| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2001, International Business Machines Corporation and * |
| * others. All Rights Reserved. * |
| ******************************************************************************* |
| */ |
| //=============================================================================== |
| // |
| // File sortkey.cpp |
| // |
| // |
| // |
| // Created by: Helena Shih |
| // |
| // Modification History: |
| // |
| // Date Name Description |
| // |
| // 6/20/97 helena Java class name change. |
| // 6/23/97 helena Added comments to make code more readable. |
| // 6/26/98 erm Canged to use byte arrays instead of UnicodeString |
| // 7/31/98 erm hashCode: minimum inc should be 2 not 1, |
| // Cleaned up operator= |
| // 07/12/99 helena HPUX 11 CC port. |
| // 03/06/01 synwee Modified compareTo, to handle the result of |
| // 2 string similar in contents, but one is longer |
| // than the other |
| //=============================================================================== |
| |
| #include "unicode/utypes.h" |
| |
| #if !UCONFIG_NO_COLLATION |
| |
| #include "unicode/sortkey.h" |
| #include "cmemory.h" |
| #include "uhash.h" |
| |
| U_NAMESPACE_BEGIN |
| |
| // A hash code of kInvalidHashCode indicates that the has code needs |
| // to be computed. A hash code of kEmptyHashCode is used for empty keys |
| // and for any key whose computed hash code is kInvalidHashCode. |
| #define kInvalidHashCode ((int32_t)0) |
| #define kEmptyHashCode ((int32_t)1) |
| |
| const char CollationKey::fgClassID=0; |
| |
| CollationKey::CollationKey() |
| : UObject(), fBogus(FALSE), fCount(0), fCapacity(0), |
| fHashCode(kEmptyHashCode), fBytes(NULL) |
| { |
| } |
| |
| // Create a collation key from a bit array. |
| CollationKey::CollationKey(const uint8_t* newValues, int32_t count) |
| : UObject(), fBogus(FALSE), fCount(count), fCapacity(count), |
| fHashCode(kInvalidHashCode) |
| { |
| fBytes = (uint8_t *)uprv_malloc(count); |
| |
| if (fBytes == NULL) |
| { |
| setToBogus(); |
| return; |
| } |
| |
| uprv_memcpy(fBytes, newValues, fCount); |
| } |
| |
| CollationKey::CollationKey(const CollationKey& other) |
| : UObject(other), fBogus(FALSE), fCount(other.fCount), fCapacity(other.fCapacity), |
| fHashCode(other.fHashCode), fBytes(NULL) |
| { |
| if (other.fBogus) |
| { |
| setToBogus(); |
| return; |
| } |
| |
| fBytes = (uint8_t *)uprv_malloc(fCapacity); |
| |
| if (fBytes == NULL) |
| { |
| setToBogus(); |
| return; |
| } |
| |
| uprv_memcpy(fBytes, other.fBytes, other.fCount); |
| if(fCapacity>fCount) { |
| uprv_memset(fBytes+fCount, 0, fCapacity-fCount); |
| } |
| } |
| |
| CollationKey::~CollationKey() |
| { |
| uprv_free(fBytes); |
| } |
| |
| void CollationKey::adopt(uint8_t *values, int32_t count) { |
| if(fBytes != NULL) { |
| uprv_free(fBytes); |
| } |
| fBogus = FALSE; |
| fBytes = values; |
| fCount = count; |
| fCapacity = count; |
| fHashCode = kInvalidHashCode; |
| } |
| |
| // set the key to an empty state |
| CollationKey& |
| CollationKey::reset() |
| { |
| fCount = 0; |
| fBogus = FALSE; |
| fHashCode = kEmptyHashCode; |
| |
| return *this; |
| } |
| |
| // set the key to a "bogus" or invalid state |
| CollationKey& |
| CollationKey::setToBogus() |
| { |
| uprv_free(fBytes); |
| fBytes = NULL; |
| |
| fCapacity = 0; |
| fCount = 0; |
| fHashCode = kInvalidHashCode; |
| |
| return *this; |
| } |
| |
| UBool |
| CollationKey::operator==(const CollationKey& source) const |
| { |
| return (this->fCount == source.fCount && |
| (this->fBytes == source.fBytes || |
| uprv_memcmp(this->fBytes, source.fBytes, this->fCount) == 0)); |
| } |
| |
| const CollationKey& |
| CollationKey::operator=(const CollationKey& other) |
| { |
| if (this != &other) |
| { |
| if (other.isBogus()) |
| { |
| return setToBogus(); |
| } |
| |
| if (other.fBytes != NULL) |
| { |
| ensureCapacity(other.fCount); |
| |
| if (isBogus()) |
| { |
| return *this; |
| } |
| |
| fHashCode = other.fHashCode; |
| uprv_memcpy(fBytes, other.fBytes, fCount); |
| } |
| else |
| { |
| fCount = 0; |
| fBogus = FALSE; |
| fHashCode = kEmptyHashCode; |
| } |
| } |
| |
| return *this; |
| } |
| |
| // Bitwise comparison for the collation keys. |
| // NOTE: this is somewhat messy 'cause we can't count |
| // on memcmp returning the exact values which match |
| // Collator::EComparisonResult |
| Collator::EComparisonResult |
| CollationKey::compareTo(const CollationKey& target) const |
| { |
| uint8_t *src = this->fBytes; |
| uint8_t *tgt = target.fBytes; |
| |
| // are we comparing the same string |
| if (src == tgt) |
| return Collator::EQUAL; |
| |
| /* |
| int count = (this->fCount < target.fCount) ? this->fCount : target.fCount; |
| if (count == 0) |
| { |
| // If count is 0, at least one of the keys is empty. |
| // An empty key is always LESS than a non-empty one |
| // and EQUAL to another empty |
| if (this->fCount < target.fCount) |
| { |
| return Collator::LESS; |
| } |
| |
| if (this->fCount > target.fCount) |
| { |
| return Collator::GREATER; |
| } |
| return Collator::EQUAL; |
| } |
| */ |
| |
| int minLength; |
| Collator::EComparisonResult result; |
| |
| // are we comparing different lengths? |
| if (this->fCount != target.fCount) { |
| if (this->fCount < target.fCount) { |
| minLength = this->fCount; |
| result = Collator::LESS; |
| } |
| else { |
| minLength = target.fCount; |
| result = Collator::GREATER; |
| } |
| } |
| else { |
| minLength = target.fCount; |
| result = Collator::EQUAL; |
| } |
| |
| if (minLength > 0) { |
| int diff = uprv_memcmp(src, tgt, minLength); |
| if (diff > 0) { |
| return Collator::GREATER; |
| } |
| else |
| if (diff < 0) { |
| return Collator::LESS; |
| } |
| } |
| |
| return result; |
| /* |
| if (result < 0) |
| { |
| return Collator::LESS; |
| } |
| |
| if (result > 0) |
| { |
| return Collator::GREATER; |
| } |
| return Collator::EQUAL; |
| */ |
| } |
| |
| CollationKey& |
| CollationKey::ensureCapacity(int32_t newSize) |
| { |
| if (fCapacity < newSize) |
| { |
| uprv_free(fBytes); |
| |
| fBytes = (uint8_t *)uprv_malloc(newSize); |
| |
| if (fBytes == NULL) |
| { |
| return setToBogus(); |
| } |
| |
| uprv_memset(fBytes, 0, fCapacity); |
| fCapacity = newSize; |
| } |
| |
| fBogus = FALSE; |
| fCount = newSize; |
| fHashCode = kInvalidHashCode; |
| |
| return *this; |
| } |
| |
| // Create a copy of the byte array. |
| uint8_t* |
| CollationKey::toByteArray(int32_t& count) const |
| { |
| uint8_t *result = (uint8_t*) uprv_malloc( sizeof(uint8_t) * fCount ); |
| |
| if (result == NULL) |
| { |
| count = 0; |
| } |
| else |
| { |
| count = fCount; |
| uprv_memcpy(result, fBytes, fCount); |
| } |
| |
| return result; |
| } |
| |
| int32_t |
| CollationKey::hashCode() const |
| { |
| // (Cribbed from UnicodeString) |
| // We cache the hashCode; when it becomes invalid, due to any change to the |
| // string, we note this by setting it to kInvalidHashCode. [LIU] |
| |
| // Note: This method is semantically const, but physically non-const. |
| |
| if (fHashCode == kInvalidHashCode) |
| { |
| UHashTok key; |
| key.pointer = fBytes; |
| ((CollationKey *)this)->fHashCode = uhash_hashChars(key); |
| #if 0 |
| // We compute the hash by iterating sparsely over 64 (at most) characters |
| // spaced evenly through the string. For each character, we multiply the |
| // previous hash value by a prime number and add the new character in, |
| // in the manner of a additive linear congruential random number generator, |
| // thus producing a pseudorandom deterministic value which should be well |
| // distributed over the output range. [LIU] |
| const uint8_t *p = fBytes, *limit = fBytes + fCount; |
| int32_t inc = (fCount >= 256) ? fCount/128 : 2; // inc = max(fSize/64, 1); |
| int32_t hash = 0; |
| |
| while (p < limit) |
| { |
| hash = ( hash * 37 ) + ((p[0] << 8) + p[1]); |
| p += inc; |
| } |
| |
| // If we happened to get kInvalidHashCode, replace it with kEmptyHashCode |
| if (hash == kInvalidHashCode) |
| { |
| hash = kEmptyHashCode; |
| } |
| |
| ((CollationKey *)this)->fHashCode = hash; // cast away const |
| #endif |
| } |
| |
| return fHashCode; |
| } |
| |
| U_NAMESPACE_END |
| |
| #endif /* #if !UCONFIG_NO_COLLATION */ |
