[hackers] [libgrapheme] Implement bidirectional rule L1.4 || Laslo Hunhold

From: <git_AT_suckless.org>
Date: Mon, 21 Nov 2022 09:48:28 +0100 (CET)

commit 3f7f44a11ce2d7a2cd804f0752da894a45ecda63
Author: Laslo Hunhold <laslo_AT_hunhold.de>
AuthorDate: Mon Nov 21 09:46:38 2022 +0100
Commit: Laslo Hunhold <laslo_AT_hunhold.de>
CommitDate: Mon Nov 21 09:46:38 2022 +0100

    Implement bidirectional rule L1.4
    
    For this, we first make use of our paragraph level slot in each
    data point and store it for each. This way, even if the data
    buffer is arbitrarily split up, we always know what the current
    paragraph level is.
    
    Secondly, we add the rule L1.4 itself, which is very similar to
    the existing implementation of rules L1.1-L1.3.

diff --git a/src/bidirectional.c b/src/bidirectional.c
index be19a59..a1736b2 100644
--- a/src/bidirectional.c
+++ b/src/bidirectional.c
_AT_@ -679,6 +679,10 @@ preprocess_paragraph(enum grapheme_bidirectional_override override,
 
         for (bufoff = 0; bufoff < buflen; bufoff++) {
                 prop = (uint_least8_t)get_state(STATE_PROP, buf[bufoff]);
+
+ /* set paragraph level, which we need for line-level-processing */
+ set_state(STATE_PARAGRAPH_LEVEL, paragraph_level,
+ &(buf[bufoff]));
 again:
                 if (prop == BIDI_PROP_RLE) {
                         /* X2 */
_AT_@ -997,7 +1001,7 @@ again:
         }
         if (runsince != SIZE_MAX) {
                 /*
- * this is the end of the line and we
+ * this is the end of the paragraph and we
                  * are in a run
                  */
                 for (i = runsince; i < buflen; i++) {
_AT_@ -1133,10 +1137,43 @@ void
 grapheme_bidirectional_get_line_embedding_levels(
         const int_least32_t *linedata, size_t linelen, int_least8_t *linelevel)
 {
- size_t i;
+ enum bidi_property prop;
+ size_t i, runsince;
 
- /* write the levels into the level-array */
+ /* rule L1.4 */
+ runsince = SIZE_MAX;
         for (i = 0; i < linelen; i++) {
- linelevel[i] = get_state(STATE_LEVEL, linedata[i]);
+ prop = (uint_least8_t)get_state(STATE_RAWPROP, linedata[i]);
+
+ /* write level into level array */
+ if ((linelevel[i] = (int_least8_t)get_state(
+ STATE_LEVEL, linedata[i])) == -1) {
+ /* ignored character */
+ continue;
+ }
+
+ if (prop == BIDI_PROP_WS || prop == BIDI_PROP_FSI ||
+ prop == BIDI_PROP_LRI || prop == BIDI_PROP_RLI ||
+ prop == BIDI_PROP_PDI) {
+ if (runsince == SIZE_MAX) {
+ /* a new run has begun */
+ runsince = i;
+ }
+ } else {
+ /* sequence ended */
+ runsince = SIZE_MAX;
+ }
+ }
+ if (runsince != SIZE_MAX) {
+ /*
+ * 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] = get_state(
+ STATE_PARAGRAPH_LEVEL, linedata[i]);
+ }
+ }
         }
 }
Received on Mon Nov 21 2022 - 09:48:28 CET