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// |
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// Copyright (c) 2011-2019 Canonical Ltd |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// http://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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|
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package yaml |
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|
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import ( |
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"encoding/base64" |
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"math" |
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"regexp" |
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"strconv" |
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"strings" |
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"time" |
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) |
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|
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type resolveMapItem struct { |
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value interface{} |
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tag string |
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} |
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|
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var resolveTable = make([]byte, 256) |
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var resolveMap = make(map[string]resolveMapItem) |
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|
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func init() { |
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t := resolveTable |
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t[int('+')] = 'S' // Sign |
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t[int('-')] = 'S' |
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for _, c := range "0123456789" { |
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t[int(c)] = 'D' // Digit |
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} |
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for _, c := range "yYnNtTfFoO~" { |
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t[int(c)] = 'M' // In map |
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} |
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t[int('.')] = '.' // Float (potentially in map) |
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|
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var resolveMapList = []struct { |
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v interface{} |
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tag string |
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l []string |
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}{ |
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{true, boolTag, []string{"true", "True", "TRUE"}}, |
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{false, boolTag, []string{"false", "False", "FALSE"}}, |
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{nil, nullTag, []string{"", "~", "null", "Null", "NULL"}}, |
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{math.NaN(), floatTag, []string{".nan", ".NaN", ".NAN"}}, |
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{math.Inf(+1), floatTag, []string{".inf", ".Inf", ".INF"}}, |
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{math.Inf(+1), floatTag, []string{"+.inf", "+.Inf", "+.INF"}}, |
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{math.Inf(-1), floatTag, []string{"-.inf", "-.Inf", "-.INF"}}, |
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{"<<", mergeTag, []string{"<<"}}, |
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} |
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|
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m := resolveMap |
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for _, item := range resolveMapList { |
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for _, s := range item.l { |
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m[s] = resolveMapItem{item.v, item.tag} |
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} |
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} |
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} |
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|
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const ( |
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nullTag = "!!null" |
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boolTag = "!!bool" |
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strTag = "!!str" |
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intTag = "!!int" |
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floatTag = "!!float" |
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timestampTag = "!!timestamp" |
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seqTag = "!!seq" |
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mapTag = "!!map" |
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binaryTag = "!!binary" |
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mergeTag = "!!merge" |
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) |
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|
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var longTags = make(map[string]string) |
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var shortTags = make(map[string]string) |
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|
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func init() { |
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for _, stag := range []string{nullTag, boolTag, strTag, intTag, floatTag, timestampTag, seqTag, mapTag, binaryTag, mergeTag} { |
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ltag := longTag(stag) |
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longTags[stag] = ltag |
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shortTags[ltag] = stag |
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} |
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} |
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|
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const longTagPrefix = "tag:yaml.org,2002:" |
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|
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func shortTag(tag string) string { |
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if strings.HasPrefix(tag, longTagPrefix) { |
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if stag, ok := shortTags[tag]; ok { |
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return stag |
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} |
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return "!!" + tag[len(longTagPrefix):] |
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} |
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return tag |
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} |
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|
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func longTag(tag string) string { |
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if strings.HasPrefix(tag, "!!") { |
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if ltag, ok := longTags[tag]; ok { |
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return ltag |
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} |
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return longTagPrefix + tag[2:] |
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} |
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return tag |
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} |
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|
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func resolvableTag(tag string) bool { |
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switch tag { |
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case "", strTag, boolTag, intTag, floatTag, nullTag, timestampTag: |
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return true |
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} |
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return false |
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} |
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|
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var yamlStyleFloat = regexp.MustCompile(`^[-+]?(\.[0-9]+|[0-9]+(\.[0-9]*)?)([eE][-+]?[0-9]+)?$`) |
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|
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func resolve(tag string, in string) (rtag string, out interface{}) { |
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tag = shortTag(tag) |
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if !resolvableTag(tag) { |
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return tag, in |
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} |
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|
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defer func() { |
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switch tag { |
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case "", rtag, strTag, binaryTag: |
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return |
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case floatTag: |
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if rtag == intTag { |
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switch v := out.(type) { |
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case int64: |
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rtag = floatTag |
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out = float64(v) |
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return |
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case int: |
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rtag = floatTag |
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out = float64(v) |
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return |
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} |
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} |
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} |
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failf("cannot decode %s `%s` as a %s", shortTag(rtag), in, shortTag(tag)) |
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}() |
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|
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// Any data is accepted as a !!str or !!binary. |
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// Otherwise, the prefix is enough of a hint about what it might be. |
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hint := byte('N') |
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if in != "" { |
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hint = resolveTable[in[0]] |
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} |
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if hint != 0 && tag != strTag && tag != binaryTag { |
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// Handle things we can lookup in a map. |
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if item, ok := resolveMap[in]; ok { |
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return item.tag, item.value |
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} |
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|
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// Base 60 floats are a bad idea, were dropped in YAML 1.2, and |
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// are purposefully unsupported here. They're still quoted on |
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// the way out for compatibility with other parser, though. |
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|
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switch hint { |
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case 'M': |
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// We've already checked the map above. |
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|
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case '.': |
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// Not in the map, so maybe a normal float. |
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floatv, err := strconv.ParseFloat(in, 64) |
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if err == nil { |
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return floatTag, floatv |
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} |
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|
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case 'D', 'S': |
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// Int, float, or timestamp. |
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// Only try values as a timestamp if the value is unquoted or there's an explicit |
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// !!timestamp tag. |
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if tag == "" || tag == timestampTag { |
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t, ok := parseTimestamp(in) |
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if ok { |
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return timestampTag, t |
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} |
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} |
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|
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plain := strings.Replace(in, "_", "", -1) |
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intv, err := strconv.ParseInt(plain, 0, 64) |
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if err == nil { |
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if intv == int64(int(intv)) { |
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return intTag, int(intv) |
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} else { |
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return intTag, intv |
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} |
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} |
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uintv, err := strconv.ParseUint(plain, 0, 64) |
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if err == nil { |
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return intTag, uintv |
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} |
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if yamlStyleFloat.MatchString(plain) { |
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floatv, err := strconv.ParseFloat(plain, 64) |
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if err == nil { |
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return floatTag, floatv |
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} |
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} |
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if strings.HasPrefix(plain, "0b") { |
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intv, err := strconv.ParseInt(plain[2:], 2, 64) |
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if err == nil { |
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if intv == int64(int(intv)) { |
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return intTag, int(intv) |
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} else { |
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return intTag, intv |
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} |
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} |
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uintv, err := strconv.ParseUint(plain[2:], 2, 64) |
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if err == nil { |
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return intTag, uintv |
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} |
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} else if strings.HasPrefix(plain, "-0b") { |
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intv, err := strconv.ParseInt("-"+plain[3:], 2, 64) |
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if err == nil { |
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if true || intv == int64(int(intv)) { |
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return intTag, int(intv) |
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} else { |
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return intTag, intv |
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} |
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} |
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} |
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// Octals as introduced in version 1.2 of the spec. |
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// Octals from the 1.1 spec, spelled as 0777, are still |
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// decoded by default in v3 as well for compatibility. |
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// May be dropped in v4 depending on how usage evolves. |
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if strings.HasPrefix(plain, "0o") { |
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intv, err := strconv.ParseInt(plain[2:], 8, 64) |
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if err == nil { |
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if intv == int64(int(intv)) { |
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return intTag, int(intv) |
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} else { |
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return intTag, intv |
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} |
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} |
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uintv, err := strconv.ParseUint(plain[2:], 8, 64) |
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if err == nil { |
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return intTag, uintv |
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} |
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} else if strings.HasPrefix(plain, "-0o") { |
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intv, err := strconv.ParseInt("-"+plain[3:], 8, 64) |
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if err == nil { |
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if true || intv == int64(int(intv)) { |
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return intTag, int(intv) |
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} else { |
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return intTag, intv |
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} |
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} |
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} |
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default: |
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panic("internal error: missing handler for resolver table: " + string(rune(hint)) + " (with " + in + ")") |
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} |
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} |
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return strTag, in |
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} |
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|
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// encodeBase64 encodes s as base64 that is broken up into multiple lines |
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// as appropriate for the resulting length. |
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func encodeBase64(s string) string { |
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const lineLen = 70 |
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encLen := base64.StdEncoding.EncodedLen(len(s)) |
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lines := encLen/lineLen + 1 |
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buf := make([]byte, encLen*2+lines) |
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in := buf[0:encLen] |
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out := buf[encLen:] |
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base64.StdEncoding.Encode(in, []byte(s)) |
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k := 0 |
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for i := 0; i < len(in); i += lineLen { |
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j := i + lineLen |
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if j > len(in) { |
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j = len(in) |
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} |
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k += copy(out[k:], in[i:j]) |
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if lines > 1 { |
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out[k] = '\n' |
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k++ |
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} |
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} |
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return string(out[:k]) |
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} |
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|
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// This is a subset of the formats allowed by the regular expression |
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// defined at http://yaml.org/type/timestamp.html. |
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var allowedTimestampFormats = []string{ |
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"2006-1-2T15:4:5.999999999Z07:00", // RCF3339Nano with short date fields. |
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"2006-1-2t15:4:5.999999999Z07:00", // RFC3339Nano with short date fields and lower-case "t". |
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"2006-1-2 15:4:5.999999999", // space separated with no time zone |
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"2006-1-2", // date only |
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// Notable exception: time.Parse cannot handle: "2001-12-14 21:59:43.10 -5" |
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// from the set of examples. |
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} |
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|
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// parseTimestamp parses s as a timestamp string and |
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// returns the timestamp and reports whether it succeeded. |
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// Timestamp formats are defined at http://yaml.org/type/timestamp.html |
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func parseTimestamp(s string) (time.Time, bool) { |
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// TODO write code to check all the formats supported by |
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// http://yaml.org/type/timestamp.html instead of using time.Parse. |
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|
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// Quick check: all date formats start with YYYY-. |
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i := 0 |
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for ; i < len(s); i++ { |
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if c := s[i]; c < '0' || c > '9' { |
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break |
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} |
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} |
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if i != 4 || i == len(s) || s[i] != '-' { |
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return time.Time{}, false |
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} |
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for _, format := range allowedTimestampFormats { |
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if t, err := time.Parse(format, s); err == nil { |
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return t, true |
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} |
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} |
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return time.Time{}, false |
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} |
