String*
Str_new_from_char(int32_t code_point) {
const size_t MAX_UTF8_BYTES = 4;
char *ptr = (char*)MALLOCATE(MAX_UTF8_BYTES + 1);
size_t size = StrHelp_encode_utf8_char(code_point, (uint8_t*)ptr);
ptr[size] = '\0';
String *self = (String*)Class_Make_Obj(STRING);
self->ptr = ptr;
self->size = size;
self->origin = self;
return self;
}
static void
test_back_utf8_char(TestBatchRunner *runner) {
char buffer[4];
char *buf = buffer + 1;
uint32_t len = StrHelp_encode_utf8_char(0x263A, buffer);
char *end = buffer + len;
TEST_TRUE(runner, StrHelp_back_utf8_char(end, buffer) == buffer,
"back_utf8_char");
TEST_TRUE(runner, StrHelp_back_utf8_char(end, buf) == NULL,
"back_utf8_char returns NULL rather than back up beyond start");
TEST_TRUE(runner, StrHelp_back_utf8_char(buffer, buffer) == NULL,
"back_utf8_char returns NULL when end == start");
}
static void
test_utf8_round_trip(TestBatchRunner *runner) {
int32_t code_point;
for (code_point = 0; code_point <= 0x10FFFF; code_point++) {
char buffer[4];
uint32_t size = StrHelp_encode_utf8_char(code_point, buffer);
char *start = buffer;
char *end = start + size;
// Verify length returned by encode_utf8_char().
if (size != StrHelp_UTF8_COUNT[(unsigned char)buffer[0]]) {
break;
}
// Verify that utf8_valid() agrees with alternate implementation.
if (!!StrHelp_utf8_valid(start, size)
!= !!S_utf8_valid_alt(start, size)
) {
break;
}
// Verify back_utf8_char().
if (StrHelp_back_utf8_char(end, start) != start) {
break;
}
// Verify round trip of encode/decode.
if (StrHelp_decode_utf8_char(buffer) != code_point) {
break;
}
}
if (code_point == 0x110000) {
PASS(runner, "Successfully round tripped 0 - 0x10FFFF");
}
else {
FAIL(runner, "Failed round trip at 0x%.1X", (unsigned)code_point);
}
}
static CharBuf*
S_unescape_text(char *const top, char *const end) {
// The unescaped string will never be longer than the escaped string
// because only a \u escape can theoretically be too long and
// StrHelp_encode_utf8_char guards against sequences over 4 bytes.
// Therefore we can allocate once and not worry about reallocating.
size_t cap = end - top + 1;
char *target_buf = (char*)MALLOCATE(cap);
size_t target_size = 0;
for (char *text = top; text < end; text++) {
if (*text != '\\') {
target_buf[target_size++] = *text;
}
else {
// Process escape.
text++;
switch (*text) {
case '"':
target_buf[target_size++] = '"';
break;
case '\\':
target_buf[target_size++] = '\\';
break;
case '/':
target_buf[target_size++] = '/';
break;
case 'b':
target_buf[target_size++] = '\b';
break;
case 'f':
target_buf[target_size++] = '\f';
break;
case 'n':
target_buf[target_size++] = '\n';
break;
case 'r':
target_buf[target_size++] = '\r';
break;
case 't':
target_buf[target_size++] = '\t';
break;
case 'u': {
// Copy into a temp buffer because strtol will overrun
// into adjacent text data for e.g. "\uAAAA1".
char temp[5] = { 0, 0, 0, 0, 0 };
memcpy(temp, text + 1, 4);
text += 4;
char *num_end;
long code_point = strtol(temp, &num_end, 16);
char *temp_ptr = temp;
if (num_end != temp_ptr + 4 || code_point < 0) {
FREEMEM(target_buf);
SET_ERROR(CB_newf("Invalid \\u escape"), text - 5, end);
return NULL;
}
if (code_point >= 0xD800 && code_point <= 0xDFFF) {
FREEMEM(target_buf);
SET_ERROR(CB_newf("Surrogate pairs not supported"),
text - 5, end);
return NULL;
}
target_size += StrHelp_encode_utf8_char((uint32_t)code_point,
target_buf + target_size);
}
break;
default:
FREEMEM(target_buf);
SET_ERROR(CB_newf("Illegal escape"), text - 1, end);
return NULL;
}
}
}
// NULL-terminate, sanity check, then return the escaped string.
target_buf[target_size] = '\0';
if (!StrHelp_utf8_valid(target_buf, target_size)) {
FREEMEM(target_buf);
CharBuf *mess = MAKE_MESS("Bad UTF-8 in JSON");
Err_set_error(Err_new(mess));
return NULL;
}
return CB_new_steal_from_trusted_str(target_buf, target_size, cap);
}
