libgrapheme

commit f320b0ad8b7b2bc7ab5b63e91379012adbd19d12
parent c0cab63c5300fa12284194fbef57aa2ed62a94c0
Author: Laslo Hunhold <dev@frign.de>
Date:   Thu, 11 May 2023 18:16:09 +0200

Allow level-array to have different size from line length

This may not be apparent at first, but it allows you to only extract
as many levels of a line as you need, e.g. only the first 10. Truncation
is indicated by the return value being larger than levlen.

Signed-off-by: Laslo Hunhold <dev@frign.de>

Diffstat:
M
grapheme.h
 | 
5
+++--
M
src/bidirectional.c
 | 
24
++++++++++++++++--------
M
test/bidirectional.c
 | 
12
+++++++++---

3 files changed, 28 insertions(+), 13 deletions(-)
diff --git a/grapheme.h b/grapheme.h
@@ -15,8 +15,9 @@ enum grapheme_bidirectional_override {
 	GRAPHEME_BIDIRECTIONAL_OVERRIDE_RTL,
 };
 
-void grapheme_bidirectional_get_line_embedding_levels(const uint_least32_t *,
-                                                      size_t, int_least8_t *);
+size_t grapheme_bidirectional_get_line_embedding_levels(const uint_least32_t *,
+                                                        size_t, int_least8_t *,
+                                                        size_t);
 
 size_t grapheme_bidirectional_preprocess(const uint_least32_t *, size_t,
                                          enum grapheme_bidirectional_override,
diff --git a/src/bidirectional.c b/src/bidirectional.c
@@ -1435,23 +1435,29 @@ grapheme_bidirectional_preprocess_utf8(
 	return preprocess(&r, override, dest, destlen);
 }
 
-void
+size_t
 grapheme_bidirectional_get_line_embedding_levels(const uint_least32_t *linedata,
                                                  size_t linelen,
-                                                 int_least8_t *linelevel)
+                                                 int_least8_t *lev,
+                                                 size_t levlen)
 {
 	enum bidi_property prop;
 	size_t i, runsince;
+	int_least8_t level;
 
 	/* rule L1.4 */
 	runsince = SIZE_MAX;
 	for (i = 0; i < linelen; i++) {
+		level = (int_least8_t)get_state(STATE_LEVEL, linedata[i]);
 		prop = (uint_least8_t)get_state(STATE_PRESERVED_PROP,
 		                                linedata[i]);
 
-		/* write level into level array */
-		if ((linelevel[i] = (int_least8_t)get_state(
-			     STATE_LEVEL, linedata[i])) == -1) {
+		/* write level into level array if we still have space */
+		if (i < levlen) {
+			lev[i] = level;
+		}
+
+		if (level == -1) {
 			/* ignored character */
 			continue;
 		}
@@ -1473,11 +1479,13 @@ grapheme_bidirectional_get_line_embedding_levels(const uint_least32_t *linedata,
 		 * we hit the end of the line but were in a run;
 		 * reset the line levels to the paragraph level
 		 */
-		for (i = runsince; i < linelen; i++) {
-			if (linelevel[i] != -1) {
-				linelevel[i] = (int_least8_t)get_state(
+		for (i = runsince; i < MIN(linelen, levlen); i++) {
+			if (lev[i] != -1) {
+				lev[i] = (int_least8_t)get_state(
 					STATE_PARAGRAPH_LEVEL, linedata[i]);
 			}
 		}
 	}
+
+	return linelen;
 }
diff --git a/test/bidirectional.c b/test/bidirectional.c
@@ -14,9 +14,10 @@ main(int argc, char *argv[])
 {
 	uint_least32_t data[512]; /* TODO iterate and get max, allocate */
 	int_least8_t lev[512];
-	size_t i, num_tests, failed, datalen, ret, j, m;
+	size_t i, num_tests, failed, datalen, levlen, ret, j, m;
 
 	datalen = LEN(data);
+	levlen = LEN(lev);
 
 	(void)argc;
 
@@ -30,14 +31,19 @@ main(int argc, char *argv[])
 				bidirectional_test[i].cp,
 				bidirectional_test[i].cplen,
 				bidirectional_test[i].mode[m], data, datalen);
-			grapheme_bidirectional_get_line_embedding_levels(
-				data, ret, lev);
 
 			if (ret != bidirectional_test[i].cplen ||
 			    ret > datalen) {
 				goto err;
 			}
 
+			ret = grapheme_bidirectional_get_line_embedding_levels(
+				data, ret, lev, levlen);
+
+			if (ret > levlen) {
+				goto err;
+			}
+
 			for (j = 0; j < ret; j++) {
 				if (lev[j] != bidirectional_test[i].level[j]) {
 					goto err;