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Diffstat (limited to 'internal/encoding/json/decode_number.go')
| -rw-r--r-- | internal/encoding/json/decode_number.go | 254 |
1 files changed, 0 insertions, 254 deletions
diff --git a/internal/encoding/json/decode_number.go b/internal/encoding/json/decode_number.go deleted file mode 100644 index 2999d713..00000000 --- a/internal/encoding/json/decode_number.go +++ /dev/null @@ -1,254 +0,0 @@ -// Copyright 2018 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 json - -import ( - "bytes" - "strconv" -) - -// parseNumber reads the given []byte for a valid JSON number. If it is valid, -// it returns the number of bytes. Parsing logic follows the definition in -// https://tools.ietf.org/html/rfc7159#section-6, and is based off -// encoding/json.isValidNumber function. -func parseNumber(input []byte) (int, bool) { - var n int - - s := input - if len(s) == 0 { - return 0, false - } - - // Optional - - if s[0] == '-' { - s = s[1:] - n++ - if len(s) == 0 { - return 0, false - } - } - - // Digits - switch { - case s[0] == '0': - s = s[1:] - n++ - - case '1' <= s[0] && s[0] <= '9': - s = s[1:] - n++ - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - n++ - } - - default: - return 0, false - } - - // . followed by 1 or more digits. - if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' { - s = s[2:] - n += 2 - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - n++ - } - } - - // e or E followed by an optional - or + and - // 1 or more digits. - if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') { - s = s[1:] - n++ - if s[0] == '+' || s[0] == '-' { - s = s[1:] - n++ - if len(s) == 0 { - return 0, false - } - } - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - n++ - } - } - - // Check that next byte is a delimiter or it is at the end. - if n < len(input) && isNotDelim(input[n]) { - return 0, false - } - - return n, true -} - -// numberParts is the result of parsing out a valid JSON number. It contains -// the parts of a number. The parts are used for integer conversion. -type numberParts struct { - neg bool - intp []byte - frac []byte - exp []byte -} - -// parseNumber constructs numberParts from given []byte. The logic here is -// similar to consumeNumber above with the difference of having to construct -// numberParts. The slice fields in numberParts are subslices of the input. -func parseNumberParts(input []byte) (numberParts, bool) { - var neg bool - var intp []byte - var frac []byte - var exp []byte - - s := input - if len(s) == 0 { - return numberParts{}, false - } - - // Optional - - if s[0] == '-' { - neg = true - s = s[1:] - if len(s) == 0 { - return numberParts{}, false - } - } - - // Digits - switch { - case s[0] == '0': - // Skip first 0 and no need to store. - s = s[1:] - - case '1' <= s[0] && s[0] <= '9': - intp = s - n := 1 - s = s[1:] - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - n++ - } - intp = intp[:n] - - default: - return numberParts{}, false - } - - // . followed by 1 or more digits. - if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' { - frac = s[1:] - n := 1 - s = s[2:] - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - n++ - } - frac = frac[:n] - } - - // e or E followed by an optional - or + and - // 1 or more digits. - if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') { - s = s[1:] - exp = s - n := 0 - if s[0] == '+' || s[0] == '-' { - s = s[1:] - n++ - if len(s) == 0 { - return numberParts{}, false - } - } - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - n++ - } - exp = exp[:n] - } - - return numberParts{ - neg: neg, - intp: intp, - frac: bytes.TrimRight(frac, "0"), // Remove unnecessary 0s to the right. - exp: exp, - }, true -} - -// normalizeToIntString returns an integer string in normal form without the -// E-notation for given numberParts. It will return false if it is not an -// integer or if the exponent exceeds than max/min int value. -func normalizeToIntString(n numberParts) (string, bool) { - intpSize := len(n.intp) - fracSize := len(n.frac) - - if intpSize == 0 && fracSize == 0 { - return "0", true - } - - var exp int - if len(n.exp) > 0 { - i, err := strconv.ParseInt(string(n.exp), 10, 32) - if err != nil { - return "", false - } - exp = int(i) - } - - var num []byte - if exp >= 0 { - // For positive E, shift fraction digits into integer part and also pad - // with zeroes as needed. - - // If there are more digits in fraction than the E value, then the - // number is not an integer. - if fracSize > exp { - return "", false - } - - // Make sure resulting digits are within max value limit to avoid - // unnecessarily constructing a large byte slice that may simply fail - // later on. - const maxDigits = 20 // Max uint64 value has 20 decimal digits. - if intpSize+exp > maxDigits { - return "", false - } - - // Set cap to make a copy of integer part when appended. - num = n.intp[:len(n.intp):len(n.intp)] - num = append(num, n.frac...) - for i := 0; i < exp-fracSize; i++ { - num = append(num, '0') - } - } else { - // For negative E, shift digits in integer part out. - - // If there are fractions, then the number is not an integer. - if fracSize > 0 { - return "", false - } - - // index is where the decimal point will be after adjusting for negative - // exponent. - index := intpSize + exp - if index < 0 { - return "", false - } - - num = n.intp - // If any of the digits being shifted to the right of the decimal point - // is non-zero, then the number is not an integer. - for i := index; i < intpSize; i++ { - if num[i] != '0' { - return "", false - } - } - num = num[:index] - } - - if n.neg { - return "-" + string(num), true - } - return string(num), true -} |