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ejecta color hash generator
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
typedef union {
unsigned int hex;
struct {
unsigned char r, g, b, a;
} rgba;
unsigned char components[4];
} EJColorRGBA;
typedef struct {
EJColorRGBA color;
char *name;
size_t length;
} CSSColor;
static CSSColor ColorNames[] = {
{{0xff000000}, "invaid"},
{{0xfffff8f0}, "aliceblue"},
{{0xffd7ebfa}, "antiquewhite"},
{{0xffffff00}, "aqua"},
{{0xffd4ff7f}, "aquamarine"},
{{0xfffffff0}, "azure"},
{{0xffdcf5f5}, "beige"},
{{0xffc4e4ff}, "bisque"},
{{0xff000000}, "black"},
{{0xffcdebff}, "blanchedalmond"},
{{0xffff0000}, "blue"},
{{0xffe22b8a}, "blueviolet"},
{{0xff2a2aa5}, "brown"},
{{0xff87b8de}, "burlywood"},
{{0xffa09e5f}, "cadetblue"},
{{0xff00ff7f}, "chartreuse"},
{{0xff1e69d2}, "chocolate"},
{{0xff507fff}, "coral"},
{{0xffed9564}, "cornflowerblue"},
{{0xffdcf8ff}, "cornsilk"},
{{0xff3c14dc}, "crimson"},
{{0xffffff00}, "cyan"},
{{0xff8b0000}, "darkblue"},
{{0xff8b8b00}, "darkcyan"},
{{0xff0b86b8}, "darkgoldenrod"},
{{0xffa9a9a9}, "darkgray"},
{{0xffa9a9a9}, "darkgrey"},
{{0xff006400}, "darkgreen"},
{{0xff6bb7bd}, "darkkhaki"},
{{0xff8b008b}, "darkmagenta"},
{{0xff2f6b55}, "darkolivegreen"},
{{0xff008cff}, "darkorange"},
{{0xffcc3299}, "darkorchid"},
{{0xff00008b}, "darkred"},
{{0xff7a96e9}, "darksalmon"},
{{0xff8fbc8f}, "darkseagreen"},
{{0xff8b3d48}, "darkslateblue"},
{{0xff4f4f2f}, "darkslategray"},
{{0xff4f4f2f}, "darkslategrey"},
{{0xffd1ce00}, "darkturquoise"},
{{0xffd30094}, "darkviolet"},
{{0xff9314ff}, "deeppink"},
{{0xffffbf00}, "deepskyblue"},
{{0xff696969}, "dimgray"},
{{0xff696969}, "dimgrey"},
{{0xffff901e}, "dodgerblue"},
{{0xff2222b2}, "firebrick"},
{{0xfff0faff}, "floralwhite"},
{{0xff228b22}, "forestgreen"},
{{0xffff00ff}, "fuchsia"},
{{0xffdcdcdc}, "gainsboro"},
{{0xfffff8f8}, "ghostwhite"},
{{0xff00d7ff}, "gold"},
{{0xff20a5da}, "goldenrod"},
{{0xff808080}, "gray"},
{{0xff808080}, "grey"},
{{0xff008000}, "green"},
{{0xff2fffad}, "greenyellow"},
{{0xfff0fff0}, "honeydew"},
{{0xffb469ff}, "hotpink"},
{{0xff5c5ccd}, "indianred"},
{{0xff82004b}, "indigo"},
{{0xfff0ffff}, "ivory"},
{{0xff8ce6f0}, "khaki"},
{{0xfffae6e6}, "lavender"},
{{0xfff5f0ff}, "lavenderblush"},
{{0xff00fc7c}, "lawngreen"},
{{0xffcdfaff}, "lemonchiffon"},
{{0xffe6d8ad}, "lightblue"},
{{0xff8080f0}, "lightcoral"},
{{0xffffffe0}, "lightcyan"},
{{0xffd2fafa}, "lightgoldenrodyellow"},
{{0xffd3d3d3}, "lightgray"},
{{0xffd3d3d3}, "lightgrey"},
{{0xff90ee90}, "lightgreen"},
{{0xffc1b6ff}, "lightpink"},
{{0xff7aa0ff}, "lightsalmon"},
{{0xffaab220}, "lightseagreen"},
{{0xffface87}, "lightskyblue"},
{{0xff998877}, "lightslategray"},
{{0xff998877}, "lightslategrey"},
{{0xffdec4b0}, "lightsteelblue"},
{{0xffe0ffff}, "lightyellow"},
{{0xff00ff00}, "lime"},
{{0xff32cd32}, "limegreen"},
{{0xffe6f0fa}, "linen"},
{{0xffff00ff}, "magenta"},
{{0xff000080}, "maroon"},
{{0xffaacd66}, "mediumaquamarine"},
{{0xffcd0000}, "mediumblue"},
{{0xffd355ba}, "mediumorchid"},
{{0xffd87093}, "mediumpurple"},
{{0xff71b33c}, "mediumseagreen"},
{{0xffee687b}, "mediumslateblue"},
{{0xff9afa00}, "mediumspringgreen"},
{{0xffccd148}, "mediumturquoise"},
{{0xff8515c7}, "mediumvioletred"},
{{0xff701919}, "midnightblue"},
{{0xfffafff5}, "mintcream"},
{{0xffe1e4ff}, "mistyrose"},
{{0xffb5e4ff}, "moccasin"},
{{0xffaddeff}, "navajowhite"},
{{0xff800000}, "navy"},
{{0xffe6f5fd}, "oldlace"},
{{0xff008080}, "olive"},
{{0xff238e6b}, "olivedrab"},
{{0xff00a5ff}, "orange"},
{{0xff0045ff}, "orangered"},
{{0xffd670da}, "orchid"},
{{0xffaae8ee}, "palegoldenrod"},
{{0xff98fb98}, "palegreen"},
{{0xffeeeeaf}, "paleturquoise"},
{{0xff9370d8}, "palevioletred"},
{{0xffd5efff}, "papayawhip"},
{{0xffb9daff}, "peachpuff"},
{{0xff3f85cd}, "peru"},
{{0xffcbc0ff}, "pink"},
{{0xffdda0dd}, "plum"},
{{0xffe6e0b0}, "powderblue"},
{{0xff800080}, "purple"},
{{0xff0000ff}, "red"},
{{0xff8f8fbc}, "rosybrown"},
{{0xffe16941}, "royalblue"},
{{0xff13458b}, "saddlebrown"},
{{0xff7280fa}, "salmon"},
{{0xff60a4f4}, "sandybrown"},
{{0xff578b2e}, "seagreen"},
{{0xffeef5ff}, "seashell"},
{{0xff2d52a0}, "sienna"},
{{0xffc0c0c0}, "silver"},
{{0xffebce87}, "skyblue"},
{{0xffcd5a6a}, "slateblue"},
{{0xff908070}, "slategray"},
{{0xff908070}, "slategrey"},
{{0xfffafaff}, "snow"},
{{0xff7fff00}, "springgreen"},
{{0xffb48246}, "steelblue"},
{{0xff8cb4d2}, "tan"},
{{0xff808000}, "teal"},
{{0xffd8bfd8}, "thistle"},
{{0xff4763ff}, "tomato"},
{{0xffd0e040}, "turquoise"},
{{0xffee82ee}, "violet"},
{{0xffb3def5}, "wheat"},
{{0xffffffff}, "white"},
{{0xfff5f5f5}, "whitesmoke"},
{{0xff00ffff}, "yellow"},
{{0xff32cd9a}, "yellowgreen"},
{{0x00000000}, "transparent"}
};
const int numColors = sizeof(ColorNames)/sizeof(CSSColor);
#define HASH_TABLE_SIZE 1000
bool collisions[HASH_TABLE_SIZE];
static inline unsigned int ColorHashForString( const char *s, size_t length, int a, int b, int hashSize ) {
unsigned int h = 0;
for( size_t i = 0; i < length; i++ ) {
h = (h << a) ^ h ^ (s[i] * b);
}
return (h % hashSize);
};
void printHash(int a, int b, int hashSize) {
unsigned char *ColorHashesToColorNames = malloc(hashSize);
memset(ColorHashesToColorNames, 0, hashSize);
for( int i = 0; i < numColors; i++ ) {
int hash = ColorHashForString(ColorNames[i].name, ColorNames[i].length, a, b, hashSize);
ColorHashesToColorNames[hash] = i;
}
printf("Found: a:%d b:%d, size:%d\n", a, b, hashSize);
printf(
"static inline unsigned int ColorHashForString( const JSChar *s, size_t length ) {\n"
" unsigned int h = 0;\n"
" for( size_t i = 0; i < length; i++ ) {\n"
" h = (h << %d) ^ h ^ (tolower(s[i]) * %d);\n"
" }\n"
" return (h %% %d);\n"
"};\n\n",
a, b, hashSize
);
printf("static const unsigned char ColorHashesToColorNames[%d] = {\n", hashSize);
for( int i = 0; i < hashSize; i++ ) {
printf("%d,", ColorHashesToColorNames[i]);
if( i % 50 == 50) {
printf("\n");
}
}
printf("};\n\n");
free(ColorHashesToColorNames);
}
int main(int argc, const char * argv[]) {
// Initialize string lengths
for( int i = 0; i < numColors; i++ ) {
ColorNames[i].length = strlen(ColorNames[i].name);
}
int smallestHash = HASH_TABLE_SIZE;
while( true ) {
int b = (rand()*rand())^(rand()*rand());
int hashSize;
for( int a = 1; a < 31; a++ ) {
for( hashSize = numColors; hashSize < smallestHash; hashSize++ ) {
memset(collisions, 0, hashSize);
bool hadCollision = false;
for( int i = 0; i < numColors; i++ ) {
int hash = ColorHashForString(ColorNames[i].name, ColorNames[i].length, a, b, hashSize);
if( collisions[hash] ) {
hadCollision = true;
break;
}
collisions[hash] = true;
}
if( !hadCollision ) {
// No collision? Print the hash function and hash table
printHash(a, b, hashSize);
smallestHash = hashSize;
break;
}
}
}
}
return 0;
}
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