From 701d08ec7c2701338ef2bc438378c22adbfb74ee Mon Sep 17 00:00:00 2001
From: Jordan Orelli <jordanorelli@gmail.com>
Date: Thu, 29 Sep 2016 16:03:03 -0400
Subject: [PATCH] fix some overflows

---
 bit/decode.go    | 20 ++++++++++++++++++++
 ent/array.go     |  2 +-
 ent/atoms.go     | 12 ++----------
 ent/env.go       |  4 +++-
 ent/generic.go   | 14 +++++++++++++-
 ent/selection.go |  2 +-
 6 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/bit/decode.go b/bit/decode.go
index 41c6d0f..6edc6b6 100644
--- a/bit/decode.go
+++ b/bit/decode.go
@@ -99,6 +99,26 @@ func ReadVarInt32(r Reader) uint32 {
 	return uint32(x)
 }
 
+// reads a 32bit varint
+func ReadVarInt16(r Reader) uint16 {
+	var (
+		x     uint64
+		b     uint64
+		shift uint
+	)
+	for ; shift < 16; shift += 7 {
+		b = r.ReadBits(8)
+		if r.Err() != nil {
+			return 0
+		}
+		x |= b & 0x7f << shift
+		if b&0x80 == 0 {
+			return uint16(x)
+		}
+	}
+	return uint16(x)
+}
+
 func ReadBool(r Reader) bool {
 	return r.ReadBits(1) != 0
 }
diff --git a/ent/array.go b/ent/array.go
index b22640b..306f016 100644
--- a/ent/array.go
+++ b/ent/array.go
@@ -50,7 +50,7 @@ type array_t struct {
 }
 
 func (t *array_t) nü() value       { return array{t: t, slots: make([]value, t.count)} }
-func (t array_t) typeName() string { return fmt.Sprintf("array:%s", t.elem.typeName()) }
+func (t array_t) typeName() string { return fmt.Sprintf("%s[%d]", t.elem.typeName(), t.count) }
 
 type array struct {
 	t     *array_t
diff --git a/ent/atoms.go b/ent/atoms.go
index c5ec09e..71c5fd2 100644
--- a/ent/atoms.go
+++ b/ent/atoms.go
@@ -48,11 +48,7 @@ type uint8_v uint8
 
 func (v uint8_v) tÿpe() tÿpe { return uint8_t }
 func (v *uint8_v) read(r bit.Reader) error {
-	u := bit.ReadVarInt(r)
-	if u > 1<<8-1 {
-		return fmt.Errorf("uint8 overflow: %d", u)
-	}
-	*v = uint8_v(u)
+	*v = uint8_v(r.ReadBits(8))
 	return r.Err()
 }
 
@@ -75,11 +71,7 @@ type uint16_v uint16
 
 func (v uint16_v) tÿpe() tÿpe { return uint16_t }
 func (v *uint16_v) read(r bit.Reader) error {
-	u := bit.ReadVarInt(r)
-	if u > 1<<16-1 {
-		return fmt.Errorf("uint16 overflow: %d", u)
-	}
-	*v = uint16_v(u)
+	*v = uint16_v(bit.ReadVarInt16(r))
 	return r.Err()
 }
 
diff --git a/ent/env.go b/ent/env.go
index 3b060e8..ca9ab38 100644
--- a/ent/env.go
+++ b/ent/env.go
@@ -2,6 +2,7 @@ package ent
 
 import (
 	"github.com/golang/protobuf/proto"
+	"os"
 	"strconv"
 
 	"github.com/jordanorelli/hyperstone/bit"
@@ -178,7 +179,8 @@ func (e *Env) syncBaselineTable(t *stbl.Table) {
 		Debug.Printf("selections: %v", selections)
 		for _, s := range selections {
 			if err := s.fillSlots(ent, r); err != nil {
-				Debug.Printf("unable to fill selection %s for %s: %v", s, className, err)
+				Debug.Printf("syncBaseline fill error: %v", err)
+				os.Exit(1)
 			}
 		}
 	}
diff --git a/ent/generic.go b/ent/generic.go
index 5a3a5e5..ea80720 100644
--- a/ent/generic.go
+++ b/ent/generic.go
@@ -2,6 +2,7 @@ package ent
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 
 	"github.com/jordanorelli/hyperstone/bit"
@@ -80,7 +81,7 @@ func (t cutl_vector_t) typeName() string {
 }
 
 type cutl_vector struct {
-	t     tÿpe
+	t     *cutl_vector_t
 	slots []value
 }
 
@@ -98,3 +99,14 @@ func (v cutl_vector) String() string {
 	}
 	return fmt.Sprintf("%s(%d)%v", v.t.typeName(), len(v.slots), v.slots)
 }
+
+func (v *cutl_vector) slotType(int) tÿpe     { return v.t.elem }
+func (v *cutl_vector) slotName(n int) string { return strconv.Itoa(n) }
+func (v *cutl_vector) setSlotValue(slot int, val value) {
+	if slot == len(v.slots) {
+		v.slots = append(v.slots, val)
+	} else {
+		v.slots[slot] = val
+	}
+}
+func (v *cutl_vector) getSlotValue(slot int) value { return v.slots[slot] }
diff --git a/ent/selection.go b/ent/selection.go
index 16c9f74..0f5f620 100644
--- a/ent/selection.go
+++ b/ent/selection.go
@@ -32,7 +32,7 @@ func (s selection) fillSlotsIter(offset int, dest slotted, path string, r bit.Re
 	case 1:
 		v := dest.slotType(slot).nü()
 		if err := v.read(r); err != nil {
-			return fmt.Errorf("unable to fill selection: %v", err)
+			return fmt.Errorf("unable to fill selection %v for %s.%s (%s): %v", s, path, dest.slotName(slot), dest.slotType(slot).typeName(), err)
 		}
 		old := dest.getSlotValue(slot)
 		dest.setSlotValue(slot, v)