Fix grapheme breaks on string-initial

test/graphemetest.c

@@ -1,74 +1,107 @@
 #include "tests.h"
 
+/* check one line in the format of GraphemeBreakTest.txt */
+void checkline(const char *_buf, bool verbose) {
+    size_t bi = 0, si = 0;
+    utf8proc_uint8_t src[1024]; /* more than long enough for all of our tests */
+    const unsigned char *buf = (const unsigned char *) _buf;
+
+    while (buf[bi]) {
+        bi = skipspaces(buf, bi);
+        if (buf[bi] == 0xc3 && buf[bi+1] == 0xb7) { /* U+00f7 = grapheme break */
+            src[si++] = '/';
+            bi += 2;
+        }
+        else if (buf[bi] == 0xc3 && buf[bi+1] == 0x97) { /* U+00d7 = no break */
+            bi += 2;
+        }
+        else if (buf[bi] == '#') { /* start of comments */
+            break;
+        }
+        else if (buf[bi] == '/') { /* for convenience, also accept / as grapheme break */
+            src[si++] = '/';
+            bi += 1;
+        }
+        else { /* hex-encoded codepoint */
+            size_t len = encode((unsigned char*) (src + si), buf + bi) - 1;
+            while (src[si]) ++si; /* advance to NUL termination */
+            bi += len;
+        }
+    }
+    if (si && src[si-1] == '/')
+        --si; /* no break after final grapheme */
+    src[si] = 0; /* NUL-terminate */
+
+    if (si) { /* test utf8proc_map */
+        utf8proc_uint8_t utf8[1024]; /* copy src without 0xff grapheme separators */
+        size_t i = 0, j = 0;
+        utf8proc_ssize_t glen, k;
+        utf8proc_uint8_t *g; /* utf8proc_map grapheme results */
+        while (i < si) {
+            if (src[i] != '/')
+                utf8[j++] = src[i++];
+            else
+                i++;
+        }
+        glen = utf8proc_map(utf8, j, &g, UTF8PROC_CHARBOUND);
+        if (glen == UTF8PROC_ERROR_INVALIDUTF8) {
+            /* the test file contains surrogate codepoints, which are only for UTF-16 */
+            printf("line %zd: ignoring invalid UTF-8 codepoints\n", lineno);
+        }
+        else {
+            check(glen >= 0, "utf8proc_map error = %s",
+                utf8proc_errmsg(glen));
+            for (k = 0; k <= glen; ++k)
+                if (g[k] == 0xff)
+                    g[k] = '/'; /* easier-to-read output (/ is not in test strings) */
+            check(!strcmp((char*)g, (char*)src),
+                "grapheme mismatch: \"%s\" instead of \"%s\"", (char*)g, (char*)src);
+        }
+        free(g);
+    }
+
+    if (si) { /* test manual calls to utf8proc_grapheme_break_stateful */
+        utf8proc_int32_t state = 0, prev_codepoint = 0;
+        size_t i = 0;
+        utf8proc_bool expectbreak = false;
+        do {
+            utf8proc_int32_t codepoint;
+            i += utf8proc_iterate(src + i, si - i, &codepoint);
+            check(codepoint >= 0, "invalid UTF-8 data");
+            if (codepoint == 0x002F)
+                expectbreak = true;
+            else {
+                if (prev_codepoint != 0) {
+                    check(expectbreak == utf8proc_grapheme_break_stateful(prev_codepoint, codepoint, &state),
+                          "grapheme mismatch: between 0x%04x and 0x%04x in \"%s\"", prev_codepoint, codepoint, (char*) src);
+                }
+                expectbreak = false;
+                prev_codepoint = codepoint;
+            }
+        } while (i < si);
+    }
+
+    if (verbose)
+        printf("passed grapheme test: \"%s\"\n", (char*) src);
+}
+
 int main(int argc, char **argv)
 {
     unsigned char buf[8192];
     FILE *f = argc > 1 ? fopen(argv[1], "r") : NULL;
-    utf8proc_uint8_t src[1024];
 
     check(f != NULL, "error opening GraphemeBreakTest.txt");
     while (simple_getline(buf, f) > 0) {
-        size_t bi = 0, si = 0;
-        lineno += 1;
-
-        if (lineno % 100 == 0)
+        if ((++lineno) % 100 == 0)
             printf("checking line %zd...\n", lineno);
-
         if (buf[0] == '#') continue;
-
-        while (buf[bi]) {
-            bi = skipspaces(buf, bi);
-            if (buf[bi] == 0xc3 && buf[bi+1] == 0xb7) { /* U+00f7 = grapheme break */
-                src[si++] = '/';
-                bi += 2;
-            }
-            else if (buf[bi] == 0xc3 && buf[bi+1] == 0x97) { /* U+00d7 = no break */
-                bi += 2;
-            }
-            else if (buf[bi] == '#') { /* start of comments */
-                break;
-            }
-	    else { /* hex-encoded codepoint */
-                size_t len = encode((unsigned char*) (src + si), buf + bi) - 1;
-                while (src[si]) ++si; /* advance to NUL termination */
-                bi += len;
-            }
-        }
-        if (si && src[si-1] == '/')
-            --si; /* no break after final grapheme */
-        src[si] = 0; /* NUL-terminate */
-
-        if (si) {
-            utf8proc_uint8_t utf8[1024]; /* copy src without 0xff grapheme separators */
-            size_t i = 0, j = 0;
-            utf8proc_ssize_t glen, k;
-            utf8proc_uint8_t *g; /* utf8proc_map grapheme results */
-            while (i < si) {
-                if (src[i] != '/')
-                    utf8[j++] = src[i++];
-                else
-                    i++;
-            }
-            glen = utf8proc_map(utf8, j, &g, UTF8PROC_CHARBOUND);
-            if (glen == UTF8PROC_ERROR_INVALIDUTF8) {
-                 /* the test file contains surrogate codepoints, which are only for UTF-16 */
-                 printf("line %zd: ignoring invalid UTF-8 codepoints\n", lineno);
-            }
-            else {
-                 check(glen >= 0, "utf8proc_map error = %s",
-                       utf8proc_errmsg(glen));
-                 for (k = 0; k <= glen; ++k)
-                      if (g[k] == 0xff)
-                          g[k] = '/'; /* easier-to-read output (/ is not in test strings) */
-                 check(!strcmp((char*)g, (char*)src),
-                       "grapheme mismatch: \"%s\" instead of \"%s\"", (char*)g, (char*)src);
-            }
-            free(g);
-        }
+        checkline((char *) buf, false);
     }
     fclose(f);
     printf("Passed tests after %zd lines!\n", lineno);
 
+    printf("Performing regression tests...\n");
+
     /* issue 144 */
     {
         utf8proc_uint8_t input[] = {0xef,0xbf,0xbf,0xef,0xbf,0xbe,0x00}; /* "\uffff\ufffe" */
@@ -80,5 +113,12 @@ int main(int argc, char **argv)
         free(g);
     };
 
+    /* https://github.com/JuliaLang/julia/issues/37680 */
+    checkline("/ 1f1f8 1f1ea / 1f1f8 1f1ea /", true); /* Two swedish flags after each other */
+    checkline("/ 1f926 1f3fc 200d 2642 fe0f /", true); /* facepalm + pale skin + zwj + male sign + FE0F */
+    checkline("/ 1f468 1f3fb 200d 1f91d 200d 1f468 1f3fd /", true); /* man face + pale skin + zwj + hand holding + zwj + man face + dark skin */
+
+    printf("Passed regression tests!\n");
+
     return 0;
 }

utf8proc.c

@@ -290,8 +290,11 @@ static utf8proc_bool grapheme_break_simple(int lbc, int tbc) {
 
 static utf8proc_bool grapheme_break_extended(int lbc, int tbc, utf8proc_int32_t *state)
 {
-  int lbc_override = ((state && *state != UTF8PROC_BOUNDCLASS_START)
-                      ? *state : lbc);
+  int lbc_override;
+  if (*state == UTF8PROC_BOUNDCLASS_START)
+    *state = lbc_override = lbc; 
+  else
+    lbc_override = *state;
   utf8proc_bool break_permitted = grapheme_break_simple(lbc_override, tbc);
   if (state) {
     // Special support for GB 12/13 made possible by GB999. After two RI