From 4e44d053e0bc1de0fd9043d024d0952328d7cbc7 Mon Sep 17 00:00:00 2001
From: glenda <glenda@r51>
Date: Fri, 31 Jan 2025 03:51:23 +0000
Subject: [PATCH] becoming a supervillain

---
 mkfile |   3 +-
 pres.c | 171 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 173 insertions(+), 1 deletion(-)
 create mode 100644 pres.c

diff --git a/mkfile b/mkfile
index e17a54c0bb68ecaa70a7641a55421a602670f4ef..f47b18040c3eb6eb285f3e873e48085cafddaa12 100644
--- a/mkfile
+++ b/mkfile
@@ -4,7 +4,8 @@ bins=\
 	pong\
 	maze\
 	spiral\
-	queuesrv
+	queuesrv\
+	pres
 
 all:VQ: $bins
 
diff --git a/pres.c b/pres.c
new file mode 100644
index 0000000000000000000000000000000000000000..a988310e5cffa070c87799e9f8522d7dd3881ca2
--- /dev/null
+++ b/pres.c
@@ -0,0 +1,171 @@
+#include <u.h>
+#include <libc.h>
+#include <stdio.h>
+#include <draw.h>
+#include <event.h>
+#include <cursor.h>
+
+int checkonly;
+char *file, *contents;
+
+typedef struct Slide {
+	char *cmd;
+	char *arg;
+	int nlines;
+	char *lines[];
+} Slide;
+
+char *
+nextline(char **p)
+{
+	char *line;
+	while(1){
+		line = *p;
+		while(**p != '\n' && **p != '\0') (*p)++;
+		if(**p == '\0')
+			return nil;
+
+		**p = '\0';
+		(*p)++;
+		return line;
+	}
+}
+
+Slide *
+nextslide(char **p)
+{
+	char *cmd, *arg, *line1, *line, *lineN;
+	int nlines, blines, i;
+	Slide *s;
+
+	while(1){
+		if((cmd = nextline(p)) == nil)
+			return nil;
+		if(cmd[0] != '%')
+			continue;
+		break;
+	}
+
+	cmd++;
+	arg = cmd;
+
+	while(*arg != ' ' && *arg != '\t' && *arg != '\0') arg++;
+	if(*arg == '\0')
+		arg = nil;
+	else
+		*(arg++) = '\0';
+
+	line1 = nextline(p);
+	if(line1 != nil && *line1 == '%'){
+		*p = line1;
+		line1[strlen(line1)] = '\n';
+		line1 = nil;
+	}
+	if(line1 == nil){
+		s = malloc(sizeof(Slide));
+		s->cmd = cmd;
+		s->arg = arg;
+		s->nlines = 0;
+		return s;
+	}
+	lineN = line1;
+	nlines = 1;
+	blines = 0;
+
+	while((line = nextline(p)) != nil){
+		if(*line == '\0'){
+			blines++;
+			continue;
+		}
+		if(*line == '%'){
+			*p = line;
+			line[strlen(line)] = '\n';
+			break;
+		}
+
+		nlines += blines;
+		blines = 0;
+		nlines++;
+		lineN = line;
+	}
+
+	s = malloc(sizeof(Slide) + sizeof(char*) * nlines);
+
+	s->cmd = cmd;
+	s->arg = arg;
+	s->nlines = nlines;
+
+	line = line1;
+	for(i = 0; line != lineN; i++){
+		s->lines[i] = line;
+		line += strlen(line) + 1;
+	}
+	s->lines[i] = lineN;
+
+	return s;
+}
+
+void
+checkfile(void)
+{
+	int i;
+	char *c2, *p;
+	Slide *s;
+
+	c2 = strdup(contents);
+	p = c2;
+
+	while((s = nextslide(&p)) != nil){
+		print("Slide: %s (%d lines)\n", s->cmd, s->nlines);
+		if(s->arg != nil)
+			print("\targ: %s\n", s->arg);
+		for(i = 0; i < s->nlines; i++)
+			print("\tline %d: %s\n", i, s->lines[i]);
+	}
+}
+
+void
+usage(void)
+{
+	fprint(2,"usage: %s [ -c ] filename\n", argv0);
+	exits("usage");
+}
+
+void
+main(int argc, char *argv[])
+{
+	int fd;
+	Dir *d;
+
+	ARGBEGIN{
+	case 'c':
+		checkonly = 1;
+		break;
+	default:
+		usage();
+	}ARGEND
+
+	if(argc != 1)
+		usage();
+
+	file = argv[0];
+
+	if((fd = open(file, OREAD)) < 0)
+		sysfatal("%r");
+	if((d = dirfstat(fd)) == nil)
+		sysfatal("%r");
+
+	contents = malloc(d->length + 2);
+	if(readn(fd, contents, d->length) < 0)
+		sysfatal("%r");
+	// cursed but makes the handling nicer above
+	contents[d->length] = '\n';
+	contents[d->length + 1] = '\0';
+	free(d);
+	close(fd);
+
+	checkfile();
+
+	if(checkonly)
+		exits(nil);
+}