Fix get system info

examples/iso_14443-read-memory.py

@@ -49,7 +49,7 @@ def main() -> int:
                     print(f"Error: {e}")
                     return 1
 
-                memory = card.read_memory()
+                memory = card.read_memory(0, 512)
 
                 # Display memory content
                 for offset in range(0, len(memory), 16):
@@ -60,6 +60,13 @@ def main() -> int:
                     )
                     print(f"({offset:03x}): {chunk.hex(' ')} {ascii_values}")
 
+                ndef_result = card.get_ndef(memory)
+                if ndef_result is not None:
+                    start, mem = ndef_result
+                    print(f"NDEF found, it starts at {start}, len={len(mem)}")
+                    print(f"Content:\n{mem.hex(' ')}")
+                    print(f"Next TLV type: {memory[start + len(mem)]:02x}")
+
         return 0
 
     except Exception as e:

examples/iso_15693-read-memory.py

@@ -58,8 +58,10 @@ def main() -> int:
                     card = session.connect_iso15693(uids[0])
 
                     try:
+                        memory = b""
                         for offset in range(0, 512, 16):
                             chunk = card.read_memory(offset, 16)
+                            memory += chunk
                             ascii_values = "".join(
                                 chr(byte) if 32 <= byte <= 126 else "."
                                 for byte in chunk
@@ -70,6 +72,14 @@ def main() -> int:
                     except TimeoutError:
                         # Done
                         pass
+                    ndef_result = card.get_ndef(memory)
+                    if ndef_result is not None:
+                        start, mem = ndef_result
+                        print(
+                            f"NDEF found, it starts at {start}, len={len(mem)}"
+                        )
+                        print(f"Content:\n{mem.hex(' ')}")
+                        print(f"Next TLV type: {memory[start + len(mem)]:02x}")
                 else:
                     print("\nNo tags found")
 

src/pn5180_tagomatic/cards.py

@@ -121,3 +121,17 @@ def write_memory(self, offset: int, data: bytes) -> None:
             TimeoutError: If card does not respond.
             MemoryWriteError: Other memory write failures.
         """
+
+    def get_ndef(self, memory: bytes) -> tuple[int, bytes] | None:
+        """Find the NDEF memory.
+
+        If found, the start index in the input memory and
+        its bytes are returned.
+
+        Args:
+            memory: The card's memory, starting from 0
+
+        Returns:
+            (start, ndef_bytes),
+            or None if it wasn't found.
+        """

src/pn5180_tagomatic/iso14443a.py

@@ -262,3 +262,79 @@ def authenticate_for_page(
             if len(key_b) != 6:
                 raise ValueError("key_b must be exactly 6 bytes")
             self._keys_b[page_num] = bytes(key_b)
+
+    def decode_cc(self, cc: bytes) -> tuple[int, int, int, bool] | None:
+        """Decode the CC memory block (block 0)
+
+        Args:
+            cc(bytes): The memory from block 0.
+
+        Returns:
+            (major_version, minor_version, memory size, is readonly)
+            or None if CC isn't valid.
+
+        Raises:
+            PN5180Error: If communication with the card fails.
+            ValueError: If cc is less than 4 bytes.
+        """
+        if len(cc) < 4:
+            raise ValueError("cc should be at least 4 bytes")
+
+        if cc[0] != 0xE1:
+            return None
+
+        major = cc[1] >> 4
+        minor = cc[1] & 0xF
+
+        mlen = (cc[2]) * 4
+
+        is_readonly = bool((cc[3] & 0xF0) == 0xF0)
+
+        return (major, minor, mlen, is_readonly)
+
+    def get_ndef(self, memory: bytes) -> tuple[int, bytes] | None:
+        """Find the NDEF memory.
+
+        Args:
+            memory: The card's memory, starting from offset 0
+
+        Returns:
+            (start, ndef_bytes),
+            or None if NDEF couldn't be found.
+        """
+
+        cc = self.decode_cc(memory[12:16])
+        if cc is None:
+            return None
+
+        major, _minor, mlen, _ = cc
+
+        if major > 1:
+            return None
+
+        if mlen > len(memory):
+            return None
+
+        pos = 16
+
+        def read_val(memory: bytes, pos: int) -> tuple[int, int]:
+            if memory[pos] < 255:
+                return memory[pos], pos + 1
+            else:
+                return (memory[pos + 1] << 8) | memory[pos + 2], pos + 3
+
+        while pos < mlen:
+            typ, pos = read_val(memory, pos)
+            if typ == 0:
+                continue
+            if typ == 0xFE:
+                # End of TLV
+                return None
+            field_len, pos = read_val(memory, pos)
+            if typ == 0x03:
+                if pos + field_len > mlen:
+                    return None
+                return (pos, memory[pos : pos + field_len])
+            pos += field_len
+
+        return None

src/pn5180_tagomatic/iso15693.py

@@ -71,6 +71,91 @@ def memory_block_size(self) -> int:
         self._ensure_sys_info_loaded()
         return self._block_size
 
+    @property
+    def memory_number_of_blocks(self) -> int:
+        """Gets the number of blocks the card contains"""
+        self._ensure_sys_info_loaded()
+        return self._num_blocks
+
+    def decode_cc(self, cc: bytes) -> tuple[int, int, int, bool] | None:
+        """Decode the CC memory block (block 0)
+
+        Args:
+            cc(bytes): The memory from block 0.
+
+        Returns:
+            (major_version, minor_version, memory size, is readonly)
+            or None if CC isn't valid.
+
+        Raises:
+            PN5180Error: If communication with the card fails.
+            ValueError: If cc is less than 4 bytes.
+        """
+        if len(cc) < 4:
+            raise ValueError("cc should be at least 4 bytes")
+
+        if cc[0] != 0xE1:
+            return None
+
+        major = cc[1] >> 4
+        minor = cc[1] & 0xF
+
+        mlen = (cc[2] + 1) * 8
+
+        is_readonly = bool(cc[3] & 1)
+
+        return (major, minor, mlen, is_readonly)
+
+    def get_ndef(self, memory: bytes) -> tuple[int, bytes] | None:
+        """Find the NDEF memory.
+
+        If found, the start index in the input memory and
+        its bytes are returned.
+
+        Args:
+            memory: The card's memory, starting from 0
+
+        Returns:
+            (start, ndef_bytes),
+            or None if it wasn't found.
+        """
+
+        cc = self.decode_cc(memory)
+        if cc is None:
+            return None
+
+        major, _minor, mlen, _ = cc
+
+        if major > 4:
+            return None
+
+        if mlen > len(memory):
+            return None
+
+        pos = 4
+
+        def read_val(memory: bytes, pos: int) -> tuple[int, int]:
+            if memory[pos] < 255:
+                return memory[pos], pos + 1
+            else:
+                return (memory[pos + 1] << 8) | memory[pos + 2], pos + 3
+
+        while pos < mlen:
+            typ, pos = read_val(memory, pos)
+            if typ == 0:
+                continue
+            if typ == 0xFE:
+                # End of TLV
+                return None
+            field_len, pos = read_val(memory, pos)
+            if typ == 0x03:
+                if pos + field_len > mlen:
+                    return None
+                return (pos, memory[pos : pos + field_len])
+            pos += field_len
+
+        return None
+
     def read_memory(self, offset: int = 0, length: int | None = None) -> bytes:
         """Read memory from card.
 
@@ -145,24 +230,24 @@ def get_system_information(self) -> dict[str, int]:
                 "Error getting system information", system_info[1]
             )
         if len(system_info) < 1:
-            system_info += b"\0"
+            raise PN5180Error("Error getting system information, no answer", 0)
 
-        pos = 9
+        pos = 10
         result = {}
-        if system_info[0] & 1:
+        if system_info[1] & 1:
             result["dsfid"] = system_info[pos]
             pos += 1
-        if system_info[0] & 2:
+        if system_info[1] & 2:
             result["afi"] = system_info[pos]
             pos += 1
-        if system_info[0] & 4:
+        if system_info[1] & 4:
             result["num_blocks"] = system_info[pos] + 1
             pos += 1
             result["block_size"] = (system_info[pos] & 31) + 1
             pos += 1
-        if system_info[0] & 8:
-            pos += 1
+        if system_info[1] & 8:
             result["ic_reference"] = system_info[pos]
+            pos += 1
 
         return result
 

src/pn5180_tagomatic/session.py

@@ -204,7 +204,7 @@ def get_all_iso14443a_uids(
             (0, b"", 0, [], True),
         ]
         while len(discovery_stack) > 0:
-            (cl, mask, coll_bit, uid, restart) = discovery_stack.pop()
+            cl, mask, coll_bit, uid, restart = discovery_stack.pop()
 
             if restart:
                 self._reader.turn_off_crc()
@@ -246,9 +246,7 @@ def get_all_iso14443a_uids(
             self._reader.set_rx_crc_and_first_bit(False, 0)
             self._reader.turn_off_tx_crc()
             cmd = self._get_cmd_for_level(cl)
-            (nvb, final_bits) = self._get_nvb_and_final_bits(
-                len(mask), coll_bit
-            )
+            nvb, final_bits = self._get_nvb_and_final_bits(len(mask), coll_bit)
 
             try:
                 self._reader.set_rx_crc_and_first_bit(False, final_bits)