1 files changed, 56 insertions, 0 deletions
diff --git a/autoutils/batches.go b/autoutils/batches.go
new file mode 100644
index 0000000..fb39fc1
--- /dev/null
+++ b/autoutils/batches.go
@@ -0,0 +1,56 @@
+/*
+Copyright (C) 2019 Leo Tenenbaum
+
+This file is part of AutoArt.
+
+AutoArt is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+AutoArt is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with AutoArt.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package autoutils
+
+import (
+    "fmt"
+)
+
+/*
+This function runs f in batches of batchSize. n will be the number in the
+sequence. f should send an error to errs if it wants this function to return
+that error, and otherwise should send nil when it is done. Before each batch,
+a message will be printed, starting with progress, and showing how many batches
+have been completed so far out of the total number of batches.
+*/
+const batchSize = 32
+func RunInBatches(number int64, progress string, f func (n int64, errs chan<- error)) error {
+    nBatches := number / batchSize
+    errs := make(chan error)
+    for batch := int64(0); batch <= nBatches; batch++ {
+        fmt.Println(progress, batch+1, "/", nBatches+1)
+        thisBatchSize := batchSize
+        if batch == nBatches {
+            // Deal with case of last batch
+            thisBatchSize = int(number - nBatches * batchSize)
+        }
+        for task := 0; task < thisBatchSize; task++ {
+            go f(int64(task) + batchSize * batch, errs)
+        }
+
+        for completed := 0; completed < thisBatchSize; completed++ {
+            err := <-errs
+            if err != nil {
+                return err
+            }
+        }
+    }
+    return nil
+}
+\ No newline at end of file