initial commit, 4.5 stable

thirdparty/icu4c/common/util.cpp

@@ -0,0 +1,435 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+**********************************************************************
+*   Copyright (c) 2001-2011, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*   Date        Name        Description
+*   11/19/2001  aliu        Creation.
+**********************************************************************
+*/
+
+#include "unicode/unimatch.h"
+#include "unicode/utf16.h"
+#include "patternprops.h"
+#include "util.h"
+
+// Define char16_t constants using hex for EBCDIC compatibility
+
+static const char16_t BACKSLASH  = 0x005C; /*\*/
+static const char16_t UPPER_U    = 0x0055; /*U*/
+static const char16_t LOWER_U    = 0x0075; /*u*/
+static const char16_t APOSTROPHE = 0x0027; // '\''
+static const char16_t SPACE      = 0x0020; // ' '
+
+// "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+static const char16_t DIGITS[] = {
+    48,49,50,51,52,53,54,55,56,57,
+    65,66,67,68,69,70,71,72,73,74,
+    75,76,77,78,79,80,81,82,83,84,
+    85,86,87,88,89,90
+};
+
+U_NAMESPACE_BEGIN
+
+UnicodeString& ICU_Utility::appendNumber(UnicodeString& result, int32_t n,
+                                     int32_t radix, int32_t minDigits) {
+    if (radix < 2 || radix > 36) {
+        // Bogus radix
+        return result.append(static_cast<char16_t>(63)/*?*/);
+    }
+    // Handle negatives
+    if (n < 0) {
+        n = -n;
+        result.append(static_cast<char16_t>(45)/*-*/);
+    }
+    // First determine the number of digits
+    int32_t nn = n;
+    int32_t r = 1;
+    while (nn >= radix) {
+        nn /= radix;
+        r *= radix;
+        --minDigits;
+    }
+    // Now generate the digits
+    while (--minDigits > 0) {
+        result.append(DIGITS[0]);
+    }
+    while (r > 0) {
+        int32_t digit = n / r;
+        result.append(DIGITS[digit]);
+        n -= digit * r;
+        r /= radix;
+    }
+    return result;
+}
+
+UBool ICU_Utility::isUnprintable(UChar32 c) {
+    return !(c >= 0x20 && c <= 0x7E);
+}
+
+UBool ICU_Utility::shouldAlwaysBeEscaped(UChar32 c) {
+    if (c < 0x20) {
+        return true;  // C0 control codes
+    } else if (c <= 0x7e) {
+        return false;  // printable ASCII
+    } else if (c <= 0x9f) {
+        return true;  // C1 control codes
+    } else if (c < 0xd800) {
+        return false;  // most of the BMP
+    } else if (c <= 0xdfff || (0xfdd0 <= c && c <= 0xfdef) || (c & 0xfffe) == 0xfffe) {
+        return true;  // surrogate or noncharacter code points
+    } else if (c <= 0x10ffff) {
+        return false;  // all else
+    } else {
+        return true;  // not a code point
+    }
+}
+
+UBool ICU_Utility::escapeUnprintable(UnicodeString& result, UChar32 c) {
+    if (isUnprintable(c)) {
+        escape(result, c);
+        return true;
+    }
+    return false;
+}
+
+UnicodeString &ICU_Utility::escape(UnicodeString& result, UChar32 c) {
+    result.append(BACKSLASH);
+    if (c & ~0xFFFF) {
+        result.append(UPPER_U);
+        result.append(DIGITS[0xF&(c>>28)]);
+        result.append(DIGITS[0xF&(c>>24)]);
+        result.append(DIGITS[0xF&(c>>20)]);
+        result.append(DIGITS[0xF&(c>>16)]);
+    } else {
+        result.append(LOWER_U);
+    }
+    result.append(DIGITS[0xF&(c>>12)]);
+    result.append(DIGITS[0xF&(c>>8)]);
+    result.append(DIGITS[0xF&(c>>4)]);
+    result.append(DIGITS[0xF&c]);
+    return result;
+}
+
+/**
+ * Returns the index of a character, ignoring quoted text.
+ * For example, in the string "abc'hide'h", the 'h' in "hide" will not be
+ * found by a search for 'h'.
+ */
+// FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
+/*
+int32_t ICU_Utility::quotedIndexOf(const UnicodeString& text,
+                               int32_t start, int32_t limit,
+                               char16_t charToFind) {
+    for (int32_t i=start; i<limit; ++i) {
+        char16_t c = text.charAt(i);
+        if (c == BACKSLASH) {
+            ++i;
+        } else if (c == APOSTROPHE) {
+            while (++i < limit
+                   && text.charAt(i) != APOSTROPHE) {}
+        } else if (c == charToFind) {
+            return i;
+        }
+    }
+    return -1;
+}
+*/
+
+/**
+ * Skip over a sequence of zero or more white space characters at pos.
+ * @param advance if true, advance pos to the first non-white-space
+ * character at or after pos, or str.length(), if there is none.
+ * Otherwise leave pos unchanged.
+ * @return the index of the first non-white-space character at or
+ * after pos, or str.length(), if there is none.
+ */
+int32_t ICU_Utility::skipWhitespace(const UnicodeString& str, int32_t& pos,
+                                    UBool advance) {
+    int32_t p = pos;
+    const char16_t* s = str.getBuffer();
+    p = static_cast<int32_t>(PatternProps::skipWhiteSpace(s + p, str.length() - p) - s);
+    if (advance) {
+        pos = p;
+    }
+    return p;
+}
+
+/**
+ * Skip over Pattern_White_Space in a Replaceable.
+ * Skipping may be done in the forward or
+ * reverse direction.  In either case, the leftmost index will be
+ * inclusive, and the rightmost index will be exclusive.  That is,
+ * given a range defined as [start, limit), the call
+ * skipWhitespace(text, start, limit) will advance start past leading
+ * whitespace, whereas the call skipWhitespace(text, limit, start),
+ * will back up limit past trailing whitespace.
+ * @param text the text to be analyzed
+ * @param pos either the start or limit of a range of 'text', to skip
+ * leading or trailing whitespace, respectively
+ * @param stop either the limit or start of a range of 'text', to skip
+ * leading or trailing whitespace, respectively
+ * @return the new start or limit, depending on what was passed in to
+ * 'pos'
+ */
+//?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
+//?int32_t ICU_Utility::skipWhitespace(const Replaceable& text,
+//?                                    int32_t pos, int32_t stop) {
+//?    UChar32 c;
+//?    UBool isForward = (stop >= pos);
+//?
+//?    if (!isForward) {
+//?        --pos; // pos is a limit, so back up by one
+//?    }
+//?    
+//?    while (pos != stop &&
+//?           PatternProps::isWhiteSpace(c = text.char32At(pos))) {
+//?        if (isForward) {
+//?            pos += U16_LENGTH(c);
+//?        } else {
+//?            pos -= U16_LENGTH(c);
+//?        }
+//?    }
+//?
+//?    if (!isForward) {
+//?        ++pos; // make pos back into a limit
+//?    }
+//?
+//?    return pos;
+//?}
+
+/**
+ * Parse a single non-whitespace character 'ch', optionally
+ * preceded by whitespace.
+ * @param id the string to be parsed
+ * @param pos INPUT-OUTPUT parameter.  On input, pos[0] is the
+ * offset of the first character to be parsed.  On output, pos[0]
+ * is the index after the last parsed character.  If the parse
+ * fails, pos[0] will be unchanged.
+ * @param ch the non-whitespace character to be parsed.
+ * @return true if 'ch' is seen preceded by zero or more
+ * whitespace characters.
+ */
+UBool ICU_Utility::parseChar(const UnicodeString& id, int32_t& pos, char16_t ch) {
+    int32_t start = pos;
+    skipWhitespace(id, pos, true);
+    if (pos == id.length() ||
+        id.charAt(pos) != ch) {
+        pos = start;
+        return false;
+    }
+    ++pos;
+    return true;
+}
+
+/**
+ * Parse a pattern string within the given Replaceable and a parsing
+ * pattern.  Characters are matched literally and case-sensitively
+ * except for the following special characters:
+ *
+ * ~  zero or more Pattern_White_Space chars
+ *
+ * If end of pattern is reached with all matches along the way,
+ * pos is advanced to the first unparsed index and returned.
+ * Otherwise -1 is returned.
+ * @param pat pattern that controls parsing
+ * @param text text to be parsed, starting at index
+ * @param index offset to first character to parse
+ * @param limit offset after last character to parse
+ * @return index after last parsed character, or -1 on parse failure.
+ */
+int32_t ICU_Utility::parsePattern(const UnicodeString& pat,
+                                  const Replaceable& text,
+                                  int32_t index,
+                                  int32_t limit) {
+    int32_t ipat = 0;
+
+    // empty pattern matches immediately
+    if (ipat == pat.length()) {
+        return index;
+    }
+
+    UChar32 cpat = pat.char32At(ipat);
+
+    while (index < limit) {
+        UChar32 c = text.char32At(index);
+
+        // parse \s*
+        if (cpat == 126 /*~*/) {
+            if (PatternProps::isWhiteSpace(c)) {
+                index += U16_LENGTH(c);
+                continue;
+            } else {
+                if (++ipat == pat.length()) {
+                    return index; // success; c unparsed
+                }
+                // fall thru; process c again with next cpat
+            }
+        }
+
+        // parse literal
+        else if (c == cpat) {
+            index += U16_LENGTH(c);
+            ipat += U16_LENGTH(cpat);
+            if (ipat == pat.length()) {
+                return index; // success; c parsed
+            }
+            // fall thru; get next cpat
+        }
+
+        // match failure of literal
+        else {
+            return -1;
+        }
+
+        cpat = pat.char32At(ipat);
+    }
+
+    return -1; // text ended before end of pat
+}
+
+int32_t ICU_Utility::parseAsciiInteger(const UnicodeString& str, int32_t& pos) {
+    int32_t result = 0;
+    char16_t c;
+    while (pos < str.length() && (c = str.charAt(pos)) >= u'0' && c <= u'9') {
+        result = result * 10 + (c - u'0');
+        pos++;
+    }
+    return result;
+}
+
+/**
+ * Append a character to a rule that is being built up.  To flush
+ * the quoteBuf to rule, make one final call with isLiteral == true.
+ * If there is no final character, pass in (UChar32)-1 as c.
+ * @param rule the string to append the character to
+ * @param c the character to append, or (UChar32)-1 if none.
+ * @param isLiteral if true, then the given character should not be
+ * quoted or escaped.  Usually this means it is a syntactic element
+ * such as > or $
+ * @param escapeUnprintable if true, then unprintable characters
+ * should be escaped using \uxxxx or \Uxxxxxxxx.  These escapes will
+ * appear outside of quotes.
+ * @param quoteBuf a buffer which is used to build up quoted
+ * substrings.  The caller should initially supply an empty buffer,
+ * and thereafter should not modify the buffer.  The buffer should be
+ * cleared out by, at the end, calling this method with a literal
+ * character.
+ */
+void ICU_Utility::appendToRule(UnicodeString& rule,
+                               UChar32 c,
+                               UBool isLiteral,
+                               UBool escapeUnprintable,
+                               UnicodeString& quoteBuf) {
+    // If we are escaping unprintables, then escape them outside
+    // quotes.  \u and \U are not recognized within quotes.  The same
+    // logic applies to literals, but literals are never escaped.
+    if (isLiteral ||
+        (escapeUnprintable && ICU_Utility::isUnprintable(c))) {
+        if (quoteBuf.length() > 0) {
+            // We prefer backslash APOSTROPHE to double APOSTROPHE
+            // (more readable, less similar to ") so if there are
+            // double APOSTROPHEs at the ends, we pull them outside
+            // of the quote.
+
+            // If the first thing in the quoteBuf is APOSTROPHE
+            // (doubled) then pull it out.
+            while (quoteBuf.length() >= 2 &&
+                   quoteBuf.charAt(0) == APOSTROPHE &&
+                   quoteBuf.charAt(1) == APOSTROPHE) {
+                rule.append(BACKSLASH).append(APOSTROPHE);
+                quoteBuf.remove(0, 2);
+            }
+            // If the last thing in the quoteBuf is APOSTROPHE
+            // (doubled) then remove and count it and add it after.
+            int32_t trailingCount = 0;
+            while (quoteBuf.length() >= 2 &&
+                   quoteBuf.charAt(quoteBuf.length()-2) == APOSTROPHE &&
+                   quoteBuf.charAt(quoteBuf.length()-1) == APOSTROPHE) {
+                quoteBuf.truncate(quoteBuf.length()-2);
+                ++trailingCount;
+            }
+            if (quoteBuf.length() > 0) {
+                rule.append(APOSTROPHE);
+                rule.append(quoteBuf);
+                rule.append(APOSTROPHE);
+                quoteBuf.truncate(0);
+            }
+            while (trailingCount-- > 0) {
+                rule.append(BACKSLASH).append(APOSTROPHE);
+            }
+        }
+        if (c != static_cast<UChar32>(-1)) {
+            /* Since spaces are ignored during parsing, they are
+             * emitted only for readability.  We emit one here
+             * only if there isn't already one at the end of the
+             * rule.
+             */
+            if (c == SPACE) {
+                int32_t len = rule.length();
+                if (len > 0 && rule.charAt(len-1) != c) {
+                    rule.append(c);
+                }
+            } else if (!escapeUnprintable || !ICU_Utility::escapeUnprintable(rule, c)) {
+                rule.append(c);
+            }
+        }
+    }
+
+    // Escape ' and '\' and don't begin a quote just for them
+    else if (quoteBuf.length() == 0 &&
+             (c == APOSTROPHE || c == BACKSLASH)) {
+        rule.append(BACKSLASH);
+        rule.append(c);
+    }
+
+    // Specials (printable ascii that isn't [0-9a-zA-Z]) and
+    // whitespace need quoting.  Also append stuff to quotes if we are
+    // building up a quoted substring already.
+    else if (quoteBuf.length() > 0 ||
+             (c >= 0x0021 && c <= 0x007E &&
+              !((c >= 0x0030/*'0'*/ && c <= 0x0039/*'9'*/) ||
+                (c >= 0x0041/*'A'*/ && c <= 0x005A/*'Z'*/) ||
+                (c >= 0x0061/*'a'*/ && c <= 0x007A/*'z'*/))) ||
+             PatternProps::isWhiteSpace(c)) {
+        quoteBuf.append(c);
+        // Double ' within a quote
+        if (c == APOSTROPHE) {
+            quoteBuf.append(c);
+        }
+    }
+    
+    // Otherwise just append
+    else {
+        rule.append(c);
+    }
+}
+
+void ICU_Utility::appendToRule(UnicodeString& rule,
+                               const UnicodeString& text,
+                               UBool isLiteral,
+                               UBool escapeUnprintable,
+                               UnicodeString& quoteBuf) {
+    for (int32_t i=0; i<text.length(); ++i) {
+        appendToRule(rule, text[i], isLiteral, escapeUnprintable, quoteBuf);
+    }
+}
+
+/**
+ * Given a matcher reference, which may be null, append its
+ * pattern as a literal to the given rule.
+ */
+void ICU_Utility::appendToRule(UnicodeString& rule,
+                               const UnicodeMatcher* matcher,
+                               UBool escapeUnprintable,
+                               UnicodeString& quoteBuf) {
+    if (matcher != nullptr) {
+        UnicodeString pat;
+        appendToRule(rule, matcher->toPattern(pat, escapeUnprintable),
+                     true, escapeUnprintable, quoteBuf);
+    }
+}
+
+U_NAMESPACE_END