Reordered functions and sections in C code for better flow for human readers, without changing functionality.
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Project Nayuki
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614169fc88
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7dbfabd388
183
c/qrcodegen.c
183
c/qrcodegen.c
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@ -187,6 +187,99 @@ testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[]
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/*---- Low-level QR Code encoding functions ----*/
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
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enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
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return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
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qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, -1, true, tempBuffer, qrcode);
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}
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
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int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
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assert(segs != NULL || len == 0);
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assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
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assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
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// Find the minimal version number to use
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int version, dataUsedBits;
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for (version = minVersion; ; version++) {
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int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
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dataUsedBits = getTotalBits(segs, len, version);
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if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
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break; // This version number is found to be suitable
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if (version >= maxVersion) { // All versions in the range could not fit the given data
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qrcode[0] = 0; // Set size to invalid value for safety
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return false;
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}
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}
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assert(dataUsedBits != -1);
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// Increase the error correction level while the data still fits in the current version number
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for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) { // From low to high
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if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
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ecl = (enum qrcodegen_Ecc)i;
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}
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// Concatenate all segments to create the data bit string
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memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
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int bitLen = 0;
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for (size_t i = 0; i < len; i++) {
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const struct qrcodegen_Segment *seg = &segs[i];
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appendBitsToBuffer((int)seg->mode, 4, qrcode, &bitLen);
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appendBitsToBuffer(seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
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for (int j = 0; j < seg->bitLength; j++)
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appendBitsToBuffer((seg->data[j >> 3] >> (7 - (j & 7))) & 1, 1, qrcode, &bitLen);
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}
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assert(bitLen == dataUsedBits);
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// Add terminator and pad up to a byte if applicable
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int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
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assert(bitLen <= dataCapacityBits);
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int terminatorBits = dataCapacityBits - bitLen;
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if (terminatorBits > 4)
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terminatorBits = 4;
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appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
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appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
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assert(bitLen % 8 == 0);
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// Pad with alternating bytes until data capacity is reached
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for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
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appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
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// Draw function and data codeword modules
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addEccAndInterleave(qrcode, version, ecl, tempBuffer);
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initializeFunctionModules(version, qrcode);
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drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
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drawWhiteFunctionModules(qrcode, version);
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initializeFunctionModules(version, tempBuffer);
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// Handle masking
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if (mask == qrcodegen_Mask_AUTO) { // Automatically choose best mask
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long minPenalty = LONG_MAX;
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for (int i = 0; i < 8; i++) {
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enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
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drawFormatBits(ecl, msk, qrcode);
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applyMask(tempBuffer, qrcode, msk);
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long penalty = getPenaltyScore(qrcode);
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if (penalty < minPenalty) {
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mask = msk;
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minPenalty = penalty;
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}
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applyMask(tempBuffer, qrcode, msk); // Undoes the mask due to XOR
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}
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}
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assert(0 <= (int)mask && (int)mask <= 7);
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drawFormatBits(ecl, mask, qrcode);
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applyMask(tempBuffer, qrcode, mask);
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return true;
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}
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/*---- Error correction code generation functions ----*/
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// Appends error correction bytes to each block of the given data array, then interleaves
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@ -851,96 +944,6 @@ struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]) {
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}
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
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enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
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return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
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qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, -1, true, tempBuffer, qrcode);
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}
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
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int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
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assert(segs != NULL || len == 0);
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assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
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assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
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// Find the minimal version number to use
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int version, dataUsedBits;
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for (version = minVersion; ; version++) {
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int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
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dataUsedBits = getTotalBits(segs, len, version);
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if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
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break; // This version number is found to be suitable
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if (version >= maxVersion) { // All versions in the range could not fit the given data
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qrcode[0] = 0; // Set size to invalid value for safety
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return false;
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}
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}
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assert(dataUsedBits != -1);
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// Increase the error correction level while the data still fits in the current version number
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for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) { // From low to high
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if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
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ecl = (enum qrcodegen_Ecc)i;
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}
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// Concatenate all segments to create the data bit string
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memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
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int bitLen = 0;
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for (size_t i = 0; i < len; i++) {
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const struct qrcodegen_Segment *seg = &segs[i];
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appendBitsToBuffer((int)seg->mode, 4, qrcode, &bitLen);
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appendBitsToBuffer(seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
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for (int j = 0; j < seg->bitLength; j++)
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appendBitsToBuffer((seg->data[j >> 3] >> (7 - (j & 7))) & 1, 1, qrcode, &bitLen);
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}
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assert(bitLen == dataUsedBits);
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// Add terminator and pad up to a byte if applicable
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int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
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assert(bitLen <= dataCapacityBits);
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int terminatorBits = dataCapacityBits - bitLen;
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if (terminatorBits > 4)
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terminatorBits = 4;
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appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
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appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
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assert(bitLen % 8 == 0);
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// Pad with alternating bytes until data capacity is reached
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for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
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appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
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// Draw function and data codeword modules
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addEccAndInterleave(qrcode, version, ecl, tempBuffer);
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initializeFunctionModules(version, qrcode);
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drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
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drawWhiteFunctionModules(qrcode, version);
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initializeFunctionModules(version, tempBuffer);
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// Handle masking
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if (mask == qrcodegen_Mask_AUTO) { // Automatically choose best mask
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long minPenalty = LONG_MAX;
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for (int i = 0; i < 8; i++) {
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enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
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drawFormatBits(ecl, msk, qrcode);
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applyMask(tempBuffer, qrcode, msk);
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long penalty = getPenaltyScore(qrcode);
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if (penalty < minPenalty) {
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mask = msk;
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minPenalty = penalty;
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}
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applyMask(tempBuffer, qrcode, msk); // Undoes the mask due to XOR
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}
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}
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assert(0 <= (int)mask && (int)mask <= 7);
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drawFormatBits(ecl, mask, qrcode);
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applyMask(tempBuffer, qrcode, mask);
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return true;
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}
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// Calculates the number of bits needed to encode the given segments at the given version.
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// Returns a non-negative number if successful. Otherwise returns -1 if a segment has too
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// many characters to fit its length field, or the total bits exceeds INT16_MAX.
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@ -145,7 +145,7 @@ struct qrcodegen_Segment {
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/*---- Functions to generate QR Codes ----*/
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/*---- Functions (high level) to generate QR Codes ----*/
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/*
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* Encodes the given text string to a QR Code, returning true if encoding succeeded.
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@ -192,6 +192,43 @@ bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcod
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enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
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/*---- Functions (low level) to generate QR Codes ----*/
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/*
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* Renders a QR Code representing the given segments at the given error correction level.
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* The smallest possible QR Code version is automatically chosen for the output. Returns true if
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* QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level
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* of the result may be higher than the ecl argument if it can be done without increasing the version.
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* This function allows the user to create a custom sequence of segments that switches
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* between modes (such as alphanumeric and byte) to encode text in less space.
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* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
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* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
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* result in them being clobbered, but the QR Code output will still be correct.
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* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
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*/
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bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
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enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
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/*
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* Renders a QR Code representing the given segments with the given encoding parameters.
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* Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions.
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* The smallest possible QR Code version within the given range is automatically
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* chosen for the output. Iff boostEcl is true, then the ECC level of the result
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* may be higher than the ecl argument if it can be done without increasing the
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* version. The mask number is either between 0 to 7 (inclusive) to force that
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* mask, or -1 to automatically choose an appropriate mask (which may be slow).
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* This function allows the user to create a custom sequence of segments that switches
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* between modes (such as alphanumeric and byte) to encode text in less space.
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* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
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* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
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* result in them being clobbered, but the QR Code output will still be correct.
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* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
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*/
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bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
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int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);
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/*
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* Tests whether the given string can be encoded as a segment in alphanumeric mode.
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* A string is encodable iff each character is in the following set: 0 to 9, A to Z
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@ -250,41 +287,6 @@ struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t bu
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struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]);
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/*
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* Renders a QR Code representing the given segments at the given error correction level.
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* The smallest possible QR Code version is automatically chosen for the output. Returns true if
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* QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level
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* of the result may be higher than the ecl argument if it can be done without increasing the version.
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* This function allows the user to create a custom sequence of segments that switches
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* between modes (such as alphanumeric and byte) to encode text in less space.
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* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
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* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
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* result in them being clobbered, but the QR Code output will still be correct.
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* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
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*/
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bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
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enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
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/*
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* Renders a QR Code representing the given segments with the given encoding parameters.
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* Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions.
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* The smallest possible QR Code version within the given range is automatically
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* chosen for the output. Iff boostEcl is true, then the ECC level of the result
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* may be higher than the ecl argument if it can be done without increasing the
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* version. The mask number is either between 0 to 7 (inclusive) to force that
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* mask, or -1 to automatically choose an appropriate mask (which may be slow).
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* This function allows the user to create a custom sequence of segments that switches
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* between modes (such as alphanumeric and byte) to encode text in less space.
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* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
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* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
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* result in them being clobbered, but the QR Code output will still be correct.
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* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
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*/
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bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
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int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);
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/*---- Functions to extract raw data from QR Codes ----*/
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/*
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