Implement proper type checking again.

4 files changed, 47 insertions, 6 deletions

diff --git a/src/upb.c b/src/upb.c
index bd41613..189dfe4 100644
--- a/src/upb.c
+++ b/src/upb.c
@@ -11,6 +11,34 @@
 
 #include "upb.h"
 
+#define alignof(t) offsetof(struct { char c; t x; }, x)
+#define TYPE_INFO(wire_type, ctype, allows_delimited) \
+    {alignof(ctype), sizeof(ctype), wire_type, \
+     (1 << wire_type) | (allows_delimited << UPB_WIRE_TYPE_DELIMITED), \
+     #ctype},
+
+upb_type_info upb_types[] = {
+  {0, 0, 0, ""} // There is no type 0.
+  TYPE_INFO(UPB_WIRE_TYPE_64BIT,       double,    1),    // DOUBLE
+  TYPE_INFO(UPB_WIRE_TYPE_32BIT,       float,     1),    // FLOAT
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      int64_t,   1),    // INT64
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      uint64_t,  1),    // UINT64
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      int32_t,   1),    // INT32
+  TYPE_INFO(UPB_WIRE_TYPE_64BIT,       uint64_t,  1),    // FIXED64
+  TYPE_INFO(UPB_WIRE_TYPE_32BIT,       uint32_t,  1),    // FIXED32
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      bool,      1),    // BOOL
+  TYPE_INFO(UPB_WIRE_TYPE_DELIMITED,   void*,     1),    // STRING
+  TYPE_INFO(UPB_WIRE_TYPE_START_GROUP, void*,     0),    // GROUP
+  TYPE_INFO(UPB_WIRE_TYPE_DELIMITED,   void*,     1),    // MESSAGE
+  TYPE_INFO(UPB_WIRE_TYPE_DELIMITED,   void*,     1),    // BYTES
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      uint32_t,  1),    // UINT32
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      uint32_t,  1),    // ENUM
+  TYPE_INFO(UPB_WIRE_TYPE_32BIT,       int32_t,   1),    // SFIXED32
+  TYPE_INFO(UPB_WIRE_TYPE_64BIT,       int64_t,   1),    // SFIXED64
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      int32_t,   1),    // SINT32
+  TYPE_INFO(UPB_WIRE_TYPE_VARINT,      int64_t,   1),    // SINT64
+};
+
 void upb_seterr(upb_status *status, enum upb_status_code code,
                 const char *msg, ...)
 {
diff --git a/src/upb.h b/src/upb.h
index 1681763..6bf548c 100644
--- a/src/upb.h
+++ b/src/upb.h
@@ -98,6 +98,18 @@ INLINE bool upb_isstringtype(upb_field_type_t type) {
   return type == UPB_TYPE(STRING) || type == UPB_TYPE(BYTES);
 }
 
+// Info for a given field type.
+typedef struct {
+  uint8_t align;
+  uint8_t size;
+  upb_wire_type_t native_wire_type;
+  uint8_t allowed_wire_types;  // For packable fields, also allows delimited.
+  char *ctype;
+} upb_type_info;
+
+// A static array of info about all of the field types, indexed by type number.
+extern upb_type_info upb_types[];
+
 // The number of a field, eg. "optional string foo = 3".
 typedef int32_t upb_field_number_t;
 
diff --git a/src/upb_decoder.c b/src/upb_decoder.c
index 5d352c2..c54a21a 100644
--- a/src/upb_decoder.c
+++ b/src/upb_decoder.c
@@ -12,9 +12,10 @@
 
 #define UPB_GROUP_END_OFFSET UINT32_MAX
 
+// Returns true if the give wire type and field type combination is valid,
+// taking into account both packed and non-packed encodings.
 static bool upb_check_type(upb_wire_type_t wt, upb_field_type_t ft) {
-  // Fake implementation.
-  return ft + wt > 3;
+  return (1 << wt) & upb_types[ft].allowed_wire_types;
 }
 
 /* Functions to read wire values. *********************************************/
@@ -348,8 +349,8 @@ upb_fielddef *upb_decoder_getdef(upb_decoder *d)
 
 bool upb_decoder_getval(upb_decoder *d, upb_valueptr val)
 {
-  int expected_type_for_field = 0;
-  if(expected_type_for_field == UPB_WIRE_TYPE_DELIMITED) {
+  upb_wire_type_t native_wire_type = upb_types[d->field->type].native_wire_type;
+  if(native_wire_type == UPB_WIRE_TYPE_DELIMITED) {
     // A string, bytes, or a length-delimited submessage.  The latter isn't
     // technically a string, but can be gotten as one to perform lazy parsing.
     d->str = upb_string_tryrecycle(d->str);
@@ -385,7 +386,7 @@ bool upb_decoder_getval(upb_decoder *d, upb_valueptr val)
     uint32_t bytes_available;
     uint32_t bytes_consumed;
     const uint8_t *buf = upb_decoder_getbuf(d, &bytes_available);
-    switch(expected_type_for_field) {
+    switch(native_wire_type) {
       case UPB_WIRE_TYPE_VARINT:
         if((bytes_consumed = upb_get_v_uint32(buf, val.uint32)) > 10) goto err;
         if(d->field->type == UPB_TYPE(SINT64)) *val.int64 = upb_zzdec_64(*val.int64);
diff --git a/src/upb_string.h b/src/upb_string.h
index 9a3957c..eab7f54 100644
--- a/src/upb_string.h
+++ b/src/upb_string.h
@@ -70,7 +70,7 @@ INLINE upb_strlen_t upb_string_len(upb_string *str) { return str->len; }
 // upb_string_endread is called().  No other functions may be called on the
 // string during this window except upb_string_len().
 INLINE const char *upb_string_getrobuf(upb_string *str) { return str->ptr; }
-INLINE void upb_string_endread(upb_string *str);
+INLINE void upb_string_endread(upb_string *str) {}
 
 // Attempts to recycle the string "str" so it may be reused and have different
 // data written to it.  The returned string is either "str" if it could be