Added test cases for C function appendErrorCorrection().

c/qrcodegen-test.c

@@ -43,8 +43,11 @@ static int numTestCases = 0;
 
 
 // Prototypes of private functions under test
+extern const int8_t ECC_CODEWORDS_PER_BLOCK[4][41];
+extern const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41];
 int getTextProperties(const char *text, bool *isNumeric, bool *isAlphanumeric, int *textBits);
 void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
+void appendErrorCorrection(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
 int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl);
 int getNumRawDataModules(int version);
 void calcReedSolomonGenerator(int degree, uint8_t result[]);
@@ -158,6 +161,73 @@ static void testAppendBitsToBuffer(void) {
 }
 
 
+// Ported from the Java version of the code.
+static uint8_t *appendErrorCorrectionReference(const uint8_t *data, int version, enum qrcodegen_Ecc ecl) {
+	// Calculate parameter numbers
+	int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(int)ecl][version];
+	int blockEccLen = ECC_CODEWORDS_PER_BLOCK[(int)ecl][version];
+	int rawCodewords = getNumRawDataModules(version) / 8;
+	int numShortBlocks = numBlocks - rawCodewords % numBlocks;
+	int shortBlockLen = rawCodewords / numBlocks;
+	
+	// Split data into blocks and append ECC to each block
+	uint8_t **blocks = malloc(numBlocks * sizeof(uint8_t*));
+	uint8_t *generator = malloc(blockEccLen * sizeof(uint8_t));
+	calcReedSolomonGenerator(blockEccLen, generator);
+	for (int i = 0, k = 0; i < numBlocks; i++) {
+		uint8_t *block = malloc((shortBlockLen + 1) * sizeof(uint8_t));
+		int blockDataLen = shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1);
+		memcpy(block, &data[k], blockDataLen * sizeof(uint8_t));
+		calcReedSolomonRemainder(&data[k], blockDataLen, generator, blockEccLen, &block[shortBlockLen + 1 - blockEccLen]);
+		k += blockDataLen;
+		blocks[i] = block;
+	}
+	free(generator);
+	
+	// Interleave (not concatenate) the bytes from every block into a single sequence
+	uint8_t *result = malloc(rawCodewords * sizeof(uint8_t));
+	for (int i = 0, k = 0; i < shortBlockLen + 1; i++) {
+		for (int j = 0; j < numBlocks; j++) {
+			// Skip the padding byte in short blocks
+			if (i != shortBlockLen - blockEccLen || j >= numShortBlocks) {
+				result[k] = blocks[j][i];
+				k++;
+			}
+		}
+	}
+	for (int i = 0; i < numBlocks; i++)
+		free(blocks[i]);
+	free(blocks);
+	return result;
+}
+
+
+static void testAppendErrorCorrection(void) {
+	for (int version = 1; version <= 40; version++) {
+		for (int ecl = 0; ecl < 4; ecl++) {
+			int dataLen = getNumDataCodewords(version, (enum qrcodegen_Ecc)ecl);
+			uint8_t *pureData = malloc(dataLen * sizeof(uint8_t));
+			for (int i = 0; i < dataLen; i++)
+				pureData[i] = rand() % 256;
+			uint8_t *expectOutput = appendErrorCorrectionReference(pureData, version, (enum qrcodegen_Ecc)ecl);
+			
+			int dataAndEccLen = getNumRawDataModules(version) / 8;
+			uint8_t *paddedData = malloc(dataAndEccLen * sizeof(uint8_t));
+			memcpy(paddedData, pureData, dataLen * sizeof(uint8_t));
+			uint8_t *actualOutput = malloc(dataAndEccLen * sizeof(uint8_t));
+			appendErrorCorrection(paddedData, version, (enum qrcodegen_Ecc)ecl, actualOutput);
+			
+			assert(memcmp(actualOutput, expectOutput, dataAndEccLen * sizeof(uint8_t)) == 0);
+			free(pureData);
+			free(expectOutput);
+			free(paddedData);
+			free(actualOutput);
+			numTestCases++;
+		}
+	}
+}
+
+
 static void testGetNumDataCodewords(void) {
 	int cases[][3] = {
 		{ 3, 1,   44},
@@ -492,6 +562,7 @@ int main(void) {
 	srand(time(NULL));
 	testGetTextProperties();
 	testAppendBitsToBuffer();
+	testAppendErrorCorrection();
 	testGetNumDataCodewords();
 	testGetNumRawDataModules();
 	testCalcReedSolomonGenerator();

c/qrcodegen.c

@@ -60,7 +60,7 @@ static void encodeQrCodeTail(uint8_t dataAndQrcode[], int bitLen, uint8_t tempBu
 	int version, enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, bool boostEcl);
 testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
 
-static void appendErrorCorrection(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
+testable void appendErrorCorrection(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
 testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl);
 testable int getNumRawDataModules(int version);
 
@@ -90,7 +90,7 @@ testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack);
 static const char *ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
 
 // For generating error correction codes.
-static const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
+testable const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
 	// Version: (note that index 0 is for padding, and is set to an illegal value)
 	//0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
 	{-1,  7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // Low
@@ -100,7 +100,7 @@ static const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
 };
 
 // For generating error correction codes.
-const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41] = {
+testable const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41] = {
 	// Version: (note that index 0 is for padding, and is set to an illegal value)
 	//0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
 	{-1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4,  4,  4,  4,  4,  6,  6,  6,  6,  7,  8,  8,  9,  9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25},  // Low
@@ -356,7 +356,7 @@ testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[]
 // from the blocks and stores them in the result array. data[0 : rawCodewords - totalEcc] contains
 // the input data. data[rawCodewords - totalEcc : rawCodewords] is used as a temporary work area
 // and will be clobbered by this function. The final answer is stored in result[0 : rawCodewords].
-static void appendErrorCorrection(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]) {
+testable void appendErrorCorrection(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]) {
 	// Calculate parameter numbers
 	assert(0 <= (int)ecl && (int)ecl < 4 && qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
 	int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(int)ecl][version];