go.net/publicsuffix: print how much wiggle room we have when encoding
the Public Suffix List as a compact sequence of uint32s.
Currently:
max children 366 (capacity 511)
max text offset 22351 (capacity 32767)
max text length 36 (capacity 63)
max hi 6406 (capacity 16383)
max lo 6399 (capacity 16383)
LGTM=dr.volker.dobler
R=dr.volker.dobler
CC=golang-codereviews
https://golang.org/cl/62000046
diff --git a/publicsuffix/gen.go b/publicsuffix/gen.go
index 596c6a1..c4263c6 100644
--- a/publicsuffix/gen.go
+++ b/publicsuffix/gen.go
@@ -47,6 +47,28 @@
childrenBitsLo = 14
)
+var (
+ maxChildren int
+ maxTextOffset int
+ maxTextLength int
+ maxHi uint32
+ maxLo uint32
+)
+
+func max(a, b int) int {
+ if a < b {
+ return b
+ }
+ return a
+}
+
+func u32max(a, b uint32) uint32 {
+ if a < b {
+ return b
+ }
+ return a
+}
+
const (
nodeTypeNormal = 0
nodeTypeException = 1
@@ -212,6 +234,14 @@
return err
}
+ if *v {
+ fmt.Fprintf(os.Stderr, "max children %d (capacity %d)\n", maxChildren, 1<<nodesBitsChildren-1)
+ fmt.Fprintf(os.Stderr, "max text offset %d (capacity %d)\n", maxTextOffset, 1<<nodesBitsTextOffset-1)
+ fmt.Fprintf(os.Stderr, "max text length %d (capacity %d)\n", maxTextLength, 1<<nodesBitsTextLength-1)
+ fmt.Fprintf(os.Stderr, "max hi %d (capacity %d)\n", maxHi, 1<<childrenBitsHi-1)
+ fmt.Fprintf(os.Stderr, "max lo %d (capacity %d)\n", maxLo, 1<<childrenBitsLo-1)
+ }
+
b, err := format.Source(buf.Bytes())
if err != nil {
return err
@@ -277,6 +307,7 @@
if offset < 0 {
return fmt.Errorf("internal error: could not find %q in text %q", label, text)
}
+ maxTextOffset, maxTextLength = max(maxTextOffset, offset), max(maxTextLength, length)
if offset >= 1<<nodesBitsTextOffset || length >= 1<<nodesBitsTextLength {
return fmt.Errorf("text offset/length is too large: %d/%d", offset, length)
}
@@ -433,12 +464,14 @@
}
// Assign childrenIndex.
+ maxChildren = max(maxChildren, len(childrenEncoding))
if len(childrenEncoding) >= 1<<nodesBitsChildren {
return fmt.Errorf("children table is too large")
}
n.childrenIndex = len(childrenEncoding)
lo := uint32(n.firstChild)
hi := lo + uint32(len(n.children))
+ maxLo, maxHi = u32max(maxLo, lo), u32max(maxHi, hi)
if lo >= 1<<childrenBitsLo || hi >= 1<<childrenBitsHi {
return fmt.Errorf("children lo/hi is too large: %d/%d", lo, hi)
}
