VPP-118: add support for variable length arrays to jvpp

* extends VPP's message definition language with the following syntax:

u32 count:
u8 array[count];

which is traslated to:

u32 count;
u8 array[0];

but now, python API representation generated by vppapigen
contains information about where the array length is stored.

* modifies existing response messages to use the new syntax

Change-Id: I68210bc7a3a755d03d067e9b79a567f40e2d31f3
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>

3 files changed, 24 insertions, 2 deletions

diff --git a/vppapigen/gram.y b/vppapigen/gram.y
index 09e20067128..ccdcc8f2573 100644
--- a/vppapigen/gram.y
+++ b/vppapigen/gram.y
@@ -31,6 +31,7 @@ void generate (YYSTYPE);
  YYSTYPE add_union(YYSTYPE, YYSTYPE);
  YYSTYPE add_scalar_vbl(YYSTYPE);
  YYSTYPE add_vector_vbl(YYSTYPE, YYSTYPE);
+ YYSTYPE add_variable_length_vector_vbl(YYSTYPE, YYSTYPE);
  YYSTYPE set_flags(YYSTYPE, YYSTYPE);
 %}
 
@@ -86,4 +87,5 @@ onedef:   PRIMTYPE vbl SEMI      {$$ = add_primtype($1, $2, 0);}
 
 vbl:      NAME                      {$$ = add_scalar_vbl($1);}
         | NAME LBRACK NUMBER RBRACK {$$ = add_vector_vbl($1, $3);}
+        | NAME LBRACK NAME RBRACK {$$ = add_variable_length_vector_vbl($1, $3);}
           ;
diff --git a/vppapigen/node.c b/vppapigen/node.c
index 2fb65c2d60b..30a3b017190 100644
--- a/vppapigen/node.c
+++ b/vppapigen/node.c
@@ -1161,7 +1161,11 @@ void node_vector_generate (node_t *this, enum passid which, FILE *fp)
         fprintf(fp, "}\n");
         break;
     case PYTHON_PASS:
-        fprintf(fp, "'%s', '%d'),\n", CDATA0, IDATA1);
+        if (CDATA2 != 0) { // variable length vector
+            fprintf(fp, "'%s', '%d', '%s'),\n", CDATA0, IDATA1, CDATA2);
+        } else {
+            fprintf(fp, "'%s', '%d'),\n", CDATA0, IDATA1);
+        }
         break;
 
     default:
@@ -1461,6 +1465,21 @@ YYSTYPE add_vector_vbl (YYSTYPE a1, YYSTYPE a2)
 }
 
 /*
+ * add_vector_vbl (char *vector_name, char *vector_length_var)
+ */
+
+YYSTYPE add_variable_length_vector_vbl (YYSTYPE vector_name, YYSTYPE vector_length_var)
+{
+    node_t *np;
+
+    np = make_node(NODE_VECTOR);
+    np->data[0] = (void *) vector_name;
+    np->data[1] = (void *) 0; // vector size used for vpe.api.h generation (array of length zero)
+    np->data[2] = (void *) vector_length_var; // name of the variable that stores vector length
+    return ((YYSTYPE) np);
+}
+
+/*
  * add_scalar_vbl (char *name)
  */
 YYSTYPE add_scalar_vbl (YYSTYPE a1)
diff --git a/vppapigen/node.h b/vppapigen/node.h
index 1f5a153c24f..fc331507485 100644
--- a/vppapigen/node.h
+++ b/vppapigen/node.h
@@ -73,12 +73,13 @@ typedef struct node_ {
     struct node_ *peer;
     struct node_ *deeper;
     int flags;
-    void *data[2];
+    void *data[3];
 } node_t;
 
 /* To shut up gcc-4.2.x warnings */
 #define CDATA0 ((char *)(this->data[0]))
 #define IDATA1 ((int)(uword)(this->data[1]))
+#define CDATA2 ((char *)(this->data[2]))
 
 #define NODE_FLAG_MANUAL_PRINT (1<<0)
 #define NODE_FLAG_MANUAL_ENDIAN (1<<1)