Add optional support for CRC64.

7 files changed, 139 insertions, 23 deletions

diff --git a/linux/include/linux/xz.h b/linux/include/linux/xz.h
index 810cb10..0a4b38d 100644
--- a/linux/include/linux/xz.h
+++ b/linux/include/linux/xz.h
@@ -251,6 +251,22 @@ XZ_EXTERN void xz_dec_end(struct xz_dec *s);
 #	endif
 #endif
 
+/*
+ * If CRC64 support has been enabled with XZ_USE_CRC64, a CRC64
+ * implementation is needed too.
+ */
+#ifndef XZ_USE_CRC64
+#	undef XZ_INTERNAL_CRC64
+#	define XZ_INTERNAL_CRC64 0
+#endif
+#ifndef XZ_INTERNAL_CRC64
+#	ifdef __KERNEL__
+#		error Using CRC64 in the kernel has not been implemented.
+#	else
+#		define XZ_INTERNAL_CRC64 1
+#	endif
+#endif
+
 #if XZ_INTERNAL_CRC32
 /*
  * This must be called before any other xz_* function to initialize
@@ -266,6 +282,21 @@ XZ_EXTERN void xz_crc32_init(void);
 XZ_EXTERN uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc);
 #endif
 
+#if XZ_INTERNAL_CRC64
+/*
+ * This must be called before any other xz_* function (except xz_crc32_init())
+ * to initialize the CRC64 lookup table.
+ */
+XZ_EXTERN void xz_crc64_init(void);
+
+/*
+ * Update CRC64 value using the polynomial from ECMA-182. To start a new
+ * calculation, the third argument must be zero. To continue the calculation,
+ * the previously returned value is passed as the third argument.
+ */
+XZ_EXTERN uint64_t xz_crc64(const uint8_t *buf, size_t size, uint64_t crc);
+#endif
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/linux/lib/xz/xz_crc64.c b/linux/lib/xz/xz_crc64.c
new file mode 100644
index 0000000..ca1caee
--- /dev/null
+++ b/linux/lib/xz/xz_crc64.c
@@ -0,0 +1,50 @@
+/*
+ * CRC64 using the polynomial from ECMA-182
+ *
+ * This file is similar to xz_crc32.c. See the comments there.
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+#include "xz_private.h"
+
+#ifndef STATIC_RW_DATA
+#	define STATIC_RW_DATA static
+#endif
+
+STATIC_RW_DATA uint64_t xz_crc64_table[256];
+
+XZ_EXTERN void xz_crc64_init(void)
+{
+	const uint64_t poly = 0xC96C5795D7870F42;
+
+	uint32_t i;
+	uint32_t j;
+	uint64_t r;
+
+	for (i = 0; i < 256; ++i) {
+		r = i;
+		for (j = 0; j < 8; ++j)
+			r = (r >> 1) ^ (poly & ~((r & 1) - 1));
+
+		xz_crc64_table[i] = r;
+	}
+
+	return;
+}
+
+XZ_EXTERN uint64_t xz_crc64(const uint8_t *buf, size_t size, uint64_t crc)
+{
+	crc = ~crc;
+
+	while (size != 0) {
+		crc = xz_crc64_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
+		--size;
+	}
+
+	return ~crc;
+}
diff --git a/linux/lib/xz/xz_dec_stream.c b/linux/lib/xz/xz_dec_stream.c
index ac809b1..d652550 100644
--- a/linux/lib/xz/xz_dec_stream.c
+++ b/linux/lib/xz/xz_dec_stream.c
@@ -10,6 +10,12 @@
 #include "xz_private.h"
 #include "xz_stream.h"
 
+#ifdef XZ_USE_CRC64
+#	define IS_CRC64(check_type) ((check_type) == XZ_CHECK_CRC64)
+#else
+#	define IS_CRC64(check_type) false
+#endif
+
 /* Hash used to validate the Index field */
 struct xz_dec_hash {
 	vli_type unpadded;
@@ -42,8 +48,13 @@ struct xz_dec {
 	size_t in_start;
 	size_t out_start;
 
+#ifdef XZ_USE_CRC64
+	/* CRC32 or CRC64 value in Block or CRC32 value in Index */
+	uint64_t crc;
+#else
 	/* CRC32 value in Block or Index */
-	uint32_t crc32;
+	uint32_t crc;
+#endif
 
 	/* Type of the integrity check calculated from uncompressed data */
 	enum xz_check check_type;
@@ -208,8 +219,8 @@ static enum xz_ret dec_vli(struct xz_dec *s, const uint8_t *in,
  * the observed compressed and uncompressed sizes of the Block so that
  * they don't exceed the values possibly stored in the Block Header
  * (validation assumes that no integer overflow occurs, since vli_type
- * is normally uint64_t). Update the CRC32 if presence of the CRC32
- * field was indicated in Stream Header.
+ * is normally uint64_t). Update the CRC32 or CRC64 value if presence of
+ * the CRC32 or CRC64 field was indicated in Stream Header.
  *
  * Once the decoding is finished, validate that the observed sizes match
  * the sizes possibly stored in the Block Header. Update the hash and
@@ -242,8 +253,13 @@ static enum xz_ret dec_block(struct xz_dec *s, struct xz_buf *b)
 		return XZ_DATA_ERROR;
 
 	if (s->check_type == XZ_CHECK_CRC32)
-		s->crc32 = xz_crc32(b->out + s->out_start,
-				b->out_pos - s->out_start, s->crc32);
+		s->crc = xz_crc32(b->out + s->out_start,
+				b->out_pos - s->out_start, s->crc);
+#ifdef XZ_USE_CRC64
+	else if (s->check_type == XZ_CHECK_CRC64)
+		s->crc = xz_crc64(b->out + s->out_start,
+				b->out_pos - s->out_start, s->crc);
+#endif
 
 	if (ret == XZ_STREAM_END) {
 		if (s->block_header.compressed != VLI_UNKNOWN
@@ -264,6 +280,8 @@ static enum xz_ret dec_block(struct xz_dec *s, struct xz_buf *b)
 #else
 		if (s->check_type == XZ_CHECK_CRC32)
 			s->block.hash.unpadded += 4;
+		else if (IS_CRC64(s->check_type))
+			s->block.hash.unpadded += 8;
 #endif
 
 		s->block.hash.uncompressed += s->block.uncompressed;
@@ -282,7 +300,7 @@ static void index_update(struct xz_dec *s, const struct xz_buf *b)
 {
 	size_t in_used = b->in_pos - s->in_start;
 	s->index.size += in_used;
-	s->crc32 = xz_crc32(b->in + s->in_start, in_used, s->crc32);
+	s->crc = xz_crc32(b->in + s->in_start, in_used, s->crc);
 }
 
 /*
@@ -340,23 +358,25 @@ static enum xz_ret dec_index(struct xz_dec *s, struct xz_buf *b)
 }
 
 /*
- * Validate that the next four input bytes match the value of s->crc32.
- * s->pos must be zero when starting to validate the first byte.
+ * Validate that the next four or eight input bytes match the value
+ * of s->crc. s->pos must be zero when starting to validate the first byte.
+ * The "bits" argument allows using the same code for both CRC32 and CRC64.
  */
-static enum xz_ret crc32_validate(struct xz_dec *s, struct xz_buf *b)
+static enum xz_ret crc_validate(struct xz_dec *s, struct xz_buf *b,
+				uint32_t bits)
 {
 	do {
 		if (b->in_pos == b->in_size)
 			return XZ_OK;
 
-		if (((s->crc32 >> s->pos) & 0xFF) != b->in[b->in_pos++])
+		if (((s->crc >> s->pos) & 0xFF) != b->in[b->in_pos++])
 			return XZ_DATA_ERROR;
 
 		s->pos += 8;
 
-	} while (s->pos < 32);
+	} while (s->pos < bits);
 
-	s->crc32 = 0;
+	s->crc = 0;
 	s->pos = 0;
 
 	return XZ_STREAM_END;
@@ -397,10 +417,11 @@ static enum xz_ret dec_stream_header(struct xz_dec *s)
 		return XZ_OPTIONS_ERROR;
 
 	/*
-	 * Of integrity checks, we support only none (Check ID = 0) and
-	 * CRC32 (Check ID = 1). However, if XZ_DEC_ANY_CHECK is defined,
-	 * we will accept other check types too, but then the check won't
-	 * be verified and a warning (XZ_UNSUPPORTED_CHECK) will be given.
+	 * Of integrity checks, we support none (Check ID = 0),
+	 * CRC32 (Check ID = 1), and optionally CRC64 (Check ID = 4).
+	 * However, if XZ_DEC_ANY_CHECK is defined, we will accept other
+	 * check types too, but then the check won't be verified and
+	 * a warning (XZ_UNSUPPORTED_CHECK) will be given.
 	 */
 	s->check_type = s->temp.buf[HEADER_MAGIC_SIZE + 1];
 
@@ -408,10 +429,10 @@ static enum xz_ret dec_stream_header(struct xz_dec *s)
 	if (s->check_type > XZ_CHECK_MAX)
 		return XZ_OPTIONS_ERROR;
 
-	if (s->check_type > XZ_CHECK_CRC32)
+	if (s->check_type > XZ_CHECK_CRC32 && !IS_CRC64(s->check_type))
 		return XZ_UNSUPPORTED_CHECK;
 #else
-	if (s->check_type > XZ_CHECK_CRC32)
+	if (s->check_type > XZ_CHECK_CRC32 && !IS_CRC64(s->check_type))
 		return XZ_OPTIONS_ERROR;
 #endif
 
@@ -645,7 +666,12 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 
 		case SEQ_BLOCK_CHECK:
 			if (s->check_type == XZ_CHECK_CRC32) {
-				ret = crc32_validate(s, b);
+				ret = crc_validate(s, b, 32);
+				if (ret != XZ_STREAM_END)
+					return ret;
+			}
+			else if (IS_CRC64(s->check_type)) {
+				ret = crc_validate(s, b, 64);
 				if (ret != XZ_STREAM_END)
 					return ret;
 			}
@@ -688,7 +714,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 			s->sequence = SEQ_INDEX_CRC32;
 
 		case SEQ_INDEX_CRC32:
-			ret = crc32_validate(s, b);
+			ret = crc_validate(s, b, 32);
 			if (ret != XZ_STREAM_END)
 				return ret;
 
@@ -802,7 +828,7 @@ XZ_EXTERN void xz_dec_reset(struct xz_dec *s)
 	s->sequence = SEQ_STREAM_HEADER;
 	s->allow_buf_error = false;
 	s->pos = 0;
-	s->crc32 = 0;
+	s->crc = 0;
 	memzero(&s->block, sizeof(s->block));
 	memzero(&s->index, sizeof(s->index));
 	s->temp.pos = 0;
diff --git a/userspace/Makefile b/userspace/Makefile
index 9d17799..5bd6b28 100644
--- a/userspace/Makefile
+++ b/userspace/Makefile
@@ -10,11 +10,11 @@
 CC = gcc -std=gnu89
 BCJ_CPPFLAGS = -DXZ_DEC_X86 -DXZ_DEC_POWERPC -DXZ_DEC_IA64 \
 		-DXZ_DEC_ARM -DXZ_DEC_ARMTHUMB -DXZ_DEC_SPARC
-CPPFLAGS = -DXZ_DEC_ANY_CHECK
+CPPFLAGS = -DXZ_USE_CRC64 -DXZ_DEC_ANY_CHECK
 CFLAGS = -ggdb3 -O2 -pedantic -Wall -Wextra
 RM = rm -f
 VPATH = ../linux/include/linux ../linux/lib/xz
-COMMON_SRCS = xz_crc32.c xz_dec_stream.c xz_dec_lzma2.c xz_dec_bcj.c
+COMMON_SRCS = xz_crc32.c xz_crc64.c xz_dec_stream.c xz_dec_lzma2.c xz_dec_bcj.c
 COMMON_OBJS = $(COMMON_SRCS:.c=.o)
 XZMINIDEC_OBJS = xzminidec.o
 BYTETEST_OBJS = bytetest.o
diff --git a/userspace/boottest.c b/userspace/boottest.c
index f5bc282..1aef5ed 100644
--- a/userspace/boottest.c
+++ b/userspace/boottest.c
@@ -19,6 +19,9 @@ static void error(/*const*/ char *msg)
 	fprintf(stderr, "%s\n", msg);
 }
 
+/* Disable the CRC64 support even if it was enabled in the Makefile. */
+#undef XZ_USE_CRC64
+
 #include "../linux/lib/decompress_unxz.c"
 
 static uint8_t in[1024 * 1024];
diff --git a/userspace/xz_config.h b/userspace/xz_config.h
index 71bb029..9a1dfef 100644
--- a/userspace/xz_config.h
+++ b/userspace/xz_config.h
@@ -10,6 +10,9 @@
 #ifndef XZ_CONFIG_H
 #define XZ_CONFIG_H
 
+/* Uncomment to enable CRC64 support. */
+/* #define XZ_USE_CRC64 */
+
 /* Uncomment as needed to enable BCJ filter decoders. */
 /* #define XZ_DEC_X86 */
 /* #define XZ_DEC_POWERPC */
diff --git a/userspace/xzminidec.c b/userspace/xzminidec.c
index 2a039c6..ba07413 100644
--- a/userspace/xzminidec.c
+++ b/userspace/xzminidec.c
@@ -37,6 +37,9 @@ int main(int argc, char **argv)
 	}
 
 	xz_crc32_init();
+#ifdef XZ_USE_CRC64
+	xz_crc64_init();
+#endif
 
 	/*
 	 * Support up to 64 MiB dictionary. The actually needed memory