msb-public
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QR-Code-generator
mirror of https://github.com/nayuki/QR-Code-generator
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Updated C code to consolidate logic for finding minimum fitting version number, also tweaked arithmetic and control flow.

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pull/11/head
Project Nayuki 9 years ago
parent 481a1c0de3
commit cb6835fecb
1 changed files with 39 additions and 39 deletions
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76
c/qrcodegen.c
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@ -31,6 +31,7 @@
/*---- Forward declarations for private functions ----*/
static int fitVersionToData(int minVersion, int maxVersion, enum qrcodegen_Ecc ecl, int dataLen, int dataBitLen, int ver1To9LenBits, int ver10To26LenBits, int ver27To40LenBits);
static void encodeQrCodeTail(uint8_t dataAndQrcode[], int bitLen, uint8_t tempBuffer[], int version, enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, bool boostEcl);
static long getPenaltyScore(const uint8_t qrcode[], int qrsize);
static void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
@ -128,31 +129,14 @@ int qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[
return qrcodegen_encodeBinary(tempBuffer, (size_t)textLen, qrcode, ecl, minVersion, maxVersion, mask, boostEcl);
}
int version;
int dataUsedBits = -1;
int dataCapacityBits = -1;
int lengthBits = -1;
for (version = minVersion; ; version++) {
if (version <= 9)
lengthBits = isNumeric ? 10 : 9;
else if (version <= 26)
lengthBits = isNumeric ? 12 : 11;
else
lengthBits = isNumeric ? 14 : 13;
if (textLen < (1 << lengthBits)) {
dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = checkedAdd(4 + lengthBits, textBits);
if (0 <= dataUsedBits && 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
int version = fitVersionToData(minVersion, maxVersion, ecl, textLen, textBits,
(isNumeric ? 10 : 9), (isNumeric ? 12 : 11), (isNumeric ? 14 : 13));
if (version == 0)
return 0;
}
assert(dataUsedBits >= 0 && dataCapacityBits >= 0);
memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
int bitLen = 0;
appendBitsToBuffer(isNumeric ? 1 : 2, 4, qrcode, &bitLen);
int lengthBits = (version <= 9 ? 9 : (version <= 26 ? 11 : 13)) + (isNumeric ? 1 : 0);
appendBitsToBuffer((unsigned int)textLen, lengthBits, qrcode, &bitLen);
if (isNumeric) {
int accumData = 0;
@ -193,25 +177,13 @@ int qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode
enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
if (dataLen > INT16_MAX)
if (dataLen > INT16_MAX / 8)
return 0;
// Now dataLen <= INT_MAX, since int has at least 16 bits
int version;
int dataUsedBits = -1;
int dataCapacityBits = -1;
for (version = minVersion; ; version++) {
if ((version <= 9 && dataLen < (1U << 8)) || dataLen < (1U << 16)) {
dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = checkedAdd(4 + (version <= 9 ? 8 : 16), checkedMultiply((int)dataLen, 8));
if (0 <= dataUsedBits && 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
return 0;
}
assert(dataUsedBits >= 0 && dataCapacityBits >= 0);
// Now dataLen * 8 <= 65535 <= INT_MAX
int version = fitVersionToData(minVersion, maxVersion, ecl, (int)dataLen, (int)dataLen * 8, 8, 16, 16);
if (version == 0)
return 0;
memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
int bitLen = 0;
appendBitsToBuffer(4, 4, qrcode, &bitLen);
@ -223,6 +195,34 @@ int qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode
}
static int fitVersionToData(int minVersion, int maxVersion, enum qrcodegen_Ecc ecl,
int dataLen, int dataBitLen, int ver1To9LenBits, int ver10To26LenBits, int ver27To40LenBits) {
assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
assert(0 <= (int)ecl && (int)ecl <= 3);
assert(dataLen >= 0 && dataBitLen >= 0);
assert(1 <= ver1To9LenBits && ver1To9LenBits <= 16);
assert(1 <= ver10To26LenBits && ver10To26LenBits <= 16);
assert(1 <= ver27To40LenBits && ver27To40LenBits <= 16);
for (int version = minVersion; ; version++) {
int lengthBits;
if (version <= 9) lengthBits = ver1To9LenBits;
else if (version <= 26) lengthBits = ver10To26LenBits;
else lengthBits = ver27To40LenBits;
if (dataLen >= (1L << lengthBits))
continue;
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
int dataUsedBits = checkedAdd(4 + lengthBits, dataBitLen);
if (0 <= dataUsedBits && dataUsedBits <= dataCapacityBits)
return version; // This version number is found to be suitable
if (version >= maxVersion) // All versions in the range could not fit the given data
return 0;
}
}
// Given data codewords in dataAndQrcode already padded to the length specified by the
// version and ECC level, this function adds ECC bytes, interleaves blocks, renders the
// QR Code symbol back to the array dataAndQrcode, and handles automatic mask selection.

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