add bsd fgetln function

optimized to avoid allocation and return lines directly out of the
stream buffer whenever possible.

3 files changed, 21 insertions, 1 deletions

diff --git a/src/internal/stdio_impl.h b/src/internal/stdio_impl.h
index d54c918b..65dcfbda 100644
--- a/src/internal/stdio_impl.h
+++ b/src/internal/stdio_impl.h
@@ -57,7 +57,7 @@ struct __FILE_s {
 	int waiters;
 	void *cookie;
 	off_t off;
-	void *dummy4;
+	char *getln_buf;
 	void *mustbezero_2;
 	unsigned char *shend;
 	off_t shlim, shcnt;
diff --git a/src/stdio/fclose.c b/src/stdio/fclose.c
index 373a2c76..8fdc3f7d 100644
--- a/src/stdio/fclose.c
+++ b/src/stdio/fclose.c
@@ -16,6 +16,7 @@ int fclose(FILE *f)
 	r = fflush(f);
 	r |= f->close(f);
 
+	if (f->getln_buf) free(f->getln_buf);
 	if (!perm) free(f);
 	
 	return r;
diff --git a/src/stdio/fgetln.c b/src/stdio/fgetln.c
new file mode 100644
index 00000000..06b88837
--- /dev/null
+++ b/src/stdio/fgetln.c
@@ -0,0 +1,19 @@
+#include "stdio_impl.h"
+
+char *fgetln(FILE *f, size_t *plen)
+{
+	char *ret = 0, *z;
+	ssize_t l;
+	FLOCK(f);
+	ungetc(getc_unlocked(f), f);
+	if ((z=memchr(f->rpos, '\n', f->rend - f->rpos))) {
+		ret = (char *)f->rpos;
+		*plen = ++z - ret;
+		f->rpos = (void *)z;
+	} else if ((l = getline(&f->getln_buf, (size_t[]){0}, f)) > 0) {
+		*plen = l;
+		ret = f->getln_buf;
+	}
+	FUNLOCK(f);
+	return ret;
+}