add buffer_fromarray, buffer_frombuf

buffer.h

@@ -143,6 +143,12 @@ void buffer_fromsa(buffer* b,stralloc* sa);	/* read from sa */
 int buffer_tosa(buffer*b,stralloc* sa);		/* write to sa, auto-growing it */
 #endif
 
+void buffer_frombuf(buffer* b,const char* x,size_t l);	/* buffer reads from static buffer */
+
+#ifdef ARRAY_H
+void buffer_fromarray(buffer* b,array* a);	/* buffer reads from array */
+#endif
+
 #ifdef __cplusplus
 }
 #endif

buffer/buffer_fromarray.c

@@ -0,0 +1,9 @@
+#include "array.h"
+#include "buffer.h"
+
+void buffer_fromarray(buffer* b,array* a) {
+  if (array_failed(a))
+    buffer_frombuf(b,NULL,0);
+  else
+    buffer_frombuf(b,array_start(a),a->initialized);
+}

buffer/buffer_frombuf.c

@@ -0,0 +1,18 @@
+#include "stralloc.h"
+#include "buffer.h"
+
+static ssize_t dummyreadwrite(int fd,char* buf,size_t len) {
+  (void)fd;
+  (void)buf;
+  (void)len;
+  return 0;
+}
+
+void buffer_frombuf(buffer* b,const char* x,size_t l) {
+  b->x=x;
+  b->p=0;
+  b->n=l;
+  b->a=l;
+  b->fd=0;
+  b->op=dummyreadwrite;
+}

buffer/buffer_fromsa.c

@@ -1,18 +1,6 @@
 #include "stralloc.h"
 #include "buffer.h"
 
-static ssize_t dummyreadwrite(int fd,char* buf,size_t len) {
-  (void)fd;
-  (void)buf;
-  (void)len;
-  return 0;
-}
-
 void buffer_fromsa(buffer* b,stralloc* sa) {
-  b->x=sa->s;
-  b->p=0;
-  b->n=sa->len;
-  b->a=sa->a;
-  b->fd=0;
-  b->op=dummyreadwrite;
+  buffer_frombuf(b,sa->s,sa->len);
 }