lzo_init.c

lzo-1.08-src.zip 高效的压缩解压代码

	/* check that the pointer constructs work as expected */
	if (r == 1)
	{
		unsigned k = 1;
		const unsigned n = (unsigned) sizeof(lzo_uint32);
		lzo_byte *p0;
		lzo_byte *p1;

		k += __lzo_align_gap(&x[k],n);
		p0 = (lzo_bytep) &x[k];
#if defined(PTR_LINEAR)
		r &= __lzo_assert((PTR_LINEAR(p0) & (n-1)) == 0);
#else
		r &= __lzo_assert(n == 4);
		r &= __lzo_assert(PTR_ALIGNED_4(p0));
#endif

		r &= __lzo_assert(k >= 1);
		p1 = (lzo_bytep) &x[1];
		r &= __lzo_assert(PTR_GE(p0,p1));

		r &= __lzo_assert(k < 1+n);
		p1 = (lzo_bytep) &x[1+n];
		r &= __lzo_assert(PTR_LT(p0,p1));

		/* now check that aligned memory access doesn't core dump */
		if (r == 1)
		{
            lzo_uint32 v0, v1;
#if 0
			v0 = * (lzo_uint32 *) &x[k];
			v1 = * (lzo_uint32 *) &x[k+n];
#else
            /* Avoid compiler warnings on architectures that
             * do not allow unaligned access. */
            u.a_uchar_p = &x[k];
            v0 = *u.a_lzo_uint32_p;
            u.a_uchar_p = &x[k+n];
            v1 = *u.a_lzo_uint32_p;
#endif
			r &= __lzo_assert(v0 > 0);
			r &= __lzo_assert(v1 > 0);
		}
	}

	return r;
}


/***********************************************************************
//
************************************************************************/

LZO_PUBLIC(int)
_lzo_config_check(void)
{
	lzo_bool r = 1;
	int i;
	union {
		lzo_uint32 a;
		unsigned short b;
		lzo_uint32 aa[4];
		unsigned char x[4*sizeof(lzo_full_align_t)];
	} u;

	/* check that the compiler correctly casts signed to unsigned */
	COMPILE_TIME_ASSERT( (int) ((unsigned char) ((signed char) -1)) == 255);
	/* check that the compiler correctly promotes integrals */
	COMPILE_TIME_ASSERT( (((unsigned char)128) << (int)(8*sizeof(int)-8)) < 0);

#if 0
	/* paranoia - the following is guaranteed by definition anyway */
	r &= __lzo_assert((const void *)&u == (const void *)&u.a);
	r &= __lzo_assert((const void *)&u == (const void *)&u.b);
	r &= __lzo_assert((const void *)&u == (const void *)&u.x[0]);
	r &= __lzo_assert((const void *)&u == (const void *)&u.aa[0]);
#endif

	r &= basic_integral_check();
	r &= basic_ptr_check();
	if (r != 1)
		return LZO_E_ERROR;

	u.a = 0; u.b = 0;
	for (i = 0; i < (int) sizeof(u.x); i++)
		u.x[i] = LZO_BYTE(i);

	/* check LZO_BYTE_ORDER */
#if defined(LZO_BYTE_ORDER)
	if (r == 1)
	{
#  if (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
		lzo_uint32 a = (lzo_uint32) (u.a & LZO_0xffffffffL);
		unsigned short b = (unsigned short) (u.b & 0xffff);
		r &= __lzo_assert(a == 0x03020100L);
		r &= __lzo_assert(b == 0x0100);
#  elif (LZO_BYTE_ORDER == LZO_BIG_ENDIAN)
		lzo_uint32 a = u.a >> (8 * sizeof(u.a) - 32);
		unsigned short b = u.b >> (8 * sizeof(u.b) - 16);
		r &= __lzo_assert(a == 0x00010203L);
		r &= __lzo_assert(b == 0x0001);
#  else
#    error "invalid LZO_BYTE_ORDER"
#  endif
	}
#endif

	/* check that unaligned memory access works as expected */
#if defined(LZO_UNALIGNED_OK_2)
	COMPILE_TIME_ASSERT(sizeof(short) == 2);
	if (r == 1)
	{
		unsigned short b[4];

        for (i = 0; i < 4; i++)
            b[i] = * (const unsigned short *) &u.x[i];

#  if (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
		r &= __lzo_assert(b[0] == 0x0100);
		r &= __lzo_assert(b[1] == 0x0201);
		r &= __lzo_assert(b[2] == 0x0302);
		r &= __lzo_assert(b[3] == 0x0403);
#  elif (LZO_BYTE_ORDER == LZO_BIG_ENDIAN)
		r &= __lzo_assert(b[0] == 0x0001);
		r &= __lzo_assert(b[1] == 0x0102);
		r &= __lzo_assert(b[2] == 0x0203);
		r &= __lzo_assert(b[3] == 0x0304);
#  endif
	}
#endif

#if defined(LZO_UNALIGNED_OK_4)
	COMPILE_TIME_ASSERT(sizeof(lzo_uint32) == 4);
	if (r == 1)
	{
		lzo_uint32 a[4];

		for (i = 0; i < 4; i++)
			a[i] = * (const lzo_uint32 *) &u.x[i];

#  if (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
		r &= __lzo_assert(a[0] == 0x03020100L);
		r &= __lzo_assert(a[1] == 0x04030201L);
		r &= __lzo_assert(a[2] == 0x05040302L);
		r &= __lzo_assert(a[3] == 0x06050403L);
#  elif (LZO_BYTE_ORDER == LZO_BIG_ENDIAN)
		r &= __lzo_assert(a[0] == 0x00010203L);
		r &= __lzo_assert(a[1] == 0x01020304L);
		r &= __lzo_assert(a[2] == 0x02030405L);
		r &= __lzo_assert(a[3] == 0x03040506L);
#  endif
	}
#endif

#if defined(LZO_ALIGNED_OK_4)
	COMPILE_TIME_ASSERT(sizeof(lzo_uint32) == 4);
#endif

	COMPILE_TIME_ASSERT(lzo_sizeof_dict_t == sizeof(lzo_dict_t));

	/* save space and don't require linking in the lzo_adler32() function */
#if defined(__LZO_IN_MINLZO)
	/* check the lzo_adler32() function */
	if (r == 1)
	{
		lzo_uint32 adler;
		adler = lzo_adler32(0, NULL, 0);
		adler = lzo_adler32(adler, lzo_copyright(), 200);
		r &= __lzo_assert(adler == 0xc76f1751L);
	}
#endif

	/* check for the gcc schedule-insns optimization bug */
	if (r == 1)
	{
		r &= __lzo_assert(!schedule_insns_bug());
	}

	/* check for the gcc strength-reduce optimization bug */
	if (r == 1)
	{
		static int x[3];
		static unsigned xn = 3;
		register unsigned j;

		for (j = 0; j < xn; j++)
			x[j] = (int)j - 3;
		r &= __lzo_assert(!strength_reduce_bug(x));
	}

	/* now for the low-level pointer checks */
	if (r == 1)
	{
		r &= ptr_check();
	}

	return r == 1 ? LZO_E_OK : LZO_E_ERROR;
}


static lzo_bool schedule_insns_bug(void)
{
#if defined(__LZO_CHECKER)
	/* for some reason checker complains about uninitialized memory access */
	return 0;
#else
	const int clone[] = {1, 2, 0};
	const int *q;
	q = clone;
	return (*q) ? 0 : 1;
#endif
}


static lzo_bool strength_reduce_bug(int *x)
{
	return x[0] != -3 || x[1] != -2 || x[2] != -1;
}


#undef COMPILE_TIME_ASSERT


/***********************************************************************
//
************************************************************************/

int __lzo_init_done = 0;

LZO_PUBLIC(int)
__lzo_init2(unsigned v, int s1, int s2, int s3, int s4, int s5,
                        int s6, int s7, int s8, int s9)
{
	int r;

	__lzo_init_done = 1;

	if (v == 0)
		return LZO_E_ERROR;

	r = (s1 == -1 || s1 == (int) sizeof(short)) &&
	    (s2 == -1 || s2 == (int) sizeof(int)) &&
	    (s3 == -1 || s3 == (int) sizeof(long)) &&
	    (s4 == -1 || s4 == (int) sizeof(lzo_uint32)) &&
	    (s5 == -1 || s5 == (int) sizeof(lzo_uint)) &&
	    (s6 == -1 || s6 == (int) lzo_sizeof_dict_t) &&
	    (s7 == -1 || s7 == (int) sizeof(char *)) &&
	    (s8 == -1 || s8 == (int) sizeof(lzo_voidp)) &&
	    (s9 == -1 || s9 == (int) sizeof(lzo_compress_t));
	if (!r)
		return LZO_E_ERROR;

	r = _lzo_config_check();
	if (r != LZO_E_OK)
		return r;

	return r;
}


/***********************************************************************
// backward compatibility with v1.01
************************************************************************/

#if !defined(__LZO_IN_MINILZO)

LZO_EXTERN(int)
__lzo_init(unsigned v,int s1,int s2,int s3,int s4,int s5,int s6,int s7);

LZO_PUBLIC(int)
__lzo_init(unsigned v,int s1,int s2,int s3,int s4,int s5,int s6,int s7)
{
	if (v == 0 || v > 0x1010)
		return LZO_E_ERROR;
	return __lzo_init2(v,s1,s2,s3,s4,s5,-1,-1,s6,s7);
}

#endif


/*
vi:ts=4:et
*/