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Diffstat (limited to 'vendor/github.com/Masterminds/goutils/stringutils.go')
-rw-r--r-- | vendor/github.com/Masterminds/goutils/stringutils.go | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/vendor/github.com/Masterminds/goutils/stringutils.go b/vendor/github.com/Masterminds/goutils/stringutils.go new file mode 100644 index 000000000..741bb530e --- /dev/null +++ b/vendor/github.com/Masterminds/goutils/stringutils.go @@ -0,0 +1,240 @@ +/* +Copyright 2014 Alexander Okoli + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package goutils + +import ( + "bytes" + "fmt" + "strings" + "unicode" +) + +// Typically returned by functions where a searched item cannot be found +const INDEX_NOT_FOUND = -1 + +/* +Abbreviate abbreviates a string using ellipses. This will turn the string "Now is the time for all good men" into "Now is the time for..." + +Specifically, the algorithm is as follows: + + - If str is less than maxWidth characters long, return it. + - Else abbreviate it to (str[0:maxWidth - 3] + "..."). + - If maxWidth is less than 4, return an illegal argument error. + - In no case will it return a string of length greater than maxWidth. + +Parameters: + str - the string to check + maxWidth - maximum length of result string, must be at least 4 + +Returns: + string - abbreviated string + error - if the width is too small +*/ +func Abbreviate(str string, maxWidth int) (string, error) { + return AbbreviateFull(str, 0, maxWidth) +} + +/* +AbbreviateFull abbreviates a string using ellipses. This will turn the string "Now is the time for all good men" into "...is the time for..." +This function works like Abbreviate(string, int), but allows you to specify a "left edge" offset. Note that this left edge is not +necessarily going to be the leftmost character in the result, or the first character following the ellipses, but it will appear +somewhere in the result. +In no case will it return a string of length greater than maxWidth. + +Parameters: + str - the string to check + offset - left edge of source string + maxWidth - maximum length of result string, must be at least 4 + +Returns: + string - abbreviated string + error - if the width is too small +*/ +func AbbreviateFull(str string, offset int, maxWidth int) (string, error) { + if str == "" { + return "", nil + } + if maxWidth < 4 { + err := fmt.Errorf("stringutils illegal argument: Minimum abbreviation width is 4") + return "", err + } + if len(str) <= maxWidth { + return str, nil + } + if offset > len(str) { + offset = len(str) + } + if len(str)-offset < (maxWidth - 3) { // 15 - 5 < 10 - 3 = 10 < 7 + offset = len(str) - (maxWidth - 3) + } + abrevMarker := "..." + if offset <= 4 { + return str[0:maxWidth-3] + abrevMarker, nil // str.substring(0, maxWidth - 3) + abrevMarker; + } + if maxWidth < 7 { + err := fmt.Errorf("stringutils illegal argument: Minimum abbreviation width with offset is 7") + return "", err + } + if (offset + maxWidth - 3) < len(str) { // 5 + (10-3) < 15 = 12 < 15 + abrevStr, _ := Abbreviate(str[offset:len(str)], (maxWidth - 3)) + return abrevMarker + abrevStr, nil // abrevMarker + abbreviate(str.substring(offset), maxWidth - 3); + } + return abrevMarker + str[(len(str)-(maxWidth-3)):len(str)], nil // abrevMarker + str.substring(str.length() - (maxWidth - 3)); +} + +/* +DeleteWhiteSpace deletes all whitespaces from a string as defined by unicode.IsSpace(rune). +It returns the string without whitespaces. + +Parameter: + str - the string to delete whitespace from, may be nil + +Returns: + the string without whitespaces +*/ +func DeleteWhiteSpace(str string) string { + if str == "" { + return str + } + sz := len(str) + var chs bytes.Buffer + count := 0 + for i := 0; i < sz; i++ { + ch := rune(str[i]) + if !unicode.IsSpace(ch) { + chs.WriteRune(ch) + count++ + } + } + if count == sz { + return str + } + return chs.String() +} + +/* +IndexOfDifference compares two strings, and returns the index at which the strings begin to differ. + +Parameters: + str1 - the first string + str2 - the second string + +Returns: + the index where str1 and str2 begin to differ; -1 if they are equal +*/ +func IndexOfDifference(str1 string, str2 string) int { + if str1 == str2 { + return INDEX_NOT_FOUND + } + if IsEmpty(str1) || IsEmpty(str2) { + return 0 + } + var i int + for i = 0; i < len(str1) && i < len(str2); i++ { + if rune(str1[i]) != rune(str2[i]) { + break + } + } + if i < len(str2) || i < len(str1) { + return i + } + return INDEX_NOT_FOUND +} + +/* +IsBlank checks if a string is whitespace or empty (""). Observe the following behavior: + + goutils.IsBlank("") = true + goutils.IsBlank(" ") = true + goutils.IsBlank("bob") = false + goutils.IsBlank(" bob ") = false + +Parameter: + str - the string to check + +Returns: + true - if the string is whitespace or empty ("") +*/ +func IsBlank(str string) bool { + strLen := len(str) + if str == "" || strLen == 0 { + return true + } + for i := 0; i < strLen; i++ { + if unicode.IsSpace(rune(str[i])) == false { + return false + } + } + return true +} + +/* +IndexOf returns the index of the first instance of sub in str, with the search beginning from the +index start point specified. -1 is returned if sub is not present in str. + +An empty string ("") will return -1 (INDEX_NOT_FOUND). A negative start position is treated as zero. +A start position greater than the string length returns -1. + +Parameters: + str - the string to check + sub - the substring to find + start - the start position; negative treated as zero + +Returns: + the first index where the sub string was found (always >= start) +*/ +func IndexOf(str string, sub string, start int) int { + + if start < 0 { + start = 0 + } + + if len(str) < start { + return INDEX_NOT_FOUND + } + + if IsEmpty(str) || IsEmpty(sub) { + return INDEX_NOT_FOUND + } + + partialIndex := strings.Index(str[start:len(str)], sub) + if partialIndex == -1 { + return INDEX_NOT_FOUND + } + return partialIndex + start +} + +// IsEmpty checks if a string is empty (""). Returns true if empty, and false otherwise. +func IsEmpty(str string) bool { + return len(str) == 0 +} + +// Returns either the passed in string, or if the string is empty, the value of defaultStr. +func DefaultString(str string, defaultStr string) string { + if IsEmpty(str) { + return defaultStr + } + return str +} + +// Returns either the passed in string, or if the string is whitespace, empty (""), the value of defaultStr. +func DefaultIfBlank(str string, defaultStr string) string { + if IsBlank(str) { + return defaultStr + } + return str +} |