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/* Copyright (C) 1990, 1993, 1994, 1996, 1998 Aladdin Enterprises. All rights reserved.
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This software is provided AS-IS with no warranty, either express or
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implied.
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This software is distributed under license and may not be copied,
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modified or distributed except as expressly authorized under the terms
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of the license contained in the file LICENSE in this distribution.
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For more information about licensing, please refer to
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http://www.ghostscript.com/licensing/. For information on
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commercial licensing, go to http://www.artifex.com/licensing/ or
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contact Artifex Software, Inc., 101 Lucas Valley Road #110,
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San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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*/
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#ifndef gxarith_INCLUDED
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# define gxarith_INCLUDED
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/* $Id: gxarith.h,v 1.5 2002/06/16 08:45:43 lpd Exp $ */
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/* Arithmetic macros for Ghostscript library */
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/* Define an in-line abs function, good for any signed numeric type. */
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#define any_abs(x) ((x) < 0 ? -(x) : (x))
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/* Compute M modulo N. Requires N > 0; guarantees 0 <= imod(M,N) < N, */
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/* regardless of the whims of the % operator for negative operands. */
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int imod(int m, int n);
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/* Compute the GCD of two integers. */
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int igcd(int x, int y);
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/*
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* Given A, B, and M, compute X such that A*X = B mod M, 0 < X < M.
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* Requires: M > 0, 0 < A < M, 0 < B < M, gcd(A, M) | gcd(A, B).
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*/
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int idivmod(int a, int b, int m);
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/*
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* Compute floor(log2(N)). Requires N > 0.
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*/
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int ilog2(int n);
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/* Test whether an integral value fits in a given number of bits. */
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/* This works for all integral types. */
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#define fits_in_bits(i, n)\
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(sizeof(i) <= sizeof(int) ? fits_in_ubits((i) + (1 << ((n) - 1)), (n) + 1) :\
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fits_in_ubits((i) + (1L << ((n) - 1)), (n) + 1))
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#define fits_in_ubits(i, n) (((i) >> (n)) == 0)
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/*
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* There are some floating point operations that can be implemented
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* very efficiently on machines that have no floating point hardware,
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* assuming IEEE representation and no range overflows.
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* We define straightforward versions of them here, and alternate versions
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* for no-floating-point machines in gxfarith.h.
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*/
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/* Test floating point values against constants. */
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#define is_fzero(f) ((f) == 0.0)
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#define is_fzero2(f1,f2) ((f1) == 0.0 && (f2) == 0.0)
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#define is_fneg(f) ((f) < 0.0)
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#define is_fge1(f) ((f) >= 1.0)
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/* Test whether a floating point value fits in a given number of bits. */
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#define f_fits_in_bits(f, n)\
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((f) >= -2.0 * (1L << ((n) - 2)) && (f) < 2.0 * (1L << ((n) - 2)))
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#define f_fits_in_ubits(f, n)\
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((f) >= 0 && (f) < 4.0 * (1L << ((n) - 2)))
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/*
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* Define a macro for computing log2(n), where n=1,2,4,...,128.
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* Because some compilers limit the total size of a statement,
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* this macro must only mention n once. The macro should really
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* only be used with compile-time constant arguments, but it will work
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* even if n is an expression computed at run-time.
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*/
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#define small_exact_log2(n)\
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((uint)(05637042010L >> ((((n) % 11) - 1) * 3)) & 7)
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/*
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* The following doesn't give rise to a macro, but is used in several
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* places in Ghostscript. We observe that if M = 2^n-1 and V < M^2,
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* then the quotient Q and remainder R can be computed as:
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* Q = V / M = (V + (V >> n) + 1) >> n;
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* R = V % M = (V + (V / M)) & M = V - (Q << n) + Q.
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*/
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#endif /* gxarith_INCLUDED */
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