Introduce new API grapheme_line_segmenter to replace scan API

Signed-off-by: Christian Parpart <christian@parpart.family>

Author: christianparpart

src/libunicode/CMakeLists.txt

@@ -101,6 +101,7 @@ add_library(unicode ${LIBUNICODE_LIB_MODE}
     capi.cpp
     codepoint_properties.cpp
     emoji_segmenter.cpp
+    grapheme_line_segmenter.cpp
     grapheme_segmenter.cpp
     scan.cpp
     script_segmenter.cpp
@@ -125,6 +126,7 @@ set(public_headers
     codepoint_properties.h
     convert.h
     emoji_segmenter.h
+    grapheme_line_segmenter.h
     grapheme_segmenter.h
     intrinsics.h
     multistage_table_view.h
@@ -219,6 +221,7 @@ if(LIBUNICODE_TESTING)
         capi_test.cpp
         convert_test.cpp
         emoji_segmenter_test.cpp
+        grapheme_line_segmenter_test.cpp
         grapheme_segmenter_test.cpp
         run_segmenter_test.cpp
         scan_test.cpp

src/libunicode/capi.cpp

@@ -49,7 +49,7 @@ int u32_gc_width(u32_char_t const* codepoints, size_t size, int mode)
     while (segmenter.codepointsAvailable())
     {
         auto const cluster = *segmenter;
-        int thisWidth = unicode::width(cluster.front());
+        int thisWidth = static_cast<int>(unicode::width(cluster.front()));
         if (mode != GC_WIDTH_MODE_NON_MODIFIABLE)
         {
             for (size_t i = 1; i < size; ++i)
@@ -60,7 +60,7 @@ int u32_gc_width(u32_char_t const* codepoints, size_t size, int mode)
                     {
                         case 0xFE0E: return 1;
                         case 0xFE0F: return 2;
-                        default: return unicode::width(codepoint);
+                        default: return static_cast<int>(unicode::width(codepoint));
                     }
                 }();
                 if (width && width != thisWidth)