FFstrbuf: add function ffStrbufAppendUtf32CodePoint

src/util/FFstrbuf.c

@@ -682,3 +682,35 @@ bool ffStrbufMatchSeparatedNS(const FFstrbuf* strbuf, uint32_t compLength, const
 
     return false;
 }
+
+int ffStrbufAppendUtf32CodePoint(FFstrbuf* strbuf, uint32_t codepoint)
+{
+    if (codepoint <= 0x7F) {
+        ffStrbufAppendC(strbuf, (char)codepoint);
+        return 1;
+    } else if (codepoint <= 0x7FF) {
+        ffStrbufAppendNS(strbuf, 2, (char[]){
+            (char) (0xC0 | (codepoint >> 6)),
+            (char) (0x80 | (codepoint & 0x3F))
+        });
+        return 2;
+    } else if (codepoint <= 0xFFFF) {
+        ffStrbufAppendNS(strbuf, 3, (char[]){
+            (char) (0xE0 | (codepoint >> 12)),
+            (char) (0x80 | ((codepoint >> 6) & 0x3F)),
+            (char) (0x80 | (codepoint & 0x3F))
+        });
+        return 3;
+    } else if (codepoint <= 0x10FFFF) {
+        ffStrbufAppendNS(strbuf, 4, (char[]){
+            (char) (0xF0 | (codepoint >> 18)),
+            (char) (0x80 | ((codepoint >> 12) & 0x3F)),
+            (char) (0x80 | ((codepoint >> 6) & 0x3F)),
+            (char) (0x80 | (codepoint & 0x3F))
+        });
+        return 4;
+    }
+
+    ffStrbufAppendS(strbuf, "�"); // U+FFFD REPLACEMENT CHARACTER
+    return 1;
+}

src/util/FFstrbuf.h

@@ -96,6 +96,8 @@ void ffStrbufGetlineRestore(char** lineptr, size_t* n, FFstrbuf* buffer);
 bool ffStrbufRemoveDupWhitespaces(FFstrbuf* strbuf);
 bool ffStrbufMatchSeparatedNS(const FFstrbuf* strbuf, uint32_t compLength, const char* comp, char separator);
 
+int ffStrbufAppendUtf32CodePoint(FFstrbuf* strbuf, uint32_t codepoint);
+
 FF_C_NODISCARD static inline FFstrbuf ffStrbufCreateA(uint32_t allocate)
 {
     FFstrbuf strbuf;

tests/strbuf.c

@@ -711,6 +711,15 @@ int main(void)
         ffStrbufDestroy(&strbuf);
     }
 
+    {
+        ffStrbufAppendUtf32CodePoint(&strbuf, 0x6587);
+        ffStrbufAppendUtf32CodePoint(&strbuf, 0x6cc9);
+        ffStrbufAppendUtf32CodePoint(&strbuf, 0x9a7f);
+        VERIFY(ffStrbufEqualS(&strbuf, u8"文泉驿"));
+
+        ffStrbufDestroy(&strbuf);
+    }
+
     //Success
     puts("\e[32mAll tests passed!" FASTFETCH_TEXT_MODIFIER_RESET);
 }