Implemented llvm::sys::locale::columnWidth and isPrint for the case of generic UTF8-capable terminal.

Summary:
This is a second attempt to get this right. After reading the Unicode
Standard I came up with the code that uses definitions of "printable" and
"column width" more suitable for terminal output (i.e. fixed-width fonts and
special treatment of many control characters).
The implementation here can probably be used for Windows and MacOS if someone
can test it properly.
The patch addresses PR14910.

Reviewers: jordan_rose, gribozavr

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1253

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187837 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/Support/LocaleTest.cpp

@@ -0,0 +1,86 @@
+//===- unittests/Support/LocaleTest.cpp - Locale.h tests ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Locale.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+namespace sys {
+namespace locale {
+namespace {
+
+TEST(Locale, columnWidth) {
+  EXPECT_EQ(0, columnWidth(""));
+  EXPECT_EQ(1, columnWidth(" "));
+  EXPECT_EQ(1, columnWidth("a"));
+  EXPECT_EQ(1, columnWidth("~"));
+
+  EXPECT_EQ(6, columnWidth("abcdef"));
+
+  EXPECT_EQ(-1, columnWidth("\x01"));
+  EXPECT_EQ(-1, columnWidth("aaaaaaaaaa\x01"));
+  EXPECT_EQ(-1, columnWidth("\342\200\213")); // 200B ZERO WIDTH SPACE
+
+  EXPECT_EQ(0, columnWidth("\314\200")); // 0300 COMBINING GRAVE ACCENT
+  EXPECT_EQ(1, columnWidth("\340\270\201")); // 0E01 THAI CHARACTER KO KAI
+  EXPECT_EQ(2, columnWidth("\344\270\200")); // CJK UNIFIED IDEOGRAPH-4E00
+
+  EXPECT_EQ(4, columnWidth("\344\270\200\344\270\200"));
+  EXPECT_EQ(3, columnWidth("q\344\270\200"));
+  EXPECT_EQ(3, columnWidth("\314\200\340\270\201\344\270\200"));
+
+  // Invalid UTF-8 strings, columnWidth should error out.
+  EXPECT_EQ(-2, columnWidth("\344"));
+  EXPECT_EQ(-2, columnWidth("\344\270"));
+  EXPECT_EQ(-2, columnWidth("\344\270\033"));
+  EXPECT_EQ(-2, columnWidth("\344\270\300"));
+  EXPECT_EQ(-2, columnWidth("\377\366\355"));
+
+  EXPECT_EQ(-2, columnWidth("qwer\344"));
+  EXPECT_EQ(-2, columnWidth("qwer\344\270"));
+  EXPECT_EQ(-2, columnWidth("qwer\344\270\033"));
+  EXPECT_EQ(-2, columnWidth("qwer\344\270\300"));
+  EXPECT_EQ(-2, columnWidth("qwer\377\366\355"));
+
+  // UTF-8 sequences longer than 4 bytes correspond to unallocated Unicode
+  // characters.
+  EXPECT_EQ(-2, columnWidth("\370\200\200\200\200"));     // U+200000
+  EXPECT_EQ(-2, columnWidth("\374\200\200\200\200\200")); // U+4000000
+}
+
+TEST(Locale, isPrint) {
+  EXPECT_EQ(false, isPrint(0)); // <control-0000>-<control-001F>
+  EXPECT_EQ(false, isPrint(0x01));
+  EXPECT_EQ(false, isPrint(0x1F));
+  EXPECT_EQ(true, isPrint(' '));
+  EXPECT_EQ(true, isPrint('A'));
+  EXPECT_EQ(true, isPrint('~'));
+  EXPECT_EQ(false, isPrint(0x7F)); // <control-007F>..<control-009F>
+  EXPECT_EQ(false, isPrint(0x90));
+  EXPECT_EQ(false, isPrint(0x9F));
+
+  EXPECT_EQ(true, isPrint(0xAC));
+  EXPECT_EQ(false, isPrint(0xAD)); // SOFT HYPHEN
+  EXPECT_EQ(true, isPrint(0xAE));
+
+  EXPECT_EQ(true, isPrint(0x0377)); // GREEK SMALL LETTER PAMPHYLIAN DIGAMMA
+  EXPECT_EQ(false, isPrint(0x0378)); // <reserved-0378>..<reserved-0379>
+
+  EXPECT_EQ(false, isPrint(0x0600)); // ARABIC NUMBER SIGN
+
+  EXPECT_EQ(false, isPrint(0x1FFFF)); // <reserved-1F774>..<noncharacter-1FFFF>
+  EXPECT_EQ(true, isPrint(0x20000)); // CJK UNIFIED IDEOGRAPH-20000
+
+  EXPECT_EQ(false, isPrint(0x10FFFF)); // noncharacter
+}
+
+} // namespace
+} // namespace locale
+} // namespace sys
+} // namespace llvm