From dd94a3df5de6cbb4e3351c4731221d3142b60500 Mon Sep 17 00:00:00 2001 From: Jack Date: Wed, 23 Sep 2015 20:00:36 -0700 Subject: add imaging --- .../src/github.com/disintegration/imaging/utils.go | 77 ++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 Godeps/_workspace/src/github.com/disintegration/imaging/utils.go (limited to 'Godeps/_workspace/src/github.com/disintegration/imaging/utils.go') diff --git a/Godeps/_workspace/src/github.com/disintegration/imaging/utils.go b/Godeps/_workspace/src/github.com/disintegration/imaging/utils.go new file mode 100644 index 000000000..8b1ab8adb --- /dev/null +++ b/Godeps/_workspace/src/github.com/disintegration/imaging/utils.go @@ -0,0 +1,77 @@ +package imaging + +import ( + "math" + "runtime" + "sync" + "sync/atomic" +) + +var parallelizationEnabled = true + +// if GOMAXPROCS = 1: no goroutines used +// if GOMAXPROCS > 1: spawn N=GOMAXPROCS workers in separate goroutines +func parallel(dataSize int, fn func(partStart, partEnd int)) { + numGoroutines := 1 + partSize := dataSize + + if parallelizationEnabled { + numProcs := runtime.GOMAXPROCS(0) + if numProcs > 1 { + numGoroutines = numProcs + partSize = dataSize / (numGoroutines * 10) + if partSize < 1 { + partSize = 1 + } + } + } + + if numGoroutines == 1 { + fn(0, dataSize) + } else { + var wg sync.WaitGroup + wg.Add(numGoroutines) + idx := uint64(0) + + for p := 0; p < numGoroutines; p++ { + go func() { + defer wg.Done() + for { + partStart := int(atomic.AddUint64(&idx, uint64(partSize))) - partSize + if partStart >= dataSize { + break + } + partEnd := partStart + partSize + if partEnd > dataSize { + partEnd = dataSize + } + fn(partStart, partEnd) + } + }() + } + + wg.Wait() + } +} + +func absint(i int) int { + if i < 0 { + return -i + } + return i +} + +// clamp & round float64 to uint8 (0..255) +func clamp(v float64) uint8 { + return uint8(math.Min(math.Max(v, 0.0), 255.0) + 0.5) +} + +// clamp int32 to uint8 (0..255) +func clampint32(v int32) uint8 { + if v < 0 { + return 0 + } else if v > 255 { + return 255 + } + return uint8(v) +} -- cgit v1.2.3-1-g7c22