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mazegame/tools/MSXtk/qrcode/qrcode.c
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/*
* QR Code generator library (C)
*
* Copyright (c) Project Nayuki. (MIT License)
* https://www.nayuki.io/page/qr-code-generator-library
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
#include "qrcode.h"
#if (QRCODE_VERSION_CUSTOM)
u8 g_QRCode_VersionMin = QRCODE_VERSION_MIN;
u8 g_QRCode_VersionMax = QRCODE_VERSION_MAX;
#define QRCODE_VERSION_CURRENT_MIN g_QRCode_VersionMin
#define QRCODE_VERSION_CURRENT_MAX g_QRCode_VersionMax
#else
#define QRCODE_VERSION_CURRENT_MIN QRCODE_VERSION_MIN
#define QRCODE_VERSION_CURRENT_MAX QRCODE_VERSION_MAX
#endif
//#if (QRCODE_MASK_DEF == QRCODE_MASK_CUSTOM)
// u8 g_QRCode_Mask = QRCODE_MASK_AUTO;
// #define QRCODE_MASK_CURRENT g_QRCode_Mask
//#else
// #define QRCODE_MASK_CURRENT QRCODE_MASK
//#endif
#define NULL ((void *)0)
#define LONG_MAX 2147483647L // 0x7FFFFFFF
int abs(int a)
{
return (a > 0) ? a : -a;
}
long labs(long a)
{
return (a > 0) ? a : -a;
}
u16 strlen(const c8* str)
{
u16 ret = 0;
while (*str++)
ret++;
return ret;
}
const c8* strchr(const c8* str, c8 chr)
{
while (*str)
{
if (*str == chr)
return str;
str++;
}
return NULL;
}
void* memset(void* src, u8 val, u16 num)
{
u8* d = (u8*)src;
for (u16 i = 0; i < num; i++)
{
*d = val;
d++;
}
return src;
}
static u8 g_Buffer[1024];
void* memmove(void* dst, const void* src, u16 num)
{
u8* tmp = g_Buffer;
const u8* s = (const u8*)src;
u8* d = tmp;
for (u16 i = 0; i < num; i++)
{
*d = *s;
s++;
d++;
}
s = tmp;
d = (u8*)dst;
for (u16 i = 0; i < num; i++)
{
*d = *s;
s++;
d++;
}
return dst;
}
void* memcpy(void* dst, const void* src, u16 num)
{
const u8* s = (const u8*)src;
u8* d = (u8*)dst;
for (u16 i = 0; i < num; i++)
{
*d = *s;
s++;
d++;
}
return dst;
}
/*---- Forward declarations for private functions ----*/
// Regarding all public and private functions defined in this source file:
// - They require all pointer/array arguments to be not null unless the array length is zero.
// - They only read input scalar/array arguments, write to output pointer/array
// arguments, and return scalar values; they are "pure" functions.
// - They don't read mutable global variables or write to any global variables.
// - They don't perform I/O, read the clock, print to console, etc.
// - They allocate a small and constant amount of stack memory.
// - They don't allocate or free any memory on the heap.
// - They don't recurse or mutually recurse. All the code
// could be inlined into the top-level public functions.
// - They run in at most quadratic time with respect to input arguments.
// Most functions run in linear time, and some in constant time.
// There are no unbounded loops or non-obvious termination conditions.
// - They are completely thread-safe if the caller does not give the
// same writable buffer to concurrent calls to these functions.
void appendBitsToBuffer(u16 val, i16 numBits, u8 buffer[], i16 *bitLen);
void addEccAndInterleave(u8 data[], i16 version, enum QRCODE_ECC ecl, u8 result[]);
i16 getNumDataCodewords(i16 version, enum QRCODE_ECC ecl);
i16 getNumRawDataModules(i16 ver);
void reedSolomonComputeDivisor(i16 degree, u8 result[]);
void reedSolomonComputeRemainder(const u8 data[], i16 dataLen, const u8 generator[], i16 degree, u8 result[]);
u8 reedSolomonMultiply(u8 x, u8 y);
void initializeFunctionModules(i16 version, u8 qrcode[]);
static void drawLightFunctionModules(u8 qrcode[], i16 version);
static void drawFormatBits(enum QRCODE_ECC ecl, enum QRCODE_MASK mask, u8 qrcode[]);
i16 getAlignmentPatternPositions(i16 version, u8 result[7]);
static void fillRectangle(i16 left, i16 top, i16 width, i16 height, u8 qrcode[]);
static void drawCodewords(const u8 data[], i16 dataLen, u8 qrcode[]);
static void applyMask(const u8 functionModules[], u8 qrcode[], enum QRCODE_MASK mask);
static long getPenaltyScore(const u8 qrcode[]);
static i16 finderPenaltyCountPatterns(const i16 runHistory[7], i16 qrsize);
static i16 finderPenaltyTerminateAndCount(bool currentRunColor, i16 currentRunLength, i16 runHistory[7], i16 qrsize);
static void finderPenaltyAddHistory(i16 currentRunLength, i16 runHistory[7], i16 qrsize);
bool getModuleBounded(const u8 qrcode[], i16 x, i16 y);
void setModuleBounded(u8 qrcode[], i16 x, i16 y, bool isDark);
void setModuleUnbounded(u8 qrcode[], i16 x, i16 y, bool isDark);
static bool getBit(i16 x, i16 i);
i16 calcSegmentBitLength(enum QRCODE_MODE mode, u16 numChars);
i16 getTotalBits(const struct QRCode_Segment segs[], u16 len, i16 version);
static i16 numCharCountBits(enum QRCODE_MODE mode, i16 version);
/*---- Private tables of constants ----*/
// The set of all legal characters in alphanumeric mode, where each character
// value maps to the index in the string. For checking text and encoding segments.
static const char *ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
// Sentinel value for use in only some functions.
#define LENGTH_OVERFLOW -1
// For generating error correction codes.
const i8 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
{-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28}, // Medium
{-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // Quartile
{-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // High
};
#define QRCode_REED_SOLOMON_DEGREE_MAX 30 // Based on the table above
// For generating error correction codes.
const i8 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
{-1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 5, 8, 9, 9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49}, // Medium
{-1, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68}, // Quartile
{-1, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81}, // High
};
// For automatic mask pattern selection.
static const i16 PENALTY_N1 = 3;
static const i16 PENALTY_N2 = 3;
static const i16 PENALTY_N3 = 40;
static const i16 PENALTY_N4 = 10;
/*---- High-level QR Code encoding functions ----*/
// Public function - see documentation comment in header file.
bool QRCode_EncodeText(const char *text, u8 tempBuffer[], u8 qrcode[], enum QRCODE_ECC ecl, enum QRCODE_MASK mask, bool boostEcl)
{
u16 textLen = (u16)strlen(text);
if (textLen == 0)
return QRCode_encodeSegmentsAdvanced(NULL, 0, ecl, mask, boostEcl, tempBuffer, qrcode);
u16 bufLen = (u16)QRCODE_BUFFER_LEN_FOR_VERSION(QRCODE_VERSION_CURRENT_MAX);
struct QRCode_Segment seg;
if (QRCode_isNumeric(text))
{
if (QRCode_CalcSegmentBufferSize(QRCODE_MODE_NUMERIC, textLen) > bufLen)
goto fail;
QRCode_MakeNumeric(text, tempBuffer, &seg);
}
else if (QRCode_isAlphanumeric(text))
{
if (QRCode_CalcSegmentBufferSize(QRCODE_MODE_ALPHANUMERIC, textLen) > bufLen)
goto fail;
QRCode_MakeAlphanumeric(text, tempBuffer, &seg);
}
else
{
if (textLen > bufLen)
goto fail;
for (u16 i = 0; i < textLen; i++)
tempBuffer[i] = (u8)text[i];
seg.mode = QRCODE_MODE_BYTE;
seg.bitLength = calcSegmentBitLength(seg.mode, textLen);
if (seg.bitLength == LENGTH_OVERFLOW)
goto fail;
seg.numChars = (i16)textLen;
seg.data = tempBuffer;
}
return QRCode_encodeSegmentsAdvanced(&seg, 1, ecl, mask, boostEcl, tempBuffer, qrcode);
fail:
qrcode[0] = 0; // Set size to invalid value for safety
return FALSE;
}
#if (QRCODE_USE_EXTRA)
// Public function - see documentation comment in header file.
bool QRCode_EncodeBinary(u8 dataAndTemp[], u16 dataLen, u8 qrcode[], enum QRCODE_ECC ecl, enum QRCODE_MASK mask, bool boostEcl)
{
struct QRCode_Segment seg;
seg.mode = QRCODE_MODE_BYTE;
seg.bitLength = calcSegmentBitLength(seg.mode, dataLen);
if (seg.bitLength == LENGTH_OVERFLOW)
{
qrcode[0] = 0; // Set size to invalid value for safety
return FALSE;
}
seg.numChars = (i16)dataLen;
seg.data = dataAndTemp;
return QRCode_encodeSegmentsAdvanced(&seg, 1, ecl, mask, boostEcl, dataAndTemp, qrcode);
}
#endif
// Appends the given number of low-order bits of the given value to the given byte-based
// bit buffer, increasing the bit length. Requires 0 <= numBits <= 16 and val < 2^numBits.
void appendBitsToBuffer(u16 val, i16 numBits, u8 buffer[], i16 *bitLen)
{
assert(0 <= numBits && numBits <= 16 && (unsigned long)val >> numBits == 0);
for (i16 i = numBits - 1; i >= 0; i--, (*bitLen)++)
buffer[*bitLen >> 3] |= ((val >> i) & 1) << (7 - (*bitLen & 7));
}
/*---- Low-level QR Code encoding functions ----*/
#if (QRCODE_USE_EXTRA)
// Public function - see documentation comment in header file.
bool QRCode_encodeSegments(const struct QRCode_Segment segs[], u16 len, enum QRCODE_ECC ecl, u8 tempBuffer[], u8 qrcode[])
{
return QRCode_encodeSegmentsAdvanced(segs, len, ecl, QRCODE_MASK_AUTO, TRUE, tempBuffer, qrcode);
}
#endif
// Public function - see documentation comment in header file.
bool QRCode_encodeSegmentsAdvanced(const struct QRCode_Segment segs[], u16 len, enum QRCODE_ECC ecl, enum QRCODE_MASK mask, bool boostEcl, u8 tempBuffer[], u8 qrcode[])
{
assert(segs != NULL || len == 0);
assert(QRCODE_VERSION_MIN <= QRCODE_VERSION_CURRENT_MIN && QRCODE_VERSION_CURRENT_MIN <= QRCODE_VERSION_CURRENT_MAX && QRCODE_VERSION_CURRENT_MAX <= QRCODE_VERSION_MAX);
assert(0 <= (i16)ecl && (i16)ecl <= 3 && -1 <= (i16)mask && (i16)mask <= 7);
// Find the minimal version number to use
i16 version, dataUsedBits;
for (version = QRCODE_VERSION_CURRENT_MIN; ; version++)
{
i16 dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = getTotalBits(segs, len, version);
if (dataUsedBits != LENGTH_OVERFLOW && dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
if (version >= QRCODE_VERSION_CURRENT_MAX)
{ // 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 != LENGTH_OVERFLOW);
// Increase the error correction level while the data still fits in the current version number
for (i16 i = (i16)QRCODE_ECC_MEDIUM; i <= (i16)QRCODE_ECC_HIGH; i++)
{ // From low to high
if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum QRCODE_ECC)i) * 8)
ecl = (enum QRCODE_ECC)i;
}
// Concatenate all segments to create the data bit string
memset(qrcode, 0, (u16)QRCODE_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
i16 bitLen = 0;
for (u16 i = 0; i < len; i++)
{
const struct QRCode_Segment *seg = &segs[i];
appendBitsToBuffer((u16)seg->mode, 4, qrcode, &bitLen);
appendBitsToBuffer((u16)seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
for (i16 j = 0; j < seg->bitLength; j++)
{
i16 bit = (seg->data[j >> 3] >> (7 - (j & 7))) & 1;
appendBitsToBuffer((u16)bit, 1, qrcode, &bitLen);
}
}
assert(bitLen == dataUsedBits);
// Add terminator and pad up to a byte if applicable
i16 dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
assert(bitLen <= dataCapacityBits);
i16 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 (u8 padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
// Compute ECC, draw modules
addEccAndInterleave(qrcode, version, ecl, tempBuffer);
initializeFunctionModules(version, qrcode);
drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
drawLightFunctionModules(qrcode, version);
initializeFunctionModules(version, tempBuffer);
// Do masking
if (mask == QRCODE_MASK_AUTO)
{ // Automatically choose best mask
long minPenalty = LONG_MAX;
for (i16 i = 0; i < 8; i++)
{
enum QRCODE_MASK msk = (enum QRCODE_MASK)i;
applyMask(tempBuffer, qrcode, msk);
drawFormatBits(ecl, msk, qrcode);
long penalty = getPenaltyScore(qrcode);
if (penalty < minPenalty)
{
mask = msk;
minPenalty = penalty;
}
applyMask(tempBuffer, qrcode, msk); // Undoes the mask due to XOR
}
}
assert(0 <= (i16)mask && (i16)mask <= 7);
applyMask(tempBuffer, qrcode, mask); // Apply the final choice of mask
drawFormatBits(ecl, mask, qrcode); // Overwrite old format bits
return TRUE;
}
/*---- Error correction code generation functions ----*/
// Appends error correction bytes to each block of the given data array, then interleaves
// bytes from the blocks and stores them in the result array. data[0 : dataLen] contains
// the input data. data[dataLen : rawCodewords] is used as a temporary work area and will
// be clobbered by this function. The final answer is stored in result[0 : rawCodewords].
void addEccAndInterleave(u8 data[], i16 version, enum QRCODE_ECC ecl, u8 result[])
{
// Calculate parameter numbers
assert(0 <= (i16)ecl && (i16)ecl < 4 && QRCODE_VERSION_MIN <= version && version <= QRCODE_VERSION_MAX);
i16 numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(i16)ecl][version];
i16 blockEccLen = ECC_CODEWORDS_PER_BLOCK [(i16)ecl][version];
i16 rawCodewords = getNumRawDataModules(version) / 8;
i16 dataLen = getNumDataCodewords(version, ecl);
i16 numShortBlocks = numBlocks - rawCodewords % numBlocks;
i16 shortBlockDataLen = rawCodewords / numBlocks - blockEccLen;
// Split data into blocks, calculate ECC, and interleave
// (not concatenate) the bytes into a single sequence
u8 rsdiv[QRCode_REED_SOLOMON_DEGREE_MAX];
reedSolomonComputeDivisor(blockEccLen, rsdiv);
const u8 *dat = data;
for (i16 i = 0; i < numBlocks; i++)
{
i16 datLen = shortBlockDataLen + (i < numShortBlocks ? 0 : 1);
u8 *ecc = &data[dataLen]; // Temporary storage
reedSolomonComputeRemainder(dat, datLen, rsdiv, blockEccLen, ecc);
for (i16 j = 0, k = i; j < datLen; j++, k += numBlocks)
{ // Copy data
if (j == shortBlockDataLen)
k -= numShortBlocks;
result[k] = dat[j];
}
for (i16 j = 0, k = dataLen + i; j < blockEccLen; j++, k += numBlocks) // Copy ECC
result[k] = ecc[j];
dat += datLen;
}
}
// Returns the number of 8-bit codewords that can be used for storing data (not ECC),
// for the given version number and error correction level. The result is in the range [9, 2956].
i16 getNumDataCodewords(i16 version, enum QRCODE_ECC ecl)
{
i16 v = version, e = (i16)ecl;
assert(0 <= e && e < 4);
return getNumRawDataModules(v) / 8 - ECC_CODEWORDS_PER_BLOCK[e][v] * NUM_ERROR_CORRECTION_BLOCKS[e][v];
}
// Returns the number of data bits that can be stored in a QR Code of the given version number, after
// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.
i16 getNumRawDataModules(i16 ver)
{
assert(QRCODE_VERSION_MIN <= ver && ver <= QRCODE_VERSION_MAX);
i16 result = (16 * ver + 128) * ver + 64;
if (ver >= 2)
{
i16 numAlign = ver / 7 + 2;
result -= (25 * numAlign - 10) * numAlign - 55;
if (ver >= 7)
result -= 36;
}
assert(208 <= result && result <= 29648);
return result;
}
/*---- Reed-Solomon ECC generator functions ----*/
// Computes a Reed-Solomon ECC generator polynomial for the given degree, storing in result[0 : degree].
// This could be implemented as a lookup table over all possible parameter values, instead of as an algorithm.
void reedSolomonComputeDivisor(i16 degree, u8 result[])
{
assert(1 <= degree && degree <= QRCode_REED_SOLOMON_DEGREE_MAX);
// Polynomial coefficients are stored from highest to lowest power, excluding the leading term which is always 1.
// For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}.
memset(result, 0, (u16)degree * sizeof(result[0]));
result[degree - 1] = 1; // Start off with the monomial x^0
// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
// drop the highest monomial term which is always 1x^degree.
// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
u8 root = 1;
for (i16 i = 0; i < degree; i++)
{
// Multiply the current product by (x - r^i)
for (i16 j = 0; j < degree; j++)
{
result[j] = reedSolomonMultiply(result[j], root);
if (j + 1 < degree)
result[j] ^= result[j + 1];
}
root = reedSolomonMultiply(root, 0x02);
}
}
// Computes the Reed-Solomon error correction codeword for the given data and divisor polynomials.
// The remainder when data[0 : dataLen] is divided by divisor[0 : degree] is stored in result[0 : degree].
// All polynomials are in big endian, and the generator has an implicit leading 1 term.
void reedSolomonComputeRemainder(const u8 data[], i16 dataLen, const u8 generator[], i16 degree, u8 result[])
{
assert(1 <= degree && degree <= QRCode_REED_SOLOMON_DEGREE_MAX);
memset(result, 0, (u16)degree * sizeof(result[0]));
for (i16 i = 0; i < dataLen; i++)
{ // Polynomial division
u8 factor = data[i] ^ result[0];
memmove(&result[0], &result[1], (u16)(degree - 1) * sizeof(result[0]));
result[degree - 1] = 0;
for (i16 j = 0; j < degree; j++)
result[j] ^= reedSolomonMultiply(generator[j], factor);
}
}
#undef QRCode_REED_SOLOMON_DEGREE_MAX
// Returns the product of the two given field elements modulo GF(2^8/0x11D).
// All inputs are valid. This could be implemented as a 256*256 lookup table.
u8 reedSolomonMultiply(u8 x, u8 y)
{
// Russian peasant multiplication
u8 z = 0;
for (i16 i = 7; i >= 0; i--) {
z = (u8)((z << 1) ^ ((z >> 7) * 0x11D));
z ^= ((y >> i) & 1) * x;
}
return z;
}
/*---- Drawing function modules ----*/
// Clears the given QR Code grid with light modules for the given
// version's size, then marks every function module as dark.
void initializeFunctionModules(i16 version, u8 qrcode[])
{
// Initialize QR Code
i16 qrsize = version * 4 + 17;
memset(qrcode, 0, (u16)((qrsize * qrsize + 7) / 8 + 1) * sizeof(qrcode[0]));
qrcode[0] = (u8)qrsize;
// Fill horizontal and vertical timing patterns
fillRectangle(6, 0, 1, qrsize, qrcode);
fillRectangle(0, 6, qrsize, 1, qrcode);
// Fill 3 finder patterns (all corners except bottom right) and format bits
fillRectangle(0, 0, 9, 9, qrcode);
fillRectangle(qrsize - 8, 0, 8, 9, qrcode);
fillRectangle(0, qrsize - 8, 9, 8, qrcode);
// Fill numerous alignment patterns
u8 alignPatPos[7];
i16 numAlign = getAlignmentPatternPositions(version, alignPatPos);
for (i16 i = 0; i < numAlign; i++)
{
for (i16 j = 0; j < numAlign; j++)
{
// Don't draw on the three finder corners
if (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)))
fillRectangle(alignPatPos[i] - 2, alignPatPos[j] - 2, 5, 5, qrcode);
}
}
// Fill version blocks
if (version >= 7)
{
fillRectangle(qrsize - 11, 0, 3, 6, qrcode);
fillRectangle(0, qrsize - 11, 6, 3, qrcode);
}
}
// Draws light function modules and possibly some dark modules onto the given QR Code, without changing
// non-function modules. This does not draw the format bits. This requires all function modules to be previously
// marked dark (namely by initializeFunctionModules()), because this may skip redrawing dark function modules.
static void drawLightFunctionModules(u8 qrcode[], i16 version)
{
// Draw horizontal and vertical timing patterns
u8 qrsize = QRCode_GetSize(qrcode);
for (i16 i = 7; i < qrsize - 7; i += 2)
{
setModuleBounded(qrcode, 6, i, FALSE);
setModuleBounded(qrcode, i, 6, FALSE);
}
// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
for (i16 dy = -4; dy <= 4; dy++)
{
for (i16 dx = -4; dx <= 4; dx++)
{
i16 dist = abs(dx);
if (abs(dy) > dist)
dist = abs(dy);
if (dist == 2 || dist == 4)
{
setModuleUnbounded(qrcode, 3 + dx, 3 + dy, FALSE);
setModuleUnbounded(qrcode, qrsize - 4 + dx, 3 + dy, FALSE);
setModuleUnbounded(qrcode, 3 + dx, qrsize - 4 + dy, FALSE);
}
}
}
// Draw numerous alignment patterns
u8 alignPatPos[7];
i16 numAlign = getAlignmentPatternPositions(version, alignPatPos);
for (i16 i = 0; i < numAlign; i++)
{
for (i16 j = 0; j < numAlign; j++)
{
if ((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0))
continue; // Don't draw on the three finder corners
for (i16 dy = -1; dy <= 1; dy++)
{
for (i16 dx = -1; dx <= 1; dx++)
setModuleBounded(qrcode, alignPatPos[i] + dx, alignPatPos[j] + dy, dx == 0 && dy == 0);
}
}
}
// Draw version blocks
if (version >= 7)
{
// Calculate error correction code and pack bits
i16 rem = version; // version is uint6, in the range [7, 40]
for (i16 i = 0; i < 12; i++)
rem = (rem << 1) ^ ((rem >> 11) * 0x1F25);
long bits = (long)version << 12 | rem; // uint18
assert(bits >> 18 == 0);
// Draw two copies
for (i16 i = 0; i < 6; i++)
{
for (i16 j = 0; j < 3; j++)
{
i16 k = qrsize - 11 + j;
setModuleBounded(qrcode, k, i, (bits & 1) != 0);
setModuleBounded(qrcode, i, k, (bits & 1) != 0);
bits >>= 1;
}
}
}
}
// Draws two copies of the format bits (with its own error correction code) based
// on the given mask and error correction level. This always draws all modules of
// the format bits, unlike drawLightFunctionModules() which might skip dark modules.
static void drawFormatBits(enum QRCODE_ECC ecl, enum QRCODE_MASK mask, u8 qrcode[])
{
// Calculate error correction code and pack bits
assert(0 <= (i16)mask && (i16)mask <= 7);
static const i16 table[] = {1, 0, 3, 2};
i16 data = table[(i16)ecl] << 3 | (i16)mask; // errCorrLvl is uint2, mask is uint3
i16 rem = data;
for (i16 i = 0; i < 10; i++)
rem = (rem << 1) ^ ((rem >> 9) * 0x537);
i16 bits = (data << 10 | rem) ^ 0x5412; // uint15
assert(bits >> 15 == 0);
// Draw first copy
for (i16 i = 0; i <= 5; i++)
setModuleBounded(qrcode, 8, i, getBit(bits, i));
setModuleBounded(qrcode, 8, 7, getBit(bits, 6));
setModuleBounded(qrcode, 8, 8, getBit(bits, 7));
setModuleBounded(qrcode, 7, 8, getBit(bits, 8));
for (i16 i = 9; i < 15; i++)
setModuleBounded(qrcode, 14 - i, 8, getBit(bits, i));
// Draw second copy
u8 qrsize = QRCode_GetSize(qrcode);
for (i16 i = 0; i < 8; i++)
setModuleBounded(qrcode, qrsize - 1 - i, 8, getBit(bits, i));
for (i16 i = 8; i < 15; i++)
setModuleBounded(qrcode, 8, qrsize - 15 + i, getBit(bits, i));
setModuleBounded(qrcode, 8, qrsize - 8, TRUE); // Always dark
}
// Calculates and stores an ascending list of positions of alignment patterns
// for this version number, returning the length of the list (in the range [0,7]).
// Each position is in the range [0,177), and are used on both the x and y axes.
// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
i16 getAlignmentPatternPositions(i16 version, u8 result[7])
{
if (version == 1)
return 0;
i16 numAlign = version / 7 + 2;
i16 step = (version == 32) ? 26 :
(version * 4 + numAlign * 2 + 1) / (numAlign * 2 - 2) * 2;
for (i16 i = numAlign - 1, pos = version * 4 + 10; i >= 1; i--, pos -= step)
result[i] = (u8)pos;
result[0] = 6;
return numAlign;
}
// Sets every module in the range [left : left + width] * [top : top + height] to dark.
static void fillRectangle(i16 left, i16 top, i16 width, i16 height, u8 qrcode[])
{
for (i16 dy = 0; dy < height; dy++)
{
for (i16 dx = 0; dx < width; dx++)
setModuleBounded(qrcode, left + dx, top + dy, TRUE);
}
}
/*---- Drawing data modules and masking ----*/
// Draws the raw codewords (including data and ECC) onto the given QR Code. This requires the initial state of
// the QR Code to be dark at function modules and light at codeword modules (including unused remainder bits).
static void drawCodewords(const u8 data[], i16 dataLen, u8 qrcode[])
{
u8 qrsize = QRCode_GetSize(qrcode);
i16 i = 0; // Bit index into the data
// Do the funny zigzag scan
for (i16 right = qrsize - 1; right >= 1; right -= 2)
{ // Index of right column in each column pair
if (right == 6)
right = 5;
for (i16 vert = 0; vert < qrsize; vert++)
{ // Vertical counter
for (i16 j = 0; j < 2; j++)
{
i16 x = right - j; // Actual x coordinate
bool upward = ((right + 1) & 2) == 0;
i16 y = upward ? qrsize - 1 - vert : vert; // Actual y coordinate
if (!getModuleBounded(qrcode, x, y) && i < dataLen * 8)
{
bool dark = getBit(data[i >> 3], 7 - (i & 7));
setModuleBounded(qrcode, x, y, dark);
i++;
}
// If this QR Code has any remainder bits (0 to 7), they were assigned as
// 0/FALSE/light by the constructor and are left unchanged by this method
}
}
}
assert(i == dataLen * 8);
}
// XORs the codeword modules in this QR Code with the given mask pattern
// and given pattern of function modules. The codeword bits must be drawn
// before masking. Due to the arithmetic of XOR, calling applyMask() with
// the same mask value a second time will undo the mask. A final well-formed
// QR Code needs exactly one (not zero, two, etc.) mask applied.
static void applyMask(const u8 functionModules[], u8 qrcode[], enum QRCODE_MASK mask)
{
assert(0 <= (i16)mask && (i16)mask <= 7); // Disallows QRCODE_MASK_AUTO
u8 qrsize = QRCode_GetSize(qrcode);
for (i16 y = 0; y < qrsize; y++)
{
for (i16 x = 0; x < qrsize; x++)
{
if (getModuleBounded(functionModules, x, y))
continue;
bool invert;
switch ((i16)mask)
{
case 0: invert = (x + y) % 2 == 0; break;
case 1: invert = y % 2 == 0; break;
case 2: invert = x % 3 == 0; break;
case 3: invert = (x + y) % 3 == 0; break;
case 4: invert = (x / 3 + y / 2) % 2 == 0; break;
case 5: invert = x * y % 2 + x * y % 3 == 0; break;
case 6: invert = (x * y % 2 + x * y % 3) % 2 == 0; break;
case 7: invert = ((x + y) % 2 + x * y % 3) % 2 == 0; break;
default: assert(FALSE); return;
}
bool val = getModuleBounded(qrcode, x, y);
setModuleBounded(qrcode, x, y, val ^ invert);
}
}
}
// Calculates and returns the penalty score based on state of the given QR Code's current modules.
// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
static long getPenaltyScore(const u8 qrcode[])
{
u8 qrsize = QRCode_GetSize(qrcode);
long result = 0;
// Adjacent modules in row having same color, and finder-like patterns
for (i16 y = 0; y < qrsize; y++)
{
bool runColor = FALSE;
i16 runX = 0;
i16 runHistory[7] = {0};
for (i16 x = 0; x < qrsize; x++)
{
if (getModuleBounded(qrcode, x, y) == runColor)
{
runX++;
if (runX == 5)
result += PENALTY_N1;
else if (runX > 5)
result++;
}
else
{
finderPenaltyAddHistory(runX, runHistory, qrsize);
if (!runColor)
result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
runColor = getModuleBounded(qrcode, x, y);
runX = 1;
}
}
result += finderPenaltyTerminateAndCount(runColor, runX, runHistory, qrsize) * PENALTY_N3;
}
// Adjacent modules in column having same color, and finder-like patterns
for (i16 x = 0; x < qrsize; x++)
{
bool runColor = FALSE;
i16 runY = 0;
i16 runHistory[7] = {0};
for (i16 y = 0; y < qrsize; y++)
{
if (getModuleBounded(qrcode, x, y) == runColor)
{
runY++;
if (runY == 5)
result += PENALTY_N1;
else if (runY > 5)
result++;
}
else
{
finderPenaltyAddHistory(runY, runHistory, qrsize);
if (!runColor)
result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
runColor = getModuleBounded(qrcode, x, y);
runY = 1;
}
}
result += finderPenaltyTerminateAndCount(runColor, runY, runHistory, qrsize) * PENALTY_N3;
}
// 2*2 blocks of modules having same color
for (i16 y = 0; y < qrsize - 1; y++)
{
for (i16 x = 0; x < qrsize - 1; x++)
{
bool color = getModuleBounded(qrcode, x, y);
if ( color == getModuleBounded(qrcode, x + 1, y) &&
color == getModuleBounded(qrcode, x, y + 1) &&
color == getModuleBounded(qrcode, x + 1, y + 1))
result += PENALTY_N2;
}
}
// Balance of dark and light modules
i16 dark = 0;
for (i16 y = 0; y < qrsize; y++)
{
for (i16 x = 0; x < qrsize; x++)
{
if (getModuleBounded(qrcode, x, y))
dark++;
}
}
i16 total = qrsize * qrsize; // Note that size is odd, so dark/total != 1/2
// Compute the smallest integer k >= 0 such that (45-5k)% <= dark/total <= (55+5k)%
i16 k = (i16)((labs(dark * 20L - total * 10L) + total - 1) / total) - 1;
assert(0 <= k && k <= 9);
result += k * PENALTY_N4;
assert(0 <= result && result <= 2568888L); // Non-tight upper bound based on default values of PENALTY_N1, ..., N4
return result;
}
// Can only be called immediately after a light run is added, and
// returns either 0, 1, or 2. A helper function for getPenaltyScore().
static i16 finderPenaltyCountPatterns(const i16 runHistory[7], i16 qrsize)
{
i16 n = runHistory[1];
assert(n <= qrsize * 3); (void)qrsize;
bool core = n > 0 && runHistory[2] == n && runHistory[3] == n * 3 && runHistory[4] == n && runHistory[5] == n;
// The maximum QR Code size is 177, hence the dark run length n <= 177.
// Arithmetic is promoted to i16, so n*4 will not overflow.
return (core && runHistory[0] >= n * 4 && runHistory[6] >= n ? 1 : 0)
+ (core && runHistory[6] >= n * 4 && runHistory[0] >= n ? 1 : 0);
}
// Must be called at the end of a line (row or column) of modules. A helper function for getPenaltyScore().
static i16 finderPenaltyTerminateAndCount(bool currentRunColor, i16 currentRunLength, i16 runHistory[7], i16 qrsize)
{
if (currentRunColor)
{ // Terminate dark run
finderPenaltyAddHistory(currentRunLength, runHistory, qrsize);
currentRunLength = 0;
}
currentRunLength += qrsize; // Add light border to final run
finderPenaltyAddHistory(currentRunLength, runHistory, qrsize);
return finderPenaltyCountPatterns(runHistory, qrsize);
}
// Pushes the given value to the front and drops the last value. A helper function for getPenaltyScore().
static void finderPenaltyAddHistory(i16 currentRunLength, i16 runHistory[7], i16 qrsize)
{
if (runHistory[0] == 0)
currentRunLength += qrsize; // Add light border to initial run
memmove(&runHistory[1], &runHistory[0], 6 * sizeof(runHistory[0]));
runHistory[0] = currentRunLength;
}
/*---- Basic QR Code information ----*/
// Public function - see documentation comment in header file.
u8 QRCode_GetSize(const u8 qrcode[])
{
assert(qrcode != NULL);
u8 result = qrcode[0];
assert((QRCODE_VERSION_MIN * 4 + 17) <= result
&& result <= (QRCODE_VERSION_MAX * 4 + 17));
return result;
}
// Public function - see documentation comment in header file.
bool QRCode_GetModule(const u8 qrcode[], i16 x, i16 y)
{
assert(qrcode != NULL);
i16 qrsize = qrcode[0];
return (0 <= x && x < qrsize && 0 <= y && y < qrsize) && getModuleBounded(qrcode, x, y);
}
// Returns the color of the module at the given coordinates, which must be in bounds.
bool getModuleBounded(const u8 qrcode[], i16 x, i16 y)
{
i16 qrsize = qrcode[0];
assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
i16 index = y * qrsize + x;
return getBit(qrcode[(index >> 3) + 1], index & 7);
}
// Sets the color of the module at the given coordinates, which must be in bounds.
void setModuleBounded(u8 qrcode[], i16 x, i16 y, bool isDark)
{
i16 qrsize = qrcode[0];
assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
i16 index = y * qrsize + x;
i16 bitIndex = index & 7;
i16 byteIndex = (index >> 3) + 1;
if (isDark)
qrcode[byteIndex] |= 1 << bitIndex;
else
qrcode[byteIndex] &= (1 << bitIndex) ^ 0xFF;
}
// Sets the color of the module at the given coordinates, doing nothing if out of bounds.
void setModuleUnbounded(u8 qrcode[], i16 x, i16 y, bool isDark)
{
i16 qrsize = qrcode[0];
if (0 <= x && x < qrsize && 0 <= y && y < qrsize)
setModuleBounded(qrcode, x, y, isDark);
}
//static const u16 g_Bits[16] =
//{
// 0b0000000000000001,
// 0b0000000000000010,
// 0b0000000000000100,
// 0b0000000000001000,
// 0b0000000000010000,
// 0b0000000000100000,
// 0b0000000001000000,
// 0b0000000010000000,
// 0b0000000100000000,
// 0b0000001000000000,
// 0b0000010000000000,
// 0b0000100000000000,
// 0b0001000000000000,
// 0b0010000000000000,
// 0b0100000000000000,
// 0b1000000000000000,
//};
// Returns TRUE iff the i'th bit of x is set to 1. Requires x >= 0 and 0 <= i <= 14.
static bool getBit(i16 x, i16 i)
{
return ((x >> i) & 1) != 0;
//return (g_Bits[i] & x) != 0;
}
/*---- Segment handling ----*/
// Public function - see documentation comment in header file.
bool QRCode_isNumeric(const char *text)
{
assert(text != NULL);
for (; *text != '\0'; text++)
{
if (*text < '0' || *text > '9')
return FALSE;
}
return TRUE;
}
// Public function - see documentation comment in header file.
bool QRCode_isAlphanumeric(const char *text)
{
assert(text != NULL);
for (; *text != '\0'; text++)
{
if (strchr(ALPHANUMERIC_CHARSET, *text) == NULL)
return FALSE;
}
return TRUE;
}
// Public function - see documentation comment in header file.
u16 QRCode_calcSegmentBufferSize(enum QRCODE_MODE mode, u16 numChars)
{
i16 temp = calcSegmentBitLength(mode, numChars);
if (temp == LENGTH_OVERFLOW)
return 0xFFFF;// SIZE_MAX;
assert(0 <= temp && temp <= INT16_MAX);
return ((u16)temp + 7) / 8;
}
// Returns the number of data bits needed to represent a segment
// containing the given number of characters using the given mode. Notes:
// - Returns LENGTH_OVERFLOW on failure, i.e. numChars > INT16_MAX
// or the number of needed bits exceeds INT16_MAX (i.e. 32767).
// - Otherwise, all valid results are in the range [0, INT16_MAX].
// - For byte mode, numChars measures the number of bytes, not Unicode code points.
// - For ECI mode, numChars must be 0, and the worst-case number of bits is returned.
// An actual ECI segment can have shorter data. For non-ECI modes, the result is exact.
i16 calcSegmentBitLength(enum QRCODE_MODE mode, u16 numChars)
{
// All calculations are designed to avoid overflow on all platforms
if (numChars > (u16)INT16_MAX)
return LENGTH_OVERFLOW;
long result = (long)numChars;
if (mode == QRCODE_MODE_NUMERIC)
result = (result * 10 + 2) / 3; // ceil(10/3 * n)
else if (mode == QRCODE_MODE_ALPHANUMERIC)
result = (result * 11 + 1) / 2; // ceil(11/2 * n)
else if (mode == QRCODE_MODE_BYTE)
result *= 8;
else if (mode == QRCODE_MODE_KANJI)
result *= 13;
else if (mode == QRCODE_MODE_ECI && numChars == 0)
result = 3 * 8;
else
{ // Invalid argument
assert(FALSE);
return LENGTH_OVERFLOW;
}
assert(result >= 0);
if (result > INT16_MAX)
return LENGTH_OVERFLOW;
return (i16)result;
}
#if (QRCODE_USE_EXTRA)
// Public function - see documentation comment in header file.
void QRCode_MakeBytes(const u8 data[], u16 len, u8 buf[], struct QRCode_Segment* seg)
{
assert(data != NULL || len == 0);
seg->mode = QRCODE_MODE_BYTE;
seg->bitLength = calcSegmentBitLength(seg->mode, len);
assert(seg->bitLength != LENGTH_OVERFLOW);
seg->numChars = (i16)len;
if (len > 0)
memcpy(buf, data, len * sizeof(buf[0]));
seg->data = buf;
}
#endif
// Public function - see documentation comment in header file.
void QRCode_MakeNumeric(const char *digits, u8 buf[], struct QRCode_Segment* seg)
{
assert(digits != NULL);
u16 len = (u16)strlen(digits);
seg->mode = QRCODE_MODE_NUMERIC;
i16 bitLen = calcSegmentBitLength(seg->mode, len);
assert(bitLen != LENGTH_OVERFLOW);
seg->numChars = (i16)len;
if (bitLen > 0)
memset(buf, 0, ((u16)bitLen + 7) / 8 * sizeof(buf[0]));
seg->bitLength = 0;
u16 accumData = 0;
i16 accumCount = 0;
for (; *digits != '\0'; digits++)
{
char c = *digits;
assert('0' <= c && c <= '9');
accumData = accumData * 10 + (u16)(c - '0');
accumCount++;
if (accumCount == 3)
{
appendBitsToBuffer(accumData, 10, buf, &seg->bitLength);
accumData = 0;
accumCount = 0;
}
}
if (accumCount > 0) // 1 or 2 digits remaining
appendBitsToBuffer(accumData, accumCount * 3 + 1, buf, &seg->bitLength);
assert(seg->bitLength == bitLen);
seg->data = buf;
}
// Public function - see documentation comment in header file.
void QRCode_MakeAlphanumeric(const char *text, u8 buf[], struct QRCode_Segment* seg)
{
assert(text != NULL);
u16 len = (u16)strlen(text);
seg->mode = QRCODE_MODE_ALPHANUMERIC;
i16 bitLen = calcSegmentBitLength(seg->mode, len);
assert(bitLen != LENGTH_OVERFLOW);
seg->numChars = (i16)len;
if (bitLen > 0)
memset(buf, 0, ((u16)bitLen + 7) / 8 * sizeof(buf[0]));
seg->bitLength = 0;
u16 accumData = 0;
i16 accumCount = 0;
for (; *text != '\0'; text++)
{
const char *temp = strchr(ALPHANUMERIC_CHARSET, *text);
assert(temp != NULL);
accumData = accumData * 45 + (u16)(temp - ALPHANUMERIC_CHARSET);
accumCount++;
if (accumCount == 2)
{
appendBitsToBuffer(accumData, 11, buf, &seg->bitLength);
accumData = 0;
accumCount = 0;
}
}
if (accumCount > 0) // 1 character remaining
appendBitsToBuffer(accumData, 6, buf, &seg->bitLength);
assert(seg->bitLength == bitLen);
seg->data = buf;
}
#if (QRCODE_USE_EXTRA)
// Public function - see documentation comment in header file.
void QRCode_MakeECI(long assignVal, u8 buf[], struct QRCode_Segment* seg)
{
seg->mode = QRCODE_MODE_ECI;
seg->numChars = 0;
seg->bitLength = 0;
if (assignVal < 0)
assert(FALSE);
else if (assignVal < (1 << 7))
{
memset(buf, 0, 1 * sizeof(buf[0]));
appendBitsToBuffer((u16)assignVal, 8, buf, &seg->bitLength);
}
else if (assignVal < (1 << 14))
{
memset(buf, 0, 2 * sizeof(buf[0]));
appendBitsToBuffer(2, 2, buf, &seg->bitLength);
appendBitsToBuffer((u16)assignVal, 14, buf, &seg->bitLength);
}
else if (assignVal < 1000000L)
{
memset(buf, 0, 3 * sizeof(buf[0]));
appendBitsToBuffer(6, 3, buf, &seg->bitLength);
appendBitsToBuffer((u16)(assignVal >> 10), 11, buf, &seg->bitLength);
appendBitsToBuffer((u16)(assignVal & 0x3FF), 10, buf, &seg->bitLength);
} else
assert(FALSE);
seg->data = buf;
}
#endif
// Calculates the number of bits needed to encode the given segments at the given version.
// Returns a non-negative number if successful. Otherwise returns LENGTH_OVERFLOW if a segment
// has too many characters to fit its length field, or the total bits exceeds INT16_MAX.
i16 getTotalBits(const struct QRCode_Segment segs[], u16 len, i16 version)
{
assert(segs != NULL || len == 0);
long result = 0;
for (u16 i = 0; i < len; i++)
{
i16 numChars = segs[i].numChars;
i16 bitLength = segs[i].bitLength;
assert(0 <= numChars && numChars <= INT16_MAX);
assert(0 <= bitLength && bitLength <= INT16_MAX);
i16 ccbits = numCharCountBits(segs[i].mode, version);
assert(0 <= ccbits && ccbits <= 16);
if (numChars >= (1L << ccbits))
return LENGTH_OVERFLOW; // The segment's length doesn't fit the field's bit width
result += 4L + ccbits + bitLength;
if (result > INT16_MAX)
return LENGTH_OVERFLOW; // The sum might overflow an i16 type
}
assert(0 <= result && result <= INT16_MAX);
return (i16)result;
}
// Returns the bit width of the character count field for a segment in the given mode
// in a QR Code at the given version number. The result is in the range [0, 16].
static i16 numCharCountBits(enum QRCODE_MODE mode, i16 version)
{
assert(QRCODE_VERSION_MIN <= version && version <= QRCODE_VERSION_MAX);
i16 i = (version + 7) / 17;
switch (mode)
{
case QRCODE_MODE_NUMERIC : { static const i16 temp[] = {10, 12, 14}; return temp[i]; }
case QRCODE_MODE_ALPHANUMERIC: { static const i16 temp[] = { 9, 11, 13}; return temp[i]; }
case QRCODE_MODE_BYTE : { static const i16 temp[] = { 8, 16, 16}; return temp[i]; }
case QRCODE_MODE_KANJI : { static const i16 temp[] = { 8, 10, 12}; return temp[i]; }
case QRCODE_MODE_ECI : return 0;
default: assert(FALSE); return -1; // Dummy value
}
}
#undef LENGTH_OVERFLOW
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