From b3ed9cf16022c1e9f63439f8c41004289579f806 Mon Sep 17 00:00:00 2001
From: John Schneiderman <JohnMS@member.fsf.org>
Date: Sun, 22 Sep 2024 12:26:46 +0200
Subject: [PATCH] Adds implementation of the get_s C function.

---
 include/stdio.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/stdio.h |  2 ++
 2 files changed, 50 insertions(+)

diff --git a/include/stdio.c b/include/stdio.c
index a806adb..60f995e 100644
--- a/include/stdio.c
+++ b/include/stdio.c
@@ -1,6 +1,7 @@
 #include "stdio.h"
 #include "conio.h"
 #include "stdlib.h"
+#include "stdbool.h"
 
 #if defined(__C128__)
 #pragma code(lowcode)
@@ -236,6 +237,53 @@ char * gets(char * str)
 	return str;
 }
 
+char* gets_s(char* str, size_t n)
+{
+	if (str == NULL)
+		return NULL;
+
+	if (n == 0 || n == 1)
+		return NULL;
+	str[0] = '\0';
+	size_t leftToStore = n - 1;
+	bool isTruncated = false;
+
+	__asm {
+		ldy #0
+
+	read_loop:
+		jsr getpch
+
+		// Check if the read in character is the line feed.
+		cmp #10
+		beq read_done
+
+		// Check to see if the maximum characters is reached.
+		ldx leftToStore
+		cpx #0
+		beq read_max
+
+		// Store the read in character & prepare for the next read.
+		sta (str), Y
+		iny
+		dec leftToStore
+		jmp read_loop
+
+	read_max:
+		ldx #1
+		stx isTruncated
+
+	read_done:
+		// Place a null character at the end of the C-string.
+		lda #0
+		sta (str), Y
+	}
+
+	if (isTruncated)
+		return NULL;
+	return str;
+}
+
 typedef void * (* putstrfn)(void * handle, const char * str);
 
 void * putstrio(void * handle, const char * str)
diff --git a/include/stdio.h b/include/stdio.h
index 21c8167..a994351 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -1,6 +1,7 @@
 #ifndef STDIO_H
 #define STDIO_H
 
+#include <stddef.h>
 #include <stdlib.h>
 
 
@@ -11,6 +12,7 @@ char getchar(void);
 void puts(const char * str);
 
 char * gets(char * str);
+char* gets_s(char* str, size_t n);
 
 void printf(const char * fmt, ...);