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/* copyright (c) 2022 grunfink - MIT license */
#ifndef _XS_ENCDEC_H
#define _XS_ENCDEC_H
d_char *xs_hex_enc(const char *data, int size);
d_char *xs_hex_dec(const char *hex);
d_char *xs_base64_enc(const char *data, int sz);
d_char *xs_base64_dec(const char *data, int *size);
d_char *xs_utf8_enc(d_char *str, unsigned int cpoint);
#ifdef XS_IMPLEMENTATION
d_char *xs_hex_enc(const char *data, int size)
/* returns an hexdump of data */
{
d_char *s;
char *p;
int n;
p = s = calloc(size * 2 + 1, 1);
for (n = 0; n < size; n++) {
sprintf(p, "%02x", (unsigned char)data[n]);
p += 2;
}
return s;
}
d_char *xs_hex_dec(const char *hex)
/* decodes an hexdump into data */
{
int sz = strlen(hex);
d_char *s;
char *p;
int n;
p = s = calloc(sz / 2, 1);
for (n = 0; n < sz; n += 2) {
int i;
if (sscanf(&hex[n], "%02x", &i) == 0) {
/* decoding error */
free(s);
s = NULL;
}
else
*p = i;
p++;
}
return s;
}
d_char *xs_base64_enc(const char *data, int sz)
/* encodes data to base64 */
{
d_char *s;
unsigned char *p;
int n;
static char *b64_tbl = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
s = xs_str_new(NULL);
p = (unsigned char *)data;
for (n = 0; n < sz; n += 3) {
int l = sz - n;
if (l == 1) {
s = xs_append_m(s, &b64_tbl[(p[n] >> 2) & 0x3f], 1);
s = xs_append_m(s, &b64_tbl[(p[n] << 4) & 0x3f], 1);
s = xs_append_m(s, "==", 2);
}
else
if (l == 2) {
s = xs_append_m(s, &b64_tbl[(p[n] >> 2) & 0x3f], 1);
s = xs_append_m(s, &b64_tbl[(p[n] << 4 | p[n + 1] >> 4) & 0x3f], 1);
s = xs_append_m(s, &b64_tbl[(p[n + 1] << 2) & 0x3f], 1);
s = xs_append_m(s, "=", 1);
}
else {
s = xs_append_m(s, &b64_tbl[(p[n] >> 2) & 0x3f], 1);
s = xs_append_m(s, &b64_tbl[(p[n] << 4 | p[n + 1] >> 4) & 0x3f], 1);
s = xs_append_m(s, &b64_tbl[(p[n + 1] << 2 | p[n + 2] >> 6) & 0x3f], 1);
s = xs_append_m(s, &b64_tbl[(p[n + 2]) & 0x3f], 1);
}
}
return s;
}
d_char *xs_base64_dec(const char *data, int *size)
/* decodes data from base64 */
{
d_char *s = NULL;
int sz = 0;
char *p;
static char *b64_tbl = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/=";
p = (char *)data;
for (p = (char *)data; *p; p += 4) {
int cs[4];
int n;
unsigned char tmp[3];
for (n = 0; n < 4; n++) {
char *ss = strchr(b64_tbl, p[n]);
if (ss == NULL) {
/* not a base64 char */
free(s);
return NULL;
}
cs[n] = ss - b64_tbl;
}
n = 0;
/* first byte */
tmp[n++] = cs[0] << 2 | ((cs[1] >> 4) & 0x0f);
/* second byte */
if (cs[2] != 64)
tmp[n++] = cs[1] << 4 | ((cs[2] >> 2) & 0x3f);
/* third byte */
if (cs[3] != 64)
tmp[n++] = cs[2] << 6 | (cs[3] & 0x3f);
/* must be done manually because data can be pure binary */
s = realloc(s, sz + n);
memcpy(s + sz, tmp, n);
sz += n;
}
*size = sz;
return s;
}
d_char *xs_utf8_enc(d_char *str, unsigned int cpoint)
/* encodes an Unicode codepoint to utf8 */
{
unsigned char tmp[4];
int n = 0;
if (cpoint < 0x80)
tmp[n++] = cpoint & 0xff;
else
if (cpoint < 0x800) {
tmp[n++] = 0xc0 | (cpoint >> 6);
tmp[n++] = 0x80 | (cpoint & 0x3f);
}
else
if (cpoint < 0x10000) {
tmp[n++] = 0xe0 | (cpoint >> 12);
tmp[n++] = 0x80 | ((cpoint >> 6) & 0x3f);
tmp[n++] = 0x80 | (cpoint & 0x3f);
}
else
if (cpoint < 0x200000) {
tmp[n++] = 0xf0 | (cpoint >> 18);
tmp[n++] = 0x80 | ((cpoint >> 12) & 0x3f);
tmp[n++] = 0x80 | ((cpoint >> 6) & 0x3f);
tmp[n++] = 0x80 | (cpoint & 0x3f);
}
return xs_append_m(str, (char *)tmp, n);
}
#endif /* XS_IMPLEMENTATION */
#endif /* _XS_ENCDEC_H */
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