[build] ICU is now configured per platform

1 files changed, 125 insertions, 0 deletions

diff --git a/platform/default/bidi.cpp b/platform/default/bidi.cpp
new file mode 100644
index 0000000000..7d5f6313bc
--- /dev/null
+++ b/platform/default/bidi.cpp
@@ -0,0 +1,125 @@
+#include <memory>
+
+#include <mbgl/text/bidi.hpp>
+#include <unicode/ubidi.h>
+#include <unicode/ushape.h>
+
+namespace mbgl {
+
+// Takes UTF16 input in logical order and applies Arabic shaping to the input while maintaining
+// logical order
+//  Output won't be intelligible until the bidirectional algorithm is applied
+std::u16string applyArabicShaping(const std::u16string& input) {
+    UErrorCode errorCode = U_ZERO_ERROR;
+
+    int32_t outputLength =
+        u_shapeArabic(input.c_str(), static_cast<int32_t>(input.size()), NULL, 0,
+                      (U_SHAPE_LETTERS_SHAPE & U_SHAPE_LETTERS_MASK) |
+                          (U_SHAPE_TEXT_DIRECTION_LOGICAL & U_SHAPE_TEXT_DIRECTION_MASK),
+                      &errorCode);
+
+    // Pre-flighting will always set U_BUFFER_OVERFLOW_ERROR
+    errorCode = U_ZERO_ERROR;
+
+    std::unique_ptr<UChar[]> outputText = std::make_unique<UChar[]>(outputLength);
+    u_shapeArabic(input.c_str(), static_cast<int32_t>(input.size()), outputText.get(), outputLength,
+                  (U_SHAPE_LETTERS_SHAPE & U_SHAPE_LETTERS_MASK) |
+                      (U_SHAPE_TEXT_DIRECTION_LOGICAL & U_SHAPE_TEXT_DIRECTION_MASK),
+                  &errorCode);
+
+    // If the algorithm fails for any reason, fall back to non-transformed text
+    if (U_FAILURE(errorCode))
+        return input;
+
+    return std::u16string(outputText.get(), outputLength);
+}
+
+ProcessedBiDiText::ProcessedBiDiText(BiDi& p_bidi) : bidi(p_bidi) {
+}
+
+void ProcessedBiDiText::mergeParagraphLineBreaks(std::set<int32_t>& lineBreakPoints) {
+    int32_t paragraphCount = ubidi_countParagraphs(bidi.bidiText);
+    for (int32_t i = 0; i < paragraphCount; i++) {
+        UErrorCode errorCode = U_ZERO_ERROR;
+        int32_t paragraphEndIndex;
+        ubidi_getParagraphByIndex(bidi.bidiText, i, NULL, &paragraphEndIndex, NULL, &errorCode);
+
+        if (U_FAILURE(errorCode))
+            throw std::runtime_error(std::string("ProcessedBiDiText::mergeParagraphLineBreaks: ") +
+                                     u_errorName(errorCode));
+
+        lineBreakPoints.insert(paragraphEndIndex);
+    }
+}
+
+std::vector<std::u16string>
+ProcessedBiDiText::applyLineBreaking(std::set<int32_t> lineBreakPoints) {
+    // BiDi::getLine will error if called across a paragraph boundary, so we need to ensure that all
+    // paragraph
+    //  boundaries are included in the set of line break points. The calling code might not include
+    //  the line break because it
+    //  didn't need to wrap at that point, or because the text was separated with a more exotic code
+    //  point such as (U+001C)
+    mergeParagraphLineBreaks(lineBreakPoints);
+
+    std::vector<std::u16string> transformedLines;
+    int32_t start = 0;
+    for (int32_t lineBreakPoint : lineBreakPoints) {
+        transformedLines.push_back(bidi.getLine(start, lineBreakPoint));
+        start = lineBreakPoint;
+    }
+
+    return transformedLines;
+}
+
+BiDi::BiDi() {
+    bidiText = ubidi_open();
+    bidiLine = ubidi_open();
+}
+
+BiDi::~BiDi() {
+    if (bidiText)
+        ubidi_close(bidiText);
+
+    if (bidiLine)
+        ubidi_close(bidiLine);
+}
+
+ProcessedBiDiText BiDi::processText(const std::u16string& input) {
+    UErrorCode errorCode = U_ZERO_ERROR;
+
+    ubidi_setPara(bidiText, input.c_str(), static_cast<int32_t>(input.size()), UBIDI_DEFAULT_LTR,
+                  NULL, &errorCode);
+
+    if (U_FAILURE(errorCode))
+        throw std::runtime_error(std::string("BiDi::processText: ") + u_errorName(errorCode));
+
+    return ProcessedBiDiText(*this);
+}
+
+std::u16string BiDi::getLine(int32_t start, int32_t end) {
+    UErrorCode errorCode = U_ZERO_ERROR;
+    ubidi_setLine(bidiText, start, end, bidiLine, &errorCode);
+
+    if (U_FAILURE(errorCode))
+        throw std::runtime_error(std::string("BiDi::getLine (setLine): ") + u_errorName(errorCode));
+
+    // Because we set UBIDI_REMOVE_BIDI_CONTROLS, the output may be smaller than what we reserve
+    //  Setting UBIDI_INSERT_LRM_FOR_NUMERIC would require
+    //  ubidi_getLength(pBiDi)+2*ubidi_countRuns(pBiDi)
+    int32_t outputLength = ubidi_getProcessedLength(bidiLine);
+    std::unique_ptr<UChar[]> outputText = std::make_unique<UChar[]>(outputLength);
+
+    // UBIDI_DO_MIRRORING: Apply unicode mirroring of characters like parentheses
+    // UBIDI_REMOVE_BIDI_CONTROLS: Now that all the lines are set, remove control characters so that
+    // they don't show up on screen (some fonts have glyphs representing them)
+    ubidi_writeReordered(bidiLine, outputText.get(), outputLength,
+                         UBIDI_DO_MIRRORING | UBIDI_REMOVE_BIDI_CONTROLS, &errorCode);
+
+    if (U_FAILURE(errorCode))
+        throw std::runtime_error(std::string("BiDi::getLine (writeReordered): ") + u_errorName(errorCode));
+
+    return std::u16string(outputText.get(), outputLength);
+}
+
+} // end namespace mbgl