New function xs_unicode_right_to_left().

3 files changed, 40 insertions, 1 deletions

diff --git a/xs_unicode.h b/xs_unicode.h
index 9663190..cfcd8ff 100644
--- a/xs_unicode.h
+++ b/xs_unicode.h
@@ -21,6 +21,7 @@
  int xs_unicode_nfd(unsigned int cpoint, unsigned int *base, unsigned int *diac);
  int xs_unicode_nfc(unsigned int base, unsigned int diac, unsigned int *cpoint);
  int xs_unicode_is_alpha(unsigned int cpoint);
+ int xs_unicode_is_right_to_left(unsigned int cpoint);
 
 #ifdef _XS_H
  xs_str *xs_utf8_insert(xs_str *str, unsigned int cpoint, int *offset);
@@ -350,6 +351,29 @@ int xs_unicode_is_alpha(unsigned int cpoint)
 }
 
 
+int xs_unicode_is_right_to_left(unsigned int cpoint)
+/* checks if a codepoint is a right-to-left letter */
+{
+    int b = 0;
+    int t = xs_countof(xs_unicode_right_to_left_table) / 2 - 1;
+
+    while (t >= b) {
+        int n = (b + t) / 2;
+        unsigned int *p = &xs_unicode_right_to_left_table[n * 2];
+
+        if (cpoint < p[0])
+            t = n - 1;
+        else
+        if (cpoint > p[1])
+            b = n + 1;
+        else
+            return 1;
+    }
+
+    return 0;
+}
+
+
 #ifdef _XS_H
 
 xs_str *xs_utf8_to_upper(const char *str)
diff --git a/xs_unicode_tbl.h b/xs_unicode_tbl.h
index ecd537b..ee8ce97 100644
--- a/xs_unicode_tbl.h
+++ b/xs_unicode_tbl.h
@@ -726,5 +726,20 @@ static unsigned int xs_unicode_alpha_table[] = {
     0x1E7E0, 0x1E8C4, 0x1E900, 0x1E943, 0x1EE00, 0x1EEBB, 0x20000, 0x323AF, 
 };
 
+static unsigned int xs_unicode_right_to_left_table[] = {
+    0x05BE, 0x05BE, 0x05C0, 0x05C0, 0x05C3, 0x05C3, 0x05C6, 0x05C6, 
+    0x05D0, 0x05F4, 0x0608, 0x0608, 0x060B, 0x060B, 0x060D, 0x060D, 
+    0x061B, 0x064A, 0x066D, 0x066F, 0x0671, 0x06D5, 0x06E5, 0x06E6, 
+    0x06EE, 0x06EF, 0x06FA, 0x0710, 0x0712, 0x072F, 0x074D, 0x07A5, 
+    0x07B1, 0x07EA, 0x07F4, 0x07F5, 0x07FA, 0x07FA, 0x07FE, 0x0815, 
+    0x081A, 0x081A, 0x0824, 0x0824, 0x0828, 0x0828, 0x0830, 0x0858, 
+    0x085E, 0x088E, 0x08A0, 0x08C9, 0x200F, 0x200F, 0xFB1D, 0xFB1D, 
+    0xFB1F, 0xFB28, 0xFB2A, 0xFD3D, 0xFD50, 0xFDC7, 0xFDF0, 0xFDFC, 
+    0xFE70, 0xFEFC, 0x10800, 0x1091B, 0x10920, 0x10A00, 0x10A10, 0x10A35, 
+    0x10A40, 0x10AE4, 0x10AEB, 0x10B35, 0x10B40, 0x10D23, 0x10E80, 0x10EA9, 
+    0x10EAD, 0x10EB1, 0x10F00, 0x10F45, 0x10F51, 0x10F81, 0x10F86, 0x10FF6, 
+    0x1E800, 0x1E8CF, 0x1E900, 0x1E943, 0x1E94B, 0x1EEBB, 
+};
+
 #endif /* _XS_UNICODE_TBL_H */
 
diff --git a/xs_version.h b/xs_version.h
index 84f7c5b..7c4246b 100644
--- a/xs_version.h
+++ b/xs_version.h
@@ -1 +1 @@
-/* 35997d2dbc505320a62d3130daa95f638be8bb26 2024-11-05T16:47:36+01:00 */
+/* ab0749f821f1c98d16cbec53201bdf2ba2a24a43 2024-11-20T17:02:42+01:00 */