// Convert an index into a pointer to its lead byte. Out of bounds indexing will raise IndexError or
// be capped to the first/last character of the string, depending on is_slice.
const byte *str_index_to_ptr(const mp_obj_type_t *type, const byte *self_data, size_t self_len,
mp_obj_t index, bool is_slice) {
(void)type;
mp_int_t i;
// Copied from mp_get_index; I don't want bounds checking, just give me
// the integer as-is. (I can't bounds-check without scanning the whole
// string; an out-of-bounds index will be caught in the loops below.)
if (MP_OBJ_IS_SMALL_INT(index)) {
i = MP_OBJ_SMALL_INT_VALUE(index);
} else if (!mp_obj_get_int_maybe(index, &i)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "string indices must be integers, not %s", mp_obj_get_type_str(index)));
}
const byte *s, *top = self_data + self_len;
if (i < 0)
{
// Negative indexing is performed by counting from the end of the string.
for (s = top - 1; i; --s) {
if (s < self_data) {
if (is_slice) {
return self_data;
}
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_IndexError, "string index out of range"));
}
if (!UTF8_IS_CONT(*s)) {
++i;
}
}
++s;
} else if (!i) {
return self_data; // Shortcut - str[0] is its base pointer
} else {
// Positive indexing, correspondingly, counts from the start of the string.
// It's assumed that negative indexing will generally be used with small
// absolute values (eg str[-1], not str[-1000000]), which means it'll be
// more efficient this way.
for (s = self_data; true; ++s) {
if (s >= top) {
if (is_slice) {
return top;
}
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_IndexError, "string index out of range"));
}
while (UTF8_IS_CONT(*s)) {
++s;
}
if (!i--) {
return s;
}
}
}
return s;
}
machine_uint_t utf8_ptr_to_index(const char *s, const char *ptr) {
machine_uint_t i = 0;
while (ptr > s) {
if (!UTF8_IS_CONT(*--ptr)) {
i++;
}
}
return i;
}
mp_uint_t utf8_ptr_to_index(const byte *s, const byte *ptr) {
mp_uint_t i = 0;
while (ptr > s) {
if (!UTF8_IS_CONT(*--ptr)) {
i++;
}
}
return i;
}
// TODO: Rename to str_next_char
const byte *utf8_next_char(const byte *s) {
#if MICROPY_PY_BUILTINS_STR_UNICODE
++s;
while (UTF8_IS_CONT(*s)) {
++s;
}
return s;
#else
return s + 1;
#endif
}
// TODO: Rename to str_charlen
machine_uint_t unichar_charlen(const char *str, machine_uint_t len)
{
#if MICROPY_PY_BUILTINS_STR_UNICODE
machine_uint_t charlen = 0;
for (const char *top = str + len; str < top; ++str) {
if (!UTF8_IS_CONT(*str)) {
++charlen;
}
}
return charlen;
#else
return len;
#endif
}
// TODO: Rename to str_get_char
unichar utf8_get_char(const byte *s) {
#if MICROPY_PY_BUILTINS_STR_UNICODE
unichar ord = *s++;
if (!UTF8_IS_NONASCII(ord)) return ord;
ord &= 0x7F;
for (unichar mask = 0x40; ord & mask; mask >>= 1) {
ord &= ~mask;
}
while (UTF8_IS_CONT(*s)) {
ord = (ord << 6) | (*s++ & 0x3F);
}
return ord;
#else
return *s;
#endif
}
// Convert an index into a pointer to its lead byte. Out of bounds indexing will raise IndexError or
// be capped to the first/last character of the string, depending on is_slice.
const byte *str_index_to_ptr(const mp_obj_type_t *type, const byte *self_data, size_t self_len,
mp_obj_t index, bool is_slice) {
// All str functions also handle bytes objects, and they call str_index_to_ptr(),
// so it must handle bytes.
if (type == &mp_type_bytes) {
// Taken from objstr.c:str_index_to_ptr()
size_t index_val = mp_get_index(type, self_len, index, is_slice);
return self_data + index_val;
}
mp_int_t i;
// Copied from mp_get_index; I don't want bounds checking, just give me
// the integer as-is. (I can't bounds-check without scanning the whole
// string; an out-of-bounds index will be caught in the loops below.)
if (MP_OBJ_IS_SMALL_INT(index)) {
i = MP_OBJ_SMALL_INT_VALUE(index);
} else if (!mp_obj_get_int_maybe(index, &i)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "string indices must be integers, not %s", mp_obj_get_type_str(index)));
}
const byte *s, *top = self_data + self_len;
if (i < 0)
{
// Negative indexing is performed by counting from the end of the string.
for (s = top - 1; i; --s) {
if (s < self_data) {
if (is_slice) {
return self_data;
}
mp_raise_msg(&mp_type_IndexError, "string index out of range");
}
if (!UTF8_IS_CONT(*s)) {
++i;
}
}
++s;
} else {
// Positive indexing, correspondingly, counts from the start of the string.
// It's assumed that negative indexing will generally be used with small
// absolute values (eg str[-1], not str[-1000000]), which means it'll be
// more efficient this way.
s = self_data;
while (1) {
// First check out-of-bounds
if (s >= top) {
if (is_slice) {
return top;
}
mp_raise_msg(&mp_type_IndexError, "string index out of range");
}
// Then check completion
if (i-- == 0) {
break;
}
// Then skip UTF-8 char
++s;
while (UTF8_IS_CONT(*s)) {
++s;
}
}
}
return s;
}
