diff options
Diffstat (limited to 'src/internal')
-rw-r--r-- | src/internal/itoa/README.md | 2 | ||||
-rw-r--r-- | src/internal/itoa/itoa.go | 33 | ||||
-rw-r--r-- | src/internal/itoa/itoa_test.go | 40 |
3 files changed, 75 insertions, 0 deletions
diff --git a/src/internal/itoa/README.md b/src/internal/itoa/README.md new file mode 100644 index 000000000..6b666d121 --- /dev/null +++ b/src/internal/itoa/README.md @@ -0,0 +1,2 @@ +internal/itoa is new to go as of 1.17. +This directory should be removed when tinygo drops support for go 1.16. diff --git a/src/internal/itoa/itoa.go b/src/internal/itoa/itoa.go new file mode 100644 index 000000000..c6062d9fe --- /dev/null +++ b/src/internal/itoa/itoa.go @@ -0,0 +1,33 @@ +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Simple conversions to avoid depending on strconv. + +package itoa + +// Itoa converts val to a decimal string. +func Itoa(val int) string { + if val < 0 { + return "-" + Uitoa(uint(-val)) + } + return Uitoa(uint(val)) +} + +// Uitoa converts val to a decimal string. +func Uitoa(val uint) string { + if val == 0 { // avoid string allocation + return "0" + } + var buf [20]byte // big enough for 64bit value base 10 + i := len(buf) - 1 + for val >= 10 { + q := val / 10 + buf[i] = byte('0' + val - q*10) + i-- + val = q + } + // val < 10 + buf[i] = byte('0' + val) + return string(buf[i:]) +} diff --git a/src/internal/itoa/itoa_test.go b/src/internal/itoa/itoa_test.go new file mode 100644 index 000000000..71931c1e3 --- /dev/null +++ b/src/internal/itoa/itoa_test.go @@ -0,0 +1,40 @@ +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package itoa_test + +import ( + "fmt" + "internal/itoa" + "math" + "testing" +) + +var ( + minInt64 int64 = math.MinInt64 + maxInt64 int64 = math.MaxInt64 + maxUint64 uint64 = math.MaxUint64 +) + +func TestItoa(t *testing.T) { + tests := []int{int(minInt64), math.MinInt32, -999, -100, -1, 0, 1, 100, 999, math.MaxInt32, int(maxInt64)} + for _, tt := range tests { + got := itoa.Itoa(tt) + want := fmt.Sprint(tt) + if want != got { + t.Fatalf("Itoa(%d) = %s, want %s", tt, got, want) + } + } +} + +func TestUitoa(t *testing.T) { + tests := []uint{0, 1, 100, 999, math.MaxUint32, uint(maxUint64)} + for _, tt := range tests { + got := itoa.Uitoa(tt) + want := fmt.Sprint(tt) + if want != got { + t.Fatalf("Uitoa(%d) = %s, want %s", tt, got, want) + } + } +} |