Update ICU to 54.1 step 1

source/i18n/collationfastlatin.cpp

+/*
+*******************************************************************************
+* Copyright (C) 2013-2014, International Business Machines
+* Corporation and others.  All Rights Reserved.
+*******************************************************************************
+* collationfastlatin.cpp
+*
+* created on: 2013aug18
+* created by: Markus W. Scherer
+*/
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_COLLATION
+
+#include "unicode/ucol.h"
+#include "collationdata.h"
+#include "collationfastlatin.h"
+#include "collationsettings.h"
+#include "putilimp.h"  // U_ALIGN_CODE
+#include "uassert.h"
+
+U_NAMESPACE_BEGIN
+
+int32_t
+CollationFastLatin::getOptions(const CollationData *data, const CollationSettings &settings,
+                               uint16_t *primaries, int32_t capacity) {
+    const uint16_t *table = data->fastLatinTable;
+    if(table == NULL) { return -1; }
+    U_ASSERT(capacity == LATIN_LIMIT);
+    if(capacity != LATIN_LIMIT) { return -1; }
+
+    uint32_t miniVarTop;
+    if((settings.options & CollationSettings::ALTERNATE_MASK) == 0) {
+        // No mini primaries are variable, set a variableTop just below the
+        // lowest long mini primary.
+        miniVarTop = MIN_LONG - 1;
+    } else {
+        uint32_t v1 = settings.variableTop >> 24;
+        int32_t headerLength = *table & 0xff;
+        int32_t i = headerLength - 1;
+        if(i <= 0 || v1 > (table[i] & 0x7f)) {
+            return -1;  // variableTop >= digits, should not occur
+        }
+        while(i > 1 && v1 <= (table[i - 1] & 0x7f)) { --i; }
+        // In the table header, the miniVarTop is in bits 15..7, with 4 zero bits 19..16 implied.
+        // Shift right to make it comparable with long mini primaries in bits 15..3.
+        miniVarTop = (table[i] & 0xff80) >> 4;
+    }
+
+    const uint8_t *reorderTable = settings.reorderTable;
+    if(reorderTable != NULL) {
+        const uint16_t *scripts = data->scripts;
+        int32_t length = data->scriptsLength;
+        uint32_t prevLastByte = 0;
+        for(int32_t i = 0; i < length;) {
+            // reordered last byte of the group
+            uint32_t lastByte = reorderTable[scripts[i] & 0xff];
+            if(lastByte < prevLastByte) {
+                // The permutation affects the groups up to Latin.
+                return -1;
+            }
+            if(scripts[i + 2] == USCRIPT_LATIN) { break; }
+            i = i + 2 + scripts[i + 1];
+            prevLastByte = lastByte;
+        }
+    }
+
+    table += (table[0] & 0xff);  // skip the header
+    for(UChar32 c = 0; c < LATIN_LIMIT; ++c) {
+        uint32_t p = table[c];
+        if(p >= MIN_SHORT) {
+            p &= SHORT_PRIMARY_MASK;
+        } else if(p > miniVarTop) {
+            p &= LONG_PRIMARY_MASK;
+        } else {
+            p = 0;
+        }
+        primaries[c] = (uint16_t)p;
+    }
+    if((settings.options & CollationSettings::NUMERIC) != 0) {
+        // Bail out for digits.
+        for(UChar32 c = 0x30; c <= 0x39; ++c) { primaries[c] = 0; }
+    }
+
+    // Shift the miniVarTop above other options.
+    return ((int32_t)miniVarTop << 16) | settings.options;
+}
+
+int32_t
+CollationFastLatin::compareUTF16(const uint16_t *table, const uint16_t *primaries, int32_t options,
+                                 const UChar *left, int32_t leftLength,
+                                 const UChar *right, int32_t rightLength) {
+    // This is a modified copy of CollationCompare::compareUpToQuaternary(),
+    // optimized for common Latin text.
+    // Keep them in sync!
+    // Keep compareUTF16() and compareUTF8() in sync very closely!
+
+    U_ASSERT((table[0] >> 8) == VERSION);
+    table += (table[0] & 0xff);  // skip the header
+    uint32_t variableTop = (uint32_t)options >> 16;  // see getOptions()
+    options &= 0xffff;  // needed for CollationSettings::getStrength() to work
+
+    // Check for supported characters, fetch mini CEs, and compare primaries.
+    U_ALIGN_CODE(16);
+    int32_t leftIndex = 0, rightIndex = 0;
+    /**
+     * Single mini CE or a pair.
+     * The current mini CE is in the lower 16 bits, the next one is in the upper 16 bits.
+     * If there is only one, then it is in the lower bits, and the upper bits are 0.
+     */
+    uint32_t leftPair = 0, rightPair = 0;
+    for(;;) {
+        // We fetch CEs until we get a non-ignorable primary or reach the end.
+        while(leftPair == 0) {
+            if(leftIndex == leftLength) {
+                leftPair = EOS;
+                break;
+            }
+            UChar32 c = left[leftIndex++];
+            if(c <= LATIN_MAX) {
+                leftPair = primaries[c];
+                if(leftPair != 0) { break; }
+                if(c <= 0x39 && c >= 0x30 && (options & CollationSettings::NUMERIC) != 0) {
+                    return BAIL_OUT_RESULT;
+                }
+                leftPair = table[c];
+            } else if(PUNCT_START <= c && c < PUNCT_LIMIT) {
+                leftPair = table[c - PUNCT_START + LATIN_LIMIT];
+            } else {
+                leftPair = lookup(table, c);
+            }
+            if(leftPair >= MIN_SHORT) {
+                leftPair &= SHORT_PRIMARY_MASK;
+                break;
+            } else if(leftPair > variableTop) {
+                leftPair &= LONG_PRIMARY_MASK;
+                break;
+            } else {
+                leftPair = nextPair(table, c, leftPair, left, NULL, leftIndex, leftLength);
+                if(leftPair == BAIL_OUT) { return BAIL_OUT_RESULT; }
+                leftPair = getPrimaries(variableTop, leftPair);
+            }
+        }
+
+        while(rightPair == 0) {
+            if(rightIndex == rightLength) {
+                rightPair = EOS;
+                break;
+            }
+            UChar32 c = right[rightIndex++];
+            if(c <= LATIN_MAX) {
+                rightPair = primaries[c];
+                if(rightPair != 0) { break; }
+                if(c <= 0x39 && c >= 0x30 && (options & CollationSettings::NUMERIC) != 0) {
+                    return BAIL_OUT_RESULT;
+                }
+                rightPair = table[c];
+            } else if(PUNCT_START <= c && c < PUNCT_LIMIT) {
+                rightPair = table[c - PUNCT_START + LATIN_LIMIT];
+            } else {
+                rightPair = lookup(table, c);
+            }
+            if(rightPair >= MIN_SHORT) {
+                rightPair &= SHORT_PRIMARY_MASK;
+                break;
+            } else if(rightPair > variableTop) {
+                rightPair &= LONG_PRIMARY_MASK;
+                break;
+            } else {
+                rightPair = nextPair(table, c, rightPair, right, NULL, rightIndex, rightLength);
+                if(rightPair == BAIL_OUT) { return BAIL_OUT_RESULT; }
+                rightPair = getPrimaries(variableTop, rightPair);
+            }
+        }
+
+        if(leftPair == rightPair) {
+            if(leftPair == EOS) { break; }
+            leftPair = rightPair = 0;
+            continue;
+        }
+        uint32_t leftPrimary = leftPair & 0xffff;
+        uint32_t rightPrimary = rightPair & 0xffff;
+        if(leftPrimary != rightPrimary) {
+            // Return the primary difference.
+            return (leftPrimary < rightPrimary) ? UCOL_LESS : UCOL_GREATER;
+        }
+        if(leftPair == EOS) { break; }
+        leftPair >>= 16;
+        rightPair >>= 16;
+    }
+    // In the following, we need to re-fetch each character because we did not buffer the CEs,
+    // but we know that the string is well-formed and
+    // only contains supported characters and mappings.
+
+    // We might skip the secondary level but continue with the case level
+    // which is turned on separately.
+    if(CollationSettings::getStrength(options) >= UCOL_SECONDARY) {
+        leftIndex = rightIndex = 0;
+        leftPair = rightPair = 0;
+        for(;;) {
+            while(leftPair == 0) {
+                if(leftIndex == leftLength) {
+                    leftPair = EOS;
+                    break;
+                }
+                UChar32 c = left[leftIndex++];
+                if(c <= LATIN_MAX) {
+                    leftPair = table[c];
+                } else if(PUNCT_START <= c && c < PUNCT_LIMIT) {
+                    leftPair = table[c - PUNCT_START + LATIN_LIMIT];
+                } else {
+                    leftPair = lookup(table, c);
+                }
+                if(leftPair >= MIN_SHORT) {
+                    leftPair = getSecondariesFromOneShortCE(leftPair);
+                    break;
+                } else if(leftPair > variableTop) {
+                    leftPair = COMMON_SEC_PLUS_OFFSET;
+                    break;
+                } else {
+                    leftPair = nextPair(table, c, leftPair, left, NULL, leftIndex, leftLength);
+                    leftPair = getSecondaries(variableTop, leftPair);
+                }
+            }
+
+            while(rightPair == 0) {
+                if(rightIndex == rightLength) {
+                    rightPair = EOS;
+                    break;
+                }
+                UChar32 c = right[rightIndex++];
+                if(c <= LATIN_MAX) {
+                    rightPair = table[c];
+                } else if(PUNCT_START <= c && c < PUNCT_LIMIT) {
+                    rightPair = table[c - PUNCT_START + LATIN_LIMIT];
+                } else {
+                    rightPair = lookup(table, c);
+                }
+                if(rightPair >= MIN_SHORT) {
+                    rightPair = getSecondariesFromOneShortCE(rightPair);
+                    break;
+                } else if(rightPair > variableTop) {
+                    rightPair = COMMON_SEC_PLUS_OFFSET;
+                    break;
+                } else {
+                    rightPair = nextPair(table, c, rightPair, right, NULL, rightIndex, rightLength);
+                    rightPair = getSecondaries(variableTop, rightPair);
+                }
+            }
+
+            if(leftPair == rightPair) {
+                if(leftPair == EOS) { break; }
+                leftPair = rightPair = 0;
+                continue;
+            }
+            uint32_t leftSecondary = leftPair & 0xffff;
+            uint32_t rightSecondary = rightPair & 0xffff;
+            if(leftSecondary != rightSecondary) {
+                if((options & CollationSettings::BACKWARD_SECONDARY) != 0) {
+                    // Full support for backwards secondary requires backwards contraction matching
+                    // and moving backwards between merge separators.
+                    return BAIL_OUT_RESULT;
+                }
+                return (leftSecondary < rightSecondary) ? UCOL_LESS : UCOL_GREATER;
+            }
+            if(leftPair == EOS) { break; }
+            leftPair >>= 16;
+            rightPair >>= 16;
+        }
+    }
+
+    if((options & CollationSettings::CASE_LEVEL) != 0) {
+        UBool strengthIsPrimary = CollationSettings::getStrength(options) == UCOL_PRIMARY;
+        leftIndex = rightIndex = 0;
+        leftPair = rightPair = 0;
+        for(;;) {
+            while(leftPair == 0) {
+                if(leftIndex == leftLength) {
+                    leftPair = EOS;
+                    break;
+                }
+                UChar32 c = left[leftIndex++];
+                leftPair = (c <= LATIN_MAX) ? table[c] : lookup(table, c);
+                if(leftPair < MIN_LONG) {
+                    leftPair = nextPair(table, c, leftPair, left, NULL, leftIndex, leftLength);
+                }
+                leftPair = getCases(variableTop, strengthIsPrimary, leftPair);
+            }
+
+            while(rightPair == 0) {
+                if(rightIndex == rightLength) {
+                    rightPair = EOS;
+                    break;
+                }
+                UChar32 c = right[rightIndex++];
+                rightPair = (c <= LATIN_MAX) ? table[c] : lookup(table, c);
+                if(rightPair < MIN_LONG) {
+                    rightPair = nextPair(table, c, rightPair, right, NULL, rightIndex, rightLength);
+                }
+                rightPair = getCases(variableTop, strengthIsPrimary, rightPair);
+            }
+
+            if(leftPair == rightPair) {
+                if(leftPair == EOS) { break; }
+                leftPair = rightPair = 0;
+                continue;
+            }
+            uint32_t leftCase = leftPair & 0xffff;
+            uint32_t rightCase = rightPair & 0xffff;
+            if(leftCase != rightCase) {
+                if((options & CollationSettings::UPPER_FIRST) == 0) {
+                    return (leftCase < rightCase) ? UCOL_LESS : UCOL_GREATER;
+                } else {
+                    return (leftCase < rightCase) ? UCOL_GREATER : UCOL_LESS;
+                }
+            }
+            if(leftPair == EOS) { break; }
+            leftPair >>= 16;
+            rightPair >>= 16;
+        }
+    }
+    if(CollationSettings::getStrength(options) <= UCOL_SECONDARY) { return UCOL_EQUAL; }
+
+    // Remove the case bits from the tertiary weight when caseLevel is on or caseFirst is off.
+    UBool withCaseBits = CollationSettings::isTertiaryWithCaseBits(options);
+
+    leftIndex = rightIndex = 0;
+    leftPair = rightPair = 0;
+    for(;;) {
+        while(leftPair == 0) {
+            if(leftIndex == leftLength) {
+                leftPair = EOS;
+                break;
+            }
+            UChar32 c = left[leftIndex++];
+            leftPair = (c <= LATIN_MAX) ? table[c] : lookup(table, c);
+            if(leftPair < MIN_LONG) {
+                leftPair = nextPair(table, c, leftPair, left, NULL, leftIndex, leftLength);
+            }
+            leftPair = getTertiaries(variableTop, withCaseBits, leftPair);
+        }
+
+        while(rightPair == 0) {
+            if(rightIndex == rightLength) {
+                rightPair = EOS;
+                break;
+            }
+            UChar32 c = right[rightIndex++];
+            rightPair = (c <= LATIN_MAX) ? table[c] : lookup(table, c);
+            if(rightPair < MIN_LONG) {
+                rightPair = nextPair(table, c, rightPair, right, NULL, rightIndex, rightLength);
+            }
+            rightPair = getTertiaries(variableTop, withCaseBits, rightPair);
+        }
+
+        if(leftPair == rightPair) {
+            if(leftPair == EOS) { break; }
+            leftPair = rightPair = 0;
+            continue;
+        }
+        uint32_t leftTertiary = leftPair & 0xffff;
+        uint32_t rightTertiary = rightPair & 0xffff;
+        if(leftTertiary != rightTertiary) {
+            if(CollationSettings::sortsTertiaryUpperCaseFirst(options)) {
+                // Pass through EOS and MERGE_WEIGHT
+                // and keep real tertiary weights larger than the MERGE_WEIGHT.
+                // Tertiary CEs (secondary ignorables) are not supported in fast Latin.
+                if(leftTertiary > MERGE_WEIGHT) {
+                    leftTertiary ^= CASE_MASK;
+                }
+                if(rightTertiary > MERGE_WEIGHT) {
+                    rightTertiary ^= CASE_MASK;
+                }
+            }
+            return (leftTertiary < rightTertiary) ? UCOL_LESS : UCOL_GREATER;
+        }
+        if(leftPair == EOS) { break; }
+        leftPair >>= 16;
+        rightPair >>= 16;
+    }
+    if(CollationSettings::getStrength(options) <= UCOL_TERTIARY) { return UCOL_EQUAL; }
+
+    leftIndex = rightIndex = 0;
+    leftPair = rightPair = 0;
+    for(;;) {
+        while(leftPair == 0) {
+            if(leftIndex == leftLength) {
+                leftPair = EOS;
+                break;
+            }
+            UChar32 c = left[leftIndex++];
+            leftPair = (c <= LATIN_MAX) ? table[c] : lookup(table, c);
+            if(leftPair < MIN_LONG) {
+                leftPair = nextPair(table, c, leftPair, left, NULL, leftIndex, leftLength);
+            }
+            leftPair = getQuaternaries(variableTop, leftPair);
+        }
+
+        while(rightPair == 0) {
+            if(rightIndex == rightLength) {
+                rightPair = EOS;
+                break;
+            }
+            UChar32 c = right[rightIndex++];
+            rightPair = (c <= LATIN_MAX) ? table[c] : lookup(table, c);
+            if(rightPair < MIN_LONG) {
+                rightPair = nextPair(table, c, rightPair, right, NULL, rightIndex, rightLength);
+            }
+            rightPair = getQuaternaries(variableTop, rightPair);
+        }
+
+        if(leftPair == rightPair) {
+            if(leftPair == EOS) { break; }
+            leftPair = rightPair = 0;
+            continue;
+        }
+        uint32_t leftQuaternary = leftPair & 0xffff;
+        uint32_t rightQuaternary = rightPair & 0xffff;
+        if(leftQuaternary != rightQuaternary) {
+            return (leftQuaternary < rightQuaternary) ? UCOL_LESS : UCOL_GREATER;
+        }
+        if(leftPair == EOS) { break; }
+        leftPair >>= 16;
+        rightPair >>= 16;
+    }
+    return UCOL_EQUAL;
+}
+
+int32_t
+CollationFastLatin::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) {
+    // Keep compareUTF16() and compareUTF8() in sync very closely!
+
+    U_ASSERT((table[0] >> 8) == VERSION);
+    table += (table[0] & 0xff);  // skip the header
+    uint32_t variableTop = (uint32_t)options >> 16;  // see RuleBasedCollator::getFastLatinOptions()
+    options &= 0xffff;  // needed for CollationSettings::getStrength() to work
+
+    // Check for supported characters, fetch mini CEs, and compare primaries.
+    U_ALIGN_CODE(16);
+    int32_t leftIndex = 0, rightIndex = 0;
+    /**
+     * Single mini CE or a pair.
+     * The current mini CE is in the lower 16 bits, the next one is in the upper 16 bits.
+     * If there is only one, then it is in the lower bits, and the upper bits are 0.
+     */
+    uint32_t leftPair = 0, rightPair = 0;
+    // Note: There is no need to assemble the code point.
+    // We only need to look up the table entry for the character,
+    // and nextPair() looks for whether c==0.
+    for(;;) {
+        // We fetch CEs until we get a non-ignorable primary or reach the end.
+        while(leftPair == 0) {
+            if(leftIndex == leftLength) {
+                leftPair = EOS;
+                break;
+            }
+            UChar32 c = left[leftIndex++];
+            uint8_t t;
+            if(c <= 0x7f) {
+                leftPair = primaries[c];
+                if(leftPair != 0) { break; }
+                if(c <= 0x39 && c >= 0x30 && (options & CollationSettings::NUMERIC) != 0) {
+                    return BAIL_OUT_RESULT;
+                }
+                leftPair = table[c];
+            } else if(c <= LATIN_MAX_UTF8_LEAD && 0xc2 <= c && leftIndex != leftLength &&
+                    0x80 <= (t = left[leftIndex]) && t <= 0xbf) {
+                ++leftIndex;
+                c = ((c - 0xc2) << 6) + t;
+                leftPair = primaries[c];
+                if(leftPair != 0) { break; }
+                leftPair = table[c];
+            } else {
+                leftPair = lookupUTF8(table, c, left, leftIndex, leftLength);
+            }
+            if(leftPair >= MIN_SHORT) {
+                leftPair &= SHORT_PRIMARY_MASK;
+                break;
+            } else if(leftPair > variableTop) {
+                leftPair &= LONG_PRIMARY_MASK;
+                break;
+            } else {
+                leftPair = nextPair(table, c, leftPair, NULL, left, leftIndex, leftLength);
+                if(leftPair == BAIL_OUT) { return BAIL_OUT_RESULT; }
+                leftPair = getPrimaries(variableTop, leftPair);
+            }
+        }
+
+        while(rightPair == 0) {
+            if(rightIndex == rightLength) {
+                rightPair = EOS;
+                break;
+            }
+            UChar32 c = right[rightIndex++];
+            uint8_t t;
+            if(c <= 0x7f) {
+                rightPair = primaries[c];
+                if(rightPair != 0) { break; }
+                if(c <= 0x39 && c >= 0x30 && (options & CollationSettings::NUMERIC) != 0) {
+                    return BAIL_OUT_RESULT;
+                }
+                rightPair = table[c];
+            } else if(c <= LATIN_MAX_UTF8_LEAD && 0xc2 <= c && rightIndex != rightLength &&
+                    0x80 <= (t = right[rightIndex]) && t <= 0xbf) {
+                ++rightIndex;
+                c = ((c - 0xc2) << 6) + t;
+                rightPair = primaries[c];
+                if(rightPair != 0) { break; }
+                rightPair = table[c];
+            } else {
+                rightPair = lookupUTF8(table, c, right, rightIndex, rightLength);
+            }
+            if(rightPair >= MIN_SHORT) {
+                rightPair &= SHORT_PRIMARY_MASK;
+                break;
+            } else if(rightPair > variableTop) {
+                rightPair &= LONG_PRIMARY_MASK;
+                break;
+            } else {
+                rightPair = nextPair(table, c, rightPair, NULL, right, rightIndex, rightLength);
+                if(rightPair == BAIL_OUT) { return BAIL_OUT_RESULT; }
+                rightPair = getPrimaries(variableTop, rightPair);
+            }
+        }
+
+        if(leftPair == rightPair) {
+            if(leftPair == EOS) { break; }
+            leftPair = rightPair = 0;
+            continue;
+        }
+        uint32_t leftPrimary = leftPair & 0xffff;
+        uint32_t rightPrimary = rightPair & 0xffff;
+        if(leftPrimary != rightPrimary) {
+            // Return the primary difference.
+            return (leftPrimary < rightPrimary) ? UCOL_LESS : UCOL_GREATER;
+        }
+        if(leftPair == EOS) { break; }
+        leftPair >>= 16;
+        rightPair >>= 16;
+    }
+    // In the following, we need to re-fetch each character because we did not buffer the CEs,
+    // but we know that the string is well-formed and
+    // only contains supported characters and mappings.
+
+    // We might skip the secondary level but continue with the case level
+    // which is turned on separately.
+    if(CollationSettings::getStrength(options) >= UCOL_SECONDARY) {
+        leftIndex = rightIndex = 0;
+        leftPair = rightPair = 0;
+        for(;;) {
+            while(leftPair == 0) {
+                if(leftIndex == leftLength) {
+                    leftPair = EOS;
+                    break;
+                }
+                UChar32 c = left[leftIndex++];
+                if(c <= 0x7f) {
+                    leftPair = table[c];
+                } else if(c <= LATIN_MAX_UTF8_LEAD) {
+                    leftPair = table[((c - 0xc2) << 6) + left[leftIndex++]];
+                } else {
+                    leftPair = lookupUTF8Unsafe(table, c, left, leftIndex);
+                }
+                if(leftPair >= MIN_SHORT) {
+                    leftPair = getSecondariesFromOneShortCE(leftPair);
+                    break;
+                } else if(leftPair > variableTop) {
+                    leftPair = COMMON_SEC_PLUS_OFFSET;
+                    break;
+                } else {
+                    leftPair = nextPair(table, c, leftPair, NULL, left, leftIndex, leftLength);
+                    leftPair = getSecondaries(variableTop, leftPair);
+                }
+            }
+
+            while(rightPair == 0) {
+                if(rightIndex == rightLength) {
+                    rightPair = EOS;
+                    break;
+                }
+                UChar32 c = right[rightIndex++];
+                if(c <= 0x7f) {
+                    rightPair = table[c];
+                } else if(c <= LATIN_MAX_UTF8_LEAD) {
+                    rightPair = table[((c - 0xc2) << 6) + right[rightIndex++]];
+                } else {
+                    rightPair = lookupUTF8Unsafe(table, c, right, rightIndex);
+                }
+                if(rightPair >= MIN_SHORT) {
+                    rightPair = getSecondariesFromOneShortCE(rightPair);
+                    break;
+                } else if(rightPair > variableTop) {
+                    rightPair = COMMON_SEC_PLUS_OFFSET;
+                    break;
+                } else {
+                    rightPair = nextPair(table, c, rightPair, NULL, right, rightIndex, rightLength);
+                    rightPair = getSecondaries(variableTop, rightPair);
+                }
+            }
+
+            if(leftPair == rightPair) {
+                if(leftPair == EOS) { break; }
+                leftPair = rightPair = 0;
+                continue;
+            }
+            uint32_t leftSecondary = leftPair & 0xffff;
+            uint32_t rightSecondary = rightPair & 0xffff;
+            if(leftSecondary != rightSecondary) {
+                if((options & CollationSettings::BACKWARD_SECONDARY) != 0) {
+                    // Full support for backwards secondary requires backwards contraction matching
+                    // and moving backwards between merge separators.
+                    return BAIL_OUT_RESULT;
+                }
+                return (leftSecondary < rightSecondary) ? UCOL_LESS : UCOL_GREATER;
+            }
+            if(leftPair == EOS) { break; }
+            leftPair >>= 16;
+            rightPair >>= 16;
+        }
+    }
+
+    if((options & CollationSettings::CASE_LEVEL) != 0) {
+        UBool strengthIsPrimary = CollationSettings::getStrength(options) == UCOL_PRIMARY;
+        leftIndex = rightIndex = 0;
+        leftPair = rightPair = 0;
+        for(;;) {
+            while(leftPair == 0) {
+                if(leftIndex == leftLength) {
+                    leftPair = EOS;
+                    break;
+                }
+                UChar32 c = left[leftIndex++];
+                leftPair = (c <= 0x7f) ? table[c] : lookupUTF8Unsafe(table, c, left, leftIndex);
+                if(leftPair < MIN_LONG) {
+                    leftPair = nextPair(table, c, leftPair, NULL, left, leftIndex, leftLength);
+                }
+                leftPair = getCases(variableTop, strengthIsPrimary, leftPair);
+            }
+
+            while(rightPair == 0) {
+                if(rightIndex == rightLength) {
+                    rightPair = EOS;
+                    break;
+                }
+                UChar32 c = right[rightIndex++];
+                rightPair = (c <= 0x7f) ? table[c] : lookupUTF8Unsafe(table, c, right, rightIndex);
+                if(rightPair < MIN_LONG) {
+                    rightPair = nextPair(table, c, rightPair, NULL, right, rightIndex, rightLength);
+                }
+                rightPair = getCases(variableTop, strengthIsPrimary, rightPair);
+            }
+
+            if(leftPair == rightPair) {
+                if(leftPair == EOS) { break; }
+                leftPair = rightPair = 0;
+                continue;
+            }
+            uint32_t leftCase = leftPair & 0xffff;
+            uint32_t rightCase = rightPair & 0xffff;
+            if(leftCase != rightCase) {
+                if((options & CollationSettings::UPPER_FIRST) == 0) {
+                    return (leftCase < rightCase) ? UCOL_LESS : UCOL_GREATER;
+                } else {
+                    return (leftCase < rightCase) ? UCOL_GREATER : UCOL_LESS;
+                }
+            }
+            if(leftPair == EOS) { break; }
+            leftPair >>= 16;
+            rightPair >>= 16;
+        }
+    }
+    if(CollationSettings::getStrength(options) <= UCOL_SECONDARY) { return UCOL_EQUAL; }
+
+    // Remove the case bits from the tertiary weight when caseLevel is on or caseFirst is off.
+    UBool withCaseBits = CollationSettings::isTertiaryWithCaseBits(options);
+
+    leftIndex = rightIndex = 0;
+    leftPair = rightPair = 0;
+    for(;;) {
+        while(leftPair == 0) {
+            if(leftIndex == leftLength) {
+                leftPair = EOS;
+                break;
+            }
+            UChar32 c = left[leftIndex++];
+            leftPair = (c <= 0x7f) ? table[c] : lookupUTF8Unsafe(table, c, left, leftIndex);
+            if(leftPair < MIN_LONG) {
+                leftPair = nextPair(table, c, leftPair, NULL, left, leftIndex, leftLength);
+            }
+            leftPair = getTertiaries(variableTop, withCaseBits, leftPair);
+        }
+
+        while(rightPair == 0) {
+            if(rightIndex == rightLength) {
+                rightPair = EOS;
+                break;
+            }
+            UChar32 c = right[rightIndex++];
+            rightPair = (c <= 0x7f) ? table[c] : lookupUTF8Unsafe(table, c, right, rightIndex);
+            if(rightPair < MIN_LONG) {
+                rightPair = nextPair(table, c, rightPair, NULL, right, rightIndex, rightLength);
+            }
+            rightPair = getTertiaries(variableTop, withCaseBits, rightPair);
+        }
+
+        if(leftPair == rightPair) {
+            if(leftPair == EOS) { break; }
+            leftPair = rightPair = 0;
+            continue;
+        }
+        uint32_t leftTertiary = leftPair & 0xffff;
+        uint32_t rightTertiary = rightPair & 0xffff;
+        if(leftTertiary != rightTertiary) {
+            if(CollationSettings::sortsTertiaryUpperCaseFirst(options)) {
+                // Pass through EOS and MERGE_WEIGHT
+                // and keep real tertiary weights larger than the MERGE_WEIGHT.
+                // Tertiary CEs (secondary ignorables) are not supported in fast Latin.
+                if(leftTertiary > MERGE_WEIGHT) {
+                    leftTertiary ^= CASE_MASK;
+                }
+                if(rightTertiary > MERGE_WEIGHT) {
+                    rightTertiary ^= CASE_MASK;
+                }
+            }
+            return (leftTertiary < rightTertiary) ? UCOL_LESS : UCOL_GREATER;
+        }
+        if(leftPair == EOS) { break; }
+        leftPair >>= 16;
+        rightPair >>= 16;
+    }
+    if(CollationSettings::getStrength(options) <= UCOL_TERTIARY) { return UCOL_EQUAL; }
+
+    leftIndex = rightIndex = 0;
+    leftPair = rightPair = 0;
+    for(;;) {
+        while(leftPair == 0) {
+            if(leftIndex == leftLength) {
+                leftPair = EOS;
+                break;
+            }
+            UChar32 c = left[leftIndex++];
+            leftPair = (c <= 0x7f) ? table[c] : lookupUTF8Unsafe(table, c, left, leftIndex);
+            if(leftPair < MIN_LONG) {
+                leftPair = nextPair(table, c, leftPair, NULL, left, leftIndex, leftLength);
+            }
+            leftPair = getQuaternaries(variableTop, leftPair);
+        }
+
+        while(rightPair == 0) {
+            if(rightIndex == rightLength) {
+                rightPair = EOS;
+                break;
+            }
+            UChar32 c = right[rightIndex++];
+            rightPair = (c <= 0x7f) ? table[c] : lookupUTF8Unsafe(table, c, right, rightIndex);
+            if(rightPair < MIN_LONG) {
+                rightPair = nextPair(table, c, rightPair, NULL, right, rightIndex, rightLength);
+            }
+            rightPair = getQuaternaries(variableTop, rightPair);
+        }
+
+        if(leftPair == rightPair) {
+            if(leftPair == EOS) { break; }
+            leftPair = rightPair = 0;
+            continue;
+        }
+        uint32_t leftQuaternary = leftPair & 0xffff;
+        uint32_t rightQuaternary = rightPair & 0xffff;
+        if(leftQuaternary != rightQuaternary) {
+            return (leftQuaternary < rightQuaternary) ? UCOL_LESS : UCOL_GREATER;
+        }
+        if(leftPair == EOS) { break; }
+        leftPair >>= 16;
+        rightPair >>= 16;
+    }
+    return UCOL_EQUAL;
+}
+
+uint32_t
+CollationFastLatin::lookup(const uint16_t *table, UChar32 c) {
+    U_ASSERT(c > LATIN_MAX);
+    if(PUNCT_START <= c && c < PUNCT_LIMIT) {
+        return table[c - PUNCT_START + LATIN_LIMIT];
+    } else if(c == 0xfffe) {
+        return MERGE_WEIGHT;
+    } else if(c == 0xffff) {
+        return MAX_SHORT | COMMON_SEC | LOWER_CASE | COMMON_TER;
+    } else {
+        return BAIL_OUT;
+    }
+}
+
+uint32_t
+CollationFastLatin::lookupUTF8(const uint16_t *table, UChar32 c,
+                               const uint8_t *s8, int32_t &sIndex, int32_t sLength) {
+    // The caller handled ASCII and valid/supported Latin.
+    U_ASSERT(c > 0x7f);
+    int32_t i2 = sIndex + 1;
+    if(i2 < sLength || sLength < 0) {
+        uint8_t t1 = s8[sIndex];
+        uint8_t t2 = s8[i2];
+        sIndex += 2;
+        if(c == 0xe2 && t1 == 0x80 && 0x80 <= t2 && t2 <= 0xbf) {
+            return table[(LATIN_LIMIT - 0x80) + t2];  // 2000..203F -> 0180..01BF
+        } else if(c == 0xef && t1 == 0xbf) {
+            if(t2 == 0xbe) {
+                return MERGE_WEIGHT;  // U+FFFE
+            } else if(t2 == 0xbf) {
+                return MAX_SHORT | COMMON_SEC | LOWER_CASE | COMMON_TER;  // U+FFFF
+            }
+        }
+    }
+    return BAIL_OUT;
+}
+
+uint32_t
+CollationFastLatin::lookupUTF8Unsafe(const uint16_t *table, UChar32 c,
+                                     const uint8_t *s8, int32_t &sIndex) {
+    // The caller handled ASCII.
+    // The string is well-formed and contains only supported characters.
+    U_ASSERT(c > 0x7f);
+    if(c <= LATIN_MAX_UTF8_LEAD) {
+        return table[((c - 0xc2) << 6) + s8[sIndex++]];  // 0080..017F
+    }
+    uint8_t t2 = s8[sIndex + 1];
+    sIndex += 2;
+    if(c == 0xe2) {
+        return table[(LATIN_LIMIT - 0x80) + t2];  // 2000..203F -> 0180..01BF
+    } else if(t2 == 0xbe) {
+        return MERGE_WEIGHT;  // U+FFFE
+    } else {
+        return MAX_SHORT | COMMON_SEC | LOWER_CASE | COMMON_TER;  // U+FFFF
+    }
+}
+
+uint32_t
+CollationFastLatin::nextPair(const uint16_t *table, UChar32 c, uint32_t ce,
+                             const UChar *s16, const uint8_t *s8, int32_t &sIndex, int32_t &sLength) {
+    if(ce >= MIN_LONG || ce < CONTRACTION) {
+        return ce;  // simple or special mini CE
+    } else if(ce >= EXPANSION) {
+        int32_t index = NUM_FAST_CHARS + (ce & INDEX_MASK);
+        return ((uint32_t)table[index + 1] << 16) | table[index];
+    } else /* ce >= CONTRACTION */ {
+        if(c == 0 && sLength < 0) {
+            sLength = sIndex - 1;
+            return EOS;
+        }
+        // Contraction list: Default mapping followed by
+        // 0 or more single-character contraction suffix mappings.
+        int32_t index = NUM_FAST_CHARS + (ce & INDEX_MASK);
+        if(sIndex != sLength) {
+            // Read the next character.
+            int32_t c2;
+            int32_t nextIndex = sIndex;
+            if(s16 != NULL) {
+                c2 = s16[nextIndex++];
+                if(c2 > LATIN_MAX) {
+                    if(PUNCT_START <= c2 && c2 < PUNCT_LIMIT) {
+                        c2 = c2 - PUNCT_START + LATIN_LIMIT;  // 2000..203F -> 0180..01BF
+                    } else if(c2 == 0xfffe || c2 == 0xffff) {
+                        c2 = -1;  // U+FFFE & U+FFFF cannot occur in contractions.
+                    } else {
+                        return BAIL_OUT;
+                    }
+                }
+            } else {
+                c2 = s8[nextIndex++];
+                if(c2 > 0x7f) {
+                    uint8_t t;
+                    if(c2 <= 0xc5 && 0xc2 <= c2 && nextIndex != sLength &&
+                            0x80 <= (t = s8[nextIndex]) && t <= 0xbf) {
+                        c2 = ((c2 - 0xc2) << 6) + t;  // 0080..017F
+                        ++nextIndex;
+                    } else {
+                        int32_t i2 = nextIndex + 1;
+                        if(i2 < sLength || sLength < 0) {
+                            if(c2 == 0xe2 && s8[nextIndex] == 0x80 &&
+                                    0x80 <= (t = s8[i2]) && t <= 0xbf) {
+                                c2 = (LATIN_LIMIT - 0x80) + t;  // 2000..203F -> 0180..01BF
+                            } else if(c2 == 0xef && s8[nextIndex] == 0xbf &&
+                                    ((t = s8[i2]) == 0xbe || t == 0xbf)) {
+                                c2 = -1;  // U+FFFE & U+FFFF cannot occur in contractions.
+                            } else {
+                                return BAIL_OUT;
+                            }
+                        } else {
+                            return BAIL_OUT;
+                        }
+                        nextIndex += 2;
+                    }
+                }
+            }
+            if(c2 == 0 && sLength < 0) {
+                sLength = sIndex;
+                c2 = -1;
+            }
+            // Look for the next character in the contraction suffix list,
+            // which is in ascending order of single suffix characters.
+            int32_t i = index;
+            int32_t head = table[i];  // first skip the default mapping
+            int32_t x;
+            do {
+                i += head >> CONTR_LENGTH_SHIFT;
+                head = table[i];
+                x = head & CONTR_CHAR_MASK;
+            } while(x < c2);
+            if(x == c2) {
+                index = i;
+                sIndex = nextIndex;
+            }
+        }
+        // Return the CE or CEs for the default or contraction mapping.
+        int32_t length = table[index] >> CONTR_LENGTH_SHIFT;
+        if(length == 1) {
+            return BAIL_OUT;
+        }
+        ce = table[index + 1];
+        if(length == 2) {
+            return ce;
+        } else {
+            return ((uint32_t)table[index + 2] << 16) | ce;
+        }
+    }
+}
+
+uint32_t
+CollationFastLatin::getSecondaries(uint32_t variableTop, uint32_t pair) {
+    if(pair <= 0xffff) {
+        // one mini CE
+        if(pair >= MIN_SHORT) {
+            pair = getSecondariesFromOneShortCE(pair);
+        } else if(pair > variableTop) {
+            pair = COMMON_SEC_PLUS_OFFSET;
+        } else if(pair >= MIN_LONG) {
+            pair = 0;  // variable
+        }
+        // else special mini CE
+    } else {
+        uint32_t ce = pair & 0xffff;
+        if(ce >= MIN_SHORT) {
+            pair = (pair & TWO_SECONDARIES_MASK) + TWO_SEC_OFFSETS;
+        } else if(ce > variableTop) {
+            pair = TWO_COMMON_SEC_PLUS_OFFSET;
+        } else {
+            U_ASSERT(ce >= MIN_LONG);
+            pair = 0;  // variable
+        }
+    }
+    return pair;
+}
+
+uint32_t
+CollationFastLatin::getCases(uint32_t variableTop, UBool strengthIsPrimary, uint32_t pair) {
+    // Primary+caseLevel: Ignore case level weights of primary ignorables.
+    // Otherwise: Ignore case level weights of secondary ignorables.
+    // For details see the comments in the CollationCompare class.
+    // Tertiary CEs (secondary ignorables) are not supported in fast Latin.
+    if(pair <= 0xffff) {
+        // one mini CE
+        if(pair >= MIN_SHORT) {
+            // A high secondary weight means we really have two CEs,
+            // a primary CE and a secondary CE.
+            uint32_t ce = pair;
+            pair &= CASE_MASK;  // explicit weight of primary CE
+            if(!strengthIsPrimary && (ce & SECONDARY_MASK) >= MIN_SEC_HIGH) {
+                pair |= LOWER_CASE << 16;  // implied weight of secondary CE
+            }
+        } else if(pair > variableTop) {
+            pair = LOWER_CASE;
+        } else if(pair >= MIN_LONG) {
+            pair = 0;  // variable
+        }
+        // else special mini CE
+    } else {
+        // two mini CEs, same primary groups, neither expands like above
+        uint32_t ce = pair & 0xffff;
+        if(ce >= MIN_SHORT) {
+            if(strengthIsPrimary && (pair & (SHORT_PRIMARY_MASK << 16)) == 0) {
+                pair &= CASE_MASK;
+            } else {
+                pair &= TWO_CASES_MASK;
+            }
+        } else if(ce > variableTop) {
+            pair = TWO_LOWER_CASES;
+        } else {
+            U_ASSERT(ce >= MIN_LONG);
+            pair = 0;  // variable
+        }
+    }
+    return pair;
+}
+
+uint32_t
+CollationFastLatin::getTertiaries(uint32_t variableTop, UBool withCaseBits, uint32_t pair) {
+    if(pair <= 0xffff) {
+        // one mini CE
+        if(pair >= MIN_SHORT) {
+            // A high secondary weight means we really have two CEs,
+            // a primary CE and a secondary CE.
+            uint32_t ce = pair;
+            if(withCaseBits) {
+                pair = (pair & CASE_AND_TERTIARY_MASK) + TER_OFFSET;
+                if((ce & SECONDARY_MASK) >= MIN_SEC_HIGH) {
+                    pair |= (LOWER_CASE | COMMON_TER_PLUS_OFFSET) << 16;
+                }
+            } else {
+                pair = (pair & TERTIARY_MASK) + TER_OFFSET;
+                if((ce & SECONDARY_MASK) >= MIN_SEC_HIGH) {
+                    pair |= COMMON_TER_PLUS_OFFSET << 16;
+                }
+            }
+        } else if(pair > variableTop) {
+            pair = (pair & TERTIARY_MASK) + TER_OFFSET;
+            if(withCaseBits) {
+                pair |= LOWER_CASE;
+            }
+        } else if(pair >= MIN_LONG) {
+            pair = 0;  // variable
+        }
+        // else special mini CE
+    } else {
+        // two mini CEs, same primary groups, neither expands like above
+        uint32_t ce = pair & 0xffff;
+        if(ce >= MIN_SHORT) {
+            if(withCaseBits) {
+                pair &= TWO_CASES_MASK | TWO_TERTIARIES_MASK;
+            } else {
+                pair &= TWO_TERTIARIES_MASK;
+            }
+            pair += TWO_TER_OFFSETS;
+        } else if(ce > variableTop) {
+            pair = (pair & TWO_TERTIARIES_MASK) + TWO_TER_OFFSETS;
+            if(withCaseBits) {
+                pair |= TWO_LOWER_CASES;
+            }
+        } else {
+            U_ASSERT(ce >= MIN_LONG);
+            pair = 0;  // variable
+        }
+    }
+    return pair;
+}
+
+uint32_t
+CollationFastLatin::getQuaternaries(uint32_t variableTop, uint32_t pair) {
+    // Return the primary weight of a variable CE,
+    // or the maximum primary weight for a non-variable, not-completely-ignorable CE.
+    if(pair <= 0xffff) {
+        // one mini CE
+        if(pair >= MIN_SHORT) {
+            // A high secondary weight means we really have two CEs,
+            // a primary CE and a secondary CE.
+            if((pair & SECONDARY_MASK) >= MIN_SEC_HIGH) {
+                pair = TWO_SHORT_PRIMARIES_MASK;
+            } else {
+                pair = SHORT_PRIMARY_MASK;
+            }
+        } else if(pair > variableTop) {
+            pair = SHORT_PRIMARY_MASK;
+        } else if(pair >= MIN_LONG) {
+            pair &= LONG_PRIMARY_MASK;  // variable
+        }
+        // else special mini CE
+    } else {
+        // two mini CEs, same primary groups, neither expands like above
+        uint32_t ce = pair & 0xffff;
+        if(ce > variableTop) {
+            pair = TWO_SHORT_PRIMARIES_MASK;
+        } else {
+            U_ASSERT(ce >= MIN_LONG);
+            pair &= TWO_LONG_PRIMARIES_MASK;  // variable
+        }
+    }
+    return pair;
+}
+
+U_NAMESPACE_END
+
+#endif  // !UCONFIG_NO_COLLATION