ICU-531.30.tar.gz

[apple/icu.git] / icuSources / i18n / collation.cpp

diff --git a/icuSources/i18n/collation.cpp b/icuSources/i18n/collation.cpp
new file mode 100644 (file)
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+++ b/icuSources/i18n/collation.cpp
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+/*
+*******************************************************************************
+* Copyright (C) 2010-2014, International Business Machines
+* Corporation and others.  All Rights Reserved.
+*******************************************************************************
+* collation.cpp
+*
+* created on: 2010oct27
+* created by: Markus W. Scherer
+*/
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_COLLATION
+
+#include "collation.h"
+#include "uassert.h"
+
+U_NAMESPACE_BEGIN
+
+// Some compilers don't care if constants are defined in the .cpp file.
+// MS Visual C++ does not like it, but gcc requires it. clang does not care.
+#ifndef _MSC_VER
+const uint32_t Collation::ONLY_TERTIARY_MASK;
+const uint32_t Collation::CASE_AND_TERTIARY_MASK;
+#endif
+
+uint32_t
+Collation::incTwoBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
+    // Extract the second byte, minus the minimum byte value,
+    // plus the offset, modulo the number of usable byte values, plus the minimum.
+    // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
+    uint32_t primary;
+    if(isCompressible) {
+        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
+        primary = (uint32_t)((offset % 251) + 4) << 16;
+        offset /= 251;
+    } else {
+        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
+        primary = (uint32_t)((offset % 254) + 2) << 16;
+        offset /= 254;
+    }
+    // First byte, assume no further overflow.
+    return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
+}
+
+uint32_t
+Collation::incThreeBytePrimaryByOffset(uint32_t basePrimary, UBool isCompressible, int32_t offset) {
+    // Extract the third byte, minus the minimum byte value,
+    // plus the offset, modulo the number of usable byte values, plus the minimum.
+    offset += ((int32_t)(basePrimary >> 8) & 0xff) - 2;
+    uint32_t primary = (uint32_t)((offset % 254) + 2) << 8;
+    offset /= 254;
+    // Same with the second byte,
+    // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
+    if(isCompressible) {
+        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 4;
+        primary |= (uint32_t)((offset % 251) + 4) << 16;
+        offset /= 251;
+    } else {
+        offset += ((int32_t)(basePrimary >> 16) & 0xff) - 2;
+        primary |= (uint32_t)((offset % 254) + 2) << 16;
+        offset /= 254;
+    }
+    // First byte, assume no further overflow.
+    return primary | ((basePrimary & 0xff000000) + (uint32_t)(offset << 24));
+}
+
+uint32_t
+Collation::decTwoBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
+    // Extract the second byte, minus the minimum byte value,
+    // minus the step, modulo the number of usable byte values, plus the minimum.
+    // Reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
+    // Assume no further underflow for the first byte.
+    U_ASSERT(0 < step && step <= 0x7f);
+    int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - step;
+    if(isCompressible) {
+        if(byte2 < 4) {
+            byte2 += 251;
+            basePrimary -= 0x1000000;
+        }
+    } else {
+        if(byte2 < 2) {
+            byte2 += 254;
+            basePrimary -= 0x1000000;
+        }
+    }
+    return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16);
+}
+
+uint32_t
+Collation::decThreeBytePrimaryByOneStep(uint32_t basePrimary, UBool isCompressible, int32_t step) {
+    // Extract the third byte, minus the minimum byte value,
+    // minus the step, modulo the number of usable byte values, plus the minimum.
+    U_ASSERT(0 < step && step <= 0x7f);
+    int32_t byte3 = ((int32_t)(basePrimary >> 8) & 0xff) - step;
+    if(byte3 >= 2) {
+        return (basePrimary & 0xffff0000) | ((uint32_t)byte3 << 8);
+    }
+    byte3 += 254;
+    // Same with the second byte,
+    // but reserve the PRIMARY_COMPRESSION_LOW_BYTE and high byte if necessary.
+    int32_t byte2 = ((int32_t)(basePrimary >> 16) & 0xff) - 1;
+    if(isCompressible) {
+        if(byte2 < 4) {
+            byte2 = 0xfe;
+            basePrimary -= 0x1000000;
+        }
+    } else {
+        if(byte2 < 2) {
+            byte2 = 0xff;
+            basePrimary -= 0x1000000;
+        }
+    }
+    // First byte, assume no further underflow.
+    return (basePrimary & 0xff000000) | ((uint32_t)byte2 << 16) | ((uint32_t)byte3 << 8);
+}
+
+uint32_t
+Collation::getThreeBytePrimaryForOffsetData(UChar32 c, int64_t dataCE) {
+    uint32_t p = (uint32_t)(dataCE >> 32);  // three-byte primary pppppp00
+    int32_t lower32 = (int32_t)dataCE;  // base code point b & step s: bbbbbbss (bit 7: isCompressible)
+    int32_t offset = (c - (lower32 >> 8)) * (lower32 & 0x7f);  // delta * increment
+    UBool isCompressible = (lower32 & 0x80) != 0;
+    return Collation::incThreeBytePrimaryByOffset(p, isCompressible, offset);
+}
+
+uint32_t
+Collation::unassignedPrimaryFromCodePoint(UChar32 c) {
+    // Create a gap before U+0000. Use c=-1 for [first unassigned].
+    ++c;
+    // Fourth byte: 18 values, every 14th byte value (gap of 13).
+    uint32_t primary = 2 + (c % 18) * 14;
+    c /= 18;
+    // Third byte: 254 values.
+    primary |= (2 + (c % 254)) << 8;
+    c /= 254;
+    // Second byte: 251 values 04..FE excluding the primary compression bytes.
+    primary |= (4 + (c % 251)) << 16;
+    // One lead byte covers all code points (c < 0x1182B4 = 1*251*254*18).
+    return primary | (UNASSIGNED_IMPLICIT_BYTE << 24);
+}
+
+U_NAMESPACE_END
+
+#endif  // !UCONFIG_NO_COLLATION