Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 285 insertions, 0 deletions

diff --git a/intl/icu/source/common/ucptrie_impl.h b/intl/icu/source/common/ucptrie_impl.h
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+// © 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.
+constexpr uint16_t UCPTRIE_OPTIONS_DATA_LENGTH_MASK = 0xf000;
+constexpr uint16_t UCPTRIE_OPTIONS_DATA_NULL_OFFSET_MASK = 0xf00;
+constexpr uint16_t UCPTRIE_OPTIONS_RESERVED_MASK = 0x38;
+constexpr uint16_t 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.
+ */
+constexpr int32_t UCPTRIE_NO_INDEX3_NULL_OFFSET = 0x7fff;
+constexpr int32_t UCPTRIE_NO_DATA_NULL_OFFSET = 0xfffff;
+
+// Internal constants.
+
+/** The length of the BMP index table. 1024=0x400 */
+constexpr int32_t UCPTRIE_BMP_INDEX_LENGTH = 0x10000 >> UCPTRIE_FAST_SHIFT;
+
+constexpr int32_t UCPTRIE_SMALL_LIMIT = 0x1000;
+constexpr int32_t UCPTRIE_SMALL_INDEX_LENGTH = UCPTRIE_SMALL_LIMIT >> UCPTRIE_FAST_SHIFT;
+
+/** Shift size for getting the index-3 table offset. */
+constexpr int32_t UCPTRIE_SHIFT_3 = 4;
+
+/** Shift size for getting the index-2 table offset. */
+constexpr int32_t UCPTRIE_SHIFT_2 = 5 + UCPTRIE_SHIFT_3;
+
+/** Shift size for getting the index-1 table offset. */
+constexpr int32_t 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
+ */
+constexpr int32_t 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
+ */
+constexpr int32_t 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.
+ */
+constexpr int32_t UCPTRIE_OMITTED_BMP_INDEX_1_LENGTH = 0x10000 >> UCPTRIE_SHIFT_1;
+
+/** Number of entries in an index-2 block. 32=0x20 */
+constexpr int32_t UCPTRIE_INDEX_2_BLOCK_LENGTH = 1 << UCPTRIE_SHIFT_1_2;
+
+/** Mask for getting the lower bits for the in-index-2-block offset. */
+constexpr int32_t UCPTRIE_INDEX_2_MASK = UCPTRIE_INDEX_2_BLOCK_LENGTH - 1;
+
+/** Number of code points per index-2 table entry. 512=0x200 */
+constexpr int32_t UCPTRIE_CP_PER_INDEX_2_ENTRY = 1 << UCPTRIE_SHIFT_2;
+
+/** Number of entries in an index-3 block. 32=0x20 */
+constexpr int32_t UCPTRIE_INDEX_3_BLOCK_LENGTH = 1 << UCPTRIE_SHIFT_2_3;
+
+/** Mask for getting the lower bits for the in-index-3-block offset. */
+constexpr int32_t UCPTRIE_INDEX_3_MASK = UCPTRIE_INDEX_3_BLOCK_LENGTH - 1;
+
+/** Number of entries in a small data block. 16=0x10 */
+constexpr int32_t UCPTRIE_SMALL_DATA_BLOCK_LENGTH = 1 << UCPTRIE_SHIFT_3;
+
+/** Mask for getting the lower bits for the in-small-data-block offset. */
+constexpr int32_t 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 https://icu.unicode.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