Index: icu4c/source/common/edits.cpp |
=================================================================== |
--- icu4c/source/common/edits.cpp (revision 0) |
+++ icu4c/source/common/edits.cpp (revision 39683) |
@@ -0,0 +1,346 @@ |
+// © 2017 and later: Unicode, Inc. and others. |
+// License & terms of use: http://www.unicode.org/copyright.html |
+ |
+// edits.cpp |
+// created: 2017feb08 Markus W. Scherer |
+ |
+#include "unicode/utypes.h" |
+#include "unicode/edits.h" |
+#include "cmemory.h" |
+#include "uassert.h" |
+ |
+U_NAMESPACE_BEGIN |
+ |
+namespace { |
+ |
+// 0000uuuuuuuuuuuu records u+1 unchanged text units. |
+const int32_t MAX_UNCHANGED_LENGTH = 0x1000; |
+const int32_t MAX_UNCHANGED = MAX_UNCHANGED_LENGTH - 1; |
+ |
+// 0wwwcccccccccccc with w=1..6 records ccc+1 replacements of w:w text units. |
+// No length change. |
+const int32_t MAX_SHORT_WIDTH = 6; |
+const int32_t MAX_SHORT_CHANGE_LENGTH = 0xfff; |
+const int32_t MAX_SHORT_CHANGE = 0x6fff; |
+ |
+// 0111mmmmmmnnnnnn records a replacement of m text units with n. |
+// m or n = 61: actual length follows in the next edits array unit. |
+// m or n = 62..63: actual length follows in the next two edits array units. |
+// Bit 30 of the actual length is in the head unit. |
+// Trailing units have bit 15 set. |
+const int32_t LENGTH_IN_1TRAIL = 61; |
+const int32_t LENGTH_IN_2TRAIL = 62; |
+ |
+} // namespace |
+ |
+Edits::~Edits() { |
+ if(array != stackArray) { |
+ uprv_free(array); |
+ } |
+} |
+ |
+void Edits::reset() { |
+ length = delta = 0; |
+} |
+ |
+void Edits::addUnchanged(int32_t unchangedLength) { |
+ if(U_FAILURE(errorCode) || unchangedLength == 0) { return; } |
+ if(unchangedLength < 0) { |
+ errorCode = U_ILLEGAL_ARGUMENT_ERROR; |
+ return; |
+ } |
+ // Merge into previous unchanged-text record, if any. |
+ int32_t last = lastUnit(); |
+ if(last < MAX_UNCHANGED) { |
+ int32_t remaining = MAX_UNCHANGED - last; |
+ if (remaining >= unchangedLength) { |
+ setLastUnit(last + unchangedLength); |
+ return; |
+ } |
+ setLastUnit(MAX_UNCHANGED); |
+ unchangedLength -= remaining; |
+ } |
+ // Split large lengths into multiple units. |
+ while(unchangedLength >= MAX_UNCHANGED_LENGTH) { |
+ append(MAX_UNCHANGED); |
+ unchangedLength -= MAX_UNCHANGED_LENGTH; |
+ } |
+ // Write a small (remaining) length. |
+ if(unchangedLength > 0) { |
+ append(unchangedLength - 1); |
+ } |
+} |
+ |
+void Edits::addReplace(int32_t oldLength, int32_t newLength) { |
+ if(U_FAILURE(errorCode)) { return; } |
+ if(oldLength == newLength && 0 < oldLength && oldLength <= MAX_SHORT_WIDTH) { |
+ // Replacement of short oldLength text units by same-length new text. |
+ // Merge into previous short-replacement record, if any. |
+ int32_t last = lastUnit(); |
+ if(MAX_UNCHANGED < last && last < MAX_SHORT_CHANGE && |
+ (last >> 12) == oldLength && (last & 0xfff) < MAX_SHORT_CHANGE_LENGTH) { |
+ setLastUnit(last + 1); |
+ return; |
+ } |
+ append(oldLength << 12); |
+ return; |
+ } |
+ |
+ if(oldLength < 0 || newLength < 0) { |
+ errorCode = U_ILLEGAL_ARGUMENT_ERROR; |
+ return; |
+ } |
+ if (oldLength == 0 && newLength == 0) { |
+ return; |
+ } |
+ int32_t newDelta = newLength - oldLength; |
+ if (newDelta != 0) { |
+ if ((newDelta > 0 && delta >= 0 && newDelta > (INT32_MAX - delta)) || |
+ (newDelta < 0 && delta < 0 && newDelta < (INT32_MIN - delta))) { |
+ // Integer overflow or underflow. |
+ errorCode = U_INDEX_OUTOFBOUNDS_ERROR; |
+ return; |
+ } |
+ delta += newDelta; |
+ } |
+ |
+ int32_t head = 0x7000; |
+ if (oldLength < LENGTH_IN_1TRAIL && newLength < LENGTH_IN_1TRAIL) { |
+ head |= oldLength << 6; |
+ head |= newLength; |
+ append(head); |
+ } else if ((capacity - length) >= 5 || growArray()) { |
+ int32_t limit = length + 1; |
+ if(oldLength < LENGTH_IN_1TRAIL) { |
+ head |= oldLength << 6; |
+ } else if(oldLength <= 0x7fff) { |
+ head |= LENGTH_IN_1TRAIL << 6; |
+ array[limit++] = (uint16_t)(0x8000 | oldLength); |
+ } else { |
+ head |= (LENGTH_IN_2TRAIL + (oldLength >> 30)) << 6; |
+ array[limit++] = (uint16_t)(0x8000 | (oldLength >> 15)); |
+ array[limit++] = (uint16_t)(0x8000 | oldLength); |
+ } |
+ if(newLength < LENGTH_IN_1TRAIL) { |
+ head |= newLength; |
+ } else if(newLength <= 0x7fff) { |
+ head |= LENGTH_IN_1TRAIL; |
+ array[limit++] = (uint16_t)(0x8000 | newLength); |
+ } else { |
+ head |= LENGTH_IN_2TRAIL + (newLength >> 30); |
+ array[limit++] = (uint16_t)(0x8000 | (newLength >> 15)); |
+ array[limit++] = (uint16_t)(0x8000 | newLength); |
+ } |
+ array[length] = (uint16_t)head; |
+ length = limit; |
+ } |
+} |
+ |
+void Edits::append(int32_t r) { |
+ if(length < capacity || growArray()) { |
+ array[length++] = (uint16_t)r; |
+ } |
+} |
+ |
+UBool Edits::growArray() { |
+ int32_t newCapacity; |
+ if (array == stackArray) { |
+ newCapacity = 2000; |
+ } else if (capacity == INT32_MAX) { |
+ // Not U_BUFFER_OVERFLOW_ERROR because that could be confused on a string transform API |
+ // with a result-string-buffer overflow. |
+ errorCode = U_INDEX_OUTOFBOUNDS_ERROR; |
+ return FALSE; |
+ } else if (capacity >= (INT32_MAX / 2)) { |
+ newCapacity = INT32_MAX; |
+ } else { |
+ newCapacity = 2 * capacity; |
+ } |
+ // Grow by at least 5 units so that a maximal change record will fit. |
+ if ((newCapacity - capacity) < 5) { |
+ errorCode = U_INDEX_OUTOFBOUNDS_ERROR; |
+ return FALSE; |
+ } |
+ uint16_t *newArray = (uint16_t *)uprv_malloc((size_t)newCapacity * 2); |
+ if (newArray == NULL) { |
+ errorCode = U_MEMORY_ALLOCATION_ERROR; |
+ return FALSE; |
+ } |
+ uprv_memcpy(newArray, array, (size_t)length * 2); |
+ if (array != stackArray) { |
+ uprv_free(array); |
+ } |
+ array = newArray; |
+ capacity = newCapacity; |
+ return TRUE; |
+} |
+ |
+UBool Edits::copyErrorTo(UErrorCode &outErrorCode) { |
+ if (U_FAILURE(outErrorCode)) { return TRUE; } |
+ if (U_SUCCESS(errorCode)) { return FALSE; } |
+ outErrorCode = errorCode; |
+ return TRUE; |
+} |
+ |
+UBool Edits::hasChanges() const { |
+ if (delta != 0) { |
+ return TRUE; |
+ } |
+ for (int32_t i = 0; i < length; ++i) { |
+ if (array[i] > MAX_UNCHANGED) { |
+ return TRUE; |
+ } |
+ } |
+ return FALSE; |
+} |
+ |
+Edits::Iterator::Iterator(const uint16_t *a, int32_t len, UBool oc, UBool crs) : |
+ array(a), index(0), length(len), remaining(0), |
+ onlyChanges_(oc), coarse(crs), |
+ changed(FALSE), oldLength_(0), newLength_(0), |
+ srcIndex(0), replIndex(0), destIndex(0) {} |
+ |
+int32_t Edits::Iterator::readLength(int32_t head) { |
+ if (head < LENGTH_IN_1TRAIL) { |
+ return head; |
+ } else if (head < LENGTH_IN_2TRAIL) { |
+ U_ASSERT(index < length); |
+ U_ASSERT(array[index] >= 0x8000); |
+ return array[index++] & 0x7fff; |
+ } else { |
+ U_ASSERT((index + 2) <= length); |
+ U_ASSERT(array[index] >= 0x8000); |
+ U_ASSERT(array[index + 1] >= 0x8000); |
+ int32_t len = ((head & 1) << 30) | |
+ ((int32_t)(array[index] & 0x7fff) << 15) | |
+ (array[index + 1] & 0x7fff); |
+ index += 2; |
+ return len; |
+ } |
+} |
+ |
+void Edits::Iterator::updateIndexes() { |
+ srcIndex += oldLength_; |
+ if (changed) { |
+ replIndex += newLength_; |
+ } |
+ destIndex += newLength_; |
+} |
+ |
+UBool Edits::Iterator::noNext() { |
+ // No change beyond the string. |
+ changed = FALSE; |
+ oldLength_ = newLength_ = 0; |
+ return FALSE; |
+} |
+ |
+UBool Edits::Iterator::next(UBool onlyChanges, UErrorCode &errorCode) { |
+ if (U_FAILURE(errorCode)) { return FALSE; } |
+ // We have an errorCode in case we need to start guarding against integer overflows. |
+ // It is also convenient for caller loops if we bail out when an error was set elsewhere. |
+ updateIndexes(); |
+ if (remaining > 0) { |
+ // Fine-grained iterator: Continue a sequence of equal-length changes. |
+ --remaining; |
+ return TRUE; |
+ } |
+ if (index >= length) { |
+ return noNext(); |
+ } |
+ int32_t u = array[index++]; |
+ if (u <= MAX_UNCHANGED) { |
+ // Combine adjacent unchanged ranges. |
+ changed = FALSE; |
+ oldLength_ = u + 1; |
+ while (index < length && (u = array[index]) <= MAX_UNCHANGED) { |
+ ++index; |
+ oldLength_ += u + 1; |
+ } |
+ newLength_ = oldLength_; |
+ if (onlyChanges) { |
+ updateIndexes(); |
+ if (index >= length) { |
+ return noNext(); |
+ } |
+ // already fetched u > MAX_UNCHANGED at index |
+ ++index; |
+ } else { |
+ return TRUE; |
+ } |
+ } |
+ changed = TRUE; |
+ if (u <= MAX_SHORT_CHANGE) { |
+ if (coarse) { |
+ int32_t w = u >> 12; |
+ int32_t len = (u & 0xfff) + 1; |
+ oldLength_ = newLength_ = len * w; |
+ } else { |
+ // Split a sequence of equal-length changes that was compressed into one unit. |
+ oldLength_ = newLength_ = u >> 12; |
+ remaining = u & 0xfff; |
+ return TRUE; |
+ } |
+ } else { |
+ U_ASSERT(u <= 0x7fff); |
+ oldLength_ = readLength((u >> 6) & 0x3f); |
+ newLength_ = readLength(u & 0x3f); |
+ if (!coarse) { |
+ return TRUE; |
+ } |
+ } |
+ // Combine adjacent changes. |
+ while (index < length && (u = array[index]) > MAX_UNCHANGED) { |
+ ++index; |
+ if (u <= MAX_SHORT_CHANGE) { |
+ int32_t w = u >> 12; |
+ int32_t len = (u & 0xfff) + 1; |
+ len = len * w; |
+ oldLength_ += len; |
+ newLength_ += len; |
+ } else { |
+ U_ASSERT(u <= 0x7fff); |
+ int32_t oldLen = readLength((u >> 6) & 0x3f); |
+ int32_t newLen = readLength(u & 0x3f); |
+ oldLength_ += oldLen; |
+ newLength_ += newLen; |
+ } |
+ } |
+ return TRUE; |
+} |
+ |
+UBool Edits::Iterator::findSourceIndex(int32_t i, UErrorCode &errorCode) { |
+ if (U_FAILURE(errorCode) || i < 0) { return FALSE; } |
+ if (i < srcIndex) { |
+ // Reset the iterator to the start. |
+ index = remaining = oldLength_ = newLength_ = srcIndex = replIndex = destIndex = 0; |
+ } else if (i < (srcIndex + oldLength_)) { |
+ // The index is in the current span. |
+ return TRUE; |
+ } |
+ while (next(FALSE, errorCode)) { |
+ if (i < (srcIndex + oldLength_)) { |
+ // The index is in the current span. |
+ return TRUE; |
+ } |
+ if (remaining > 0) { |
+ // Is the index in one of the remaining compressed edits? |
+ // srcIndex is the start of the current span, before the remaining ones. |
+ int32_t len = (remaining + 1) * oldLength_; |
+ if (i < (srcIndex + len)) { |
+ int32_t n = (i - srcIndex) / oldLength_; // 1 <= n <= remaining |
+ len = n * oldLength_; |
+ srcIndex += len; |
+ replIndex += len; |
+ destIndex += len; |
+ remaining -= n; |
+ return TRUE; |
+ } |
+ // Make next() skip all of these edits at once. |
+ oldLength_ = newLength_ = len; |
+ remaining = 0; |
+ } |
+ } |
+ return FALSE; |
+} |
+ |
+U_NAMESPACE_END |
Property changes on: icu4c/source/common/edits.cpp |
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