
+ filters[0].options = &opt;
+
+ filters[1].id = LZMA_VLI_UNKNOWN;
+ filters[1].options = NULL;
+
+ ret = lzma_stream_buffer_encode(filters, LZMA_CHECK_CRC32, NULL,
+ in, size, out, &written, outsize);
+
+ if (ret == LZMA_OK)
+ return (written >= size) ? 0 : written;
+
+ if (ret != LZMA_BUF_ERROR) {
+ fputs("xz block compress failed\n", stderr);
+ return -1;
+ }
+
+ return 0;
+}
+
+static ssize_t xz_uncomp_block(compressor_t *base, const uint8_t *in,
+ size_t size, uint8_t *out, size_t outsize)
+{
+ uint64_t memlimit = 32 * 1024 * 1024;
+ size_t dest_pos = 0;
+ size_t src_pos = 0;
+ lzma_ret ret;
+ (void)base;
+
+ ret = lzma_stream_buffer_decode(&memlimit, 0, NULL,
+ in, &src_pos, size,
+ out, &dest_pos, outsize);
+
+ if (ret == LZMA_OK && size == src_pos)
+ return (ssize_t)dest_pos;
+
+ fputs("xz block extract failed\n", stderr);
+ return -1;
+}
+
+static void xz_destroy(compressor_t *base)
+{
+ free(base);
+}
+
+compressor_t *create_xz_compressor(bool compress, size_t block_size)
+{
+ xz_compressor_t *xz = calloc(1, sizeof(*xz));
+ compressor_t *base = (compressor_t *)xz;
+
+ if (xz == NULL) {
+ perror("creating xz compressor");
+ return NULL;
+ }
+
+ xz->block_size = block_size;
+ base->destroy = xz_destroy;
+ base->do_block = compress ? xz_comp_block : xz_uncomp_block;
+ return base;
+}