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