Introduced custom type for crc result (#61)

abobija · Sep 22, 2024 · 949af61 · 949af61
1 parent fb2c9db
commit 949af61
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Showing 5 changed files with 37 additions and 27 deletions.
diff --git a/idf_component.yml b/idf_component.yml
@@ -1,4 +1,4 @@
-version: "3.1.4"
+version: "3.1.5"
 description: "Library for communication with RFID / NFC cards using MFRC522 module"
 url: "https://github.com/abobija/esp-idf-rc522"
 repository: "https://github.com/abobija/esp-idf-rc522.git"

diff --git a/private_include/rc522_pcd_private.h b/private_include/rc522_pcd_private.h
@@ -413,9 +413,19 @@ typedef enum
     RC522_PCD_FIRMWARE_COUNTERFEIT = 0x12, // counterfeit chip
 } rc522_pcd_firmware_t;
 
+typedef union
+{
+    uint16_t value;
+    struct
+    {
+        uint8_t lsb;
+        uint8_t msb;
+    };
+} rc522_pcd_crc_t;
+
 esp_err_t rc522_pcd_reset(const rc522_handle_t rc522, uint32_t timeout_ms);
 
-esp_err_t rc522_pcd_calculate_crc(const rc522_handle_t rc522, const rc522_bytes_t *bytes, uint16_t *result);
+esp_err_t rc522_pcd_calculate_crc(const rc522_handle_t rc522, const rc522_bytes_t *bytes, rc522_pcd_crc_t *result);
 
 esp_err_t rc522_pcd_init(const rc522_handle_t rc522);
 

diff --git a/src/picc/rc522_mifare.c b/src/picc/rc522_mifare.c
@@ -158,11 +158,11 @@ esp_err_t rc522_mifare_read(
     buffer_clone[1] = block_address;
 
     // Calculate CRC_A
-    uint16_t crc = 0;
+    rc522_pcd_crc_t crc = { 0 };
     RC522_RETURN_ON_ERROR(rc522_pcd_calculate_crc(rc522, &(rc522_bytes_t) { .ptr = buffer_clone, .length = 2 }, &crc));
 
-    buffer_clone[2] = crc & 0xFF;
-    buffer_clone[3] = crc >> 8;
+    buffer_clone[2] = crc.lsb;
+    buffer_clone[3] = crc.msb;
 
     // Transmit the buffer and receive the response, validate CRC_A.
     uint8_t _ = sizeof(buffer_clone);
@@ -187,12 +187,12 @@ static esp_err_t rc522_mifare_send(
     // Copy sendData[] to cmdBuffer[] and add CRC_A
     memcpy(cmd_buffer, send_data, send_length);
 
-    uint16_t crc = 0;
+    rc522_pcd_crc_t crc = { 0 };
     RC522_RETURN_ON_ERROR(
         rc522_pcd_calculate_crc(rc522, &(rc522_bytes_t) { .ptr = cmd_buffer, .length = send_length }, &crc));
 
-    cmd_buffer[send_length] = crc & 0xFF;
-    cmd_buffer[send_length + 1] = crc >> 8;
+    cmd_buffer[send_length] = crc.lsb;
+    cmd_buffer[send_length + 1] = crc.msb;
 
     send_length += 2;
 

diff --git a/src/rc522_pcd.c b/src/rc522_pcd.c
@@ -12,7 +12,7 @@ RC522_LOG_DEFINE_BASE();
 /**
  * @see https://stackoverflow.com/a/48705557
  */
-esp_err_t rc522_pcd_calculate_crc(const rc522_handle_t rc522, const rc522_bytes_t *bytes, uint16_t *result)
+esp_err_t rc522_pcd_calculate_crc(const rc522_handle_t rc522, const rc522_bytes_t *bytes, rc522_pcd_crc_t *result)
 {
     RC522_CHECK(rc522 == NULL);
     RC522_CHECK_BYTES(bytes);
@@ -44,20 +44,20 @@ esp_err_t rc522_pcd_calculate_crc(const rc522_handle_t rc522, const rc522_bytes_
         return ESP_ERR_TIMEOUT;
     }
 
-    uint8_t msb;
-    uint8_t lsb;
-    RC522_RETURN_ON_ERROR(rc522_pcd_stop_active_command(rc522));
-    RC522_RETURN_ON_ERROR(rc522_pcd_read(rc522, RC522_PCD_CRC_RESULT_MSB_REG, &msb));
-    RC522_RETURN_ON_ERROR(rc522_pcd_read(rc522, RC522_PCD_CRC_RESULT_LSB_REG, &lsb));
+    rc522_pcd_crc_t crc = { 0 };
 
-    *result = (msb << 8) | lsb;
+    RC522_RETURN_ON_ERROR(rc522_pcd_stop_active_command(rc522));
+    RC522_RETURN_ON_ERROR(rc522_pcd_read(rc522, RC522_PCD_CRC_RESULT_MSB_REG, &crc.msb));
+    RC522_RETURN_ON_ERROR(rc522_pcd_read(rc522, RC522_PCD_CRC_RESULT_LSB_REG, &crc.lsb));
 
     if (RC522_LOG_LEVEL >= ESP_LOG_DEBUG) {
         char debug_buffer[64];
         rc522_buffer_to_hex_str(bytes->ptr, bytes->length, debug_buffer, sizeof(debug_buffer));
-        RC522_LOGD("crc(%s) = 0x%04" RC522_X, debug_buffer, *result);
+        RC522_LOGD("crc(%s) = 0x%04" RC522_X, debug_buffer, crc.value);
     }
 
+    *result = crc;
+
     return ESP_OK;
 }
 

diff --git a/src/rc522_picc.c b/src/rc522_picc.c
@@ -171,11 +171,11 @@ esp_err_t rc522_picc_comm(const rc522_handle_t rc522, rc522_pcd_command_t comman
         }
 
         // Verify CRC_A
-        uint16_t crc = 0;
+        rc522_pcd_crc_t crc = { 0 };
         RC522_RETURN_ON_ERROR(
             rc522_pcd_calculate_crc(rc522, &(rc522_bytes_t) { .ptr = back_data, .length = *back_data_len - 2 }, &crc));
 
-        if ((back_data[*back_data_len - 2] != (crc & 0xFF)) || (back_data[*back_data_len - 1] != (crc >> 8))) {
+        if ((back_data[*back_data_len - 2] != crc.lsb) || (back_data[*back_data_len - 1] != crc.msb)) {
             return RC522_ERR_CRC_WRONG;
         }
     }
@@ -421,12 +421,12 @@ esp_err_t rc522_picc_select(const rc522_handle_t rc522, rc522_picc_uid_t *out_ui
                 buffer[6] = buffer[2] ^ buffer[3] ^ buffer[4] ^ buffer[5];
                 // Calculate CRC_A
 
-                uint16_t crc = 0;
+                rc522_pcd_crc_t crc = { 0 };
                 RC522_RETURN_ON_ERROR(
                     rc522_pcd_calculate_crc(rc522, &(rc522_bytes_t) { .ptr = buffer, .length = 7 }, &crc));
 
-                buffer[7] = crc & 0xFF;
-                buffer[8] = crc >> 8;
+                buffer[7] = crc.lsb;
+                buffer[8] = crc.msb;
 
                 tx_last_bits = 0; // 0 => All 8 bits are valid.
                 buffer_used = 9;
@@ -544,12 +544,12 @@ esp_err_t rc522_picc_select(const rc522_handle_t rc522, rc522_picc_uid_t *out_ui
 // compiler complains about uninitialized response_buffer even is
 // no chance that response_buffer is NULL here, so ignore warning here
 #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
-        uint16_t crc = 0;
+        rc522_pcd_crc_t crc = { 0 };
         RC522_RETURN_ON_ERROR(
             rc522_pcd_calculate_crc(rc522, &(rc522_bytes_t) { .ptr = response_buffer, .length = 1 }, &crc));
 
-        buffer[2] = crc & 0xFF;
-        buffer[3] = crc >> 8;
+        buffer[2] = crc.lsb;
+        buffer[3] = crc.msb;
 
         if ((buffer[2] != response_buffer[1]) || (buffer[3] != response_buffer[2])) {
             RC522_LOGD("crc wrong");
@@ -679,11 +679,11 @@ esp_err_t rc522_picc_halta(const rc522_handle_t rc522, rc522_picc_t *picc)
     buffer[0] = RC522_PICC_CMD_HLTA;
     buffer[1] = 0;
     // Calculate CRC_A
-    uint16_t crc = 0;
+    rc522_pcd_crc_t crc = { 0 };
     RC522_RETURN_ON_ERROR(rc522_pcd_calculate_crc(rc522, &(rc522_bytes_t) { .ptr = buffer, .length = 2 }, &crc));
 
-    buffer[2] = crc & 0xFF;
-    buffer[3] = crc >> 8;
+    buffer[2] = crc.lsb;
+    buffer[3] = crc.msb;
 
     // Send the command.
     // The standard says: