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Some penalty calculation optimizations.
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@ricmoo
ricmoo committed Apr 9, 2017
1 parent 48dde53 commit 0d50ea4
Showing 1 changed file with 42 additions and 49 deletions.
91 changes: 42 additions & 49 deletions src/qrcode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -182,31 +182,31 @@ void bb_dump(BitBucket *bitBuffer) {
}
*/

uint16_t bb_getGridSizeBytes(uint8_t size) {
static uint16_t bb_getGridSizeBytes(uint8_t size) {
return (((size * size) + 7) / 8);
}

uint16_t bb_getBufferSizeBytes(uint32_t bits) {
static uint16_t bb_getBufferSizeBytes(uint32_t bits) {
return ((bits + 7) / 8);
}

void bb_initBuffer(BitBucket *bitBuffer, uint8_t *data, int32_t capacityBytes) {
static void bb_initBuffer(BitBucket *bitBuffer, uint8_t *data, int32_t capacityBytes) {
bitBuffer->bitOffsetOrWidth = 0;
bitBuffer->capacityBytes = capacityBytes;
bitBuffer->data = data;

memset(data, 0, bitBuffer->capacityBytes);
}

void bb_initGrid(BitBucket *bitGrid, uint8_t *data, uint8_t size) {
static void bb_initGrid(BitBucket *bitGrid, uint8_t *data, uint8_t size) {
bitGrid->bitOffsetOrWidth = size;
bitGrid->capacityBytes = bb_getGridSizeBytes(size);
bitGrid->data = data;

memset(data, 0, bitGrid->capacityBytes);
}

void bb_appendBits(BitBucket *bitBuffer, uint32_t val, uint8_t length) {
static void bb_appendBits(BitBucket *bitBuffer, uint32_t val, uint8_t length) {
uint32_t offset = bitBuffer->bitOffsetOrWidth;
for (int8_t i = length - 1; i >= 0; i--, offset++) {
bitBuffer->data[offset >> 3] |= ((val >> i) & 1) << (7 - (offset & 7));
Expand All @@ -220,7 +220,7 @@ void bb_setBits(BitBucket *bitBuffer, uint32_t val, int offset, uint8_t length)
}
}
*/
void bb_setBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool on) {
static void bb_setBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool on) {
uint32_t offset = y * bitGrid->bitOffsetOrWidth + x;
uint8_t mask = 1 << (7 - (offset & 0x07));
if (on) {
Expand All @@ -230,7 +230,7 @@ void bb_setBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool on) {
}
}

void bb_invertBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool invert) {
static void bb_invertBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool invert) {
uint32_t offset = y * bitGrid->bitOffsetOrWidth + x;
uint8_t mask = 1 << (7 - (offset & 0x07));
bool on = ((bitGrid->data[offset >> 3] & (1 << (7 - (offset & 0x07)))) != 0);
Expand All @@ -241,7 +241,7 @@ void bb_invertBit(BitBucket *bitGrid, uint8_t x, uint8_t y, bool invert) {
}
}

bool bb_getBit(BitBucket *bitGrid, uint8_t x, uint8_t y) {
static bool bb_getBit(BitBucket *bitGrid, uint8_t x, uint8_t y) {
uint32_t offset = y * bitGrid->bitOffsetOrWidth + x;
return (bitGrid->data[offset >> 3] & (1 << (7 - (offset & 0x07)))) != 0;
}
Expand Down Expand Up @@ -276,7 +276,7 @@ static void applyMask(BitBucket *modules, BitBucket *isFunction, uint8_t mask) {
}
}

void setFunctionModule(BitBucket *modules, BitBucket *isFunction, uint8_t x, uint8_t y, bool on) {
static void setFunctionModule(BitBucket *modules, BitBucket *isFunction, uint8_t x, uint8_t y, bool on) {
bb_setBit(modules, x, y, on);
bb_setBit(isFunction, x, y, true);
}
Expand Down Expand Up @@ -393,7 +393,7 @@ static void drawFunctionPatterns(BitBucket *modules, BitBucket *isFunction, uint
drawFinderPattern(modules, isFunction, size - 4, 3);
drawFinderPattern(modules, isFunction, 3, size - 4);

#if LOCK_VERSION ==0 || LOCK_VERSION > 1
#if LOCK_VERSION == 0 || LOCK_VERSION > 1

if (version > 1) {

Expand Down Expand Up @@ -479,7 +479,7 @@ static void drawCodewords(BitBucket *modules, BitBucket *isFunction, BitBucket *

// Calculates and returns the penalty score based on state of this QR Code's current modules.
// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
// @TODO: There is likely some optimizations we can make here, since memory access is slow on AVR
// @TODO: This can be optimized by working with the bytes instead of bits.
static uint32_t getPenaltyScore(BitBucket *modules) {
uint32_t result = 0;

Expand Down Expand Up @@ -525,45 +525,38 @@ static uint32_t getPenaltyScore(BitBucket *modules) {
}
}

// 2*2 blocks of modules having same color
for (uint8_t y = 0; y < size - 1; y++) {
for (uint8_t x = 0; x < size - 1; x++) {
bool color = bb_getBit(modules, x, y);
if (color == bb_getBit(modules, x + 1, y) && color == bb_getBit(modules, x, y + 1) && color == bb_getBit(modules, x + 1, y + 1)) {
result += PENALTY_N2;
}
}
}

// Finder-like pattern in rows
for (uint8_t y = 0; y < size; y++) {
uint16_t bits = 0;
for (uint8_t x = 0; x < size; x++) {
bits = ((bits << 1) & 0x7FF) | (bb_getBit(modules, x, y) ? 1 : 0);
if (x >= 10 && (bits == 0x05D || bits == 0x5D0)) { // Needs 11 bits accumulated
result += PENALTY_N3;
}
}
}

// Finder-like pattern in columns
for (uint8_t x = 0; x < size; x++) {
uint16_t bits = 0;
for (uint8_t y = 0; y < size; y++) {
bits = ((bits << 1) & 0x7FF) | (bb_getBit(modules, x, y) ? 1 : 0);
if (y >= 10 && (bits == 0x05D || bits == 0x5D0)) { // Needs 11 bits accumulated
result += PENALTY_N3;
}
}
}

// Balance of black and white modules
uint16_t black = 0;
for (uint8_t y = 0; y < size; y++) {
uint16_t bitsRow = 0, bitsCol = 0;
for (uint8_t x = 0; x < size; x++) {
if (bb_getBit(modules, x, y)) {
black++;
bool color = bb_getBit(modules, x, y);

// 2*2 blocks of modules having same color
if (x > 0 && y > 0) {
bool colorUL = bb_getBit(modules, x - 1, y - 1);
bool colorUR = bb_getBit(modules, x, y - 1);
bool colorL = bb_getBit(modules, x - 1, y);
if (color == colorUL && color == colorUR && color == colorL) {
result += PENALTY_N2;
}
}

// Finder-like pattern in rows and columns
bitsRow = ((bitsRow << 1) & 0x7FF) | color;
bitsCol = ((bitsCol << 1) & 0x7FF) | bb_getBit(modules, y, x);

// Needs 11 bits accumulated
if (x >= 10) {
if (bitsRow == 0x05D || bitsRow == 0x5D0) {
result += PENALTY_N3;
}
if (bitsCol == 0x05D || bitsCol == 0x5D0) {
result += PENALTY_N3;
}
}

// Balance of black and white modules
if (color) { black++; }
}
}

Expand All @@ -579,7 +572,7 @@ static uint32_t getPenaltyScore(BitBucket *modules) {

#pragma mark - Reed-Solomon Generator

uint8_t rs_multiply(uint8_t x, uint8_t y) {
static uint8_t rs_multiply(uint8_t x, uint8_t y) {
// Russian peasant multiplication
// See: https://en.wikipedia.org/wiki/Ancient_Egyptian_multiplication
uint16_t z = 0;
Expand All @@ -590,7 +583,7 @@ uint8_t rs_multiply(uint8_t x, uint8_t y) {
return z;
}

void rs_init(uint8_t degree, uint8_t *coeff) {
static void rs_init(uint8_t degree, uint8_t *coeff) {
memset(coeff, 0, degree);
coeff[degree - 1] = 1;

Expand All @@ -610,7 +603,7 @@ void rs_init(uint8_t degree, uint8_t *coeff) {
}
}

void rs_getRemainder(uint8_t degree, uint8_t *coeff, uint8_t *data, uint8_t length, uint8_t *result, uint8_t stride) {
static void rs_getRemainder(uint8_t degree, uint8_t *coeff, uint8_t *data, uint8_t length, uint8_t *result, uint8_t stride) {
// Compute the remainder by performing polynomial division

//for (uint8_t i = 0; i < degree; i++) { result[] = 0; }
Expand Down

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