mirror of
https://github.com/mruby/mruby
synced 2026-06-08 16:11:16 +00:00
Yukihiro "Matz" Matsumoto
9a7211bb25
The previous implementation of mrb_int_mul_overflow performed the multiplication before checking for overflow. This is undefined behavior for signed integers and can lead to incorrect results on some compilers (e.g., MSVC). The implementation has been changed to perform the overflow checks before the multiplication. Co-authored-by: Gemini <gemini@google.com>
175 lines
5.1 KiB
C
175 lines
5.1 KiB
C
/**
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** @file mruby/numeric.h - Numeric, Integer, Float class
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**
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** See Copyright Notice in mruby.h
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*/
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#ifndef MRUBY_NUMERIC_H
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#define MRUBY_NUMERIC_H
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#include "common.h"
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/**
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* Numeric class and it's sub-classes.
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*
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* Integer and Float
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*/
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MRB_BEGIN_DECL
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#define TYPED_POSFIXABLE(f,t) ((f) <= (t)MRB_FIXNUM_MAX)
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#define TYPED_NEGFIXABLE(f,t) ((f) >= (t)MRB_FIXNUM_MIN)
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#define TYPED_FIXABLE(f,t) (TYPED_POSFIXABLE(f,t) && TYPED_NEGFIXABLE(f,t))
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#define POSFIXABLE(f) TYPED_POSFIXABLE(f,mrb_int)
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#define NEGFIXABLE(f) TYPED_NEGFIXABLE(f,mrb_int)
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#define FIXABLE(f) TYPED_FIXABLE(f,mrb_int)
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#ifndef MRB_NO_FLOAT
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#ifdef MRB_INT64
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#define FIXABLE_FLOAT(f) ((f)>=-9223372036854775808.0 && (f)<9223372036854775808.0)
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#else
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#define FIXABLE_FLOAT(f) TYPED_FIXABLE(f,mrb_float)
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#endif
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#endif
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/* utility functions */
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MRB_API mrb_value mrb_num_add(mrb_state *mrb, mrb_value x, mrb_value y);
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MRB_API mrb_value mrb_num_sub(mrb_state *mrb, mrb_value x, mrb_value y);
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MRB_API mrb_value mrb_num_mul(mrb_state *mrb, mrb_value x, mrb_value y);
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/* obsolete old names */
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#define mrb_num_plus(mrb, x, y) mrb_num_add(mrb, x, y)
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#define mrb_num_minus(mrb, x, y) mrb_num_sub(mrb, x, y)
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MRB_API mrb_value mrb_integer_to_str(mrb_state *mrb, mrb_value x, mrb_int base);
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MRB_API char *mrb_int_to_cstr(char *buf, size_t len, mrb_int n, mrb_int base);
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/* obsolete function(s); will be removed */
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#define mrb_fixnum_to_str(mrb, x, base) mrb_integer_to_str(mrb, x, base)
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#ifndef __has_builtin
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#define __has_builtin(x) 0
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#endif
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#if (defined(__GNUC__) && __GNUC__ >= 5) || \
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(__has_builtin(__builtin_add_overflow) && \
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__has_builtin(__builtin_sub_overflow) && \
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__has_builtin(__builtin_mul_overflow))
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# define MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
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#endif
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/*
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// Clang 3.8 and 3.9 have problem compiling mruby in 32-bit mode, when MRB_INT64 is set
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// because of missing __mulodi4 and similar functions in its runtime. We need to use custom
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// implementation for them.
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*/
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#ifdef MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
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#if defined(__clang__) && (__clang_major__ == 3) && (__clang_minor__ >= 8) && \
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defined(MRB_32BIT) && defined(MRB_INT64)
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#undef MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
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#endif
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#endif
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#ifdef MRB_HAVE_TYPE_GENERIC_CHECKED_ARITHMETIC_BUILTINS
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static inline mrb_bool
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mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum)
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{
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return __builtin_add_overflow(augend, addend, sum);
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}
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static inline mrb_bool
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mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference)
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{
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return __builtin_sub_overflow(minuend, subtrahend, difference);
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}
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static inline mrb_bool
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mrb_int_mul_overflow(mrb_int multiplier, mrb_int multiplicand, mrb_int *product)
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{
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return __builtin_mul_overflow(multiplier, multiplicand, product);
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}
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#else
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#define MRB_INT_OVERFLOW_MASK ((mrb_uint)1 << (MRB_INT_BIT - 1))
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static inline mrb_bool
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mrb_int_add_overflow(mrb_int a, mrb_int b, mrb_int *c)
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{
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mrb_uint x = (mrb_uint)a;
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mrb_uint y = (mrb_uint)b;
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mrb_uint z = (mrb_uint)(x + y);
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*c = (mrb_int)z;
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return !!(((x ^ z) & (y ^ z)) & MRB_INT_OVERFLOW_MASK);
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}
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static inline mrb_bool
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mrb_int_sub_overflow(mrb_int a, mrb_int b, mrb_int *c)
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{
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mrb_uint x = (mrb_uint)a;
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mrb_uint y = (mrb_uint)b;
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mrb_uint z = (mrb_uint)(x - y);
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*c = (mrb_int)z;
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return !!(((x ^ z) & (~y ^ z)) & MRB_INT_OVERFLOW_MASK);
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}
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static inline mrb_bool
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mrb_int_mul_overflow(mrb_int a, mrb_int b, mrb_int *c)
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{
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#ifdef MRB_INT32
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int64_t n = (int64_t)a * b;
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*c = (mrb_int)n;
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return n > MRB_INT_MAX || n < MRB_INT_MIN;
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#else /* MRB_INT64 */
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*c = a * b;
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if (a > 0 && b > 0 && a > MRB_INT_MAX / b) return TRUE;
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if (a < 0 && b > 0 && a < MRB_INT_MIN / b) return TRUE;
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if (a > 0 && b < 0 && b < MRB_INT_MIN / a) return TRUE;
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if (a < 0 && b < 0 && (a <= MRB_INT_MIN || b <= MRB_INT_MIN || -a > MRB_INT_MAX / -b))
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return TRUE;
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return FALSE;
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#endif
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}
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#undef MRB_INT_OVERFLOW_MASK
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#endif
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#ifndef MRB_NO_FLOAT
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# define MRB_FLT_RADIX FLT_RADIX
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# ifdef MRB_USE_FLOAT32
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# define MRB_FLT_MANT_DIG FLT_MANT_DIG
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# define MRB_FLT_EPSILON FLT_EPSILON
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# define MRB_FLT_DIG FLT_DIG
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# define MRB_FLT_MIN_EXP FLT_MIN_EXP
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# define MRB_FLT_MIN FLT_MIN
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# define MRB_FLT_MIN_10_EXP FLT_MIN_10_EXP
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# define MRB_FLT_MAX_EXP FLT_MAX_EXP
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# define MRB_FLT_MAX FLT_MAX
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# define MRB_FLT_MAX_10_EXP FLT_MAX_10_EXP
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# else /* not MRB_USE_FLOAT32 */
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# define MRB_FLT_MANT_DIG DBL_MANT_DIG
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# define MRB_FLT_EPSILON DBL_EPSILON
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# define MRB_FLT_DIG DBL_DIG
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# define MRB_FLT_MIN_EXP DBL_MIN_EXP
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# define MRB_FLT_MIN DBL_MIN
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# define MRB_FLT_MIN_10_EXP DBL_MIN_10_EXP
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# define MRB_FLT_MAX_EXP DBL_MAX_EXP
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# define MRB_FLT_MAX DBL_MAX
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# define MRB_FLT_MAX_10_EXP DBL_MAX_10_EXP
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# endif /* MRB_USE_FLOAT32 */
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MRB_API mrb_value mrb_float_to_integer(mrb_state *mrb, mrb_value val);
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/* internal functions */
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mrb_float mrb_div_float(mrb_float x, mrb_float y);
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mrb_value mrb_float_to_str(mrb_state *mrb, mrb_value x, const char *fmt);
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int mrb_format_float(mrb_float f, char *buf, size_t buf_size, char fmt, int prec, char sign);
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#endif /* MRB_NO_FLOAT */
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MRB_END_DECL
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#endif /* MRUBY_NUMERIC_H */
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