4 files changed, 254 insertions, 0 deletions
diff --git a/lib/comp/compressor.c b/lib/comp/compressor.c
new file mode 100644
index 0000000..3bc2b4d
--- /dev/null
+++ b/lib/comp/compressor.c
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include <string.h>
+
+#include "internal.h"
+
+typedef compressor_t *(*compressor_fun_t)(bool compress, size_t block_size);
+
+static compressor_fun_t compressors[SQFS_COMP_MAX + 1] = {
+#ifdef WITH_ZLIB
+	[SQFS_COMP_GZIP] = create_zlib_compressor,
+#endif
+#ifdef WITH_LZMA
+	[SQFS_COMP_XZ] = create_lzma_compressor,
+#endif
+};
+
+bool compressor_exists(E_SQFS_COMPRESSOR id)
+{
+	if (id < SQFS_COMP_MIN || id > SQFS_COMP_MAX)
+		return false;
+
+	return (compressors[id] != NULL);
+}
+
+compressor_t *compressor_create(E_SQFS_COMPRESSOR id, bool compress,
+				size_t block_size)
+{
+	if (id < SQFS_COMP_MIN || id > SQFS_COMP_MAX)
+		return NULL;
+
+	if (compressors[id] == NULL)
+		return NULL;
+
+	return compressors[id](compress, block_size);
+}
diff --git a/lib/comp/internal.h b/lib/comp/internal.h
new file mode 100644
index 0000000..17fffe1
--- /dev/null
+++ b/lib/comp/internal.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#ifndef INTERNAL_H
+#define INTERNAL_H
+
+#include "compress.h"
+
+compressor_t *create_lzma_compressor(bool compress, size_t block_size);
+
+compressor_t *create_zlib_compressor(bool compress, size_t block_size);
+
+#endif /* INTERNAL_H */
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;
+}
diff --git a/lib/comp/zlib.c b/lib/comp/zlib.c
new file mode 100644
index 0000000..d3bfe70
--- /dev/null
+++ b/lib/comp/zlib.c
@@ -0,0 +1,108 @@
+/* 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;
+	uint8_t buffer[];
+} zlib_compressor_t;
+
+static void zlib_destroy(compressor_t *base)
+{
+	zlib_compressor_t *zlib = (zlib_compressor_t *)base;
+
+	if (zlib->compress) {
+		deflateEnd(&zlib->strm);
+	} else {
+		inflateEnd(&zlib->strm);
+	}
+
+	free(zlib);
+}
+
+static ssize_t zlib_do_block(compressor_t *base, uint8_t *block, size_t size)
+{
+	zlib_compressor_t *zlib = (zlib_compressor_t *)base;
+	size_t written;
+	int ret;
+
+	if (zlib->compress) {
+		ret = deflateReset(&zlib->strm);
+	} else {
+		ret = inflateReset(&zlib->strm);
+	}
+
+	if (ret != Z_OK) {
+		fputs("resetting zlib stream failed\n", stderr);
+		return -1;
+	}
+
+	zlib->strm.next_in = (void *)block;
+	zlib->strm.avail_in = size;
+	zlib->strm.next_out = zlib->buffer;
+	zlib->strm.avail_out = zlib->block_size;
+
+	if (zlib->compress) {
+		ret = deflate(&zlib->strm, Z_FINISH);
+	} else {
+		ret = inflate(&zlib->strm, Z_FINISH);
+	}
+
+	if (ret == Z_STREAM_END) {
+		written = zlib->strm.total_out;
+
+		if (zlib->compress && written >= size)
+			return 0;
+
+		memcpy(block, zlib->buffer, written);
+		return (ssize_t)written;
+	}
+
+	if (ret != Z_OK) {
+		fputs("zlib block processing failed\n", stderr);
+		return -1;
+	}
+
+	return 0;
+}
+
+compressor_t *create_zlib_compressor(bool compress, size_t block_size)
+{
+	zlib_compressor_t *zlib = calloc(1, sizeof(*zlib) + block_size);
+	compressor_t *base = (compressor_t *)zlib;
+	int ret;
+
+	if (zlib == NULL) {
+		perror("creating zlib stream");
+		return NULL;
+	}
+
+	zlib->compress = compress;
+	zlib->block_size = block_size;
+	base->do_block = zlib_do_block;
+	base->destroy = zlib_destroy;
+
+	if (compress) {
+		ret = deflateInit(&zlib->strm, Z_BEST_COMPRESSION);
+	} else {
+		ret = inflateInit(&zlib->strm);
+	}
+
+	if (ret != Z_OK) {
+		fputs("internal error creating zlib stream\n", stderr);
+		free(zlib);
+		return NULL;
+	}
+
+	return base;
+}