1package jsonparser
 2
 3import (
 4	bio "bytes"
 5)
 6
 7// minInt64 '-9223372036854775808' is the smallest representable number in int64
 8const minInt64 = `9223372036854775808`
 9
10// About 2x faster then strconv.ParseInt because it only supports base 10, which is enough for JSON
11func parseInt(bytes []byte) (v int64, ok bool, overflow bool) {
12	if len(bytes) == 0 {
13		return 0, false, false
14	}
15
16	var neg bool = false
17	if bytes[0] == '-' {
18		neg = true
19		bytes = bytes[1:]
20	}
21
22	var b int64 = 0
23	for _, c := range bytes {
24		if c >= '0' && c <= '9' {
25			b = (10 * v) + int64(c-'0')
26		} else {
27			return 0, false, false
28		}
29		if overflow = (b < v); overflow {
30			break
31		}
32		v = b
33	}
34
35	if overflow {
36		if neg && bio.Equal(bytes, []byte(minInt64)) {
37			return b, true, false
38		}
39		return 0, false, true
40	}
41
42	if neg {
43		return -v, true, false
44	} else {
45		return v, true, false
46	}
47}