More work on serialization.

src/upb_serialize.h

@@ -51,13 +51,24 @@ INLINE upb_status_t upb_put_v_uint32_t(uint8_t *buf, uint8_t *end,
   return UPB_STATUS_OK;
 }
 
+INLINE void upb_put32(uint8_t *buf, uint32_t val) {
+  buf[0] = val & 0xff;
+  buf[1] = (val >> 8) & 0xff;
+  buf[2] = (val >> 16) & 0xff;
+  buf[3] = (val >> 24);
+}
+
 /* Puts a fixed-length 32-bit integer (wire type: UPB_WIRE_TYPE_32BIT). */
 INLINE upb_status_t upb_put_f_uint32_t(uint8_t *buf, uint8_t *end,
                                        uint32_t val, uint8_t **outbuf)
 {
   uint8_t *uint32_end = buf + sizeof(uint32_t);
   if(uint32_end > end) return UPB_STATUS_NEED_MORE_DATA;
+#if UPB_UNALIGNED_READS_OK
   *(uint32_t*)buf = val;
+#else
+  upb_put32(buf, val);
+#endif
   *outbuf = uint32_end;
   return UPB_STATUS_OK;
 }
@@ -68,11 +79,43 @@ INLINE upb_status_t upb_put_f_uint64_t(uint8_t *buf, uint8_t *end,
 {
   uint8_t *uint64_end = buf + sizeof(uint64_t);
   if(uint64_end > end) return UPB_STATUS_NEED_MORE_DATA;
+#if UPB_UNALIGNED_READS_OK
   *(uint64_t*)buf = val;
+#else
+  upb_put32(buf, (uint32_t)val);
+  upb_put32(buf, (uint32_t)(val >> 32));
+#endif
   *outbuf = uint64_end;
   return UPB_STATUS_OK;
 }
 
+INLINE size_t upb_v_uint64_t_size(uint64_t val) {
+#ifdef __GNUC__
+  int high_bit = 63 - __builtin_clzll(val);  /* 0-based, undef if val == 0. */
+#else
+  int high_bit = 0;
+  uint64_t tmp = val;
+  while(tmp >>= 1) high_bit++;
+#endif
+  return val == 0 ? 1 : high_bit / 7 + 1;
+}
+
+INLINE size_t upb_v_int32_t_size(int32_t val) {
+  /* v_uint32's are sign-extended to maintain wire compatibility with int64s. */
+  return upb_v_uint64_t_size((int64_t)val);
+}
+INLINE size_t upb_v_uint32_t_size(uint32_t val) {
+  return upb_v_uint64_t_size(val);
+}
+INLINE size_t upb_f_uint64_t_size(uint64_t val) {
+  (void)val;  /* Length is independent of value. */
+  return sizeof(uint64_t);
+}
+INLINE size_t upb_f_uint32_t_size(uint32_t val) {
+  (void)val;  /* Length is independent of value. */
+  return sizeof(uint32_t);
+}
+
 /* Functions to write .proto values. ******************************************/
 
 /* Performs zig-zag encoding, which is used by sint32 and sint64. */
@@ -88,6 +131,9 @@ INLINE uint64_t upb_zzenc_64(int64_t n) { return (n << 1) ^ (n >> 63); }
  *  upb_status_t upb_put_INT32(uint8_t *buf, uint8_t *end, int32_t val,
  *                             uint8_t **outbuf);
  *
+ *  // Returns the number of bytes required to serialize val.
+ *  size_t upb_get_INT32_size(int32_t val);
+ *
  *  // Given a .proto value s (source) convert it to a wire value.
  *  uint32_t upb_vtowv_INT32(int32_t s);
  */
@@ -104,6 +150,9 @@ INLINE uint64_t upb_zzenc_64(int64_t n) { return (n << 1) ^ (n >> 63); }
   }
 
 #define T(type, v_or_f, wire_t, val_t, member_name) \
+  INLINE size_t upb_get_ ## type ## _size(val_t val) { \
+    return upb_ ## v_or_f ## _ ## wire_t ## _size(val); \
+  } \
   VTOWV(type, wire_t, val_t);  /* prototype for PUT below */ \
   PUT(type, v_or_f, wire_t, val_t, member_name) \
   VTOWV(type, wire_t, val_t)
@@ -134,6 +183,10 @@ T(FLOAT,    f, uint32_t, float,    _float)  {
 #undef PUT
 #undef T
 
+/* Functions to get sizes of serialized values without serializing. ***********/
+
+
+
 #ifdef __cplusplus
 }  /* extern "C" */
 #endif