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| 1 | +/* |
| 2 | + * Copyright (c) Facebook, Inc. and its affiliates. |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +#include "velox/dwio/parquet/common/UnicodeUtil.h" |
| 18 | + |
| 19 | +#include "velox/external/utf8proc/utf8proc.h" |
| 20 | +#include "velox/functions/lib/string/StringImpl.h" |
| 21 | + |
| 22 | +namespace facebook::velox::parquet { |
| 23 | + |
| 24 | +std::string UnicodeUtil::truncateStringMin( |
| 25 | + const char* input, |
| 26 | + int32_t inputLength, |
| 27 | + int32_t numCodePoints) { |
| 28 | + auto length = functions::stringImpl::cappedByteLength<false>( |
| 29 | + StringView(input, inputLength), numCodePoints); |
| 30 | + return std::string(input, length); |
| 31 | +} |
| 32 | + |
| 33 | +std::string UnicodeUtil::truncateStringMax( |
| 34 | + const char* input, |
| 35 | + int32_t inputLength, |
| 36 | + int32_t numCodePoints) { |
| 37 | + auto truncatedLength = functions::stringImpl::cappedByteLength<false>( |
| 38 | + StringView(input, inputLength), numCodePoints); |
| 39 | + |
| 40 | + if (truncatedLength == inputLength) { |
| 41 | + return std::string(input, inputLength); |
| 42 | + } |
| 43 | + |
| 44 | + // Try to increment the last code point. |
| 45 | + for (auto i = numCodePoints - 1; i >= 0; --i) { |
| 46 | + const char* current = input; |
| 47 | + int32_t currentCodePoint = 0; |
| 48 | + |
| 49 | + // Find the i-th code point position. |
| 50 | + while (current < input + truncatedLength && currentCodePoint < i) { |
| 51 | + int32_t charLength; |
| 52 | + utf8proc_codepoint(current, input + truncatedLength, charLength); |
| 53 | + current += charLength; |
| 54 | + currentCodePoint++; |
| 55 | + } |
| 56 | + |
| 57 | + if (current >= input + truncatedLength) |
| 58 | + continue; |
| 59 | + |
| 60 | + int32_t charLength; |
| 61 | + auto codePoint = |
| 62 | + utf8proc_codepoint(current, input + truncatedLength, charLength); |
| 63 | + auto nextCodePoint = codePoint + 1; |
| 64 | + |
| 65 | + // Check if the incremented code point is valid. |
| 66 | + if (nextCodePoint != 0 && utf8proc_codepoint_valid(nextCodePoint)) { |
| 67 | + std::string result; |
| 68 | + result.reserve(truncatedLength + 4); |
| 69 | + result.assign(input, current - input); |
| 70 | + char buffer[4]; |
| 71 | + auto bytesWritten = utf8proc_encode_char( |
| 72 | + nextCodePoint, reinterpret_cast<utf8proc_uint8_t*>(buffer)); |
| 73 | + result.append(buffer, bytesWritten); |
| 74 | + return result; |
| 75 | + } |
| 76 | + } |
| 77 | + |
| 78 | + return std::string(input, truncatedLength); |
| 79 | +} |
| 80 | + |
| 81 | +} // namespace facebook::velox::parquet |
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