Update ICU to 54.1 step 1

source/i18n/collationfastlatin.h

+/*
+*******************************************************************************
+* Copyright (C) 2013-2014, International Business Machines
+* Corporation and others.  All Rights Reserved.
+*******************************************************************************
+* collationfastlatin.h
+*
+* created on: 2013aug09
+* created by: Markus W. Scherer
+*/
+
+#ifndef __COLLATIONFASTLATIN_H__
+#define __COLLATIONFASTLATIN_H__
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_COLLATION
+
+U_NAMESPACE_BEGIN
+
+struct CollationData;
+struct CollationSettings;
+
+class U_I18N_API CollationFastLatin /* all static */ {
+public:
+    /**
+     * Fast Latin format version (one byte 1..FF).
+     * Must be incremented for any runtime-incompatible changes,
+     * in particular, for changes to any of the following constants.
+     *
+     * When the major version number of the main data format changes,
+     * we can reset this fast Latin version to 1.
+     */
+    static const uint16_t VERSION = 1;
+
+    static const int32_t LATIN_MAX = 0x17f;
+    static const int32_t LATIN_LIMIT = LATIN_MAX + 1;
+
+    static const int32_t LATIN_MAX_UTF8_LEAD = 0xc5;  // UTF-8 lead byte of LATIN_MAX
+
+    static const int32_t PUNCT_START = 0x2000;
+    static const int32_t PUNCT_LIMIT = 0x2040;
+
+    // excludes U+FFFE & U+FFFF
+    static const int32_t NUM_FAST_CHARS = LATIN_LIMIT + (PUNCT_LIMIT - PUNCT_START);
+
+    // Note on the supported weight ranges:
+    // Analysis of UCA 6.3 and CLDR 23 non-search tailorings shows that
+    // the CEs for characters in the above ranges, excluding expansions with length >2,
+    // excluding contractions of >2 characters, and other restrictions
+    // (see the builder's getCEsFromCE32()),
+    // use at most about 150 primary weights,
+    // where about 94 primary weights are possibly-variable (space/punct/symbol/currency),
+    // at most 4 secondary before-common weights,
+    // at most 4 secondary after-common weights,
+    // at most 16 secondary high weights (in secondary CEs), and
+    // at most 4 tertiary after-common weights.
+    // The following ranges are designed to support slightly more weights than that.
+    // (en_US_POSIX is unusual: It creates about 64 variable + 116 Latin primaries.)
+
+    // Digits may use long primaries (preserving more short ones)
+    // or short primaries (faster) without changing this data structure.
+    // (If we supported numeric collation, then digits would have to have long primaries
+    // so that special handling does not affect the fast path.)
+
+    static const uint32_t SHORT_PRIMARY_MASK = 0xfc00;  // bits 15..10
+    static const uint32_t INDEX_MASK = 0x3ff;  // bits 9..0 for expansions & contractions
+    static const uint32_t SECONDARY_MASK = 0x3e0;  // bits 9..5
+    static const uint32_t CASE_MASK = 0x18;  // bits 4..3
+    static const uint32_t LONG_PRIMARY_MASK = 0xfff8;  // bits 15..3
+    static const uint32_t TERTIARY_MASK = 7;  // bits 2..0
+    static const uint32_t CASE_AND_TERTIARY_MASK = CASE_MASK | TERTIARY_MASK;
+
+    static const uint32_t TWO_SHORT_PRIMARIES_MASK =
+            (SHORT_PRIMARY_MASK << 16) | SHORT_PRIMARY_MASK;  // 0xfc00fc00
+    static const uint32_t TWO_LONG_PRIMARIES_MASK =
+            (LONG_PRIMARY_MASK << 16) | LONG_PRIMARY_MASK;  // 0xfff8fff8
+    static const uint32_t TWO_SECONDARIES_MASK =
+            (SECONDARY_MASK << 16) | SECONDARY_MASK;  // 0x3e003e0
+    static const uint32_t TWO_CASES_MASK =
+            (CASE_MASK << 16) | CASE_MASK;  // 0x180018
+    static const uint32_t TWO_TERTIARIES_MASK =
+            (TERTIARY_MASK << 16) | TERTIARY_MASK;  // 0x70007
+
+    /**
+     * Contraction with one fast Latin character.
+     * Use INDEX_MASK to find the start of the contraction list after the fixed table.
+     * The first entry contains the default mapping.
+     * Otherwise use CONTR_CHAR_MASK for the contraction character index
+     * (in ascending order).
+     * Use CONTR_LENGTH_SHIFT for the length of the entry
+     * (1=BAIL_OUT, 2=one CE, 3=two CEs).
+     *
+     * Also, U+0000 maps to a contraction entry, so that the fast path need not
+     * check for NUL termination.
+     * It usually maps to a contraction list with only the completely ignorable default value.
+     */
+    static const uint32_t CONTRACTION = 0x400;
+    /**
+     * An expansion encodes two CEs.
+     * Use INDEX_MASK to find the pair of CEs after the fixed table.
+     *
+     * The higher a mini CE value, the easier it is to process.
+     * For expansions and higher, no context needs to be considered.
+     */
+    static const uint32_t EXPANSION = 0x800;
+    /**
+     * Encodes one CE with a long/low mini primary (there are 128).
+     * All potentially-variable primaries must be in this range,
+     * to make the short-primary path as fast as possible.
+     */
+    static const uint32_t MIN_LONG = 0xc00;
+    static const uint32_t LONG_INC = 8;
+    static const uint32_t MAX_LONG = 0xff8;
+    /**
+     * Encodes one CE with a short/high primary (there are 60),
+     * plus a secondary CE if the secondary weight is high.
+     * Fast handling: At least all letter primaries should be in this range.
+     */
+    static const uint32_t MIN_SHORT = 0x1000;
+    static const uint32_t SHORT_INC = 0x400;
+    /** The highest primary weight is reserved for U+FFFF. */
+    static const uint32_t MAX_SHORT = SHORT_PRIMARY_MASK;
+
+    static const uint32_t MIN_SEC_BEFORE = 0;  // must add SEC_OFFSET
+    static const uint32_t SEC_INC = 0x20;
+    static const uint32_t MAX_SEC_BEFORE = MIN_SEC_BEFORE + 4 * SEC_INC;  // 5 before common
+    static const uint32_t COMMON_SEC = MAX_SEC_BEFORE + SEC_INC;
+    static const uint32_t MIN_SEC_AFTER = COMMON_SEC + SEC_INC;
+    static const uint32_t MAX_SEC_AFTER = MIN_SEC_AFTER + 5 * SEC_INC;  // 6 after common
+    static const uint32_t MIN_SEC_HIGH = MAX_SEC_AFTER + SEC_INC;  // 20 high secondaries
+    static const uint32_t MAX_SEC_HIGH = SECONDARY_MASK;
+
+    /**
+     * Lookup: Add this offset to secondary weights, except for completely ignorable CEs.
+     * Must be greater than any special value, e.g., MERGE_WEIGHT.
+     * The exact value is not relevant for the format version.
+     */
+    static const uint32_t SEC_OFFSET = SEC_INC;
+    static const uint32_t COMMON_SEC_PLUS_OFFSET = COMMON_SEC + SEC_OFFSET;
+
+    static const uint32_t TWO_SEC_OFFSETS =
+            (SEC_OFFSET << 16) | SEC_OFFSET;  // 0x200020
+    static const uint32_t TWO_COMMON_SEC_PLUS_OFFSET =
+            (COMMON_SEC_PLUS_OFFSET << 16) | COMMON_SEC_PLUS_OFFSET;
+
+    static const uint32_t LOWER_CASE = 8;  // case bits include this offset
+    static const uint32_t TWO_LOWER_CASES = (LOWER_CASE << 16) | LOWER_CASE;  // 0x80008
+
+    static const uint32_t COMMON_TER = 0;  // must add TER_OFFSET
+    static const uint32_t MAX_TER_AFTER = 7;  // 7 after common
+
+    /**
+     * Lookup: Add this offset to tertiary weights, except for completely ignorable CEs.
+     * Must be greater than any special value, e.g., MERGE_WEIGHT.
+     * Must be greater than case bits as well, so that with combined case+tertiary weights
+     * plus the offset the tertiary bits does not spill over into the case bits.
+     * The exact value is not relevant for the format version.
+     */
+    static const uint32_t TER_OFFSET = SEC_OFFSET;
+    static const uint32_t COMMON_TER_PLUS_OFFSET = COMMON_TER + TER_OFFSET;
+
+    static const uint32_t TWO_TER_OFFSETS = (TER_OFFSET << 16) | TER_OFFSET;
+    static const uint32_t TWO_COMMON_TER_PLUS_OFFSET =
+            (COMMON_TER_PLUS_OFFSET << 16) | COMMON_TER_PLUS_OFFSET;
+
+    static const uint32_t MERGE_WEIGHT = 3;
+    static const uint32_t EOS = 2;  // end of string
+    static const uint32_t BAIL_OUT = 1;
+
+    /**
+     * Contraction result first word bits 8..0 contain the
+     * second contraction character, as a char index 0..NUM_FAST_CHARS-1.
+     * Each contraction list is terminated with a word containing CONTR_CHAR_MASK.
+     */
+    static const uint32_t CONTR_CHAR_MASK = 0x1ff;
+    /**
+     * Contraction result first word bits 10..9 contain the result length:
+     * 1=bail out, 2=one mini CE, 3=two mini CEs
+     */
+    static const uint32_t CONTR_LENGTH_SHIFT = 9;
+
+    /**
+     * Comparison return value when the regular comparison must be used.
+     * The exact value is not relevant for the format version.
+     */
+    static const int32_t BAIL_OUT_RESULT = -2;
+
+    static inline int32_t getCharIndex(UChar c) {
+        if(c <= LATIN_MAX) {
+            return c;
+        } else if(PUNCT_START <= c && c < PUNCT_LIMIT) {
+            return c - (PUNCT_START - LATIN_LIMIT);
+        } else {
+            // Not a fast Latin character.
+            // Note: U+FFFE & U+FFFF are forbidden in tailorings
+            // and thus do not occur in any contractions.
+            return -1;
+        }
+    }
+
+    /**
+     * Computes the options value for the compare functions
+     * and writes the precomputed primary weights.
+     * Returns -1 if the Latin fastpath is not supported for the data and settings.
+     * The capacity must be LATIN_LIMIT.
+     */
+    static int32_t getOptions(const CollationData *data, const CollationSettings &settings,
+                              uint16_t *primaries, int32_t capacity);
+
+    static int32_t compareUTF16(const uint16_t *table, const uint16_t *primaries, int32_t options,
+                                const UChar *left, int32_t leftLength,
+                                const UChar *right, int32_t rightLength);
+
+    static int32_t compareUTF8(const uint16_t *table, const uint16_t *primaries, int32_t options,
+                               const uint8_t *left, int32_t leftLength,
+                               const uint8_t *right, int32_t rightLength);
+
+private:
+    static uint32_t lookup(const uint16_t *table, UChar32 c);
+    static uint32_t lookupUTF8(const uint16_t *table, UChar32 c,
+                               const uint8_t *s8, int32_t &sIndex, int32_t sLength);
+    static uint32_t lookupUTF8Unsafe(const uint16_t *table, UChar32 c,
+                                     const uint8_t *s8, int32_t &sIndex);
+
+    static uint32_t nextPair(const uint16_t *table, UChar32 c, uint32_t ce,
+                             const UChar *s16, const uint8_t *s8, int32_t &sIndex, int32_t &sLength);
+
+    static inline uint32_t getPrimaries(uint32_t variableTop, uint32_t pair) {
+        uint32_t ce = pair & 0xffff;
+        if(ce >= MIN_SHORT) { return pair & TWO_SHORT_PRIMARIES_MASK; }
+        if(ce > variableTop) { return pair & TWO_LONG_PRIMARIES_MASK; }
+        if(ce >= MIN_LONG) { return 0; }  // variable
+        return pair;  // special mini CE
+    }
+    static inline uint32_t getSecondariesFromOneShortCE(uint32_t ce) {
+        ce &= SECONDARY_MASK;
+        if(ce < MIN_SEC_HIGH) {
+            return ce + SEC_OFFSET;
+        } else {
+            return ((ce + SEC_OFFSET) << 16) | COMMON_SEC_PLUS_OFFSET;
+        }
+    }
+    static uint32_t getSecondaries(uint32_t variableTop, uint32_t pair);
+    static uint32_t getCases(uint32_t variableTop, UBool strengthIsPrimary, uint32_t pair);
+    static uint32_t getTertiaries(uint32_t variableTop, UBool withCaseBits, uint32_t pair);
+    static uint32_t getQuaternaries(uint32_t variableTop, uint32_t pair);
+
+private:
+    CollationFastLatin();  // no constructor
+};
+
+/*
+ * Format of the CollationFastLatin data table.
+ * CollationFastLatin::VERSION = 1.
+ *
+ * This table contains data for a Latin-text collation fastpath.
+ * The data is stored as an array of uint16_t which contains the following parts.
+ *
+ * uint16_t  -- version & header length
+ *   Bits 15..8: version, must match the VERSION
+ *         7..0: length of the header
+ *
+ * uint16_t varTops[header length - 1]
+ *   Each of these values maps the variable top lead byte of a supported maxVariable group
+ *   to the highest CollationFastLatin long-primary weight.
+ *   The values are stored in ascending order.
+ *   Bits 15..7: max fast-Latin long-primary weight (bits 11..3 shifted left by 4 bits)
+ *         6..0: regular primary lead byte
+ *
+ * uint16_t miniCEs[0x1c0]
+ *   A mini collation element for each character U+0000..U+017F and U+2000..U+203F.
+ *   Each value encodes one or two mini CEs (two are possible if the first one
+ *   has a short mini primary and the second one is a secondary CE, i.e., primary == 0),
+ *   or points to an expansion or to a contraction table.
+ *   U+0000 always has a contraction entry,
+ *   so that NUL-termination need not be tested in the fastpath.
+ *   If the collation elements for a character or contraction cannot be encoded in this format,
+ *   then the BAIL_OUT value is stored.
+ *   For details see the comments for the class constants.
+ *
+ * uint16_t expansions[variable length];
+ *   Expansion mini CEs contain an offset relative to just after the miniCEs table.
+ *   An expansions contains exactly 2 mini CEs.
+ *
+ * uint16_t contractions[variable length];
+ *   Contraction mini CEs contain an offset relative to just after the miniCEs table.
+ *   It points to a list of tuples which map from a contraction suffix character to a result.
+ *   First uint16_t of each tuple:
+ *     Bits 10..9: Length of the result (1..3), see comments on CONTR_LENGTH_SHIFT.
+ *     Bits  8..0: Contraction character, see comments on CONTR_CHAR_MASK.
+ *   This is followed by 0, 1, or 2 uint16_t according to the length.
+ *   Each list is terminated by an entry with CONTR_CHAR_MASK.
+ *   Each list starts with such an entry which also contains the default result
+ *   for when there is no contraction match.
+ */
+
+U_NAMESPACE_END
+
+#endif  // !UCONFIG_NO_COLLATION
+#endif  // __COLLATIONFASTLATIN_H__