Migrate to using musl libc sscanf to improve performance. Keep the existing JS vfscanf for Emscripten FS compatibility, and add the musl-specific version to be used when called from sscanf and vsscanf.

1 files changed, 16 insertions, 0 deletions

diff --git a/system/lib/libc/musl/src/stdio/__string_read.c b/system/lib/libc/musl/src/stdio/__string_read.c
new file mode 100644
index 00000000..7b50a7e1
--- /dev/null
+++ b/system/lib/libc/musl/src/stdio/__string_read.c
@@ -0,0 +1,16 @@
+#include "stdio_impl.h"
+#include <string.h>
+
+size_t __string_read(FILE *f, unsigned char *buf, size_t len)
+{
+	char *src = f->cookie;
+	size_t k = len+256;
+	char *end = memchr(src, 0, k);
+	if (end) k = end-src;
+	if (k < len) len = k;
+	memcpy(buf, src, len);
+	f->rpos = (void *)(src+len);
+	f->rend = (void *)(src+k);
+	f->cookie = src+k;
+	return len;
+}