增加推流码流统计

stream/bitrate_statistics.go

@@ -0,0 +1,56 @@
+package stream
+
+import "time"
+
+// BitrateStatistics 码流统计, 单位Byte
+type BitrateStatistics struct {
+	totalBytes     int64 // 总共传输的字节数
+	elapsedSeconds int   // 经过的秒数
+	currentSecond  int   // 当前秒数
+
+	previousSecondBytes int // 前一秒传输的字节数
+	latestSecondBytes   int // 当前秒正在传输的字节数
+}
+
+func (b *BitrateStatistics) Input(size int) {
+	b.totalBytes += int64(size)
+
+	second := time.Now().Second()
+	if b.currentSecond == -1 {
+		b.currentSecond = second
+	}
+
+	if second != b.currentSecond {
+		b.elapsedSeconds++
+		b.currentSecond = second
+		b.previousSecondBytes = b.latestSecondBytes
+		b.latestSecondBytes = 0
+	}
+
+	b.latestSecondBytes += size
+}
+
+// Average 返回每秒平均码流大小
+func (b *BitrateStatistics) Average() int {
+	if b.elapsedSeconds < 1 {
+		return b.latestSecondBytes
+	}
+
+	return int((b.totalBytes - int64(b.latestSecondBytes)) / int64(b.elapsedSeconds))
+}
+
+// Total 返回总码流大小
+func (b *BitrateStatistics) Total() int64 {
+	return b.totalBytes
+}
+
+// PreviousSecond 返回前一秒的码流大小
+func (b *BitrateStatistics) PreviousSecond() int {
+	return b.previousSecondBytes
+}
+
+func NewBitrateStatistics() *BitrateStatistics {
+	return &BitrateStatistics{
+		currentSecond: -1,
+	}
+}