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authorRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
committerRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
commit8528da672cc093d4dd06732819abc1f7b6b5a46e (patch)
tree334be80d4a4c85b77db6f6fdb67cbf0528cba5f5 /src/strconv/atoi.go
parent73bcb69f272cbf34ddcc9daa56427a8683b5a95d (diff)
downloadgo-8528da672cc093d4dd06732819abc1f7b6b5a46e.tar.gz
build: move package sources from src/pkg to src
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
Diffstat (limited to 'src/strconv/atoi.go')
-rw-r--r--src/strconv/atoi.go198
1 files changed, 198 insertions, 0 deletions
diff --git a/src/strconv/atoi.go b/src/strconv/atoi.go
new file mode 100644
index 000000000..9ecec5a58
--- /dev/null
+++ b/src/strconv/atoi.go
@@ -0,0 +1,198 @@
+// Copyright 2009 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 strconv
+
+import "errors"
+
+// ErrRange indicates that a value is out of range for the target type.
+var ErrRange = errors.New("value out of range")
+
+// ErrSyntax indicates that a value does not have the right syntax for the target type.
+var ErrSyntax = errors.New("invalid syntax")
+
+// A NumError records a failed conversion.
+type NumError struct {
+ Func string // the failing function (ParseBool, ParseInt, ParseUint, ParseFloat)
+ Num string // the input
+ Err error // the reason the conversion failed (ErrRange, ErrSyntax)
+}
+
+func (e *NumError) Error() string {
+ return "strconv." + e.Func + ": " + "parsing " + Quote(e.Num) + ": " + e.Err.Error()
+}
+
+func syntaxError(fn, str string) *NumError {
+ return &NumError{fn, str, ErrSyntax}
+}
+
+func rangeError(fn, str string) *NumError {
+ return &NumError{fn, str, ErrRange}
+}
+
+const intSize = 32 << (^uint(0) >> 63)
+
+// IntSize is the size in bits of an int or uint value.
+const IntSize = intSize
+
+// Return the first number n such that n*base >= 1<<64.
+func cutoff64(base int) uint64 {
+ if base < 2 {
+ return 0
+ }
+ return (1<<64-1)/uint64(base) + 1
+}
+
+// ParseUint is like ParseInt but for unsigned numbers.
+func ParseUint(s string, base int, bitSize int) (n uint64, err error) {
+ var cutoff, maxVal uint64
+
+ if bitSize == 0 {
+ bitSize = int(IntSize)
+ }
+
+ s0 := s
+ switch {
+ case len(s) < 1:
+ err = ErrSyntax
+ goto Error
+
+ case 2 <= base && base <= 36:
+ // valid base; nothing to do
+
+ case base == 0:
+ // Look for octal, hex prefix.
+ switch {
+ case s[0] == '0' && len(s) > 1 && (s[1] == 'x' || s[1] == 'X'):
+ base = 16
+ s = s[2:]
+ if len(s) < 1 {
+ err = ErrSyntax
+ goto Error
+ }
+ case s[0] == '0':
+ base = 8
+ default:
+ base = 10
+ }
+
+ default:
+ err = errors.New("invalid base " + Itoa(base))
+ goto Error
+ }
+
+ n = 0
+ cutoff = cutoff64(base)
+ maxVal = 1<<uint(bitSize) - 1
+
+ for i := 0; i < len(s); i++ {
+ var v byte
+ d := s[i]
+ switch {
+ case '0' <= d && d <= '9':
+ v = d - '0'
+ case 'a' <= d && d <= 'z':
+ v = d - 'a' + 10
+ case 'A' <= d && d <= 'Z':
+ v = d - 'A' + 10
+ default:
+ n = 0
+ err = ErrSyntax
+ goto Error
+ }
+ if int(v) >= base {
+ n = 0
+ err = ErrSyntax
+ goto Error
+ }
+
+ if n >= cutoff {
+ // n*base overflows
+ n = 1<<64 - 1
+ err = ErrRange
+ goto Error
+ }
+ n *= uint64(base)
+
+ n1 := n + uint64(v)
+ if n1 < n || n1 > maxVal {
+ // n+v overflows
+ n = 1<<64 - 1
+ err = ErrRange
+ goto Error
+ }
+ n = n1
+ }
+
+ return n, nil
+
+Error:
+ return n, &NumError{"ParseUint", s0, err}
+}
+
+// ParseInt interprets a string s in the given base (2 to 36) and
+// returns the corresponding value i. If base == 0, the base is
+// implied by the string's prefix: base 16 for "0x", base 8 for
+// "0", and base 10 otherwise.
+//
+// The bitSize argument specifies the integer type
+// that the result must fit into. Bit sizes 0, 8, 16, 32, and 64
+// correspond to int, int8, int16, int32, and int64.
+//
+// The errors that ParseInt returns have concrete type *NumError
+// and include err.Num = s. If s is empty or contains invalid
+// digits, err.Err = ErrSyntax and the returned value is 0;
+// if the value corresponding to s cannot be represented by a
+// signed integer of the given size, err.Err = ErrRange and the
+// returned value is the maximum magnitude integer of the
+// appropriate bitSize and sign.
+func ParseInt(s string, base int, bitSize int) (i int64, err error) {
+ const fnParseInt = "ParseInt"
+
+ if bitSize == 0 {
+ bitSize = int(IntSize)
+ }
+
+ // Empty string bad.
+ if len(s) == 0 {
+ return 0, syntaxError(fnParseInt, s)
+ }
+
+ // Pick off leading sign.
+ s0 := s
+ neg := false
+ if s[0] == '+' {
+ s = s[1:]
+ } else if s[0] == '-' {
+ neg = true
+ s = s[1:]
+ }
+
+ // Convert unsigned and check range.
+ var un uint64
+ un, err = ParseUint(s, base, bitSize)
+ if err != nil && err.(*NumError).Err != ErrRange {
+ err.(*NumError).Func = fnParseInt
+ err.(*NumError).Num = s0
+ return 0, err
+ }
+ cutoff := uint64(1 << uint(bitSize-1))
+ if !neg && un >= cutoff {
+ return int64(cutoff - 1), rangeError(fnParseInt, s0)
+ }
+ if neg && un > cutoff {
+ return -int64(cutoff), rangeError(fnParseInt, s0)
+ }
+ n := int64(un)
+ if neg {
+ n = -n
+ }
+ return n, nil
+}
+
+// Atoi is shorthand for ParseInt(s, 10, 0).
+func Atoi(s string) (i int, err error) {
+ i64, err := ParseInt(s, 10, 0)
+ return int(i64), err
+}