char *genStr(char *filename, int len) {
int fh;
unsigned char *data;
if ((fh = open(filename, O_RDONLY)) == -1) FILE_ERR(filename, "open");
struct stat finfo;
fstat(fh, &finfo);
if ((data = mmap(0, finfo.st_size, PROT_READ, MAP_SHARED, fh, 0))
== MAP_FAILED) FILE_ERR(filename, "mmap");
if (close(fh) == -1) FILE_ERR(filename, "close");
int dataIdx = 0, alphabetSize = 1;
for (; data[dataIdx]; dataIdx += byteLength(data[dataIdx]), ++alphabetSize);
++dataIdx; // we're on the null byte, want to be where data actually starts
if (alphabetSize*alphabetSize*(8+4*alphabetSize) != finfo.st_size - dataIdx) {
return "!!! CORRUPT DATA FILE !!!";
}
char *str = malloc((len+1) * 4*sizeof *str);
int a = alphabetSize - 1, b = alphabetSize - 1;
int strpos = 0;
for (int i = 0; i < len; ++i) {
unsigned char *dataPtr = DATA(a, b);
unsigned long long n = longRand(getLong(dataPtr));
dataPtr += 8;
int nextCharPos = 0;
for (; nextCharPos < alphabetSize; ++nextCharPos) {
unsigned int m = getInt(dataPtr);
if (m > n) break;
n -= m;
dataPtr += 4;
}
a = b;
b = nextCharPos;
int alphabetIdx = 0;
for (; nextCharPos; --nextCharPos) {
alphabetIdx += byteLength(ALPHABET[alphabetIdx]);
}
int nextCharLen = byteLength(ALPHABET[alphabetIdx]);
for (int i = nextCharLen; i >= 0; --i) {
str[strpos + i] = ALPHABET[alphabetIdx + i];
}
strpos += nextCharLen;
}
str[strpos] = '\0';
//for (int i = 0; i < len*2; ++i) printf("str[%d]: %c\n", i, str[i]);
if (munmap(data, finfo.st_size) == -1) FILE_ERR(filename, "munmap");
return str;
}
long selectBetween( long lo, long hi ) {
long r;
r = longRand();
return ( r % ( hi - lo + 1 ) + lo );
}
