Hybrid comparison for unicode text strings consisting primarily of ASCII characters

US10540425B2 · kind B2 · utility

Assignee

• Tableau Software, Inc. · US

Inventors

• Thomas Neumann · Munich, DE
• Viktor Leis · Munich, DE
• Alfons Kemper · Munich, DE

Key dates

• Filing date: Jun 18, 2019
• Grant date: Jan 21, 2020
• Expiry date: Jun 18, 2039

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03M7/705
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A method compares text strings having Unicode encoding. The method receives a first string S=s1 s2 . . . sn and a second string T=t1 t2 . . . tm, where s1, s2, . . . , sn and t1, t2, . . . , tm are Unicode characters. The method computes a first string weight for the first string S according to a weight function ƒ. When S consists of ASCII characters, ƒ(S)=S. When S consists of ASCII characters and some accented ASCII characters that are replaceable by ASCII characters, ƒ(S)=g(s1) g(s2) . . . g(sn), where g(si)=si when si is an ASCII character and g(si)=si′ when si is an accented ASCII character that is replaceable by the corresponding ASCII character si′. When S includes one or more non-replaceable non-ASCII characters, the first string weight concatenates an ASCII weight prefix ƒA (S) and a Unicode weight suffix ƒU(S). The method also computes a second string weight for the second text string T. Equality of the strings is tested using the string weights.