/* Copyright (c) 2018, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/bytestring.h>
#include "internal.h"
static int is_valid_code_point(uint32_t v) {
// References in the following are to Unicode 9.0.0.
if (// The Unicode space runs from zero to 0x10ffff (3.4 D9).
v > 0x10ffff ||
// Values 0x...fffe, 0x...ffff, and 0xfdd0-0xfdef are permanently reserved
// (3.4 D14)
(v & 0xfffe) == 0xfffe ||
(v >= 0xfdd0 && v <= 0xfdef) ||
// Surrogate code points are invalid (3.2 C1).
(v >= 0xd800 && v <= 0xdfff)) {
return 0;
}
return 1;
}
// BOTTOM_BITS returns a byte with the bottom |n| bits set.
#define BOTTOM_BITS(n) (uint8_t)((1u << (n)) - 1)
// TOP_BITS returns a byte with the top |n| bits set.
#define TOP_BITS(n) ((uint8_t)~BOTTOM_BITS(8 - (n)))
int cbs_get_utf8(CBS *cbs, uint32_t *out) {
uint8_t c;
if (!CBS_get_u8(cbs, &c)) {
return 0;
}
if (c <= 0x7f) {
*out = c;
return 1;
}
uint32_t v, lower_bound;
size_t len;
if ((c & TOP_BITS(3)) == TOP_BITS(2)) {
v = c & BOTTOM_BITS(5);
len = 1;
lower_bound = 0x80;
} else if ((c & TOP_BITS(4)) == TOP_BITS(3)) {
v = c & BOTTOM_BITS(4);
len = 2;
lower_bound = 0x800;
} else if ((c & TOP_BITS(5)) == TOP_BITS(4)) {
v = c & BOTTOM_BITS(3);
len = 3;
lower_bound = 0x10000;
} else {
return 0;
}
for (size_t i = 0; i < len; i++) {
if (!CBS_get_u8(cbs, &c) ||
(c & TOP_BITS(2)) != TOP_BITS(1)) {
return 0;
}
v <<= 6;
v |= c & BOTTOM_BITS(6);
}
if (!is_valid_code_point(v) ||
v < lower_bound) {
return 0;
}
*out = v;
return 1;
}
int cbs_get_latin1(CBS *cbs, uint32_t *out) {
uint8_t c;
if (!CBS_get_u8(cbs, &c)) {
return 0;
}
*out = c;
return 1;
}
int cbs_get_ucs2_be(CBS *cbs, uint32_t *out) {
// Note UCS-2 (used by BMPString) does not support surrogates.
uint16_t c;
if (!CBS_get_u16(cbs, &c) ||
!is_valid_code_point(c)) {
return 0;
}
*out = c;
return 1;
}
int cbs_get_utf32_be(CBS *cbs, uint32_t *out) {
return CBS_get_u32(cbs, out) && is_valid_code_point(*out);
}
size_t cbb_get_utf8_len(uint32_t u) {
if (u <= 0x7f) {
return 1;
}
if (u <= 0x7ff) {
return 2;
}
if (u <= 0xffff) {
return 3;
}
return 4;
}
int cbb_add_utf8(CBB *cbb, uint32_t u) {
if (!is_valid_code_point(u)) {
return 0;
}
if (u <= 0x7f) {
return CBB_add_u8(cbb, (uint8_t)u);
}
if (u <= 0x7ff) {
return CBB_add_u8(cbb, TOP_BITS(2) | (u >> 6)) &&
CBB_add_u8(cbb, TOP_BITS(1) | (u & BOTTOM_BITS(6)));
}
if (u <= 0xffff) {
return CBB_add_u8(cbb, TOP_BITS(3) | (u >> 12)) &&
CBB_add_u8(cbb, TOP_BITS(1) | ((u >> 6) & BOTTOM_BITS(6))) &&
CBB_add_u8(cbb, TOP_BITS(1) | (u & BOTTOM_BITS(6)));
}
if (u <= 0x10ffff) {
return CBB_add_u8(cbb, TOP_BITS(4) | (u >> 18)) &&
CBB_add_u8(cbb, TOP_BITS(1) | ((u >> 12) & BOTTOM_BITS(6))) &&
CBB_add_u8(cbb, TOP_BITS(1) | ((u >> 6) & BOTTOM_BITS(6))) &&
CBB_add_u8(cbb, TOP_BITS(1) | (u & BOTTOM_BITS(6)));
}
return 0;
}
int cbb_add_latin1(CBB *cbb, uint32_t u) {
return u <= 0xff && CBB_add_u8(cbb, (uint8_t)u);
}
int cbb_add_ucs2_be(CBB *cbb, uint32_t u) {
return u <= 0xffff && is_valid_code_point(u) && CBB_add_u16(cbb, (uint16_t)u);
}
int cbb_add_utf32_be(CBB *cbb, uint32_t u) {
return is_valid_code_point(u) && CBB_add_u32(cbb, u);
}