mirror of https://github.com/status-im/op-geth.git
62 lines
1.9 KiB
Go
62 lines
1.9 KiB
Go
// Contains the Whisper protocol Topic element. For formal details please see
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// the specs at https://github.com/ethereum/wiki/wiki/Whisper-PoC-1-Protocol-Spec#topics.
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package whisper
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import "github.com/ethereum/go-ethereum/crypto"
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// Topic represents a cryptographically secure, probabilistic partial
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// classifications of a message, determined as the first (left) 4 bytes of the
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// SHA3 hash of some arbitrary data given by the original author of the message.
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type Topic [4]byte
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// NewTopic creates a topic from the 4 byte prefix of the SHA3 hash of the data.
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func NewTopic(data []byte) Topic {
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prefix := [4]byte{}
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copy(prefix[:], crypto.Sha3(data)[:4])
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return Topic(prefix)
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}
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// NewTopics creates a list of topics from a list of binary data elements, by
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// iteratively calling NewTopic on each of them.
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func NewTopics(data ...[]byte) []Topic {
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topics := make([]Topic, len(data))
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for i, element := range data {
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topics[i] = NewTopic(element)
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}
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return topics
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}
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// NewTopicFromString creates a topic using the binary data contents of the
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// specified string.
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func NewTopicFromString(data string) Topic {
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return NewTopic([]byte(data))
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}
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// NewTopicsFromStrings creates a list of topics from a list of textual data
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// elements, by iteratively calling NewTopicFromString on each of them.
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func NewTopicsFromStrings(data ...string) []Topic {
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topics := make([]Topic, len(data))
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for i, element := range data {
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topics[i] = NewTopicFromString(element)
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}
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return topics
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}
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// String converts a topic byte array to a string representation.
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func (self *Topic) String() string {
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return string(self[:])
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}
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// TopicSet represents a hash set to check if a topic exists or not.
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type topicSet map[string]struct{}
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// NewTopicSet creates a topic hash set from a slice of topics.
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func newTopicSet(topics []Topic) topicSet {
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set := make(map[string]struct{})
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for _, topic := range topics {
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set[topic.String()] = struct{}{}
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}
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return topicSet(set)
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}
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