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36 lines
1.6 KiB
Go
36 lines
1.6 KiB
Go
/*
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Package iterator provides functions to work with Neo iterators.
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*/
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package iterator
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import "github.com/nspcc-dev/neo-go/pkg/interop/neogointernal"
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// Iterator represents a Neo iterator, it's an opaque data structure that can
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// be properly created by Create or storage.Find. Unlike enumerators, iterators
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// range over key-value pairs, so it's convenient to use them for maps. This
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// structure is similar in function to Neo .net framework's Iterator.
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type Iterator struct{}
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// Create creates an iterator from the given items (array, struct, map, byte
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// array or integer and boolean converted to byte array). A new iterator is set
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// to point at element -1, so to access its first element you need to call Next
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// first. This function uses `System.Iterator.Create` syscall.
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func Create(items interface{}) Iterator {
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return neogointernal.Syscall1("System.Iterator.Create", items).(Iterator)
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}
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// Next advances the iterator returning true if it is was successful (and you
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// can use Key or Value) and false otherwise (and there are no more elements in
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// this Iterator). This function uses `System.Iterator.Next` syscall.
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func Next(it Iterator) bool {
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return neogointernal.Syscall1("System.Iterator.Next", it).(bool)
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}
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// Value returns iterator's current value. It's only valid to call after
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// successful Next call. This function uses `System.Iterator.Value` syscall.
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// For slices the result is just value.
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// For maps the result can be casted to a slice of 2 elements: key and value.
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// For storage iterators refer to `storage.FindFlags` documentation.
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func Value(it Iterator) interface{} {
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return neogointernal.Syscall1("System.Iterator.Value", it)
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}
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