Fix GetTextString() and GetByteString() error handling (#303)

GetTextString() and GetByteString() where returning the wrong error code when the input CBOR was the wrong type

* Fix GetTextString() and GetByteString() error handling

* Improve test and doc for GetString

* Miniscule header fix

---------

Co-authored-by: Laurence Lundblade <[email protected]>

inc/qcbor/qcbor_spiffy_decode.h

@@ -823,6 +823,13 @@ QCBORDecode_GetSimpleInMapSZ(QCBORDecodeContext *pCtx,
  *    BEGINNING OF PRIVATE INLINE IMPLEMENTATION                             *
  * ========================================================================= */
 
+
+/** @private  Semi-private function. See qcbor_spiffy_decode.c */
+void
+QCBORDecode_Private_GetString(QCBORDecodeContext *pMe,
+                              uint8_t             uType,
+                              UsefulBufC         *pText);
+
 /** @private  Semi-private function. See qcbor_spiffy_decode.c */
 void
 QCBORDecode_Private_EnterBoundedMapOrArray(QCBORDecodeContext *pCtx,
@@ -1009,20 +1016,10 @@ QCBORDecode_GetMapFromMapSZ(QCBORDecodeContext *pMe,
 }
 
 
-
-
 static inline void
 QCBORDecode_GetByteString(QCBORDecodeContext *pMe, UsefulBufC *pBytes)
 {
-   QCBORItem  Item;
-
-   QCBORDecode_VGetNext(pMe, &Item);
-
-   if(pMe->uLastError == QCBOR_SUCCESS && Item.uDataType == QCBOR_TYPE_BYTE_STRING) {
-      *pBytes = Item.val.string;
-   } else {
-      *pBytes = NULLUsefulBufC;
-   }
+   QCBORDecode_Private_GetString(pMe, QCBOR_TYPE_BYTE_STRING, pBytes);
 }
 
 static inline void
@@ -1061,15 +1058,7 @@ QCBORDecode_GetByteStringInMapSZ(QCBORDecodeContext *pMe,
 static inline void
 QCBORDecode_GetTextString(QCBORDecodeContext *pMe, UsefulBufC *pText)
 {
-   QCBORItem  Item;
-
-   QCBORDecode_VGetNext(pMe, &Item);
-
-   if(pMe->uLastError == QCBOR_SUCCESS && Item.uDataType == QCBOR_TYPE_TEXT_STRING) {
-      *pText = Item.val.string;
-   } else {
-      *pText = NULLUsefulBufC;
-   }
+   QCBORDecode_Private_GetString(pMe, QCBOR_TYPE_TEXT_STRING, pText);
 }
 
 static inline void

src/qcbor_spiffy_decode.c

@@ -66,6 +66,34 @@
 #endif
 
 
+/**
+ * @brief Spiffy decode get a byte string.
+ *
+ * @param[in] pMe       The decode context.
+ * @param[in] uType     The CBOR qcbor type requested.
+ * @param[out] pString  The returned string.
+ *
+ * This sets the spiffy decode last error if there is a problem
+ * deocing or the string is not of the requested type.
+ */
+void
+QCBORDecode_Private_GetString(QCBORDecodeContext *pMe, const uint8_t uType, UsefulBufC *pString)
+{
+   QCBORItem  Item;
+
+   QCBORDecode_VGetNext(pMe, &Item);
+
+   *pString = NULLUsefulBufC;
+   if(pMe->uLastError == QCBOR_SUCCESS) {
+      if(Item.uDataType == uType) {
+         *pString = Item.val.string;
+      } else {
+         pMe->uLastError = QCBOR_ERR_UNEXPECTED_TYPE;
+      }
+   }
+}
+
+
 /* Return true if the labels in Item1 and Item2 are the same.
    Works only for integer and string labels. Returns false
    for any other type. */

test/qcbor_decode_tests.c

@@ -9323,7 +9323,7 @@ int32_t TooLargeInputTest(void)
 
 /*
  An array of three map entries
- 1) Indefinite length string label for indefinite lenght byte string
+ 1) Indefinite length string label for indefinite length byte string
  2) Indefinite length string label for an integer
  3) Indefinite length string label for an indefinite-length negative big num
  */
@@ -9416,6 +9416,58 @@ int32_t SpiffyIndefiniteLengthStringsTests(void)
 #endif /* QCBOR_DISABLE_INDEFINITE_LENGTH_STRINGS */
 
 
+static const uint8_t spStringsTest[] = {
+   0x63, 'a', 'b', 'c',
+   0x43, 'd', 'e', 'f'
+};
+
+static const uint8_t spNotWellFormed[] = {
+   0xff
+};
+
+int32_t SpiffyStringTest(void)
+{
+   QCBORDecodeContext DC;
+   UsefulBufC         String;
+
+   QCBORDecode_Init(&DC, ByteArrayLiteralToUsefulBufC(spStringsTest), 0);
+
+   QCBORDecode_GetTextString(&DC, &String);
+   if(QCBORDecode_GetError(&DC) != QCBOR_SUCCESS &&
+      UsefulBuf_Compare(String,  SZLiteralToUsefulBufC("abc"))) {
+      return 1;
+   }
+
+   QCBORDecode_GetByteString(&DC, &String);
+   if(QCBORDecode_GetError(&DC) != QCBOR_SUCCESS &&
+      UsefulBuf_Compare(String,  SZLiteralToUsefulBufC("def"))) {
+      return 2;
+   }
+
+   QCBORDecode_Init(&DC, ByteArrayLiteralToUsefulBufC(spStringsTest), 0);
+   QCBORDecode_GetByteString(&DC, &String);
+   if(QCBORDecode_GetError(&DC) != QCBOR_ERR_UNEXPECTED_TYPE &&
+      !UsefulBuf_IsNULLC(String)) {
+      return 3;
+   }
+
+   QCBORDecode_Init(&DC, ByteArrayLiteralToUsefulBufC(spNotWellFormed), 0);
+   QCBORDecode_GetByteString(&DC, &String);
+   if(QCBORDecode_GetError(&DC) != QCBOR_ERR_BAD_BREAK &&
+      !UsefulBuf_IsNULLC(String)) {
+      return 4;
+   }
+
+#ifndef QCBOR_DISABLE_INDEFINITE_LENGTH_STRINGS
+   return SpiffyIndefiniteLengthStringsTests();
+#else
+   return 0;
+#endif
+
+}
+
+
+
 #ifndef QCBOR_DISABLE_NON_INTEGER_LABELS
 /*
  * An array of an integer and an array. The second array contains

test/qcbor_decode_tests.h

@@ -299,7 +299,7 @@ int32_t TooLargeInputTest(void);
 /*
  Test spiffy decoding of indefinite length strings.
  */
-int32_t SpiffyIndefiniteLengthStringsTests(void);
+int32_t SpiffyStringTest(void);
 
 
 /*

test/run_tests.c

@@ -131,7 +131,7 @@ static test_entry s_tests[] = {
    TEST_ENTRY(MemPoolTest),
    TEST_ENTRY(IndefiniteLengthStringTest),
 #ifndef QCBOR_DISABLE_NON_INTEGER_LABELS
-   TEST_ENTRY(SpiffyIndefiniteLengthStringsTests),
+   TEST_ENTRY(SpiffyStringTest),
 #endif /* ! QCBOR_DISABLE_NON_INTEGER_LABELS */
    TEST_ENTRY(SetUpAllocatorTest),
    TEST_ENTRY(CBORTestIssue134),