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Diffstat (limited to 'lib.go')
| -rw-r--r-- | lib.go | 53 |
1 files changed, 53 insertions, 0 deletions
@@ -1,3 +1,12 @@ +// Copyright 2016 - 2018 The excelize 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 excelize providing a set of functions that allow you to write to +// and read from XLSX files. Support reads and writes XLSX file generated by +// Microsoft Excel™ 2007 and later. Support save file without losing original +// charts of XLSX. This library needs Go version 1.8 or later. + package excelize import ( @@ -6,6 +15,8 @@ import ( "io" "log" "math" + "strconv" + "strings" "unicode" ) @@ -174,3 +185,45 @@ func parseFormatSet(formatSet string) []byte { } return []byte("{}") } + +// namespaceStrictToTransitional provides a method to convert Strict and +// Transitional namespaces. +func namespaceStrictToTransitional(content []byte) []byte { + var namespaceTranslationDic = map[string]string{ + StrictSourceRelationship: SourceRelationship, + StrictSourceRelationshipChart: SourceRelationshipChart, + StrictSourceRelationshipComments: SourceRelationshipComments, + StrictSourceRelationshipImage: SourceRelationshipImage, + StrictNameSpaceSpreadSheet: NameSpaceSpreadSheet, + } + for s, n := range namespaceTranslationDic { + content = bytes.Replace(content, []byte(s), []byte(n), -1) + } + return content +} + +// genSheetPasswd provides a method to generate password for worksheet +// protection by given plaintext. When an Excel sheet is being protected with +// a password, a 16-bit (two byte) long hash is generated. To verify a +// password, it is compared to the hash. Obviously, if the input data volume +// is great, numerous passwords will match the same hash. Here is the +// algorithm to create the hash value: +// +// take the ASCII values of all characters shift left the first character 1 bit, the second 2 bits and so on (use only the lower 15 bits and rotate all higher bits, the highest bit of the 16-bit value is always 0 [signed short]) +// XOR all these values +// XOR the count of characters +// XOR the constant 0xCE4B +func genSheetPasswd(plaintext string) string { + var password int64 = 0x0000 + var charPos uint = 1 + for _, v := range plaintext { + value := int64(v) << charPos + charPos++ + rotatedBits := value >> 15 // rotated bits beyond bit 15 + value &= 0x7fff // first 15 bits + password ^= (value | rotatedBits) + } + password ^= int64(len(plaintext)) + password ^= 0xCE4B + return strings.ToUpper(strconv.FormatInt(password, 16)) +} |