Check in the pristine copy of ICU 4.6...

icu46/source/common/util_props.cpp

+/*
+**********************************************************************
+*   Copyright (c) 2001-2006, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*   Date        Name        Description
+*   11/19/2001  aliu        Creation.
+**********************************************************************
+*/
+
+#include "util.h"
+#include "unicode/uchar.h"
+
+U_NAMESPACE_BEGIN
+
+/**
+ * Parse an integer at pos, either of the form \d+ or of the form
+ * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
+ * or octal format.
+ * @param pos INPUT-OUTPUT parameter.  On input, the first
+ * character to parse.  On output, the character after the last
+ * parsed character.
+ */
+int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
+    int32_t count = 0;
+    int32_t value = 0;
+    int32_t p = pos;
+    int8_t radix = 10;
+
+    if (p < limit && rule.charAt(p) == 48 /*0*/) {
+        if (p+1 < limit && (rule.charAt(p+1) == 0x78 /*x*/ || rule.charAt(p+1) == 0x58 /*X*/)) {
+            p += 2;
+            radix = 16;
+        }
+        else {
+            p++;
+            count = 1;
+            radix = 8;
+        }
+    }
+
+    while (p < limit) {
+        int32_t d = u_digit(rule.charAt(p++), radix);
+        if (d < 0) {
+            --p;
+            break;
+        }
+        ++count;
+        int32_t v = (value * radix) + d;
+        if (v <= value) {
+            // If there are too many input digits, at some point
+            // the value will go negative, e.g., if we have seen
+            // "0x8000000" already and there is another '0', when
+            // we parse the next 0 the value will go negative.
+            return 0;
+        }
+        value = v;
+    }
+    if (count > 0) {
+        pos = p;
+    }
+    return value;
+}
+
+/**
+ * Parse a pattern string starting at offset pos.  Keywords are
+ * matched case-insensitively.  Spaces may be skipped and may be
+ * optional or required.  Integer values may be parsed, and if
+ * they are, they will be returned in the given array.  If
+ * successful, the offset of the next non-space character is
+ * returned.  On failure, -1 is returned.
+ * @param pattern must only contain lowercase characters, which
+ * will match their uppercase equivalents as well.  A space
+ * character matches one or more required spaces.  A '~' character
+ * matches zero or more optional spaces.  A '#' character matches
+ * an integer and stores it in parsedInts, which the caller must
+ * ensure has enough capacity.
+ * @param parsedInts array to receive parsed integers.  Caller
+ * must ensure that parsedInts.length is >= the number of '#'
+ * signs in 'pattern'.
+ * @return the position after the last character parsed, or -1 if
+ * the parse failed
+ */
+int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
+                              const UnicodeString& pattern, int32_t* parsedInts) {
+    // TODO Update this to handle surrogates
+    int32_t p;
+    int32_t intCount = 0; // number of integers parsed
+    for (int32_t i=0; i<pattern.length(); ++i) {
+        UChar cpat = pattern.charAt(i);
+        UChar c;
+        switch (cpat) {
+        case 32 /*' '*/:
+            if (pos >= limit) {
+                return -1;
+            }
+            c = rule.charAt(pos++);
+            if (!uprv_isRuleWhiteSpace(c)) {
+                return -1;
+            }
+            // FALL THROUGH to skipWhitespace
+        case 126 /*'~'*/:
+            pos = skipWhitespace(rule, pos);
+            break;
+        case 35 /*'#'*/:
+            p = pos;
+            parsedInts[intCount++] = parseInteger(rule, p, limit);
+            if (p == pos) {
+                // Syntax error; failed to parse integer
+                return -1;
+            }
+            pos = p;
+            break;
+        default:
+            if (pos >= limit) {
+                return -1;
+            }
+            c = (UChar) u_tolower(rule.charAt(pos++));
+            if (c != cpat) {
+                return -1;
+            }
+            break;
+        }
+    }
+    return pos;
+}
+
+/**
+ * Parse a Unicode identifier from the given string at the given
+ * position.  Return the identifier, or an empty string if there
+ * is no identifier.
+ * @param str the string to parse
+ * @param pos INPUT-OUPUT parameter.  On INPUT, pos is the
+ * first character to examine.  It must be less than str.length(),
+ * and it must not point to a whitespace character.  That is, must
+ * have pos < str.length() and
+ * !uprv_isRuleWhiteSpace(str.char32At(pos)).  On
+ * OUTPUT, the position after the last parsed character.
+ * @return the Unicode identifier, or an empty string if there is
+ * no valid identifier at pos.
+ */
+UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) {
+    // assert(pos < str.length());
+    // assert(!uprv_isRuleWhiteSpace(str.char32At(pos)));
+    UnicodeString buf;
+    int p = pos;
+    while (p < str.length()) {
+        UChar32 ch = str.char32At(p);
+        if (buf.length() == 0) {
+            if (u_isIDStart(ch)) {
+                buf.append(ch);
+            } else {
+                buf.truncate(0);
+                return buf;
+            }
+        } else {
+            if (u_isIDPart(ch)) {
+                buf.append(ch);
+            } else {
+                break;
+            }
+        }
+        p += UTF_CHAR_LENGTH(ch);
+    }
+    pos = p;
+    return buf;
+}
+
+/**
+ * Parse an unsigned 31-bit integer at the given offset.  Use
+ * UCharacter.digit() to parse individual characters into digits.
+ * @param text the text to be parsed
+ * @param pos INPUT-OUTPUT parameter.  On entry, pos[0] is the
+ * offset within text at which to start parsing; it should point
+ * to a valid digit.  On exit, pos[0] is the offset after the last
+ * parsed character.  If the parse failed, it will be unchanged on
+ * exit.  Must be >= 0 on entry.
+ * @param radix the radix in which to parse; must be >= 2 and <=
+ * 36.
+ * @return a non-negative parsed number, or -1 upon parse failure.
+ * Parse fails if there are no digits, that is, if pos[0] does not
+ * point to a valid digit on entry, or if the number to be parsed
+ * does not fit into a 31-bit unsigned integer.
+ */
+int32_t ICU_Utility::parseNumber(const UnicodeString& text,
+                                 int32_t& pos, int8_t radix) {
+    // assert(pos[0] >= 0);
+    // assert(radix >= 2);
+    // assert(radix <= 36);
+    int32_t n = 0;
+    int32_t p = pos;
+    while (p < text.length()) {
+        UChar32 ch = text.char32At(p);
+        int32_t d = u_digit(ch, radix);
+        if (d < 0) {
+            break;
+        }
+        n = radix*n + d;
+        // ASSUME that when a 32-bit integer overflows it becomes
+        // negative.  E.g., 214748364 * 10 + 8 => negative value.
+        if (n < 0) {
+            return -1;
+        }
+        ++p;
+    }
+    if (p == pos) {
+        return -1;
+    }
+    pos = p;
+    return n;
+}
+
+U_NAMESPACE_END
+