examples

commit b85fe016df137f5a661738d397167e6c6400afbc
parent 94a2185f3e15a7e6a3b0abed8baca35d5b959d41
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Wed, 15 Feb 2023 22:42:24 +0000

mremap: Add growable fixed memory address buffer example

Diffstat:
M
src/morse.c
 | 
24
++++++++++++++++--------
A
src/mremap.c
 | 
31
+++++++++++++++++++++++++++++++

2 files changed, 47 insertions(+), 8 deletions(-)
diff --git a/src/morse.c b/src/morse.c
@@ -8,12 +8,12 @@ void put_morse_char(unsigned dit)
 
 void put_morse_seq(unsigned seq)
 {
-	putchar(' ');
 	while (seq > 1)
 	{
 		put_morse_char(seq & 1);
 		seq >>= 1;
 	}
+	putchar(' ');
 }
 
 unsigned char seqs[] =
@@ -84,11 +84,17 @@ unsigned char seqs[] =
 
 void put_morse(char c)
 {
-	unsigned char m = seqs[toupper(c)];
-	if (m)
-		put_morse_seq(m);
-	else
-		putchar('\n');
+	switch (c)
+	{
+	case ' ':
+	case '\n':
+		putchar(c);
+		break;
+	default:
+		unsigned char m = seqs[toupper(c)];
+		if (m)
+			put_morse_seq(m);
+	}
 }
 
 void put_morse_str(char const* str)
@@ -102,11 +108,13 @@ int main()
 	for (;;)
 	{
 		int c = getchar();
-		if (c <= 0)
+		if (c == EOF)
 			break;
+		if (c >= (int)sizeof(seqs))
+			return 1;
 		put_morse(c);
 	}
 
-	putchar ('\n');
+//	putchar ('\n');
 	return 0;
 }
diff --git a/src/mremap.c b/src/mremap.c
@@ -0,0 +1,31 @@
+#define _GNU_SOURCE
+#include <sys/mman.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+int main()
+{
+	unsigned long long* mem;
+	size_t size = 0x1000;
+	mem = mmap((void*)0x1000000, size, PROT_READ | PROT_WRITE,  MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+
+	unsigned i;
+	for (i = 0; i < 0x1000; ++i)
+	{
+		if (i * sizeof (*mem) >= size)
+		{
+			if(mem != mremap(mem, size, size * 2, 0))
+				exit(1);
+			size = size*2;
+		}
+		mem[i] = i % 256;
+	}
+
+	unsigned long long total = 0;
+
+	while (i--)
+		total += mem[i];
+	printf("total = %llx\n", total);
+
+	munmap(mem, size);
+}