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QR-Code-generator
mirror of https://github.com/nayuki/QR-Code-generator
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Reordered functions and sections in C code for better flow for human readers, without changing functionality.

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pull/39/merge
Project Nayuki 6 years ago
parent 614169fc88
commit 7dbfabd388
2 changed files with 131 additions and 126 deletions
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183
c/qrcodegen.c
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@ -187,6 +187,99 @@ testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[]
/*---- Low-level QR Code encoding functions ----*/
// Public function - see documentation comment in header file.
bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, -1, true, tempBuffer, qrcode);
}
// Public function - see documentation comment in header file.
bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
assert(segs != NULL || len == 0);
assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
// Find the minimal version number to use
int version, dataUsedBits;
for (version = minVersion; ; version++) {
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = getTotalBits(segs, len, version);
if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
if (version >= maxVersion) { // All versions in the range could not fit the given data
qrcode[0] = 0; // Set size to invalid value for safety
return false;
}
}
assert(dataUsedBits != -1);
// Increase the error correction level while the data still fits in the current version number
for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) { // From low to high
if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
ecl = (enum qrcodegen_Ecc)i;
}
// Concatenate all segments to create the data bit string
memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
int bitLen = 0;
for (size_t i = 0; i < len; i++) {
const struct qrcodegen_Segment *seg = &segs[i];
appendBitsToBuffer((int)seg->mode, 4, qrcode, &bitLen);
appendBitsToBuffer(seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
for (int j = 0; j < seg->bitLength; j++)
appendBitsToBuffer((seg->data[j >> 3] >> (7 - (j & 7))) & 1, 1, qrcode, &bitLen);
}
assert(bitLen == dataUsedBits);
// Add terminator and pad up to a byte if applicable
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
assert(bitLen <= dataCapacityBits);
int terminatorBits = dataCapacityBits - bitLen;
if (terminatorBits > 4)
terminatorBits = 4;
appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
assert(bitLen % 8 == 0);
// Pad with alternating bytes until data capacity is reached
for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
// Draw function and data codeword modules
addEccAndInterleave(qrcode, version, ecl, tempBuffer);
initializeFunctionModules(version, qrcode);
drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
drawWhiteFunctionModules(qrcode, version);
initializeFunctionModules(version, tempBuffer);
// Handle masking
if (mask == qrcodegen_Mask_AUTO) { // Automatically choose best mask
long minPenalty = LONG_MAX;
for (int i = 0; i < 8; i++) {
enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
drawFormatBits(ecl, msk, qrcode);
applyMask(tempBuffer, qrcode, msk);
long penalty = getPenaltyScore(qrcode);
if (penalty < minPenalty) {
mask = msk;
minPenalty = penalty;
}
applyMask(tempBuffer, qrcode, msk); // Undoes the mask due to XOR
}
}
assert(0 <= (int)mask && (int)mask <= 7);
drawFormatBits(ecl, mask, qrcode);
applyMask(tempBuffer, qrcode, mask);
return true;
}
/*---- Error correction code generation functions ----*/
// Appends error correction bytes to each block of the given data array, then interleaves
@ -851,96 +944,6 @@ struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]) {
}
// Public function - see documentation comment in header file.
bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, -1, true, tempBuffer, qrcode);
}
// Public function - see documentation comment in header file.
bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
assert(segs != NULL || len == 0);
assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
// Find the minimal version number to use
int version, dataUsedBits;
for (version = minVersion; ; version++) {
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = getTotalBits(segs, len, version);
if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
if (version >= maxVersion) { // All versions in the range could not fit the given data
qrcode[0] = 0; // Set size to invalid value for safety
return false;
}
}
assert(dataUsedBits != -1);
// Increase the error correction level while the data still fits in the current version number
for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) { // From low to high
if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
ecl = (enum qrcodegen_Ecc)i;
}
// Concatenate all segments to create the data bit string
memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
int bitLen = 0;
for (size_t i = 0; i < len; i++) {
const struct qrcodegen_Segment *seg = &segs[i];
appendBitsToBuffer((int)seg->mode, 4, qrcode, &bitLen);
appendBitsToBuffer(seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
for (int j = 0; j < seg->bitLength; j++)
appendBitsToBuffer((seg->data[j >> 3] >> (7 - (j & 7))) & 1, 1, qrcode, &bitLen);
}
assert(bitLen == dataUsedBits);
// Add terminator and pad up to a byte if applicable
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
assert(bitLen <= dataCapacityBits);
int terminatorBits = dataCapacityBits - bitLen;
if (terminatorBits > 4)
terminatorBits = 4;
appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
assert(bitLen % 8 == 0);
// Pad with alternating bytes until data capacity is reached
for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
// Draw function and data codeword modules
addEccAndInterleave(qrcode, version, ecl, tempBuffer);
initializeFunctionModules(version, qrcode);
drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
drawWhiteFunctionModules(qrcode, version);
initializeFunctionModules(version, tempBuffer);
// Handle masking
if (mask == qrcodegen_Mask_AUTO) { // Automatically choose best mask
long minPenalty = LONG_MAX;
for (int i = 0; i < 8; i++) {
enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
drawFormatBits(ecl, msk, qrcode);
applyMask(tempBuffer, qrcode, msk);
long penalty = getPenaltyScore(qrcode);
if (penalty < minPenalty) {
mask = msk;
minPenalty = penalty;
}
applyMask(tempBuffer, qrcode, msk); // Undoes the mask due to XOR
}
}
assert(0 <= (int)mask && (int)mask <= 7);
drawFormatBits(ecl, mask, qrcode);
applyMask(tempBuffer, qrcode, mask);
return true;
}
// Calculates the number of bits needed to encode the given segments at the given version.
// Returns a non-negative number if successful. Otherwise returns -1 if a segment has too
// many characters to fit its length field, or the total bits exceeds INT16_MAX.

74
c/qrcodegen.h
Unescape View File

@ -145,7 +145,7 @@ struct qrcodegen_Segment {
/*---- Functions to generate QR Codes ----*/
/*---- Functions (high level) to generate QR Codes ----*/
/*
* Encodes the given text string to a QR Code, returning true if encoding succeeded.
@ -192,6 +192,43 @@ bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcod
enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
/*---- Functions (low level) to generate QR Codes ----*/
/*
* Renders a QR Code representing the given segments at the given error correction level.
* The smallest possible QR Code version is automatically chosen for the output. Returns true if
* QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level
* of the result may be higher than the ecl argument if it can be done without increasing the version.
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and byte) to encode text in less space.
* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
* result in them being clobbered, but the QR Code output will still be correct.
* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
*/
bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
/*
* Renders a QR Code representing the given segments with the given encoding parameters.
* Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions.
* The smallest possible QR Code version within the given range is automatically
* chosen for the output. Iff boostEcl is true, then the ECC level of the result
* may be higher than the ecl argument if it can be done without increasing the
* version. The mask number is either between 0 to 7 (inclusive) to force that
* mask, or -1 to automatically choose an appropriate mask (which may be slow).
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and byte) to encode text in less space.
* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
* result in them being clobbered, but the QR Code output will still be correct.
* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
*/
bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);
/*
* Tests whether the given string can be encoded as a segment in alphanumeric mode.
* A string is encodable iff each character is in the following set: 0 to 9, A to Z
@ -250,41 +287,6 @@ struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t bu
struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]);
/*
* Renders a QR Code representing the given segments at the given error correction level.
* The smallest possible QR Code version is automatically chosen for the output. Returns true if
* QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level
* of the result may be higher than the ecl argument if it can be done without increasing the version.
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and byte) to encode text in less space.
* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
* result in them being clobbered, but the QR Code output will still be correct.
* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
*/
bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
/*
* Renders a QR Code representing the given segments with the given encoding parameters.
* Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions.
* The smallest possible QR Code version within the given range is automatically
* chosen for the output. Iff boostEcl is true, then the ECC level of the result
* may be higher than the ecl argument if it can be done without increasing the
* version. The mask number is either between 0 to 7 (inclusive) to force that
* mask, or -1 to automatically choose an appropriate mask (which may be slow).
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and byte) to encode text in less space.
* This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
* To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
* result in them being clobbered, but the QR Code output will still be correct.
* But the qrcode array must not overlap tempBuffer or any segment's data buffer.
*/
bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);
/*---- Functions to extract raw data from QR Codes ----*/
/*

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