Add compressor library

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

1 files changed, 100 insertions, 0 deletions

diff --git a/lib/comp/lzma.c b/lib/comp/lzma.c
new file mode 100644
index 0000000..fd2a6c7
--- /dev/null
+++ b/lib/comp/lzma.c
@@ -0,0 +1,100 @@
+/* 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;
+	uint8_t buffer[];
+} lzma_compressor_t;
+
+static ssize_t lzma_comp_block(compressor_t *base, uint8_t *block, size_t size)
+{
+	lzma_compressor_t *lzma = (lzma_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 LZMA options\n", stderr);
+		return -1;
+	}
+
+	opt.dict_size = lzma->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,
+					block, size, lzma->buffer,
+					&written, lzma->block_size);
+
+	if (ret == LZMA_OK) {
+		if (written >= size)
+			return 0;
+
+		memcpy(block, lzma->buffer, size);
+		return written;
+	}
+
+	if (ret != LZMA_BUF_ERROR) {
+		fputs("lzma block compress failed\n", stderr);
+		return -1;
+	}
+
+	return 0;
+}
+
+static ssize_t lzma_uncomp_block(compressor_t *base, uint8_t *block,
+				 size_t size)
+{
+	lzma_compressor_t *lzma = (lzma_compressor_t *)base;
+	uint64_t memlimit = 32 * 1024 * 1024;
+	size_t dest_pos = 0;
+	size_t src_pos = 0;
+	lzma_ret ret;
+
+	ret = lzma_stream_buffer_decode(&memlimit, 0, NULL,
+					block, &src_pos, size,
+					lzma->buffer, &dest_pos,
+					lzma->block_size);
+
+	if (ret == LZMA_OK && size == src_pos) {
+		memcpy(block, lzma->buffer, dest_pos);
+		return (ssize_t)dest_pos;
+	}
+
+	fputs("lzma block extract failed\n", stderr);
+	return -1;
+}
+
+static void lzma_destroy(compressor_t *base)
+{
+	free(base);
+}
+
+compressor_t *create_lzma_compressor(bool compress, size_t block_size)
+{
+	lzma_compressor_t *lzma = calloc(1, sizeof(*lzma) + block_size);
+	compressor_t *base = (compressor_t *)lzma;
+
+	if (lzma == NULL) {
+		perror("creating lzma stream");
+		return NULL;
+	}
+
+	lzma->block_size = block_size;
+	base->destroy = lzma_destroy;
+	base->do_block = compress ? lzma_comp_block : lzma_uncomp_block;
+	return base;
+}