1// Copyright (C) 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4*******************************************************************************
5* Copyright (C) 2013-2014, International Business Machines
6* Corporation and others.  All Rights Reserved.
7*******************************************************************************
8* collationrootelements.h
9*
10* created on: 2013mar01
11* created by: Markus W. Scherer
12*/
13
14#ifndef __COLLATIONROOTELEMENTS_H__
15#define __COLLATIONROOTELEMENTS_H__
16
17#include "unicode/utypes.h"
18
19#if !UCONFIG_NO_COLLATION
20
21#include "unicode/uobject.h"
22#include "collation.h"
23
24U_NAMESPACE_BEGIN
25
26/**
27 * Container and access methods for collation elements and weights
28 * that occur in the root collator.
29 * Needed for finding boundaries for building a tailoring.
30 *
31 * This class takes and returns 16-bit secondary and tertiary weights.
32 */
33class U_I18N_API CollationRootElements : public UMemory {
34public:
35    CollationRootElements(const uint32_t *rootElements, int32_t rootElementsLength)
36            : elements(rootElements), length(rootElementsLength) {}
37
38    /**
39     * Higher than any root primary.
40     */
41    static const uint32_t PRIMARY_SENTINEL = 0xffffff00;
42
43    /**
44     * Flag in a root element, set if the element contains secondary & tertiary weights,
45     * rather than a primary.
46     */
47    static const uint32_t SEC_TER_DELTA_FLAG = 0x80;
48    /**
49     * Mask for getting the primary range step value from a primary-range-end element.
50     */
51    static const uint8_t PRIMARY_STEP_MASK = 0x7f;
52
53    enum {
54        /**
55         * Index of the first CE with a non-zero tertiary weight.
56         * Same as the start of the compact root elements table.
57         */
58        IX_FIRST_TERTIARY_INDEX,
59        /**
60         * Index of the first CE with a non-zero secondary weight.
61         */
62        IX_FIRST_SECONDARY_INDEX,
63        /**
64         * Index of the first CE with a non-zero primary weight.
65         */
66        IX_FIRST_PRIMARY_INDEX,
67        /**
68         * Must match Collation::COMMON_SEC_AND_TER_CE.
69         */
70        IX_COMMON_SEC_AND_TER_CE,
71        /**
72         * Secondary & tertiary boundaries.
73         * Bits 31..24: [fixed last secondary common byte 45]
74         * Bits 23..16: [fixed first ignorable secondary byte 80]
75         * Bits 15.. 8: reserved, 0
76         * Bits  7.. 0: [fixed first ignorable tertiary byte 3C]
77         */
78        IX_SEC_TER_BOUNDARIES,
79        /**
80         * The current number of indexes.
81         * Currently the same as elements[IX_FIRST_TERTIARY_INDEX].
82         */
83        IX_COUNT
84    };
85
86    /**
87     * Returns the boundary between tertiary weights of primary/secondary CEs
88     * and those of tertiary CEs.
89     * This is the upper limit for tertiaries of primary/secondary CEs.
90     * This minus one is the lower limit for tertiaries of tertiary CEs.
91     */
92    uint32_t getTertiaryBoundary() const {
93        return (elements[IX_SEC_TER_BOUNDARIES] << 8) & 0xff00;
94    }
95
96    /**
97     * Returns the first assigned tertiary CE.
98     */
99    uint32_t getFirstTertiaryCE() const {
100        return elements[elements[IX_FIRST_TERTIARY_INDEX]] & ~SEC_TER_DELTA_FLAG;
101    }
102
103    /**
104     * Returns the last assigned tertiary CE.
105     */
106    uint32_t getLastTertiaryCE() const {
107        return elements[elements[IX_FIRST_SECONDARY_INDEX] - 1] & ~SEC_TER_DELTA_FLAG;
108    }
109
110    /**
111     * Returns the last common secondary weight.
112     * This is the lower limit for secondaries of primary CEs.
113     */
114    uint32_t getLastCommonSecondary() const {
115        return (elements[IX_SEC_TER_BOUNDARIES] >> 16) & 0xff00;
116    }
117
118    /**
119     * Returns the boundary between secondary weights of primary CEs
120     * and those of secondary CEs.
121     * This is the upper limit for secondaries of primary CEs.
122     * This minus one is the lower limit for secondaries of secondary CEs.
123     */
124    uint32_t getSecondaryBoundary() const {
125        return (elements[IX_SEC_TER_BOUNDARIES] >> 8) & 0xff00;
126    }
127
128    /**
129     * Returns the first assigned secondary CE.
130     */
131    uint32_t getFirstSecondaryCE() const {
132        return elements[elements[IX_FIRST_SECONDARY_INDEX]] & ~SEC_TER_DELTA_FLAG;
133    }
134
135    /**
136     * Returns the last assigned secondary CE.
137     */
138    uint32_t getLastSecondaryCE() const {
139        return elements[elements[IX_FIRST_PRIMARY_INDEX] - 1] & ~SEC_TER_DELTA_FLAG;
140    }
141
142    /**
143     * Returns the first assigned primary weight.
144     */
145    uint32_t getFirstPrimary() const {
146        return elements[elements[IX_FIRST_PRIMARY_INDEX]];  // step=0: cannot be a range end
147    }
148
149    /**
150     * Returns the first assigned primary CE.
151     */
152    int64_t getFirstPrimaryCE() const {
153        return Collation::makeCE(getFirstPrimary());
154    }
155
156    /**
157     * Returns the last root CE with a primary weight before p.
158     * Intended only for reordering group boundaries.
159     */
160    int64_t lastCEWithPrimaryBefore(uint32_t p) const;
161
162    /**
163     * Returns the first root CE with a primary weight of at least p.
164     * Intended only for reordering group boundaries.
165     */
166    int64_t firstCEWithPrimaryAtLeast(uint32_t p) const;
167
168    /**
169     * Returns the primary weight before p.
170     * p must be greater than the first root primary.
171     */
172    uint32_t getPrimaryBefore(uint32_t p, UBool isCompressible) const;
173
174    /** Returns the secondary weight before [p, s]. */
175    uint32_t getSecondaryBefore(uint32_t p, uint32_t s) const;
176
177    /** Returns the tertiary weight before [p, s, t]. */
178    uint32_t getTertiaryBefore(uint32_t p, uint32_t s, uint32_t t) const;
179
180    /**
181     * Finds the index of the input primary.
182     * p must occur as a root primary, and must not be 0.
183     */
184    int32_t findPrimary(uint32_t p) const;
185
186    /**
187     * Returns the primary weight after p where index=findPrimary(p).
188     * p must be at least the first root primary.
189     */
190    uint32_t getPrimaryAfter(uint32_t p, int32_t index, UBool isCompressible) const;
191    /**
192     * Returns the secondary weight after [p, s] where index=findPrimary(p)
193     * except use index=0 for p=0.
194     *
195     * Must return a weight for every root [p, s] as well as for every weight
196     * returned by getSecondaryBefore(). If p!=0 then s can be BEFORE_WEIGHT16.
197     *
198     * Exception: [0, 0] is handled by the CollationBuilder:
199     * Both its lower and upper boundaries are special.
200     */
201    uint32_t getSecondaryAfter(int32_t index, uint32_t s) const;
202    /**
203     * Returns the tertiary weight after [p, s, t] where index=findPrimary(p)
204     * except use index=0 for p=0.
205     *
206     * Must return a weight for every root [p, s, t] as well as for every weight
207     * returned by getTertiaryBefore(). If s!=0 then t can be BEFORE_WEIGHT16.
208     *
209     * Exception: [0, 0, 0] is handled by the CollationBuilder:
210     * Both its lower and upper boundaries are special.
211     */
212    uint32_t getTertiaryAfter(int32_t index, uint32_t s, uint32_t t) const;
213
214private:
215    /**
216     * Returns the first secondary & tertiary weights for p where index=findPrimary(p)+1.
217     */
218    uint32_t getFirstSecTerForPrimary(int32_t index) const;
219
220    /**
221     * Finds the largest index i where elements[i]<=p.
222     * Requires first primary<=p<0xffffff00 (PRIMARY_SENTINEL).
223     * Does not require that p is a root collator primary.
224     */
225    int32_t findP(uint32_t p) const;
226
227    static inline UBool isEndOfPrimaryRange(uint32_t q) {
228        return (q & SEC_TER_DELTA_FLAG) == 0 && (q & PRIMARY_STEP_MASK) != 0;
229    }
230
231    /**
232     * Data structure:
233     *
234     * The first few entries are indexes, up to elements[IX_FIRST_TERTIARY_INDEX].
235     * See the comments on the IX_ constants.
236     *
237     * All other elements are a compact form of the root collator CEs
238     * in mostly collation order.
239     *
240     * A sequence of one or more root CEs with the same primary weight is stored as
241     * one element with the primary weight, with the SEC_TER_DELTA_FLAG flag not set,
242     * followed by elements with only the secondary/tertiary weights,
243     * each with that flag set.
244     * If the lowest secondary/tertiary combination is Collation::COMMON_SEC_AND_TER_CE,
245     * then the element for that combination is omitted.
246     *
247     * Note: If the first actual secondary/tertiary combination is higher than
248     * Collation::COMMON_SEC_AND_TER_CE (which is unusual),
249     * the runtime code will assume anyway that Collation::COMMON_SEC_AND_TER_CE is present.
250     *
251     * A range of only-primary CEs with a consistent "step" increment
252     * from each primary to the next may be stored as a range.
253     * Only the first and last primary are stored, and the last has the step
254     * value in the low bits (PRIMARY_STEP_MASK).
255     *
256     * An range-end element may also either start a new range or be followed by
257     * elements with secondary/tertiary deltas.
258     *
259     * A primary element that is not a range end has zero step bits.
260     *
261     * There is no element for the completely ignorable CE (all weights 0).
262     *
263     * Before elements[IX_FIRST_PRIMARY_INDEX], all elements are secondary/tertiary deltas,
264     * for all of the ignorable root CEs.
265     *
266     * There are no elements for unassigned-implicit primary CEs.
267     * All primaries stored here are at most 3 bytes long.
268     */
269    const uint32_t *elements;
270    int32_t length;
271};
272
273U_NAMESPACE_END
274
275#endif  // !UCONFIG_NO_COLLATION
276#endif  // __COLLATIONROOTELEMENTS_H__
277