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#include <gu/assert.h>
#include <gu/utf8.h>
GuUCS
gu_utf8_decode(const uint8_t** src_inout)
{
const uint8_t* src = *src_inout;
uint8_t c = src[0];
if (c < 0x80) {
*src_inout = src + 1;
return (GuUCS) c;
}
size_t len = (c < 0xe0 ? 1 :
c < 0xf0 ? 2 :
c < 0xf8 ? 3 :
c < 0xfc ? 4 :
5
);
uint64_t mask = 0x0103070F1f7f;
uint32_t u = c & (mask >> (len * 8));
for (size_t i = 1; i <= len; i++) {
c = src[i];
u = u << 6 | (c & 0x3f);
}
*src_inout = &src[len + 1];
return (GuUCS) u;
}
GuUCS
gu_in_utf8_(GuIn* in, GuExn* err)
{
uint8_t c = gu_in_u8(in, err);
if (!gu_ok(err)) {
return 0;
}
int len = (c < 0x80 ? 0 :
c < 0xc2 ? -1 :
c < 0xe0 ? 1 :
c < 0xf0 ? 2 :
c < 0xf5 ? 3 :
-1);
if (len < 0) {
goto fail;
} else if (len == 0) {
return c;
}
static const uint8_t mask[4] = { 0x7f, 0x1f, 0x0f, 0x07 };
uint32_t u = c & mask[len];
uint8_t buf[3];
// If reading the extra bytes causes EOF, it is an encoding
// error, not a legitimate end of character stream.
GuExn* tmp_err = gu_exn(err, GuEOF, NULL);
gu_in_bytes(in, buf, len, tmp_err);
if (tmp_err->caught) {
goto fail;
}
if (!gu_ok(err)) {
return 0;
}
for (int i = 0; i < len; i++) {
c = buf[i];
if ((c & 0xc0) != 0x80) {
goto fail;
}
u = u << 6 | (c & 0x3f);
}
GuUCS ucs = (GuUCS) u;
if (!gu_ucs_valid(ucs)) {
goto fail;
}
return ucs;
fail:
gu_raise(err, GuUCSExn);
return 0;
}
extern inline GuUCS
gu_in_utf8(GuIn* in, GuExn* err);
static size_t
gu_advance_utf8(GuUCS ucs, uint8_t* buf)
{
gu_require(gu_ucs_valid(ucs));
if (ucs < 0x80) {
buf[0] = (uint8_t) ucs;
return 1;
} else if (ucs < 0x800) {
buf[0] = 0xc0 | (ucs >> 6);
buf[1] = 0x80 | (ucs & 0x3f);
return 2;
} else if (ucs < 0x10000) {
buf[0] = 0xe0 | (ucs >> 12);
buf[1] = 0x80 | ((ucs >> 6) & 0x3f);
buf[2] = 0x80 | (ucs & 0x3f);
return 3;
} else {
buf[0] = 0xf0 | (ucs >> 18);
buf[1] = 0x80 | ((ucs >> 12) & 0x3f);
buf[2] = 0x80 | ((ucs >> 6) & 0x3f);
buf[3] = 0x80 | (ucs & 0x3f);
return 4;
}
}
void
gu_out_utf8_(GuUCS ucs, GuOut* out, GuExn* err)
{
uint8_t buf[4];
size_t sz = gu_advance_utf8(ucs, buf);
switch (sz) {
case 2:
gu_out_bytes(out, buf, 2, err);
break;
case 3:
gu_out_bytes(out, buf, 3, err);
break;
case 4:
gu_out_bytes(out, buf, 4, err);
break;
default:
gu_impossible();
}
}
extern inline void
gu_out_utf8(GuUCS ucs, GuOut* out, GuExn* err);
void
gu_in_utf8_buf(uint8_t** buf, GuIn* in, GuExn* err)
{
uint8_t* p = *buf;
uint8_t c = gu_in_u8(in, err);
if (!gu_ok(err)) {
return;
}
*(p++) = c;
int len = (c < 0x80 ? 0 :
c < 0xc2 ? -1 :
c < 0xe0 ? 1 :
c < 0xf0 ? 2 :
c < 0xf5 ? 3 :
-1);
if (len < 0) {
goto fail;
} else if (len == 0) {
*buf = p;
return;
}
// If reading the extra bytes causes EOF, it is an encoding
// error, not a legitimate end of character stream.
GuExn* tmp_err = gu_exn(err, GuEOF, NULL);
gu_in_bytes(in, p, len, tmp_err);
if (tmp_err->caught) {
goto fail;
}
if (!gu_ok(err)) {
return;
}
*buf = p+len;
return;
fail:
gu_raise(err, GuUCSExn);
return;
}
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