diff options
Diffstat (limited to 'vendor/google.golang.org/protobuf/internal/encoding/text/decode_number.go')
-rw-r--r-- | vendor/google.golang.org/protobuf/internal/encoding/text/decode_number.go | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/text/decode_number.go b/vendor/google.golang.org/protobuf/internal/encoding/text/decode_number.go new file mode 100644 index 0000000000..f2d90b7899 --- /dev/null +++ b/vendor/google.golang.org/protobuf/internal/encoding/text/decode_number.go @@ -0,0 +1,190 @@ +// 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 text + +// parseNumberValue parses a number from the input and returns a Token object. +func (d *Decoder) parseNumberValue() (Token, bool) { + in := d.in + num := parseNumber(in) + if num.size == 0 { + return Token{}, false + } + numAttrs := num.kind + if num.neg { + numAttrs |= isNegative + } + strSize := num.size + last := num.size - 1 + if num.kind == numFloat && (d.in[last] == 'f' || d.in[last] == 'F') { + strSize = last + } + tok := Token{ + kind: Scalar, + attrs: numberValue, + pos: len(d.orig) - len(d.in), + raw: d.in[:num.size], + str: string(d.in[:strSize]), + numAttrs: numAttrs, + } + d.consume(num.size) + return tok, true +} + +const ( + numDec uint8 = (1 << iota) / 2 + numHex + numOct + numFloat +) + +// number is the result of parsing out a valid number from parseNumber. It +// contains data for doing float or integer conversion via the strconv package +// in conjunction with the input bytes. +type number struct { + kind uint8 + neg bool + size int +} + +// parseNumber constructs a number object from given input. It allows for the +// following patterns: +// integer: ^-?([1-9][0-9]*|0[xX][0-9a-fA-F]+|0[0-7]*) +// float: ^-?((0|[1-9][0-9]*)?([.][0-9]*)?([eE][+-]?[0-9]+)?[fF]?) +// It also returns the number of parsed bytes for the given number, 0 if it is +// not a number. +func parseNumber(input []byte) number { + kind := numDec + var size int + var neg bool + + s := input + if len(s) == 0 { + return number{} + } + + // Optional - + if s[0] == '-' { + neg = true + s = s[1:] + size++ + if len(s) == 0 { + return number{} + } + } + + // C++ allows for whitespace and comments in between the negative sign and + // the rest of the number. This logic currently does not but is consistent + // with v1. + + switch { + case s[0] == '0': + if len(s) > 1 { + switch { + case s[1] == 'x' || s[1] == 'X': + // Parse as hex number. + kind = numHex + n := 2 + s = s[2:] + for len(s) > 0 && (('0' <= s[0] && s[0] <= '9') || + ('a' <= s[0] && s[0] <= 'f') || + ('A' <= s[0] && s[0] <= 'F')) { + s = s[1:] + n++ + } + if n == 2 { + return number{} + } + size += n + + case '0' <= s[1] && s[1] <= '7': + // Parse as octal number. + kind = numOct + n := 2 + s = s[2:] + for len(s) > 0 && '0' <= s[0] && s[0] <= '7' { + s = s[1:] + n++ + } + size += n + } + + if kind&(numHex|numOct) > 0 { + if len(s) > 0 && !isDelim(s[0]) { + return number{} + } + return number{kind: kind, neg: neg, size: size} + } + } + s = s[1:] + size++ + + case '1' <= s[0] && s[0] <= '9': + n := 1 + s = s[1:] + for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { + s = s[1:] + n++ + } + size += n + + case s[0] == '.': + // Set kind to numFloat to signify the intent to parse as float. And + // that it needs to have other digits after '.'. + kind = numFloat + + default: + return number{} + } + + // . followed by 0 or more digits. + if len(s) > 0 && s[0] == '.' { + n := 1 + s = s[1:] + // If decimal point was before any digits, it should be followed by + // other digits. + if len(s) == 0 && kind == numFloat { + return number{} + } + for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { + s = s[1:] + n++ + } + size += n + kind = numFloat + } + + // e or E followed by an optional - or + and 1 or more digits. + if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') { + kind = numFloat + s = s[1:] + n := 1 + if s[0] == '+' || s[0] == '-' { + s = s[1:] + n++ + if len(s) == 0 { + return number{} + } + } + for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { + s = s[1:] + n++ + } + size += n + } + + // Optional suffix f or F for floats. + if len(s) > 0 && (s[0] == 'f' || s[0] == 'F') { + kind = numFloat + s = s[1:] + size++ + } + + // Check that next byte is a delimiter or it is at the end. + if len(s) > 0 && !isDelim(s[0]) { + return number{} + } + + return number{kind: kind, neg: neg, size: size} +} |