Move the duplicated UTF-8 decoding code out of functions utf8_character_count and utf8_decode and into new function decode_utf8_char, which only decodes a single UTF-8 character sequence

git-svn-id: svn+ssh://svn.gna.org/svn/warzone/trunk@5897 4a71c877-e1ca-e34f-864e-861f7616d084
master
Giel van Schijndel 2008-08-30 13:24:27 +00:00
parent b10871a0ab
commit 5222037799
1 changed files with 127 additions and 182 deletions

View File

@ -34,6 +34,131 @@
#define ASSERT_START_OCTECT(octet) \
assert((octet & 0x80) == 0x00 || (octet & 0xC0) == 0xC0 || !"invalid starting UTF-8 octet")
/** Decodes a single Unicode character from the given UTF-8 string.
*
* \param utf8_char Points to a character string that should contain at
* least one valid UTF-8 character sequence.
* \param[out] next_char Will be modified to point to the first character
* following the UTF-8 character sequence.
*
* \return The Unicode character encoded as UTF-32 with native endianness.
*/
static utf_32_char decode_utf8_char(const char * const utf8_char, const char** next_char)
{
utf_32_char decoded;
*next_char = utf8_char;
ASSERT_START_OCTECT(*utf8_char);
// first octect: 0xxxxxxx: 7 bit (ASCII)
if ((*utf8_char & 0x80) == 0x00)
{
// 1 byte long encoding
decoded = *((*next_char)++);
}
// first octect: 110xxxxx: 11 bit
else if ((*utf8_char & 0xe0) == 0xc0)
{
// 2 byte long encoding
ASSERT_NON_START_OCTET(utf8_char[1]);
decoded = (*((*next_char)++) & 0x1f) << 6;
decoded |= (*((*next_char)++) & 0x3f) << 0;
}
// first octect: 1110xxxx: 16 bit
else if ((*utf8_char & 0xf0) == 0xe0)
{
// 3 byte long encoding
ASSERT_NON_START_OCTET(utf8_char[1]);
ASSERT_NON_START_OCTET(utf8_char[2]);
decoded = (*((*next_char)++) & 0x0f) << 12;
decoded |= (*((*next_char)++) & 0x3f) << 6;
decoded |= (*((*next_char)++) & 0x3f) << 0;
}
// first octect: 11110xxx: 21 bit
else if ((*utf8_char & 0xf8) == 0xf0)
{
// 4 byte long encoding
ASSERT_NON_START_OCTET(utf8_char[1]);
ASSERT_NON_START_OCTET(utf8_char[2]);
ASSERT_NON_START_OCTET(utf8_char[3]);
decoded = (*((*next_char)++) & 0x07) << 18;
decoded |= (*((*next_char)++) & 0x3f) << 12;
decoded |= (*((*next_char)++) & 0x3f) << 6;
decoded |= (*((*next_char)++) & 0x3f) << 0;
}
// first octect: 111110xx: 26 bit
else if ((*utf8_char & 0xfc) == 0xf8)
{
// 5 byte long encoding
ASSERT_NON_START_OCTET(utf8_char[1]);
ASSERT_NON_START_OCTET(utf8_char[2]);
ASSERT_NON_START_OCTET(utf8_char[3]);
ASSERT_NON_START_OCTET(utf8_char[4]);
decoded = (*((*next_char)++) & 0x03) << 24;
decoded |= (*((*next_char)++) & 0x3f) << 18;
decoded |= (*((*next_char)++) & 0x3f) << 12;
decoded |= (*((*next_char)++) & 0x3f) << 6;
decoded |= (*((*next_char)++) & 0x3f) << 0;
}
// first octect: 1111110x: 31 bit
else if ((*utf8_char & 0xfe) == 0xfc)
{
// 6 byte long encoding
ASSERT_NON_START_OCTET(utf8_char[1]);
ASSERT_NON_START_OCTET(utf8_char[2]);
ASSERT_NON_START_OCTET(utf8_char[3]);
ASSERT_NON_START_OCTET(utf8_char[4]);
ASSERT_NON_START_OCTET(utf8_char[5]);
decoded = (*((*next_char)++) & 0x01) << 30;
decoded |= (*((*next_char)++) & 0x3f) << 24;
decoded |= (*((*next_char)++) & 0x3f) << 18;
decoded |= (*((*next_char)++) & 0x3f) << 12;
decoded |= (*((*next_char)++) & 0x3f) << 6;
decoded |= (*((*next_char)++) & 0x3f) << 0;
}
// first octect: 11111110: 36 bit (we'll only use 32bit though)
else if ((*utf8_char & 0xff) == 0xfe)
{
// 7 byte long encoding
ASSERT_NON_START_OCTET(utf8_char[1]);
ASSERT_NON_START_OCTET(utf8_char[2]);
ASSERT_NON_START_OCTET(utf8_char[3]);
ASSERT_NON_START_OCTET(utf8_char[4]);
ASSERT_NON_START_OCTET(utf8_char[5]);
ASSERT_NON_START_OCTET(utf8_char[6]);
// original: decoded = (*((*next_char)++) & 0x00) << 36;
// The first octect contains no data bits
decoded = 0; ++(*next_char);
// original: decoded |= (*((*next_char)++) & 0x3f) << 30;
// Use only the 2 least significant bits of this byte
// to make sure we use 32bit at maximum
decoded |= (*((*next_char)++) & 0x03) << 30;
decoded |= (*((*next_char)++) & 0x3f) << 24;
decoded |= (*((*next_char)++) & 0x3f) << 18;
decoded |= (*((*next_char)++) & 0x3f) << 12;
decoded |= (*((*next_char)++) & 0x3f) << 6;
decoded |= (*((*next_char)++) & 0x3f) << 0;
}
// first octet: 11111111: 41 bit or more
else
{
// apparently this character uses more than 36 bit
// this decoder is not developed to cope with those
// characters so error out
ASSERT(!"out-of-range UTF-8 character", "utf8_character_count: this UTF-8 character is too large (> 36bits) for this UTF-8 decoder");
}
return decoded;
}
size_t utf8_character_count(const char* utf8_string)
{
const char* curChar = utf8_string;
@ -41,79 +166,7 @@ size_t utf8_character_count(const char* utf8_string)
size_t length = 0;
while (*curChar != '\0')
{
ASSERT_START_OCTECT(*curChar);
// first octect: 0xxxxxxx: 7 bit (ASCII)
if ((*curChar & 0x80) == 0x00)
{
// 1 byte long encoding
curChar += 1;
}
// first octect: 110xxxxx
else if ((*curChar & 0xe0) == 0xc0)
{
// 2 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
curChar += 2;
}
// first octect: 1110xxxx
else if ((*curChar & 0xf0) == 0xe0)
{
// 3 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
curChar += 3;
}
// first octect: 11110xxx
else if ((*curChar & 0xf8) == 0xf0)
{
// 4 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
curChar += 4;
}
// first octect: 111110xx
else if ((*curChar & 0xfc) == 0xf8)
{
// 5 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
ASSERT_NON_START_OCTET(curChar[4]);
curChar += 5;
}
// first octect: 1111110x
else if ((*curChar & 0xfe) == 0xfc)
{
// 6 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
ASSERT_NON_START_OCTET(curChar[4]);
ASSERT_NON_START_OCTET(curChar[5]);
curChar += 6;
}
// first octect: 11111110
else if ((*curChar & 0xff) == 0xfe)
{
// 7 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
ASSERT_NON_START_OCTET(curChar[4]);
ASSERT_NON_START_OCTET(curChar[5]);
ASSERT_NON_START_OCTET(curChar[6]);
curChar += 7;
}
// first octet: 11111111
else
{
// apparently this character uses more than 36 bit
// this decoder is not developed to cope with those
// characters so error out
ASSERT(!"out-of-range UTF-8 character", "utf8_character_count: this UTF-8 character is too large (> 36bits) for this UTF-8 decoder");
}
decode_utf8_char(curChar, &curChar);
++length;
}
@ -265,115 +318,7 @@ utf_32_char* utf8_decode(const char* utf8_string)
while (*curChar != '\0')
{
ASSERT_START_OCTECT(*curChar);
// first octect: 0xxxxxxx: 7 bit (ASCII)
if ((*curChar & 0x80) == 0x00)
{
// 1 byte long encoding
*curOutPos = *(curChar++);
}
// first octect: 110xxxxx: 11 bit
else if ((*curChar & 0xe0) == 0xc0)
{
// 2 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
*curOutPos = (*(curChar++) & 0x1f) << 6;
*curOutPos |= (*(curChar++) & 0x3f) << 0;
}
// first octect: 1110xxxx: 16 bit
else if ((*curChar & 0xf0) == 0xe0)
{
// 3 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
*curOutPos = (*(curChar++) & 0x0f) << 12;
*curOutPos |= (*(curChar++) & 0x3f) << 6;
*curOutPos |= (*(curChar++) & 0x3f) << 0;
}
// first octect: 11110xxx: 21 bit
else if ((*curChar & 0xf8) == 0xf0)
{
// 4 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
*curOutPos = (*(curChar++) & 0x07) << 18;
*curOutPos |= (*(curChar++) & 0x3f) << 12;
*curOutPos |= (*(curChar++) & 0x3f) << 6;
*curOutPos |= (*(curChar++) & 0x3f) << 0;
}
// first octect: 111110xx: 26 bit
else if ((*curChar & 0xfc) == 0xf8)
{
// 5 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
ASSERT_NON_START_OCTET(curChar[4]);
*curOutPos = (*(curChar++) & 0x03) << 24;
*curOutPos |= (*(curChar++) & 0x3f) << 18;
*curOutPos |= (*(curChar++) & 0x3f) << 12;
*curOutPos |= (*(curChar++) & 0x3f) << 6;
*curOutPos |= (*(curChar++) & 0x3f) << 0;
}
// first octect: 1111110x: 31 bit
else if ((*curChar & 0xfe) == 0xfc)
{
// 6 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
ASSERT_NON_START_OCTET(curChar[4]);
ASSERT_NON_START_OCTET(curChar[5]);
*curOutPos = (*(curChar++) & 0x01) << 30;
*curOutPos |= (*(curChar++) & 0x3f) << 24;
*curOutPos |= (*(curChar++) & 0x3f) << 18;
*curOutPos |= (*(curChar++) & 0x3f) << 12;
*curOutPos |= (*(curChar++) & 0x3f) << 6;
*curOutPos |= (*(curChar++) & 0x3f) << 0;
}
// first octect: 11111110: 36 bit (we'll only use 32bit though)
else if ((*curChar & 0xff) == 0xfe)
{
// 7 byte long encoding
ASSERT_NON_START_OCTET(curChar[1]);
ASSERT_NON_START_OCTET(curChar[2]);
ASSERT_NON_START_OCTET(curChar[3]);
ASSERT_NON_START_OCTET(curChar[4]);
ASSERT_NON_START_OCTET(curChar[5]);
ASSERT_NON_START_OCTET(curChar[6]);
// original: *curOutPos = (*(curChar++) & 0x00) << 36;
// The first octect contains no data bits
*curOutPos = 0; ++curChar;
// original: *curOutPos |= (*(curChar++) & 0x3f) << 30;
// Use only the 2 least significant bits of this byte
// to make sure we use 32bit at maximum
*curOutPos |= (*(curChar++) & 0x03) << 30;
*curOutPos |= (*(curChar++) & 0x3f) << 24;
*curOutPos |= (*(curChar++) & 0x3f) << 18;
*curOutPos |= (*(curChar++) & 0x3f) << 12;
*curOutPos |= (*(curChar++) & 0x3f) << 6;
*curOutPos |= (*(curChar++) & 0x3f) << 0;
}
// first octet: 11111111: 41 bit or more
else
{
// apparently this character uses more than 36 bit
// this decoder is not developed to cope with those
// characters so error out
ASSERT(!"out-of-range UTF-8 character", "utf8_character_count: this UTF-8 character is too large (> 36bits) for this UTF-8 decoder");
}
++curOutPos;
*(curOutPos++) = decode_utf8_char(curChar, &curChar);
}
// Terminate the string with a nul