#define ALPHANUMS "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" /** converts an integer to a string, using a base of 10 by default. * * if you NULL out the output buffer it will return the expected * output string length anyway. */ int itoa(int number, char* out, int base) { int t, count; char *p, *q; char c; p = q = out; if (base < 2 || base > 36) base = 10; do { t = number; number /= base; if (out) *p = ALPHANUMS[t+35 - number*base]; p++; } while (number); if (t < 0) { if (out) *p = '-'; p++; } count = p-out; if (out) { *p-- = '\0'; while(q < p) { c = *p; *p-- = *q; *q++ = c; } } return count; } /* This little test program shows that itoa() is roughly 3 times faster * than sprintf --lynX */ #ifdef CMDTOOL #include #include #include int main(int argc, char **argv) { char out[4404]; int in[44]; int c, i, j; if (argc < 3 || argc > sizeof(in)) { printf("Usage: %s +\n\nExample: %s 999999 123 234 345 -49 -21892\n", argv[0], argv[0]); return -1; } for (j=argc-1; j; j--) { // printf("Looking at arg #%d: %s\n", j, argv[j]); in[j] = atoi(argv[j]); // printf("Got %d: %d\n", j, in[j]); } for (i=in[1]; i; i--) { c = 0; for (j=argc-1; j>1; j--) { # if 0 // use good old sprintf c += sprintf(&out[c], " %d", in[j]); # else # if 1 // use the itoa implementation out[c++] = ' '; c += itoa(in[j], &out[c], 10); # else // just count the needed space c += itoa(in[j], NULL, 10) + 1; # endif # endif } } printf("%d times, %d count, buffer len: %d, buffer: %s\n", in[1], c, strlen(out), ""); // out return 0; } #endif