Add sshchat dependencies in vendor

vendor/github.com/shazow/rateio/limiter.go

@@ -0,0 +1,62 @@
+package rateio
+
+import (
+	"errors"
+	"time"
+)
+
+const minInt = -int(^uint(0)>>1) - 1
+
+// The error returned when the read rate exceeds our specification.
+var ErrRateExceeded = errors.New("Read rate exceeded.")
+
+// Limiter is an interface for a rate limiter.
+// There are a few example limiters included in the package, but feel free to go wild with your own.
+type Limiter interface {
+	// Apply this many bytes to the limiter, return ErrRateExceeded if the defined rate is exceeded.
+	Count(int) error
+}
+
+// simpleLimiter is a rate limiter that restricts Amount bytes in Frequency duration.
+type simpleLimiter struct {
+	Amount    int
+	Frequency time.Duration
+
+	numRead  int
+	timeRead time.Time
+}
+
+// NewSimpleLimiter creates a Limiter that restricts a given number of bytes per frequency.
+func NewSimpleLimiter(amount int, frequency time.Duration) Limiter {
+	return &simpleLimiter{
+		Amount:    amount,
+		Frequency: frequency,
+	}
+}
+
+// NewGracefulLimiter returns a Limiter that is the same as a
+// SimpleLimiter but adds a grace period at the start of the rate
+// limiting where it allows unlimited bytes to be read during that
+// period.
+func NewGracefulLimiter(amount int, frequency time.Duration, grace time.Duration) Limiter {
+	return &simpleLimiter{
+		Amount:    amount,
+		Frequency: frequency,
+		numRead:   minInt,
+		timeRead:  time.Now().Add(grace),
+	}
+}
+
+// Count applies n bytes to the limiter.
+func (limit *simpleLimiter) Count(n int) error {
+	now := time.Now()
+	if now.After(limit.timeRead) {
+		limit.numRead = 0
+		limit.timeRead = now.Add(limit.Frequency)
+	}
+	limit.numRead += n
+	if limit.numRead > limit.Amount {
+		return ErrRateExceeded
+	}
+	return nil
+}