From ae57646896bd218b1c5c3087d8937da635fb9ef7 Mon Sep 17 00:00:00 2001
From: Mark Nudelman <markn@greenwoodsoftware.com>
Date: Wed, 12 Oct 2022 09:35:22 -0700
Subject: [PATCH 21/48] lesstest: add support for combining and composing
 chars.

---
 lesstest/display.c   |  1 +
 lesstest/lt_screen.c | 11 ++++++++---
 lesstest/parse.c     |  1 +
 lesstest/pipeline.c  |  4 ++--
 lesstest/run.c       |  5 +++--
 lesstest/unicode.c   | 23 +++++++++++++++++++++++
 lesstest/wchar.h     |  2 ++
 7 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/lesstest/display.c b/lesstest/display.c
index 5243337..54ae7c5 100644
--- a/lesstest/display.c
+++ b/lesstest/display.c
@@ -119,6 +119,7 @@ void display_screen_debug(const byte* img, int imglen, int screen_width, int scr
 }
 
 void print_strings(const char* title, char* const* strings) {
+	if (1) return; ///
 	fprintf(stderr, "%s:\n", title);
 	char* const* s;
 	for (s = strings; *s != NULL; ++s) {
diff --git a/lesstest/lt_screen.c b/lesstest/lt_screen.c
index 4bc1c50..6677650 100644
--- a/lesstest/lt_screen.c
+++ b/lesstest/lt_screen.c
@@ -277,10 +277,15 @@ static int exec_esc(wchar ch) {
 static int add_char(wchar ch) {
 	//if (verbose) fprintf(stderr, "add (%c) %lx at %d,%d\n", (char)ch, (long)ch, screen.cx, screen.cy);
 	screen_char_set(screen.cx, screen.cy, ch, screen.curr_attr, screen.curr_color);
-	int fits = screen_incr(&screen.cx, &screen.cy);
-	if (fits && is_wide_char(ch)) {
-		screen_char_set(screen.cx, screen.cy, 0, 0, NULL_COLOR);
+	int fits = 1;
+	int zero_width = (is_composing_char(ch) || 
+	    (screen.cx > 0 && is_combining_char(screen_char(screen.cx-1,screen.cy)->ch, ch)));
+	if (!zero_width) {
 		fits = screen_incr(&screen.cx, &screen.cy);
+		if (fits && is_wide_char(ch)) {
+			screen_char_set(screen.cx, screen.cy, 0, 0, NULL_COLOR);
+			fits = screen_incr(&screen.cx, &screen.cy);
+		}
 	}
 	if (!fits) { // Wrap at bottom of screen = scroll
 		screen.cx = 0;
diff --git a/lesstest/parse.c b/lesstest/parse.c
index 3d79a83..d1e8c74 100644
--- a/lesstest/parse.c
+++ b/lesstest/parse.c
@@ -100,6 +100,7 @@ int read_zline(FILE* fd, char* line, int line_len) {
 	return nread;
 }
 
+// Read the header of a .lt file (up to the R line).
 TestSetup* read_test_setup(FILE* fd, const char* less) {
 	TestSetup* setup = new_test_setup();
 	int hdr_complete = 0;
diff --git a/lesstest/pipeline.c b/lesstest/pipeline.c
index 4122f4a..01fe15d 100644
--- a/lesstest/pipeline.c
+++ b/lesstest/pipeline.c
@@ -42,7 +42,7 @@ static void become_child_less(char* less, int argc, char* const* argv, char* con
 		less_argv[less_argc++] = (argc > 1 || tempfile == NULL) ? arg : (char*) tempfile;
 	}
 	less_argv[less_argc] = NULL;
-	//if (verbose) { print_strings("less argv", less_argv); print_strings("less envp", envp); }
+	if (verbose) { print_strings("less argv", less_argv); print_strings("less envp", envp); }
 	execve(less, less_argv, envp);
 	fprintf(stderr, "cannot exec %s: %s\n", less, strerror(errno));
 	exit(1);
@@ -74,7 +74,7 @@ static void become_child_screen(char* lt_screen, int screen_width, int screen_he
 	if (1)
 		screen_argv[screen_argc++] = "-q";
 	screen_argv[screen_argc] = NULL;
-	//if (verbose) print_strings("screen argv", screen_argv);
+	if (verbose) print_strings("screen argv", screen_argv);
 	char* const screen_envp[] = { NULL };
 	execve(lt_screen, screen_argv, screen_envp);
 	fprintf(stderr, "cannot exec %s: %s\n", lt_screen, strerror(errno));
diff --git a/lesstest/run.c b/lesstest/run.c
index 25850d5..f35781f 100644
--- a/lesstest/run.c
+++ b/lesstest/run.c
@@ -178,7 +178,8 @@ static int run_test(TestSetup* setup, FILE* testfd) {
 	return ok;
 }
 
-// Should run in empty directory.
+// Should be run in an empty temp directory;
+// it creates its own files in the current directory.
 int run_testfile(const char* testfile, const char* less) {
 	FILE* testfd = fopen(testfile, "r");
 	if (testfd == NULL) {
@@ -187,7 +188,7 @@ int run_testfile(const char* testfile, const char* less) {
 	}
 	int tests = 0;
 	int fails = 0;
-	for (;;) {
+	for (;;) { // might be multiple tests in one file
 		TestSetup* setup = read_test_setup(testfd, less);
 		if (setup == NULL)
 			break;
diff --git a/lesstest/unicode.c b/lesstest/unicode.c
index beb9bfc..c2320a8 100644
--- a/lesstest/unicode.c
+++ b/lesstest/unicode.c
@@ -5,6 +5,15 @@ typedef struct wchar_range { wchar first, last; } wchar_range;
 static wchar_range wide_chars[] = {
 #include "../wide.uni"
 };
+static wchar_range compose_table[] = {
+#include "../compose.uni"
+};
+static wchar_range fmt_table[] = {
+#include "../fmt.uni"
+};
+static wchar_range comb_table[] = {
+	{0x0644,0x0622}, {0x0644,0x0623}, {0x0644,0x0625}, {0x0644,0x0627},
+};
 
 static int is_in_table(wchar ch, wchar_range table[], int count) {
 	if (ch < table[0].first)
@@ -26,3 +35,17 @@ static int is_in_table(wchar ch, wchar_range table[], int count) {
 int is_wide_char(wchar ch) {
 	return is_in_table(ch, wide_chars, countof(wide_chars));
 }
+
+int is_composing_char(wchar ch) {
+	return is_in_table(ch, compose_table, countof(compose_table)) ||
+	       is_in_table(ch, fmt_table, countof(fmt_table));
+}
+
+int is_combining_char(wchar ch1, wchar ch2) {
+	for (int i = 0; i < countof(comb_table); i++) {
+		if (ch1 == comb_table[i].first &&
+		    ch2 == comb_table[i].last)
+			return 1;
+	}
+	return 0;
+}
diff --git a/lesstest/wchar.h b/lesstest/wchar.h
index 0ffd541..84af5ee 100644
--- a/lesstest/wchar.h
+++ b/lesstest/wchar.h
@@ -3,3 +3,5 @@ void store_wchar(byte** p, wchar ch);
 wchar load_wchar(const byte** p);
 wchar read_wchar(int fd);
 int is_wide_char(wchar ch);
+int is_composing_char(wchar ch);
+int is_combining_char(wchar ch1, wchar ch2);
-- 
2.27.0