From c0df0b6fca4fa6bca114bba4df74f1b4e53124c0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mikkel=20Fahn=C3=B8e=20J=C3=B8rgensen?= <mikkel@dvide.com>
Date: Sat, 9 Jun 2018 11:10:24 +0200
Subject: [PATCH] Remove strncpy gcc-8 warning, add
 flatbuffers_type_hash_from_string

[baruch: drop CHANGELOG hunk]
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
Upstream status: commit c0df0b6fca4

 include/flatcc/flatcc_identifier.h            | 21 +++++++++++++++++++
 .../reflection/flatbuffers_common_reader.h    |  4 +---
 src/compiler/codegen_c_reader.c               |  4 +---
 src/runtime/json_printer.c                    |  7 +++++--
 src/runtime/verifier.c                        |  5 ++---
 6 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/include/flatcc/flatcc_identifier.h b/include/flatcc/flatcc_identifier.h
index cd918cb42b48..31af3074f4db 100644
--- a/include/flatcc/flatcc_identifier.h
+++ b/include/flatcc/flatcc_identifier.h
@@ -77,6 +77,27 @@ static inline flatbuffers_thash_t flatbuffers_type_hash_from_identifier(const fl
         (uint32_t)p[0] + (((uint32_t)p[1]) << 8) + (((uint32_t)p[2]) << 16) + (((uint32_t)p[3]) << 24) : 0;
 }
 
+/*
+ * Convert a null terminated string identifier like "MONS" or "X" into a
+ * native type hash identifier, usually for comparison. This will not
+ * work with type hash strings because they can contain null bytes.
+ */
+static inline flatbuffers_thash_t flatbuffers_type_hash_from_string(const char *identifier)
+{
+    flatbuffers_thash_t h = 0;
+    const uint8_t *p = (const uint8_t *)identifier;
+
+    if (!p[0]) return h;
+    h += p[0];
+    if (!p[1]) return h;
+    h += p[1] << 8;
+    if (!p[2]) return h;
+    h += p[2] << 16;
+    /* No need to test for termination here. */
+    h += p[3] << 24;
+    return h;
+}
+
 /*
  * Computes the little endian wire format of the type hash. It can be
  * used as a file identifer argument to various flatcc buffer calls.
diff --git a/include/flatcc/reflection/flatbuffers_common_reader.h b/include/flatcc/reflection/flatbuffers_common_reader.h
index dee44ad653f1..9604052685f6 100644
--- a/include/flatcc/reflection/flatbuffers_common_reader.h
+++ b/include/flatcc/reflection/flatbuffers_common_reader.h
@@ -464,9 +464,7 @@ static inline T N ## _ ## NK (N ## _struct_t t__tmp) { return t__tmp ? &(t__tmp-
 /* If fid is null, the function returns true without testing as buffer is not expected to have any id. */
 static inline int flatbuffers_has_identifier(const void *buffer, const char *fid)
 { flatbuffers_thash_t id, id2 = 0; if (fid == 0) { return 1; };
-  strncpy((char *)&id2, fid, sizeof(id2));
-  /* Identifier strings are always considered little endian. */
-  id2 = __flatbuffers_thash_cast_from_le(id2);
+  id2 = flatbuffers_type_hash_from_string(fid);
   id = __flatbuffers_thash_read_from_pe(((flatbuffers_uoffset_t *)buffer) + 1);
   return id2 == 0 || id == id2; }
 static inline int flatbuffers_has_type_hash(const void *buffer, flatbuffers_thash_t thash)
diff --git a/src/compiler/codegen_c_reader.c b/src/compiler/codegen_c_reader.c
index e3df74754344..559731050a15 100644
--- a/src/compiler/codegen_c_reader.c
+++ b/src/compiler/codegen_c_reader.c
@@ -748,9 +748,7 @@ static void gen_helpers(fb_output_t *out)
             "/* If fid is null, the function returns true without testing as buffer is not expected to have any id. */\n"
             "static inline int %shas_identifier(const void *buffer, const char *fid)\n"
             "{ %sthash_t id, id2 = 0; if (fid == 0) { return 1; };\n"
-            "  strncpy((char *)&id2, fid, sizeof(id2));\n"
-            "  /* Identifier strings are always considered little endian. */\n"
-            "  id2 = __%sthash_cast_from_le(id2);\n"
+            "  id2 = %stype_hash_from_string(fid);\n"
             "  id = __%sthash_read_from_pe(((%suoffset_t *)buffer) + 1);\n"
             "  return id2 == 0 || id == id2; }\n"
             "static inline int %shas_type_hash(const void *buffer, %sthash_t thash)\n"
diff --git a/src/runtime/json_printer.c b/src/runtime/json_printer.c
index 8fe248331f43..bc86d21f8f9d 100644
--- a/src/runtime/json_printer.c
+++ b/src/runtime/json_printer.c
@@ -20,6 +20,7 @@
 
 #include "flatcc/flatcc_flatbuffers.h"
 #include "flatcc/flatcc_json_printer.h"
+#include "flatcc/flatcc_identifier.h"
 
 #include "flatcc/portable/pprintint.h"
 #include "flatcc/portable/pprintfp.h"
@@ -1008,6 +1009,9 @@ void flatcc_json_printer_struct_field(flatcc_json_printer_t *ctx,
 /*
  * Make sure the buffer identifier is valid before assuming the rest of
  * the buffer is sane.
+ * NOTE: this won't work with type hashes because these can contain
+ * nulls in the fid string. In this case use null as fid to disable
+ * check.
  */
 static int accept_header(flatcc_json_printer_t * ctx,
         const void *buf, size_t bufsiz, const char *fid)
@@ -1020,8 +1024,7 @@ static int accept_header(flatcc_json_printer_t * ctx,
         return 0;
     }
     if (fid != 0) {
-        strncpy((char *)&id2, fid, FLATBUFFERS_IDENTIFIER_SIZE);
-        id2 = __flatbuffers_thash_cast_from_le(id2);
+        id2 = flatbuffers_type_hash_from_string(fid);
         id = __flatbuffers_thash_read_from_pe((uint8_t *)buf + offset_size);
         if (!(id2 == 0 || id == id2)) {
             RAISE_ERROR(bad_input);
diff --git a/src/runtime/verifier.c b/src/runtime/verifier.c
index 68dbc1b6fb0b..3b7c68cca4d7 100644
--- a/src/runtime/verifier.c
+++ b/src/runtime/verifier.c
@@ -10,6 +10,7 @@
 #include "flatcc/flatcc_rtconfig.h"
 #include "flatcc/flatcc_flatbuffers.h"
 #include "flatcc/flatcc_verifier.h"
+#include "flatcc/flatcc_identifier.h"
 
 /* Customization for testing. */
 #if FLATCC_DEBUG_VERIFY
@@ -110,9 +111,7 @@ static inline uoffset_t read_uoffset(const void *p, uoffset_t base)
 
 static inline thash_t read_thash_identifier(const char *identifier)
 {
-    flatbuffers_thash_t id = 0;
-    strncpy((char *)&id, identifier, sizeof(id));
-    return __flatbuffers_thash_cast_from_le(id);
+    return flatbuffers_type_hash_from_string(identifier);
 }
 
 static inline thash_t read_thash(const void *p, uoffset_t base)
-- 
2.17.1