#include    <ctype.h>
#include    <stdio.h>
#include    <stdlib.h>
#include    <string.h>
#include    <malloc.h>

/* *-._ はそのまま、スペースは +、あとはエンコード */
static char enctbl[256] = {
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  '+', 0, 0, 0, 0, 0, 0, 0, 0, 0, '*', 0, 0, '-', '.', 0,
  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',   0,   0,   0,   0,   0,   0,
  0, 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
  'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',   0,   0,   0,   0, '_',
  0, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
  'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',   0,   0,   0,   0,   0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

static char codetbl[16] = {
  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
  'A', 'B', 'C', 'D', 'E', 'F' };

URLencode(char *in, char **out)
{
	int				len;		/* data length */
	char			*str = in;	/* in data pointer */
	unsigned char	hi, lo;
	unsigned char	cstr;
	char			*outp;
	int				cnt = 0;

	/* in param nodata */
	if (!in || (len = strlen(in)) == 0)
		return -1;

	/* output area */
	outp = (char *)malloc(sizeof(char) * ((len * 3) + 1));
	memset( outp, 0, (len * 3) + 1);

	/**/
	while( *str ) {
		cstr = *str;

		if ( enctbl[cstr] > 0) {
			outp[cnt++] = enctbl[cstr];
		} else {
			hi = cstr >> 4;
			lo = cstr << 4; lo = lo >> 4;
			outp[cnt++] = '%';
			outp[cnt++] = codetbl[hi];
			outp[cnt++] = codetbl[lo];
		}

		str++;
	}

	/* data output area malloc */
	if ((*out = (char *)malloc(sizeof(char) * cnt + 1)) == NULL) {
		free(outp);
		return(-1);
	}

	/**/
	strcpy(*out, outp);
	free(outp);

	return (cnt + 1);
}

main()
{
	char	*ecbuf;
	unsigned char	a = 0xa3;
	char	b;
	char	c;


	URLencode("abZ ()'~!あ*-._\nあああ", &ecbuf );

	printf("%s\n", ecbuf);

}