| // © 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 |