Class Range
- java.lang.Object
-
- org.checkerframework.common.value.util.Range
-
public class Range extends java.lang.Object
The Range class models a 64-bit two's-complement integral interval, such as all integers between 1 and 10, inclusive.Range
is immutable.
-
-
Field Summary
Fields Modifier and Type Field Description static Range
BYTE_EVERYTHING
A range containing all possible 8-bit values.static Range
CHAR_EVERYTHING
A range containing all possible char values.static Range
EVERYTHING
An alias to the range containing all possible 64-bit values.long
from
The lower bound of the interval, inclusive.static boolean
ignoreOverflow
Should ranges take overflow into account or ignore it? IfignoreOverflow
is true, then operations that would result in more than the max value are clipped to the max value (and similarly for the min).static Range
INT_EVERYTHING
A range containing all possible 32-bit values.static Range
LONG_EVERYTHING
A range containing all possible 64-bit values.static @InternedDistinct Range
NOTHING
The empty range.static Range
SHORT_EVERYTHING
A range containing all possible 16-bit values.long
to
The upper bound of the interval, inclusive.
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description Range
bitwiseAnd(Range right)
Returns a range that includes all possible values resulting from performing the bitwise and operation on a value in this range by a mask in the specified range.Range
bitwiseComplement()
Returns the range of a variable that falls within this range after applying the bitwise complement operation.Range
bitwiseOr(Range right)
We give up the analysis for bitwise OR operation.Range
bitwiseXor(Range right)
We give up the analysis for bitwise XOR operation.Range
byteRange()
Converts this range to an 8-bit byte range.Range
charRange()
Converts this range to a char range.boolean
contains(long element)
Returns true if the element is contained in this range.boolean
contains(Range other)
Returns true if the other range is contained in this range.static Range
create(long from, long to)
Constructs a range with its bounds specified by two parameters,from
andto
.static Range
create(java.util.Collection<? extends java.lang.Number> values)
Create a Range from a collection of Numbers.static Range
create(javax.lang.model.type.TypeKind typeKind)
Returns a Range representing all possible values for the given primitive type.Range
divide(Range right)
Returns the smallest range that includes all possible values resulting from dividing (integer division) an arbitrary value in this range by an arbitrary value in the specified range.boolean
equals(@Nullable java.lang.Object obj)
int
hashCode()
Range
intersect(Range right)
Returns the smallest range that includes all values contained in both of the two ranges.Range
intRange()
Converts this range to a 32-bit integral range.boolean
isByteEverything()
Return true if this range contains everybyte
value.boolean
isCharEverything()
Return true if this range contains everychar
value.boolean
isConstant()
Returns true if this range represents a constant value.boolean
isIntEverything()
Return true if this range contains everyint
value.boolean
isLongEverything()
Return true if this range contains everylong
value.boolean
isNothing()
Return true if this range contains no values.boolean
isShortEverything()
Return true if this range contains everyshort
value.boolean
isWiderThan(long value)
Returns true if the range is wider than a given value, i.e., if the number of possible values enclosed by this range is more than the given value.boolean
isWithin(long lb, long ub)
Returns true if this range is completely contained in the range specified by the given lower bound inclusive and upper bound inclusive.boolean
isWithinInteger()
Returns true if this range is completely contained in the scope of the Integer type.Range
max(Range other)
Returns the range with the highest to and from values of this range and the passed range.Range
min(Range other)
Returns the range with the lowest to and from values of this range and the passed range.Range
minus(Range right)
Returns the smallest range that includes all possible values resulting from subtracting an arbitrary value in the specified range from an arbitrary value in this range.Range
plus(Range right)
Returns the smallest range that includes all possible values resulting from adding an arbitrary value in the specified range to an arbitrary value in this range.Range
refineEqualTo(Range right)
Refines this range to reflect that some value in it can be equal to a value in the given range.Range
refineGreaterThan(Range right)
Refines this range to reflect that some value in it can be greater than a value in the given range.Range
refineGreaterThanEq(Range right)
Refines this range to reflect that some value in it can be greater than or equal to a value in the given range.Range
refineLessThan(Range right)
Refines this range to reflect that some value in it can be less than a value in the given range.Range
refineLessThanEq(Range right)
Refines this range to reflect that some value in it can be less than or equal to a value in the given range.Range
refineNotEqualTo(Range right)
Refines this range to reflect that some value in it must not be equal to a value in the given range.Range
remainder(Range right)
Returns a range that includes all possible values of the remainder of dividing an arbitrary value in this range by an arbitrary value in the specified range.Range
shiftLeft(Range right)
Returns a range that includes all possible values resulting from left shifting an arbitrary value in this range by an arbitrary number of bits in the specified range.Range
shortRange()
Converts a this range to a 16-bit short range.Range
signedShiftRight(Range right)
Returns a range that includes all possible values resulting from signed right shifting an arbitrary value in this range by an arbitrary number of bits in the specified range.Range
times(Range right)
Returns the smallest range that includes all possible values resulting from multiplying an arbitrary value in the specified range by an arbitrary value in this range.java.lang.String
toString()
Range
unaryMinus()
Returns the range of a variable that falls within this range after applying the unary minus operation.Range
unaryPlus()
Returns the range of a variable that falls within this range after applying the unary plus operation (which is a no-op).Range
union(Range right)
Returns the smallest range that includes all values contained in either of the two ranges.Range
unsignedShiftRight(Range right)
When this range only contains non-negative values, the refined result should be the same assignedShiftRight(Range)
.
-
-
-
Field Detail
-
from
public final long from
The lower bound of the interval, inclusive.
-
to
public final long to
The upper bound of the interval, inclusive.
-
ignoreOverflow
public static boolean ignoreOverflow
Should ranges take overflow into account or ignore it?- If
ignoreOverflow
is true, then operations that would result in more than the max value are clipped to the max value (and similarly for the min). - If
ignoreOverflow
is false, then operations that would result in more than the max wrap around according to the rules of twos-complement arithmetic and produce a smaller value (and similarly for the min).
Any checker that uses this library should set this field. By default, this field is set to false (meaning overflow is taken into account), but a previous checker might have set it to true.
A static field is used because passing an instance field throughout the class bloats the code.
- If
-
LONG_EVERYTHING
public static final Range LONG_EVERYTHING
A range containing all possible 64-bit values.
-
INT_EVERYTHING
public static final Range INT_EVERYTHING
A range containing all possible 32-bit values.
-
SHORT_EVERYTHING
public static final Range SHORT_EVERYTHING
A range containing all possible 16-bit values.
-
CHAR_EVERYTHING
public static final Range CHAR_EVERYTHING
A range containing all possible char values.
-
BYTE_EVERYTHING
public static final Range BYTE_EVERYTHING
A range containing all possible 8-bit values.
-
NOTHING
public static final @InternedDistinct Range NOTHING
The empty range. This is the only Range object that contains nothing
-
EVERYTHING
public static final Range EVERYTHING
An alias to the range containing all possible 64-bit values.
-
-
Method Detail
-
create
public static Range create(long from, long to)
Constructs a range with its bounds specified by two parameters,from
andto
. Requiresfrom <= to
.- Parameters:
from
- the lower bound (inclusive)to
- the upper bound (inclusive)- Returns:
- the Range [from..to]
-
create
public static Range create(java.util.Collection<? extends java.lang.Number> values)
Create a Range from a collection of Numbers.- Parameters:
values
- collection whose min and max values will be used as the range's from and to values- Returns:
- a range that encompasses all the argument's values (
NOTHING
if the argument is an empty collection)
-
create
public static Range create(javax.lang.model.type.TypeKind typeKind)
Returns a Range representing all possible values for the given primitive type.- Parameters:
typeKind
- one of INT, SHORT, BYTE, CHAR, or LONG- Returns:
- the range for the given primitive type
-
toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
-
equals
public boolean equals(@Nullable java.lang.Object obj)
- Overrides:
equals
in classjava.lang.Object
-
hashCode
public int hashCode()
- Overrides:
hashCode
in classjava.lang.Object
-
isLongEverything
public boolean isLongEverything()
Return true if this range contains everylong
value.
-
isIntEverything
public boolean isIntEverything()
Return true if this range contains everyint
value.
-
isShortEverything
public boolean isShortEverything()
Return true if this range contains everyshort
value.
-
isCharEverything
public boolean isCharEverything()
Return true if this range contains everychar
value.
-
isByteEverything
public boolean isByteEverything()
Return true if this range contains everybyte
value.
-
isNothing
public boolean isNothing()
Return true if this range contains no values.
-
intRange
public Range intRange()
Converts this range to a 32-bit integral range.If
ignoreOverflow
is true and one of the bounds is outside the Integer range, then that bound is set to the bound of the Integer range.If
ignoreOverflow
is false and this range is too wide, i.e., wider than the full range of the Integer class, return INT_EVERYTHING.If
ignoreOverflow
is false and the bounds of this range are not representable as 32-bit integers, convert the bounds to Integer type in accordance with Java twos-complement overflow rules, e.g., Integer.MAX_VALUE + 1 is converted to Integer.MIN_VALUE.- Returns:
- this range, converted to a 32-bit integral range
-
shortRange
public Range shortRange()
Converts a this range to a 16-bit short range.If
ignoreOverflow
is true and one of the bounds is outside the Short range, then that bound is set to the bound of the Short range.If
ignoreOverflow
is false and this range is too wide, i.e., wider than the full range of the Short class, return SHORT_EVERYTHING.If
ignoreOverflow
is false and the bounds of this range are not representable as 16-bit integers, convert the bounds to Short type in accordance with Java twos-complement overflow rules, e.g., Short.MAX_VALUE + 1 is converted to Short.MIN_VALUE.- Returns:
- this range, converted to a 16-bit short range
-
charRange
public Range charRange()
Converts this range to a char range.If
ignoreOverflow
is true and one of the bounds is outside the Character range, then that bound is set to the bound of the Character range.If
ignoreOverflow
is false and this range is too wide, i.e., wider than the full range of the Character class, return CHAR_EVERYTHING.If
ignoreOverflow
is false and the bounds of this range are not representable as 8-bit integers, convert the bounds to Character type in accordance with Java overflow rules (twos-complement), e.g., Character.MAX_VALUE + 1 is converted to Character.MIN_VALUE.
-
byteRange
public Range byteRange()
Converts this range to an 8-bit byte range.If
ignoreOverflow
is true and one of the bounds is outside the Byte range, then that bound is set to the bound of the Byte range.If
ignoreOverflow
is false and this range is too wide, i.e., wider than the full range of the Byte class, return BYTE_EVERYTHING.If
ignoreOverflow
is false and the bounds of this range are not representable as 8-bit integers, convert the bounds to Byte type in accordance with Java twos-complement overflow rules, e.g., Byte.MAX_VALUE + 1 is converted to Byte.MIN_VALUE.- Returns:
- this range, converted to an 8-bit byte range
-
contains
public boolean contains(long element)
Returns true if the element is contained in this range.- Parameters:
element
- the value to seek- Returns:
- true if
element
is in this range
-
contains
public boolean contains(Range other)
Returns true if the other range is contained in this range.- Parameters:
other
- the range that might be within this one- Returns:
- true if
other
is within this range
-
union
public Range union(Range right)
Returns the smallest range that includes all values contained in either of the two ranges. We call this the union of two ranges.- Parameters:
right
- a range to union with this range- Returns:
- a range resulting from the union of the specified range and this range
-
intersect
public Range intersect(Range right)
Returns the smallest range that includes all values contained in both of the two ranges. We call this the intersection of two ranges. If there is no overlap between the two ranges, returns an empty range.- Parameters:
right
- the range to intersect with this range- Returns:
- a range resulting from the intersection of the specified range and this range
-
min
public Range min(Range other)
Returns the range with the lowest to and from values of this range and the passed range.- Parameters:
other
- the range to compare- Returns:
- the range with the lowest to and from values of this range and the passed range
-
max
public Range max(Range other)
Returns the range with the highest to and from values of this range and the passed range.- Parameters:
other
- the range to compare- Returns:
- the range with the highest to and from values of this range and the passed range
-
plus
public Range plus(Range right)
Returns the smallest range that includes all possible values resulting from adding an arbitrary value in the specified range to an arbitrary value in this range. We call this the addition of two ranges.- Parameters:
right
- a range to be added to this range- Returns:
- the range resulting from the addition of the specified range and this range
-
minus
public Range minus(Range right)
Returns the smallest range that includes all possible values resulting from subtracting an arbitrary value in the specified range from an arbitrary value in this range. We call this the subtraction of two ranges.- Parameters:
right
- the range to be subtracted from this range- Returns:
- the range resulting from subtracting the specified range from this range
-
times
public Range times(Range right)
Returns the smallest range that includes all possible values resulting from multiplying an arbitrary value in the specified range by an arbitrary value in this range. We call this the multiplication of two ranges.- Parameters:
right
- the specified range to be multiplied by this range- Returns:
- the range resulting from multiplying the specified range by this range
-
divide
public Range divide(Range right)
Returns the smallest range that includes all possible values resulting from dividing (integer division) an arbitrary value in this range by an arbitrary value in the specified range. We call this the division of two ranges.- Parameters:
right
- the specified range by which this range is divided- Returns:
- the range resulting from dividing this range by the specified range
-
remainder
public Range remainder(Range right)
Returns a range that includes all possible values of the remainder of dividing an arbitrary value in this range by an arbitrary value in the specified range.In the current implementation, the result might not be the smallest range that includes all the possible values.
- Parameters:
right
- the specified range by which this range is divided- Returns:
- the range of the remainder of dividing this range by the specified range
-
shiftLeft
public Range shiftLeft(Range right)
Returns a range that includes all possible values resulting from left shifting an arbitrary value in this range by an arbitrary number of bits in the specified range. We call this the left shift of a range.- Parameters:
right
- the range of bits by which this range is left shifted- Returns:
- the range resulting from left shifting this range by the specified range
-
signedShiftRight
public Range signedShiftRight(Range right)
Returns a range that includes all possible values resulting from signed right shifting an arbitrary value in this range by an arbitrary number of bits in the specified range. We call this the signed right shift operation of a range.- Parameters:
right
- the range of bits by which this range is signed right shifted- Returns:
- the range resulting from signed right shifting this range by the specified range
-
unsignedShiftRight
public Range unsignedShiftRight(Range right)
When this range only contains non-negative values, the refined result should be the same assignedShiftRight(Range)
. We give up the analysis when this range contains negative value(s).
-
bitwiseAnd
public Range bitwiseAnd(Range right)
Returns a range that includes all possible values resulting from performing the bitwise and operation on a value in this range by a mask in the specified range. We call this the bitwise and operation of a range.The current implementation is conservative: it only refines the cases where the range of mask represents a constant. In other cases, it gives up on the refinement and returns
EVERYTHING
instead.- Parameters:
right
- the range of mask of the bitwise and operation- Returns:
- the range resulting from the bitwise and operation of this range and the specified range of mask
-
unaryPlus
public Range unaryPlus()
Returns the range of a variable that falls within this range after applying the unary plus operation (which is a no-op).- Returns:
- this range
-
unaryMinus
public Range unaryMinus()
Returns the range of a variable that falls within this range after applying the unary minus operation.- Returns:
- the resulted range of applying unary minus on an arbitrary value in this range
-
bitwiseComplement
public Range bitwiseComplement()
Returns the range of a variable that falls within this range after applying the bitwise complement operation.- Returns:
- the resulting range of applying bitwise complement on an arbitrary value in this range
-
refineLessThan
public Range refineLessThan(Range right)
Refines this range to reflect that some value in it can be less than a value in the given range. This is used for calculating the control-flow-refined result of the < operator. For example:@IntRange(from = 0, to = 10) int a; @IntRange(from = 3, to = 7) int b; ... if (a < b) { // range of a is now refined to [0, 6] because a value in range [7, 10] // cannot be smaller than variable b with range [3, 7]. ... }
refineGreaterThanEq(Range)
method if you are also interested in refining the range ofb
in the code above.- Parameters:
right
- the specifiedRange
to compare with- Returns:
- the refined
Range
-
refineLessThanEq
public Range refineLessThanEq(Range right)
Refines this range to reflect that some value in it can be less than or equal to a value in the given range. This is used for calculating the control-flow-refined result of the <= operator. For example:@IntRange(from = 0, to = 10) int a; @IntRange(from = 3, to = 7) int b; ... if (a <= b) { // range of a is now refined to [0, 7] because a value in range [8, 10] // cannot be less than or equal to variable b with range [3, 7]. ... }
refineGreaterThan(Range)
method if you are also interested in refining the range ofb
in the code above.- Parameters:
right
- the specifiedRange
to compare with- Returns:
- the refined
Range
-
refineGreaterThan
public Range refineGreaterThan(Range right)
Refines this range to reflect that some value in it can be greater than a value in the given range. This is used for calculating the control-flow-refined result of the > operator. For example:@IntRange(from = 0, to = 10) int a; @IntRange(from = 3, to = 7) int b; ... if (a > b) { // range of a is now refined to [4, 10] because a value in range [0, 3] // cannot be greater than variable b with range [3, 7]. ... }
refineLessThanEq(Range)
method if you are also interested in refining the range ofb
in the code above.- Parameters:
right
- the specifiedRange
to compare with- Returns:
- the refined
Range
-
refineGreaterThanEq
public Range refineGreaterThanEq(Range right)
Refines this range to reflect that some value in it can be greater than or equal to a value in the given range. This is used for calculating the control-flow-refined result of the >= operator. For example:@IntRange(from = 0, to = 10) int a; @IntRange(from = 3, to = 7) int b; ... if (a >= b) { // range of a is now refined to [3, 10] because a value in range [0, 2] // cannot be greater than or equal to variable b with range [3, 7]. ... }
refineLessThan(Range)
method if you are also interested in refining the range ofb
in the code above.- Parameters:
right
- the specifiedRange
to compare with- Returns:
- the refined
Range
-
refineEqualTo
public Range refineEqualTo(Range right)
Refines this range to reflect that some value in it can be equal to a value in the given range. This is used for calculating the control-flow-refined result of the == operator. For example:@IntRange(from = 0, to = 10) int a; @IntRange(from = 3, to = 15) int b; ... if (a == b) { // range of a is now refined to [3, 10] because a value in range [0, 2] // cannot be equal to variable b with range [3, 15]. ... }
- Parameters:
right
- the specifiedRange
to compare with- Returns:
- the refined
Range
-
refineNotEqualTo
public Range refineNotEqualTo(Range right)
Refines this range to reflect that some value in it must not be equal to a value in the given range. This only changes the range if the given range (right) contains exactly one integer, and that integer is one of the bounds of this range. This is used for calculating the control-flow-refined result of the != operator. For example:@IntRange(from = 0, to = 10) int a; @IntRange(from = 0, to = 0) int b; ... if (a != b) { // range of a is now refined to [1, 10] because it cannot // be zero. ... }
- Parameters:
right
- the specifiedRange
to compare with- Returns:
- the refined
Range
-
isWiderThan
public boolean isWiderThan(long value)
Returns true if the range is wider than a given value, i.e., if the number of possible values enclosed by this range is more than the given value.- Parameters:
value
- the value to compare with- Returns:
- true if wider than the given value
-
isConstant
public boolean isConstant()
Returns true if this range represents a constant value.- Returns:
- true if this range represents a constant value
-
isWithin
public boolean isWithin(long lb, long ub)
Returns true if this range is completely contained in the range specified by the given lower bound inclusive and upper bound inclusive.- Parameters:
lb
- lower bound for the range that might contain this oneub
- upper bound for the range that might contain this one- Returns:
- true if this range is within the given bounds
-
isWithinInteger
public boolean isWithinInteger()
Returns true if this range is completely contained in the scope of the Integer type.- Returns:
- true if the range is contained within the Integer range inclusive
-
-