290 lines
11 KiB
C
290 lines
11 KiB
C
// © 2017 and later: Unicode, Inc. and others.
|
|
// License & terms of use: http://www.unicode.org/copyright.html
|
|
|
|
// ucptrie_impl.h (modified from utrie2_impl.h)
|
|
// created: 2017dec29 Markus W. Scherer
|
|
|
|
#ifndef __UCPTRIE_IMPL_H__
|
|
#define __UCPTRIE_IMPL_H__
|
|
|
|
#include "unicode/ucptrie.h"
|
|
#ifdef UCPTRIE_DEBUG
|
|
#include "unicode/umutablecptrie.h"
|
|
#endif
|
|
|
|
// UCPTrie signature values, in platform endianness and opposite endianness.
|
|
// The UCPTrie signature ASCII byte values spell "Tri3".
|
|
#define UCPTRIE_SIG 0x54726933
|
|
#define UCPTRIE_OE_SIG 0x33697254
|
|
|
|
/**
|
|
* Header data for the binary, memory-mappable representation of a UCPTrie/CodePointTrie.
|
|
* @internal
|
|
*/
|
|
struct UCPTrieHeader {
|
|
/** "Tri3" in big-endian US-ASCII (0x54726933) */
|
|
uint32_t signature;
|
|
|
|
/**
|
|
* Options bit field:
|
|
* Bits 15..12: Data length bits 19..16.
|
|
* Bits 11..8: Data null block offset bits 19..16.
|
|
* Bits 7..6: UCPTrieType
|
|
* Bits 5..3: Reserved (0).
|
|
* Bits 2..0: UCPTrieValueWidth
|
|
*/
|
|
uint16_t options;
|
|
|
|
/** Total length of the index tables. */
|
|
uint16_t indexLength;
|
|
|
|
/** Data length bits 15..0. */
|
|
uint16_t dataLength;
|
|
|
|
/** Index-3 null block offset, 0x7fff or 0xffff if none. */
|
|
uint16_t index3NullOffset;
|
|
|
|
/** Data null block offset bits 15..0, 0xfffff if none. */
|
|
uint16_t dataNullOffset;
|
|
|
|
/**
|
|
* First code point of the single-value range ending with U+10ffff,
|
|
* rounded up and then shifted right by UCPTRIE_SHIFT_2.
|
|
*/
|
|
uint16_t shiftedHighStart;
|
|
};
|
|
|
|
/**
|
|
* Constants for use with UCPTrieHeader.options.
|
|
* @internal
|
|
*/
|
|
enum {
|
|
UCPTRIE_OPTIONS_DATA_LENGTH_MASK = 0xf000,
|
|
UCPTRIE_OPTIONS_DATA_NULL_OFFSET_MASK = 0xf00,
|
|
UCPTRIE_OPTIONS_RESERVED_MASK = 0x38,
|
|
UCPTRIE_OPTIONS_VALUE_BITS_MASK = 7,
|
|
/**
|
|
* Value for index3NullOffset which indicates that there is no index-3 null block.
|
|
* Bit 15 is unused for this value because this bit is used if the index-3 contains
|
|
* 18-bit indexes.
|
|
*/
|
|
UCPTRIE_NO_INDEX3_NULL_OFFSET = 0x7fff,
|
|
UCPTRIE_NO_DATA_NULL_OFFSET = 0xfffff
|
|
};
|
|
|
|
// Internal constants.
|
|
enum {
|
|
/** The length of the BMP index table. 1024=0x400 */
|
|
UCPTRIE_BMP_INDEX_LENGTH = 0x10000 >> UCPTRIE_FAST_SHIFT,
|
|
|
|
UCPTRIE_SMALL_LIMIT = 0x1000,
|
|
UCPTRIE_SMALL_INDEX_LENGTH = UCPTRIE_SMALL_LIMIT >> UCPTRIE_FAST_SHIFT,
|
|
|
|
/** Shift size for getting the index-3 table offset. */
|
|
UCPTRIE_SHIFT_3 = 4,
|
|
|
|
/** Shift size for getting the index-2 table offset. */
|
|
UCPTRIE_SHIFT_2 = 5 + UCPTRIE_SHIFT_3,
|
|
|
|
/** Shift size for getting the index-1 table offset. */
|
|
UCPTRIE_SHIFT_1 = 5 + UCPTRIE_SHIFT_2,
|
|
|
|
/**
|
|
* Difference between two shift sizes,
|
|
* for getting an index-2 offset from an index-3 offset. 5=9-4
|
|
*/
|
|
UCPTRIE_SHIFT_2_3 = UCPTRIE_SHIFT_2 - UCPTRIE_SHIFT_3,
|
|
|
|
/**
|
|
* Difference between two shift sizes,
|
|
* for getting an index-1 offset from an index-2 offset. 5=14-9
|
|
*/
|
|
UCPTRIE_SHIFT_1_2 = UCPTRIE_SHIFT_1 - UCPTRIE_SHIFT_2,
|
|
|
|
/**
|
|
* Number of index-1 entries for the BMP. (4)
|
|
* This part of the index-1 table is omitted from the serialized form.
|
|
*/
|
|
UCPTRIE_OMITTED_BMP_INDEX_1_LENGTH = 0x10000 >> UCPTRIE_SHIFT_1,
|
|
|
|
/** Number of entries in an index-2 block. 32=0x20 */
|
|
UCPTRIE_INDEX_2_BLOCK_LENGTH = 1 << UCPTRIE_SHIFT_1_2,
|
|
|
|
/** Mask for getting the lower bits for the in-index-2-block offset. */
|
|
UCPTRIE_INDEX_2_MASK = UCPTRIE_INDEX_2_BLOCK_LENGTH - 1,
|
|
|
|
/** Number of code points per index-2 table entry. 512=0x200 */
|
|
UCPTRIE_CP_PER_INDEX_2_ENTRY = 1 << UCPTRIE_SHIFT_2,
|
|
|
|
/** Number of entries in an index-3 block. 32=0x20 */
|
|
UCPTRIE_INDEX_3_BLOCK_LENGTH = 1 << UCPTRIE_SHIFT_2_3,
|
|
|
|
/** Mask for getting the lower bits for the in-index-3-block offset. */
|
|
UCPTRIE_INDEX_3_MASK = UCPTRIE_INDEX_3_BLOCK_LENGTH - 1,
|
|
|
|
/** Number of entries in a small data block. 16=0x10 */
|
|
UCPTRIE_SMALL_DATA_BLOCK_LENGTH = 1 << UCPTRIE_SHIFT_3,
|
|
|
|
/** Mask for getting the lower bits for the in-small-data-block offset. */
|
|
UCPTRIE_SMALL_DATA_MASK = UCPTRIE_SMALL_DATA_BLOCK_LENGTH - 1
|
|
};
|
|
|
|
typedef UChar32
|
|
UCPTrieGetRange(const void *trie, UChar32 start,
|
|
UCPMapValueFilter *filter, const void *context, uint32_t *pValue);
|
|
|
|
U_CFUNC UChar32
|
|
ucptrie_internalGetRange(UCPTrieGetRange *getRange,
|
|
const void *trie, UChar32 start,
|
|
UCPMapRangeOption option, uint32_t surrogateValue,
|
|
UCPMapValueFilter *filter, const void *context, uint32_t *pValue);
|
|
|
|
#ifdef UCPTRIE_DEBUG
|
|
U_CFUNC void
|
|
ucptrie_printLengths(const UCPTrie *trie, const char *which);
|
|
|
|
U_CFUNC void umutablecptrie_setName(UMutableCPTrie *builder, const char *name);
|
|
#endif
|
|
|
|
/*
|
|
* Format of the binary, memory-mappable representation of a UCPTrie/CodePointTrie.
|
|
* For overview information see http://site.icu-project.org/design/struct/utrie
|
|
*
|
|
* The binary trie data should be 32-bit-aligned.
|
|
* The overall layout is:
|
|
*
|
|
* UCPTrieHeader header; -- 16 bytes, see struct definition above
|
|
* uint16_t index[header.indexLength];
|
|
* uintXY_t data[header.dataLength];
|
|
*
|
|
* The trie data array is an array of uint16_t, uint32_t, or uint8_t,
|
|
* specified via the UCPTrieValueWidth when building the trie.
|
|
* The data array is 32-bit-aligned for uint32_t, otherwise 16-bit-aligned.
|
|
* The overall length of the trie data is a multiple of 4 bytes.
|
|
* (Padding is added at the end of the index array and/or near the end of the data array as needed.)
|
|
*
|
|
* The length of the data array (dataLength) is stored as an integer split across two fields
|
|
* of the header struct (high bits in header.options).
|
|
*
|
|
* The trie type can be "fast" or "small" which determines the index structure,
|
|
* specified via the UCPTrieType when building the trie.
|
|
*
|
|
* The type and valueWidth are stored in the header.options.
|
|
* There are reserved type and valueWidth values, and reserved header.options bits.
|
|
* They could be used in future format extensions.
|
|
* Code reading the trie structure must fail with an error when unknown values or options are set.
|
|
*
|
|
* Values for ASCII character (U+0000..U+007F) can always be found at the start of the data array.
|
|
*
|
|
* Values for code points below a type-specific fast-indexing limit are found via two-stage lookup.
|
|
* For a "fast" trie, the limit is the BMP/supplementary boundary at U+10000.
|
|
* For a "small" trie, the limit is UCPTRIE_SMALL_MAX+1=U+1000.
|
|
*
|
|
* All code points in the range highStart..U+10FFFF map to a single highValue
|
|
* which is stored at the second-to-last position of the data array.
|
|
* (See UCPTRIE_HIGH_VALUE_NEG_DATA_OFFSET.)
|
|
* The highStart value is header.shiftedHighStart<<UCPTRIE_SHIFT_2.
|
|
* (UCPTRIE_SHIFT_2=9)
|
|
*
|
|
* Values for code points fast_limit..highStart-1 are found via four-stage lookup.
|
|
* The data block size is smaller for this range than for the fast range.
|
|
* This together with more index stages with small blocks makes this range
|
|
* more easily compactable.
|
|
*
|
|
* There is also a trie error value stored at the last position of the data array.
|
|
* (See UCPTRIE_ERROR_VALUE_NEG_DATA_OFFSET.)
|
|
* It is intended to be returned for inputs that are not Unicode code points
|
|
* (outside U+0000..U+10FFFF), or in string processing for ill-formed input
|
|
* (unpaired surrogate in UTF-16, ill-formed UTF-8 subsequence).
|
|
*
|
|
* For a "fast" trie:
|
|
*
|
|
* The index array starts with the BMP index table for BMP code point lookup.
|
|
* Its length is 1024=0x400.
|
|
*
|
|
* The supplementary index-1 table follows the BMP index table.
|
|
* Variable length, for code points up to highStart-1.
|
|
* Maximum length 64=0x40=0x100000>>UCPTRIE_SHIFT_1.
|
|
* (For 0x100000 supplementary code points U+10000..U+10ffff.)
|
|
*
|
|
* After this index-1 table follow the variable-length index-3 and index-2 tables.
|
|
*
|
|
* The supplementary index tables are omitted completely
|
|
* if there is only BMP data (highStart<=U+10000).
|
|
*
|
|
* For a "small" trie:
|
|
*
|
|
* The index array starts with a fast-index table for lookup of code points U+0000..U+0FFF.
|
|
*
|
|
* The "supplementary" index tables are always stored.
|
|
* The index-1 table starts from U+0000, its maximum length is 68=0x44=0x110000>>UCPTRIE_SHIFT_1.
|
|
*
|
|
* For both trie types:
|
|
*
|
|
* The last index-2 block may be a partial block, storing indexes only for code points
|
|
* below highStart.
|
|
*
|
|
* Lookup for ASCII code point c:
|
|
*
|
|
* Linear access from the start of the data array.
|
|
*
|
|
* value = data[c];
|
|
*
|
|
* Lookup for fast-range code point c:
|
|
*
|
|
* Shift the code point right by UCPTRIE_FAST_SHIFT=6 bits,
|
|
* fetch the index array value at that offset,
|
|
* add the lower code point bits, index into the data array.
|
|
*
|
|
* value = data[index[c>>6] + (c&0x3f)];
|
|
*
|
|
* (This works for ASCII as well.)
|
|
*
|
|
* Lookup for small-range code point c below highStart:
|
|
*
|
|
* Split the code point into four bit fields using several sets of shifts & masks
|
|
* to read consecutive values from the index-1, index-2, index-3 and data tables.
|
|
*
|
|
* If all of the data block offsets in an index-3 block fit within 16 bits (up to 0xffff),
|
|
* then the data block offsets are stored directly as uint16_t.
|
|
*
|
|
* Otherwise (this is very unusual but possible), the index-2 entry for the index-3 block
|
|
* has bit 15 (0x8000) set, and each set of 8 index-3 entries is preceded by
|
|
* an additional uint16_t word. Data block offsets are 18 bits wide, with the top 2 bits stored
|
|
* in the additional word.
|
|
*
|
|
* See ucptrie_internalSmallIndex() for details.
|
|
*
|
|
* (In a "small" trie, this works for ASCII and below-fast_limit code points as well.)
|
|
*
|
|
* Compaction:
|
|
*
|
|
* Multiple code point ranges ("blocks") that are aligned on certain boundaries
|
|
* (determined by the shifting/bit fields of code points) and
|
|
* map to the same data values normally share a single subsequence of the data array.
|
|
* Data blocks can also overlap partially.
|
|
* (Depending on the builder code finding duplicate and overlapping blocks.)
|
|
*
|
|
* Iteration over same-value ranges:
|
|
*
|
|
* Range iteration (ucptrie_getRange()) walks the structure from a start code point
|
|
* until some code point is found that maps to a different value;
|
|
* the end of the returned range is just before that.
|
|
*
|
|
* The header.dataNullOffset (split across two header fields, high bits in header.options)
|
|
* is the offset of a widely shared data block filled with one single value.
|
|
* It helps quickly skip over large ranges of data with that value.
|
|
* The builder must ensure that if the start of any data block (fast or small)
|
|
* matches the dataNullOffset, then the whole block must be filled with the null value.
|
|
* Special care must be taken if there is no fast null data block
|
|
* but a small one, which is shorter, and it matches the *start* of some fast data block.
|
|
*
|
|
* Similarly, the header.index3NullOffset is the index-array offset of an index-3 block
|
|
* where all index entries point to the dataNullOffset.
|
|
* If there is no such data or index-3 block, then these offsets are set to
|
|
* values that cannot be reached (data offset out of range/reserved index offset),
|
|
* normally UCPTRIE_NO_DATA_NULL_OFFSET or UCPTRIE_NO_INDEX3_NULL_OFFSET respectively.
|
|
*/
|
|
|
|
#endif
|