Documentation
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Overview ¶
Package offsetrange defines a restriction and restriction tracker for offset ranges. An offset range is just a range, with a start and end, that can begin at an offset, and is commonly used to represent byte ranges for files or indices for iterable containers.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Restriction ¶
type Restriction struct {
Start, End int64
}
Restriction is an offset range restriction, which represents a range of integers as a half-closed interval with boundaries [start, end).
func (*Restriction) EvenSplits ¶
func (r *Restriction) EvenSplits(num int64) (splits []Restriction)
EvenSplits splits a restriction into a number of evenly sized restrictions. Each split restriction is guaranteed to not be empty, and each unit from the original restriction is guaranteed to be contained in one split restriction.
Num should be greater than 0. Otherwise there is no way to split the restriction and this function will return the original restriction.
func (*Restriction) Size ¶
func (r *Restriction) Size() float64
Size returns the restriction's size as the difference between Start and End.
type Tracker ¶
type Tracker struct {
Rest Restriction
Claimed int64 // Tracks the last claimed position.
Stopped bool // Tracks whether TryClaim has indicated to stop processing elements.
Err error
}
Tracker tracks a restriction that can be represented as a range of integer values, for example for byte offsets in a file, or indices in an array. Note that this tracker makes no assumptions about the positions of blocks within the range, so users must handle validation of block positions if needed.
func NewTracker ¶
func NewTracker(rest Restriction) *Tracker
NewTracker is a constructor for an Tracker given a start and end range.
func (*Tracker) GetError ¶
GetError returns the error that caused the tracker to stop, if there is one.
func (*Tracker) GetProgress ¶
GetProgress reports progress based on the claimed size and unclaimed sizes of the restriction.
func (*Tracker) IsDone ¶
IsDone returns true if the most recent claimed element is past the end of the restriction.
func (*Tracker) TryClaim ¶
TryClaim accepts an int64 position representing the starting position of a block of work. It successfully claims it if the position is greater than the previously claimed position and within the restriction. Claiming a position at or beyond the end of the restriction signals that the entire restriction has been processed and is now done, at which point this method signals to end processing.
The tracker stops with an error if a claim is attempted after the tracker has signalled to stop, if a position is claimed before the start of the restriction, or if a position is claimed before the latest successfully claimed.
Source Files