From 9294b8f10f1fceb662a06f9d45aaf7a6b2492f05 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Mon, 1 Apr 2019 14:56:43 +0300
Subject: [PATCH] core/vm: polish gas PR, fix tests, make table driven
---
core/vm/gas_table.go | 14 +++++---------
core/vm/gas_table_test.go | 27 +++++++++++++++------------
2 files changed, 20 insertions(+), 21 deletions(-)
diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
index 8b034a0e7..8270300ba 100644
--- a/core/vm/gas_table.go
+++ b/core/vm/gas_table.go
@@ -25,21 +25,17 @@ import (
// memoryGasCost calculates the quadratic gas for memory expansion. It does so
// only for the memory region that is expanded, not the total memory.
func memoryGasCost(mem *Memory, newMemSize uint64) (uint64, error) {
-
if newMemSize == 0 {
return 0, nil
}
- // The maximum that will fit in a uint64 is max_word_count - 1
- // anything above that will result in an overflow.
- // Additionally, a newMemSize which results in a
- // newMemSizeWords larger than 0xFFFFFFFF will cause the square operation
- // to overflow.
- // The constant 0x1FFFFFFFE0 is the highest number that can be used without
- // overflowing the gas calculation
+ // The maximum that will fit in a uint64 is max_word_count - 1. Anything above
+ // that will result in an overflow. Additionally, a newMemSize which results in
+ // a newMemSizeWords larger than 0xFFFFFFFF will cause the square operation to
+ // overflow. The constant 0x1FFFFFFFE0 is the highest number that can be used
+ // without overflowing the gas calculation.
if newMemSize > 0x1FFFFFFFE0 {
return 0, errGasUintOverflow
}
-
newMemSizeWords := toWordSize(newMemSize)
newMemSize = newMemSizeWords * 32
diff --git a/core/vm/gas_table_test.go b/core/vm/gas_table_test.go
index 1b91aee56..2c1e11894 100644
--- a/core/vm/gas_table_test.go
+++ b/core/vm/gas_table_test.go
@@ -19,18 +19,21 @@ package vm
import "testing"
func TestMemoryGasCost(t *testing.T) {
- //size := uint64(math.MaxUint64 - 64)
- size := uint64(0xffffffffe0)
- v, err := memoryGasCost(&Memory{}, size)
- if err != nil {
- t.Error("didn't expect error:", err)
+ tests := []struct {
+ size uint64
+ cost uint64
+ overflow bool
+ }{
+ {0x1fffffffe0, 36028809887088637, false},
+ {0x1fffffffe1, 0, true},
}
- if v != 36028899963961341 {
- t.Errorf("Expected: 36028899963961341, got %d", v)
- }
-
- _, err = memoryGasCost(&Memory{}, size+1)
- if err == nil {
- t.Error("expected error")
+ for i, tt := range tests {
+ v, err := memoryGasCost(&Memory{}, tt.size)
+ if (err == errGasUintOverflow) != tt.overflow {
+ t.Errorf("test %d: overflow mismatch: have %v, want %v", i, err == errGasUintOverflow, tt.overflow)
+ }
+ if v != tt.cost {
+ t.Errorf("test %d: gas cost mismatch: have %v, want %v", i, v, tt.cost)
+ }
}
}
--
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