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- // Copyright 2018 Google LLC
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
-
- package bigquery
-
- import (
- "math/rand"
- "os"
- "sync"
- "time"
- )
-
- // Support for random values (typically job IDs and insert IDs).
-
- const alphanum = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
-
- var (
- rngMu sync.Mutex
- rng = rand.New(rand.NewSource(time.Now().UnixNano() ^ int64(os.Getpid())))
- )
-
- // For testing.
- var randomIDFn = randomID
-
- // As of August 2017, the BigQuery service uses 27 alphanumeric characters for
- // suffixes.
- const randomIDLen = 27
-
- func randomID() string {
- // This is used for both job IDs and insert IDs.
- var b [randomIDLen]byte
- rngMu.Lock()
- for i := 0; i < len(b); i++ {
- b[i] = alphanum[rng.Intn(len(alphanum))]
- }
- rngMu.Unlock()
- return string(b[:])
- }
-
- // Seed seeds this package's random number generator, used for generating job and
- // insert IDs. Use Seed to obtain repeatable, deterministic behavior from bigquery
- // clients. Seed should be called before any clients are created.
- func Seed(s int64) {
- rng = rand.New(rand.NewSource(s))
- }
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