From e195d5379deb5699ea7cb76e4b3077a2cffa40da Mon Sep 17 00:00:00 2001
From: Joshua Haberman <joshua@reverberate.org>
Date: Thu, 26 Feb 2009 17:41:43 -0800
Subject: Since the stack has a fixed size, don't allocate dynamically.

---
 pbstream.c | 11 ++---------
 pbstream.h |  8 +++++---
 tests.c    |  8 +++-----
 3 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/pbstream.c b/pbstream.c
index 4ce8cc3..d5ddc1c 100644
--- a/pbstream.c
+++ b/pbstream.c
@@ -4,7 +4,6 @@
  * Copyright (c) 2008-2009 Joshua Haberman.  See LICENSE for details.
  */
 
-#include <stdlib.h>
 #include <string.h>
 #include "pbstream.h"
 
@@ -292,14 +291,8 @@ void pbstream_init_parser(
     struct pbstream_fieldset *toplevel_fieldset)
 {
   state->offset = 0;
-  /* We match proto2's limit of 64 for maximum stack depth. */
-  state->top = state->base = malloc(64*sizeof(*state->base));
-  state->limit = state->base + 64;
+  state->top = state->stack;
+  state->limit = state->top + PBSTREAM_MAX_STACK;
   state->top->fieldset = toplevel_fieldset;
   state->top->end_offset = SIZE_MAX;
 }
-
-void pbstream_free_parser(struct pbstream_parse_state *state)
-{
-  free(state->base);
-}
diff --git a/pbstream.h b/pbstream.h
index d564970..b8befc6 100644
--- a/pbstream.h
+++ b/pbstream.h
@@ -7,6 +7,9 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+/* The maximum that any submessages can be nested.  Matches proto2's limit. */
+#define PBSTREAM_MAX_STACK 64
+
 /* A list of types as they can appear in a .proto file. */
 typedef enum pbstream_type {
   PBSTREAM_TYPE_DOUBLE = 0,
@@ -101,7 +104,8 @@ struct pbstream_parse_stack_frame {
 /* The stream parser's state. */
 struct pbstream_parse_state {
   size_t offset;
-  struct pbstream_parse_stack_frame *base, *top, *limit;
+  struct pbstream_parse_stack_frame stack[PBSTREAM_MAX_STACK];
+  struct pbstream_parse_stack_frame *top, *limit;
 };
 
 /* Call this once before parsing to initialize the data structures.
@@ -111,8 +115,6 @@ void pbstream_init_parser(
     struct pbstream_parse_state *state,
     struct pbstream_fieldset *toplevel_fieldset);
 
-void pbstream_free_parser(struct pbstream_parse_state *state);
-
 /* Status as returned by pbstream_parse().  Status codes <0 are fatal errors
  * that cannot be recovered.  Status codes >0 are unusual but nonfatal events,
  * which nonetheless must be handled differently since they do not return data
diff --git a/tests.c b/tests.c
index 7a6e51b..2cc9128 100644
--- a/tests.c
+++ b/tests.c
@@ -1,5 +1,6 @@
 #include <assert.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include "pbstream.c"
 
 void test_get_v_uint64_t()
@@ -66,7 +67,6 @@ void test_simple_proto()
   assert(val.field == &fieldset1->fields[0]);
   assert(val.v.int32 == 150);
   assert(s.offset == 3);
-  pbstream_free_parser(&s);
 
   char message2[] = {0x12, 0x07, 0x74, 0x65, 0x73, 0x74, 0x69, 0x6e, 0x67};
   pbstream_init_parser(&s, fieldset1);
@@ -76,7 +76,6 @@ void test_simple_proto()
   assert(val.v.delimited.offset == 2);
   assert(val.v.delimited.len == 7);
   assert(s.offset == 9);
-  pbstream_free_parser(&s);
 
   struct pbstream_fieldset *fieldset2 = malloc(sizeof(*fieldset1) +
                                                sizeof(struct pbstream_field[3]));
@@ -92,7 +91,7 @@ void test_simple_proto()
   assert(val.v.delimited.offset == 2);
   assert(val.v.delimited.len == 3);
   assert(s.offset == 2);
-  assert(s.top-1 == s.base);
+  assert(s.top-1 == s.stack);
   assert(s.top->fieldset == fieldset1);
   assert(s.top->end_offset == 5);
 
@@ -105,8 +104,7 @@ void test_simple_proto()
   assert(pbstream_parse_field(&s, NULL /* shouldn't be read */,
                               &fieldnum, &val, &wv) ==
          PBSTREAM_STATUS_SUBMESSAGE_END);
-  assert(s.top == s.base);
-  pbstream_free_parser(&s);
+  assert(s.top == s.stack);
 
   free(fieldset1);
   free(fieldset2);
-- 
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