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-rw-r--r--ChangeLog14
-rw-r--r--bignum.c187
-rw-r--r--internal.h37
-rw-r--r--pack.c37
-rw-r--r--test/-ext-/bignum/test_pack.rb76
5 files changed, 311 insertions, 40 deletions
diff --git a/ChangeLog b/ChangeLog
index 953c83cb6b..249dc2ae95 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+Sat Jun 22 02:18:07 2013 Tanaka Akira <akr@fsij.org>
+
+ * bignum.c (bary_pack): Specialized packers implemented.
+ (HOST_BIGENDIAN_P): New macro.
+ (ALIGNOF): New macro.
+ (CLEAR_LOWBITS): New macro.
+ (FILL_LOWBITS): New macro.
+ (swap_bdigit): New macro.
+ (bary_2comp): Returns an int.
+
+ * internal.h (swap16): Moved from pack.c
+ (swap32): Ditto.
+ (swap64): Ditto.
+
Fri Jun 21 21:29:49 2013 Masaya Tarui <tarui@ruby-lang.org>
* gc.c (typedef enum): Introduce flags of major gc reason.
diff --git a/bignum.c b/bignum.c
index cc26f072a8..b580dee595 100644
--- a/bignum.c
+++ b/bignum.c
@@ -33,6 +33,15 @@ static VALUE big_three = Qnil;
#define USHORT _USHORT
#endif
+#ifdef WORDS_BIGENDIAN
+# define HOST_BIGENDIAN_P 1
+#else
+# define HOST_BIGENDIAN_P 0
+#endif
+#define ALIGNOF(type) ((int)offsetof(struct { char f1; type f2; }, f2))
+#define CLEAR_LOWBITS(d, numbits) (sizeof(d) * CHAR_BIT <= (numbits) ? 0 : ((d) >> (numbits)) << (numbits))
+#define FILL_LOWBITS(d, numbits) (sizeof(d) * CHAR_BIT <= (numbits) ? ~((d)*0) : (d) | ((((d)*0+1) << (numbits))-1))
+
#define BDIGITS(x) (RBIGNUM_DIGITS(x))
#define BITSPERDIG (SIZEOF_BDIGITS*CHAR_BIT)
#define BIGRAD ((BDIGIT_DBL)1 << BITSPERDIG)
@@ -48,6 +57,14 @@ static VALUE big_three = Qnil;
#define BIGLO(x) ((BDIGIT)((x) & BDIGMAX))
#define BDIGMAX ((BDIGIT)(BIGRAD-1))
+#if SIZEOF_BDIGITS == 2
+# define swap_bdigit(x) swap16(x)
+#elif SIZEOF_BDIGITS == 4
+# define swap_bdigit(x) swap32(x)
+#elif SIZEOF_BDIGITS == 8
+# define swap_bdigit(x) swap64(x)
+#endif
+
#define BIGZEROP(x) (RBIGNUM_LEN(x) == 0 || \
(BDIGITS(x)[0] == 0 && \
(RBIGNUM_LEN(x) == 1 || bigzero_p(x))))
@@ -76,7 +93,7 @@ static void bary_sub(BDIGIT *zds, size_t zn, BDIGIT *xds, size_t xn, BDIGIT *yds
static void bary_divmod(BDIGIT *qds, size_t nq, BDIGIT *rds, size_t nr, BDIGIT *xds, size_t nx, BDIGIT *yds, size_t ny);
static void bary_add(BDIGIT *zds, size_t zn, BDIGIT *xds, size_t xn, BDIGIT *yds, size_t yn);
static int bary_pack(int sign, BDIGIT *ds, size_t num_bdigits, void *words, size_t numwords, size_t wordsize, size_t nails, int flags);
-static BDIGIT bary_2comp(BDIGIT *ds, size_t n);
+static int bary_2comp(BDIGIT *ds, size_t n);
#define BIGNUM_DEBUG 0
#if BIGNUM_DEBUG
@@ -231,7 +248,7 @@ rb_big_clone(VALUE x)
return z;
}
-static BDIGIT
+static int
bary_2comp(BDIGIT *ds, size_t n)
{
size_t i = n;
@@ -244,7 +261,7 @@ bary_2comp(BDIGIT *ds, size_t n)
ds[i++] = BIGLO(num);
num = BIGDN(num);
} while (i < n);
- return (BDIGIT)num;
+ return num != 0;
}
/* modify a bignum by 2's complement */
@@ -901,6 +918,170 @@ bary_pack(int sign, BDIGIT *ds, size_t num_bdigits, void *words, size_t numwords
sign = 0;
}
+ if (nails == 0 && sign == 0) {
+ MEMZERO(words, unsigned char, numwords * wordsize);
+ return 0;
+ }
+ if (nails == 0 && numwords == 1) {
+ int need_swap = wordsize != 1 &&
+ (flags & INTEGER_PACK_BYTEORDER_MASK) != INTEGER_PACK_NATIVE_BYTE_ORDER &&
+ ((flags & INTEGER_PACK_MSBYTE_FIRST) ? !HOST_BIGENDIAN_P : HOST_BIGENDIAN_P);
+ if (0 < sign || !(flags & INTEGER_PACK_2COMP)) {
+ BDIGIT d;
+ if (wordsize == 1) {
+ *((unsigned char *)words) = (unsigned char)(d = dp[0]);
+ return ((1 < de - dp || CLEAR_LOWBITS(d, 8) != 0) ? 2 : 1) * sign;
+ }
+#if defined(HAVE_UINT16_T) && 2 <= SIZEOF_BDIGITS
+ if (wordsize == 2 && (uintptr_t)words % ALIGNOF(uint16_t) == 0) {
+ uint16_t u = (uint16_t)(d = dp[0]);
+ if (need_swap) u = swap16(u);
+ *((uint16_t *)words) = u;
+ return ((1 < de - dp || CLEAR_LOWBITS(d, 16) != 0) ? 2 : 1) * sign;
+ }
+#endif
+#if defined(HAVE_UINT32_T) && 4 <= SIZEOF_BDIGITS
+ if (wordsize == 4 && (uintptr_t)words % ALIGNOF(uint32_t) == 0) {
+ uint32_t u = (uint32_t)(d = dp[0]);
+ if (need_swap) u = swap32(u);
+ *((uint32_t *)words) = u;
+ return ((1 < de - dp || CLEAR_LOWBITS(d, 32) != 0) ? 2 : 1) * sign;
+ }
+#endif
+#if defined(HAVE_UINT64_T) && 8 <= SIZEOF_BDIGITS
+ if (wordsize == 8 && (uintptr_t)words % ALIGNOF(uint64_t) == 0) {
+ uint64_t u = (uint64_t)(d = dp[0]);
+ if (need_swap) u = swap64(u);
+ *((uint64_t *)words) = u;
+ return ((1 < de - dp || CLEAR_LOWBITS(d, 64) != 0) ? 2 : 1) * sign;
+ }
+#endif
+ }
+ else { /* sign < 0 && (flags & INTEGER_PACK_2COMP) */
+ BDIGIT_DBL_SIGNED d;
+ if (wordsize == 1) {
+ *((unsigned char *)words) = (unsigned char)(d = -(BDIGIT_DBL_SIGNED)dp[0]);
+ return (1 < de - dp || FILL_LOWBITS(d, 8) != -1) ? -2 : -1;
+ }
+#if defined(HAVE_UINT16_T) && 2 <= SIZEOF_BDIGITS
+ if (wordsize == 2 && (uintptr_t)words % ALIGNOF(uint16_t) == 0) {
+ uint16_t u = (uint16_t)(d = -(BDIGIT_DBL_SIGNED)dp[0]);
+ if (need_swap) u = swap16(u);
+ *((uint16_t *)words) = u;
+ return (wordsize == SIZEOF_BDIGITS && de - dp == 2 && dp[1] == 1 && dp[0] == 0) ? -1 :
+ (1 < de - dp || FILL_LOWBITS(d, 16) != -1) ? -2 : -1;
+ }
+#endif
+#if defined(HAVE_UINT32_T) && 4 <= SIZEOF_BDIGITS
+ if (wordsize == 4 && (uintptr_t)words % ALIGNOF(uint32_t) == 0) {
+ uint32_t u = (uint32_t)(d = -(BDIGIT_DBL_SIGNED)dp[0]);
+ if (need_swap) u = swap32(u);
+ *((uint32_t *)words) = u;
+ return (wordsize == SIZEOF_BDIGITS && de - dp == 2 && dp[1] == 1 && dp[0] == 0) ? -1 :
+ (1 < de - dp || FILL_LOWBITS(d, 32) != -1) ? -2 : -1;
+ }
+#endif
+#if defined(HAVE_UINT64_T) && 8 <= SIZEOF_BDIGITS
+ if (wordsize == 8 && (uintptr_t)words % ALIGNOF(uint64_t) == 0) {
+ uint64_t u = (uint64_t)(d = -(BDIGIT_DBL_SIGNED)dp[0]);
+ if (need_swap) u = swap64(u);
+ *((uint64_t *)words) = u;
+ return (wordsize == SIZEOF_BDIGITS && de - dp == 2 && dp[1] == 1 && dp[0] == 0) ? -1 :
+ (1 < de - dp || FILL_LOWBITS(d, 64) != -1) ? -2 : -1;
+ }
+#endif
+ }
+ }
+#if !defined(WORDS_BIGENDIAN)
+ if (nails == 0 && SIZEOF_BDIGITS == sizeof(BDIGIT) &&
+ (flags & INTEGER_PACK_WORDORDER_MASK) == INTEGER_PACK_LSWORD_FIRST &&
+ (flags & INTEGER_PACK_BYTEORDER_MASK) != INTEGER_PACK_MSBYTE_FIRST) {
+ size_t src_size = num_bdigits * SIZEOF_BDIGITS;
+ size_t dst_size = numwords * wordsize;
+ int overflow = 0;
+ while (0 < src_size && ((unsigned char *)ds)[src_size-1] == 0)
+ src_size--;
+ if (src_size <= dst_size) {
+ MEMCPY(words, dp, char, src_size);
+ MEMZERO((char*)words + src_size, char, dst_size - src_size);
+ }
+ else {
+ MEMCPY(words, dp, char, dst_size);
+ overflow = 1;
+ }
+ if (sign < 0 && (flags & INTEGER_PACK_2COMP)) {
+ unsigned char *p = words, *e = (unsigned char *)words + dst_size;
+ while (p < e && *p == 0)
+ p++;
+ if (p < e) {
+ *p = 1 + (unsigned char)~*p;
+ p++;
+ while (p < e) {
+ *p = (unsigned char)~*p;
+ p++;
+ }
+ }
+ else if (overflow) {
+ p = (unsigned char *)dp + dst_size;
+ e = (unsigned char *)dp + src_size;
+ if (p < e && *p++ == 1) {
+ while (p < e && *p == 0)
+ p++;
+ if (p == e)
+ overflow = 0;
+ }
+ }
+ }
+ if (overflow)
+ sign *= 2;
+ return sign;
+ }
+#endif
+ if (nails == 0 && SIZEOF_BDIGITS == sizeof(BDIGIT) &&
+ wordsize % SIZEOF_BDIGITS == 0 && (uintptr_t)words % ALIGNOF(BDIGIT) == 0) {
+ size_t buf_num_bdigits = numwords * wordsize / SIZEOF_BDIGITS;
+ int need_swap =
+ (flags & INTEGER_PACK_BYTEORDER_MASK) != INTEGER_PACK_NATIVE_BYTE_ORDER &&
+ ((flags & INTEGER_PACK_MSBYTE_FIRST) ? !HOST_BIGENDIAN_P : HOST_BIGENDIAN_P);
+ size_t i;
+ int overflow = 0;
+ if (num_bdigits <= buf_num_bdigits) {
+ MEMCPY(words, dp, BDIGIT, num_bdigits);
+ MEMZERO((BDIGIT*)words + num_bdigits, BDIGIT, buf_num_bdigits - num_bdigits);
+ }
+ else {
+ MEMCPY(words, dp, BDIGIT, buf_num_bdigits);
+ overflow = 1;
+ }
+ if (sign < 0 && (flags & INTEGER_PACK_2COMP)) {
+ int zero_p = bary_2comp(words, buf_num_bdigits);
+ if (overflow &&
+ buf_num_bdigits == num_bdigits-1 &&
+ dp[buf_num_bdigits] == 1 &&
+ zero_p)
+ overflow = 0;
+ }
+ if (need_swap) {
+ for (i = 0; i < buf_num_bdigits; i++) {
+ BDIGIT d = ((BDIGIT*)words)[i];
+ ((BDIGIT*)words)[i] = swap_bdigit(d);
+ }
+ }
+ if (flags & INTEGER_PACK_MSWORD_FIRST) {
+ BDIGIT *p1 = words, *p2 = p1 + buf_num_bdigits - 1;
+ while (p1 < p2) {
+ BDIGIT tmp = *p1;
+ *p1 = *p2;
+ *p2 = tmp;
+ p1++;
+ p2--;
+ }
+ }
+ if (overflow)
+ sign *= 2;
+ return sign;
+ }
+
buf = words;
bufend = buf + numwords * wordsize;
diff --git a/internal.h b/internal.h
index 267d388363..de4403761e 100644
--- a/internal.h
+++ b/internal.h
@@ -73,6 +73,43 @@ extern "C" {
(INTEGER_PACK_MSWORD_FIRST | \
INTEGER_PACK_MSBYTE_FIRST)
+#ifndef swap16
+# define swap16(x) ((uint16_t)((((x)&0xFF)<<8) | (((x)>>8)&0xFF)))
+#endif
+
+#ifndef swap32
+# if GCC_VERSION_SINCE(4,3,0)
+# define swap32(x) __builtin_bswap32(x)
+# endif
+#endif
+
+#ifndef swap32
+# define swap32(x) ((uint32_t)((((x)&0xFF)<<24) \
+ |(((x)>>24)&0xFF) \
+ |(((x)&0x0000FF00)<<8) \
+ |(((x)&0x00FF0000)>>8) ))
+#endif
+
+#ifndef swap64
+# if GCC_VERSION_SINCE(4,3,0)
+# define swap64(x) __builtin_bswap64(x)
+# endif
+#endif
+
+#ifndef swap64
+# ifdef HAVE_INT64_T
+# define byte_in_64bit(n) ((uint64_t)0xff << (n))
+# define swap64(x) ((uint64_t)((((x)&byte_in_64bit(0))<<56) \
+ |(((x)>>56)&0xFF) \
+ |(((x)&byte_in_64bit(8))<<40) \
+ |(((x)&byte_in_64bit(48))>>40) \
+ |(((x)&byte_in_64bit(16))<<24) \
+ |(((x)&byte_in_64bit(40))>>24) \
+ |(((x)&byte_in_64bit(24))<<8) \
+ |(((x)&byte_in_64bit(32))>>8)))
+# endif
+#endif
+
struct rb_deprecated_classext_struct {
char conflict[sizeof(VALUE) * 3];
};
diff --git a/pack.c b/pack.c
index afeb843e1b..5607f3b6ff 100644
--- a/pack.c
+++ b/pack.c
@@ -100,43 +100,6 @@ TOKEN_PASTE(swap,x)(xtype z) \
return r; \
}
-#ifndef swap32
-# if GCC_VERSION_SINCE(4,3,0)
-# define swap32(x) __builtin_bswap32(x)
-# endif
-#endif
-
-#ifndef swap64
-# if GCC_VERSION_SINCE(4,3,0)
-# define swap64(x) __builtin_bswap64(x)
-# endif
-#endif
-
-#ifndef swap16
-# define swap16(x) ((uint16_t)((((x)&0xFF)<<8) | (((x)>>8)&0xFF)))
-#endif
-
-#ifndef swap32
-# define swap32(x) ((uint32_t)((((x)&0xFF)<<24) \
- |(((x)>>24)&0xFF) \
- |(((x)&0x0000FF00)<<8) \
- |(((x)&0x00FF0000)>>8) ))
-#endif
-
-#ifndef swap64
-# ifdef HAVE_INT64_T
-# define byte_in_64bit(n) ((uint64_t)0xff << (n))
-# define swap64(x) ((uint64_t)((((x)&byte_in_64bit(0))<<56) \
- |(((x)>>56)&0xFF) \
- |(((x)&byte_in_64bit(8))<<40) \
- |(((x)&byte_in_64bit(48))>>40) \
- |(((x)&byte_in_64bit(16))<<24) \
- |(((x)&byte_in_64bit(40))>>24) \
- |(((x)&byte_in_64bit(24))<<8) \
- |(((x)&byte_in_64bit(32))>>8)))
-# endif
-#endif
-
#if SIZEOF_SHORT == 2
# define swaps(x) swap16(x)
#elif SIZEOF_SHORT == 4
diff --git a/test/-ext-/bignum/test_pack.rb b/test/-ext-/bignum/test_pack.rb
index c2c19a32a2..202395324b 100644
--- a/test/-ext-/bignum/test_pack.rb
+++ b/test/-ext-/bignum/test_pack.rb
@@ -69,6 +69,55 @@ class TestBignum < Test::Unit::TestCase
assert_equal([1, "\x00\x12\x00\x34\x00\x56\x00\x78"], 0x12345678.test_pack(4, 2, 8, BIG_ENDIAN))
end
+ def test_pack_overflow
+ assert_equal([-2, "\x1"], (-0x11).test_pack(1, 1, 4, BIG_ENDIAN))
+ assert_equal([-2, "\x0"], (-0x10).test_pack(1, 1, 4, BIG_ENDIAN))
+ assert_equal([-1, "\xF"], (-0x0F).test_pack(1, 1, 4, BIG_ENDIAN))
+ assert_equal([+1, "\xF"], (+0x0F).test_pack(1, 1, 4, BIG_ENDIAN))
+ assert_equal([+2, "\x0"], (+0x10).test_pack(1, 1, 4, BIG_ENDIAN))
+ assert_equal([+2, "\x1"], (+0x11).test_pack(1, 1, 4, BIG_ENDIAN))
+
+ assert_equal([-2, "\x01"], (-0x101).test_pack(1, 1, 0, BIG_ENDIAN))
+ assert_equal([-2, "\x00"], (-0x100).test_pack(1, 1, 0, BIG_ENDIAN))
+ assert_equal([-1, "\xFF"], (-0x0FF).test_pack(1, 1, 0, BIG_ENDIAN))
+ assert_equal([+1, "\xFF"], (+0x0FF).test_pack(1, 1, 0, BIG_ENDIAN))
+ assert_equal([+2, "\x00"], (+0x100).test_pack(1, 1, 0, BIG_ENDIAN))
+ assert_equal([+2, "\x01"], (+0x101).test_pack(1, 1, 0, BIG_ENDIAN))
+
+ assert_equal([-2, "\x00\x00\x00\x00\x00\x00\x00\x01"], (-0x10000000000000001).test_pack(2, 4, 0, BIG_ENDIAN))
+ assert_equal([-2, "\x00\x00\x00\x00\x00\x00\x00\x00"], (-0x10000000000000000).test_pack(2, 4, 0, BIG_ENDIAN))
+ assert_equal([-1, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"], (-0x0FFFFFFFFFFFFFFFF).test_pack(2, 4, 0, BIG_ENDIAN))
+ assert_equal([+1, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"], (+0x0FFFFFFFFFFFFFFFF).test_pack(2, 4, 0, BIG_ENDIAN))
+ assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x00"], (+0x10000000000000000).test_pack(2, 4, 0, BIG_ENDIAN))
+ assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x01"], (+0x10000000000000001).test_pack(2, 4, 0, BIG_ENDIAN))
+
+ 1.upto(16) {|wordsize|
+ 1.upto(20) {|numwords|
+ w = numwords*wordsize
+ n = 256**w
+ assert_equal([-2, "\x00"*(w-1)+"\x01"], (-n-1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
+ assert_equal([-2, "\x00"*w], (-n ).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
+ assert_equal([-1, "\xFF"*w], (-n+1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
+ assert_equal([+1, "\xFF"*w], (+n-1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
+ assert_equal([+2, "\x00"*w], (+n ).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
+ assert_equal([+2, "\x00"*(w-1)+"\x01"], (+n+1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
+ }
+ }
+
+ 1.upto(16) {|wordsize|
+ 1.upto(20) {|numwords|
+ w = numwords*wordsize
+ n = 256**w
+ assert_equal([-2, "\x01"+"\x00"*(w-1)], (-n-1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
+ assert_equal([-2, "\x00"*w], (-n ).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
+ assert_equal([-1, "\xFF"*w], (-n+1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
+ assert_equal([+1, "\xFF"*w], (+n-1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
+ assert_equal([+2, "\x00"*w], (+n ).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
+ assert_equal([+2, "\x01"+"\x00"*(w-1)], (+n+1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
+ }
+ }
+ end
+
def test_pack_sign
assert_equal([-1, "\x01"], (-1).test_pack(1, 1, 0, BIG_ENDIAN))
assert_equal([-1, "\x80\x70\x60\x50\x40\x30\x20\x10"], (-0x8070605040302010).test_pack(8, 1, 0, BIG_ENDIAN))
@@ -116,6 +165,33 @@ class TestBignum < Test::Unit::TestCase
assert_equal([+1, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"], (+0x0FFFFFFFFFFFFFFFF).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x00"], (+0x10000000000000000).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x01"], (+0x10000000000000001).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
+
+ 1.upto(16) {|wordsize|
+ 1.upto(20) {|numwords|
+ w = numwords*wordsize
+ n = 256**w
+ assert_equal([-2, "\xFF"*w ], (-n-1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
+ assert_equal([-1, "\x00"*w], (-n ).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
+ assert_equal([-1, "\x00"*(w-1)+"\x01"], (-n+1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
+ assert_equal([+1, "\xFF"*w], (+n-1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
+ assert_equal([+2, "\x00"*w], (+n ).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
+ assert_equal([+2, "\x00"*(w-1)+"\x01"], (+n+1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
+ }
+ }
+
+ 1.upto(16) {|wordsize|
+ 1.upto(20) {|numwords|
+ w = numwords*wordsize
+ n = 256**w
+ assert_equal([-2, "\xFF"*w ], (-n-1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
+ assert_equal([-1, "\x00"*w], (-n ).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
+ assert_equal([-1, "\x01"+"\x00"*(w-1)], (-n+1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
+ assert_equal([+1, "\xFF"*w], (+n-1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
+ assert_equal([+2, "\x00"*w], (+n ).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
+ assert_equal([+2, "\x01"+"\x00"*(w-1)], (+n+1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
+ }
+ }
+
end
def test_unpack_zero