Add substitutes for snprintf() and vsnprintf()

To deal with fools^Wpeople trying to keep really old systems alive,
create a proper framework for substitution functions, and make it
possible to deal with the lack of snprintf/vsnprintf in particular.

2 files changed, 73 insertions, 0 deletions

diff --git a/lib/snprintf.c b/lib/snprintf.c
new file mode 100644
index 0000000..f56a492
--- /dev/null
+++ b/lib/snprintf.c
@@ -0,0 +1,24 @@
+/*
+ * snprintf()
+ *
+ * Implement snprintf() in terms of vsnprintf()
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include "nasmlib.h"
+
+int snprintf(char *str, size_t size, const char *format, ...)
+{
+    va_list ap;
+    int rv;
+
+    va_start(ap, format);
+    rv = vsnprintf(str, size, format, ap);
+    va_end(ap);
+
+    return rv;
+}
+
diff --git a/lib/vsnprintf.c b/lib/vsnprintf.c
new file mode 100644
index 0000000..b2b19d9
--- /dev/null
+++ b/lib/vsnprintf.c
@@ -0,0 +1,49 @@
+/*
+ * vsnprintf()
+ *
+ * Poor substitute for a real vsnprintf() function for systems
+ * that don't have them...
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+
+#include "nasmlib.h"
+
+extern efunc nasm_malloc_error;
+
+#define BUFFER_SIZE	65536	/* Bigger than any string we might print... */
+
+static char snprintf_buffer[BUFFER_SIZE];
+
+int vsnprintf(char *str, size_t size, const char *format, va_list ap)
+{
+    int rv, bytes;
+
+    if (size > BUFFER_SIZE) {
+	nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
+			  "snprintf: size (%d) > BUFFER_SIZE (%d)",
+			  size, BUFFER_SIZE);
+	size = BUFFER_SIZE;
+    }
+
+    rv = vsprintf(snprintf_buffer, format, ap);
+    if (rv > BUFFER_SIZE) {
+	nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
+			  "snprintf buffer overflow");
+    }
+
+    if (rv < (int)size-1)
+	bytes = rv;
+    else
+	bytes = size-1;
+
+    if (size > 0) {
+	memcpy(str, snprintf_buffer, bytes);
+	str[bytes] = '\0';
+    }
+
+    return rv;
+}