1 files changed, 188 insertions, 0 deletions
diff --git a/lib/sqfs/comp/zstd.c b/lib/sqfs/comp/zstd.c
new file mode 100644
index 0000000..e206338
--- /dev/null
+++ b/lib/sqfs/comp/zstd.c
@@ -0,0 +1,188 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * zstd.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <ctype.h>
+
+#include <zstd.h>
+
+#include "internal.h"
+
+#define ZSTD_DEFAULT_COMPRESSION_LEVEL 15
+
+typedef struct {
+	compressor_t base;
+	ZSTD_CCtx *zctx;
+	int level;
+} zstd_compressor_t;
+
+typedef struct {
+	uint32_t level;
+} zstd_options_t;
+
+static int zstd_write_options(compressor_t *base, int fd)
+{
+	zstd_compressor_t *zstd = (zstd_compressor_t *)base;
+	zstd_options_t opt;
+	(void)fd;
+
+	if (zstd->level == ZSTD_DEFAULT_COMPRESSION_LEVEL)
+		return 0;
+
+	opt.level = htole32(zstd->level);
+	return generic_write_options(fd, &opt, sizeof(opt));
+}
+
+static int zstd_read_options(compressor_t *base, int fd)
+{
+	zstd_options_t opt;
+	(void)base;
+
+	if (generic_read_options(fd, &opt, sizeof(opt)))
+		return -1;
+
+	opt.level = le32toh(opt.level);
+	return 0;
+}
+
+static ssize_t zstd_comp_block(compressor_t *base, const uint8_t *in,
+			       size_t size, uint8_t *out, size_t outsize)
+{
+	zstd_compressor_t *zstd = (zstd_compressor_t *)base;
+	size_t ret;
+
+	ret = ZSTD_compressCCtx(zstd->zctx, out, outsize, in, size,
+				zstd->level);
+
+	if (ZSTD_isError(ret)) {
+		fprintf(stderr, "internal error in ZSTD compressor: %s\n",
+			ZSTD_getErrorName(ret));
+		return -1;
+	}
+
+	return ret < size ? ret : 0;
+}
+
+static ssize_t zstd_uncomp_block(compressor_t *base, const uint8_t *in,
+				 size_t size, uint8_t *out, size_t outsize)
+{
+	size_t ret;
+	(void)base;
+
+	ret = ZSTD_decompress(out, outsize, in, size);
+
+	if (ZSTD_isError(ret)) {
+		fprintf(stderr, "error uncompressing ZSTD compressed data: %s",
+			ZSTD_getErrorName(ret));
+		return -1;
+	}
+
+	return ret;
+}
+
+static compressor_t *zstd_create_copy(compressor_t *cmp)
+{
+	zstd_compressor_t *zstd = malloc(sizeof(*zstd));
+
+	if (zstd == NULL) {
+		perror("creating additional zstd compressor");
+		return NULL;
+	}
+
+	memcpy(zstd, cmp, sizeof(*zstd));
+
+	zstd->zctx = ZSTD_createCCtx();
+
+	if (zstd->zctx == NULL) {
+		fputs("error creating addtional zstd compression context\n",
+		      stderr);
+		free(zstd);
+		return NULL;
+	}
+
+	return (compressor_t *)zstd;
+}
+
+static void zstd_destroy(compressor_t *base)
+{
+	zstd_compressor_t *zstd = (zstd_compressor_t *)base;
+
+	ZSTD_freeCCtx(zstd->zctx);
+	free(zstd);
+}
+
+compressor_t *create_zstd_compressor(bool compress, size_t block_size,
+				     char *options)
+{
+	zstd_compressor_t *zstd = calloc(1, sizeof(*zstd));
+	compressor_t *base = (compressor_t *)zstd;
+	size_t i;
+	(void)block_size;
+
+	if (zstd == NULL) {
+		perror("creating zstd compressor");
+		return NULL;
+	}
+
+	zstd->level = ZSTD_DEFAULT_COMPRESSION_LEVEL;
+
+	if (options != NULL) {
+		if (strncmp(options, "level=", 6) == 0) {
+			options += 6;
+
+			for (i = 0; isdigit(options[i]); ++i)
+				;
+
+			if (i == 0 || options[i] != '\0' || i > 6)
+				goto fail_level;
+
+			zstd->level = atoi(options);
+
+			if (zstd->level < 1 || zstd->level > ZSTD_maxCLevel())
+				goto fail_level;
+		} else {
+			goto fail_opt;
+		}
+	}
+
+	zstd->zctx = ZSTD_createCCtx();
+	if (zstd->zctx == NULL) {
+		fputs("error creating zstd compression context\n", stderr);
+		free(zstd);
+		return NULL;
+	}
+
+	base->destroy = zstd_destroy;
+	base->do_block = compress ? zstd_comp_block : zstd_uncomp_block;
+	base->write_options = zstd_write_options;
+	base->read_options = zstd_read_options;
+	base->create_copy = zstd_create_copy;
+	return base;
+fail_level:
+	fprintf(stderr, "zstd compression level must be a number in the range "
+		"1...%d\n", ZSTD_maxCLevel());
+	free(zstd);
+	return NULL;
+fail_opt:
+	fputs("Unsupported extra options for zstd compressor\n", stderr);
+	free(zstd);
+	return NULL;
+}
+
+void compressor_zstd_print_help(void)
+{
+	printf("Available options for zstd compressor:\n"
+	       "\n"
+	       "    level=<value>    Set compression level. Defaults to %d.\n"
+	       "                     Maximum is %d.\n"
+	       "\n",
+	       ZSTD_DEFAULT_COMPRESSION_LEVEL, ZSTD_maxCLevel());
+}