| 137 | } |
| 138 | |
| 139 | void GetSingleTextLineRuns(TextSegments & segments) |
| 140 | { |
| 141 | auto const & text = segments.m_text; |
| 142 | auto const textLength = static_cast<int32_t>(text.length()); |
| 143 | |
| 144 | // Deliberately not checking for nullptr. |
| 145 | thread_local UBiDi * const bidi = ubidi_open(); |
| 146 | UErrorCode error = U_ZERO_ERROR; |
| 147 | ::ubidi_setPara(bidi, text.data(), textLength, UBIDI_DEFAULT_LTR, nullptr, &error); |
| 148 | if (U_FAILURE(error)) |
| 149 | { |
| 150 | LOG(LERROR, ("ubidi_setPara failed with code", error)); |
| 151 | segments.m_segments.emplace_back(0, 0, HB_SCRIPT_UNKNOWN, HB_DIRECTION_INVALID); |
| 152 | return; |
| 153 | } |
| 154 | |
| 155 | // Split the original text by logical runs, then each logical run by common script and each sequence at special |
| 156 | // characters and style boundaries. This invariant holds: bidiRunStart <= scriptRunStart <= breakingRunStart |
| 157 | // <= breakingRunEnd <= scriptRunStart <= bidiRunEnd. AB: Breaking runs are dropped now, they may not be needed. |
| 158 | for (int32_t bidiRunStart = 0; bidiRunStart < textLength;) |
| 159 | { |
| 160 | // Determine the longest logical run (e.g. same bidi direction) from this point. |
| 161 | int32_t bidiRunBreak = 0; |
| 162 | UBiDiLevel bidiLevel = 0; |
| 163 | ::ubidi_getLogicalRun(bidi, bidiRunStart, &bidiRunBreak, &bidiLevel); |
| 164 | int32_t const bidiRunEnd = bidiRunBreak; |
| 165 | ASSERT_LESS(bidiRunStart, bidiRunEnd, ()); |
| 166 | |
| 167 | for (int32_t scriptRunStart = bidiRunStart; scriptRunStart < bidiRunEnd;) |
| 168 | { |
| 169 | // Find the longest sequence of characters that have at least one common UScriptCode value. |
| 170 | UScriptCode script = USCRIPT_INVALID_CODE; |
| 171 | size_t const scriptRunEnd = |
| 172 | ScriptInterval(segments.m_text, scriptRunStart, bidiRunEnd - scriptRunStart, script) + scriptRunStart; |
| 173 | ASSERT_LESS(scriptRunStart, base::asserted_cast<int32_t>(scriptRunEnd), ()); |
| 174 | |
| 175 | // TODO(AB): May need to break on different unicode blocks, parentheses, and control chars (spaces). |
| 176 | |
| 177 | // TODO(AB): Support vertical layouts if necessary. |
| 178 | segments.m_segments.emplace_back(scriptRunStart, scriptRunEnd - scriptRunStart, ICUScriptToHarfbuzzScript(script), |
| 179 | bidiLevel & 0x01 ? HB_DIRECTION_RTL : HB_DIRECTION_LTR); |
| 180 | |
| 181 | // Move to the next script sequence. |
| 182 | scriptRunStart = static_cast<int32_t>(scriptRunEnd); |
| 183 | } |
| 184 | // Move to the next direction sequence. |
| 185 | bidiRunStart = bidiRunEnd; |
| 186 | } |
| 187 | } |
| 188 | |
| 189 | void ReorderRTL(TextSegments & segments) |
| 190 | { |
no test coverage detected