+ GLubyte c1 = p[1];
+ if ((c1 & 0xC0) != 0x80) {
+ // Stop processing the UTF byte sequence early.
+ return false;
+ }
+ if ((c0 & 0xE0) == 0xC0) {
+ // One contination (128 to 2047)
+ code_point = ((c0 & 0x1F) << 6) | (c1 & 0x3F);
+ if (code_point < 128) {
+ return false;
+ }
+ assert(code_point >= 128 && code_point <= 2047);
+ p += 2;
+ } else {
+ GLubyte c2 = p[2];
+ if ((c2 & 0xC0) != 0x80) {
+ // Stop processing the UTF byte sequence early.
+ return false;
+ }
+ if ((c0 & 0xF0) == 0xE0) {
+ // Two continuation (2048 to 55295 and 57344 to 65535)
+ code_point = ((c0 & 0x0F) << 12) |
+ ((c1 & 0x3F) << 6) |
+ (c2 & 0x3F);
+ // "The definition of UTF-8 prohibits encoding character numbers between
+ // U+D800 and U+DFFF, which are reserved for use with the UTF-16
+ // encoding form (as surrogate pairs) and do not directly represent
+ // characters."
+ // 0xD800 = 55,296
+ // 0xDFFF = 57,343
+ if ((code_point >= 55296) && (code_point <= 57343)) {
+ // Stop processing the UTF byte sequence early.
+ return false;
+ }
+ if (code_point < 2048) {
+ return false;
+ }
+ assert(code_point >= 2048 && code_point <= 65535);
+ assert(code_point < 55296 || code_point > 57343);
+ p += 3;
+ } else {
+ GLubyte c3 = p[3];
+ if ((c3 & 0xC0) != 0x80) {
+ // Stop processing the UTF byte sequence early.
+ return false;
+ }
+ if ((c0 & 0xF8) == 0xF0) {
+ // Three continuation (65536 to 1114111)
+ code_point = ((c0 & 0x07) << 18) |
+ ((c1 & 0x3F) << 12) |
+ ((c2 & 0x3F) << 6) |
+ (c3 & 0x3F);
+ if (code_point < 65536 && code_point > 1114111) {
+ return false;
+ }
+ assert(code_point >= 65536 && code_point <= 1114111);
+ p += 4;
+ } else {
+ // Skip invalid or restricted encodings.
+ // Stop processing the UTF byte sequence early.
+ return false;
+ }
+ }
+ }
+ }
+ utf_string = p;
+ return true;
+}
+
+// See RFC-2781 "UTF-16, a transformation format of ISO 10646"
+// http://rfc-ref.org/RFC-TEXTS/2781/index.html
+// http://www.rfc-editor.org/rfc/rfc2781.txt
+static bool
+__glPathGetCodePointUTF16(const void *&utf_string,
+ GLuint &code_point)
+{
+ // Section 2.2 (Decoding UTF-16) of http://www.rfc-editor.org/rfc/rfc2781.txt
+ // "Decoding of a single character from UTF-16 to an ISO 10646 character
+ // value proceeds as follows."
+ const GLushort *p = reinterpret_cast<const GLushort*>(utf_string);
+
+ // "Let W1 be the next 16-bit integer in the
+ // sequence of integers representing the text."
+ GLushort W1 = p[0];
+ // "1) If W1 < 0xD800 or W1 > 0xDFFF, the character value U is the value
+ // of W1. Terminate."
+ if ((W1 < 0xDB00) || (W1 > 0xDFFF)) {
+ code_point = W1;
+ p += 1;
+ } else {
+ // "2) Determine if W1 is between 0xD800 and 0xDBFF."
+ bool between1 = (W1 >= 0xDB00) && (W1 <= 0xDBFF);
+ if (!between1) {
+ // "If not, the sequence
+ // is in error and no valid character can be obtained using W1.
+ // Terminate."
+ return false;
+ }
+ // "Let W2 be the (eventual) next integer following W1."
+ GLushort W2 = p[1];
+ // DOES NOT APPLY because API provides character (not byte) count.
+ // "3) If there is no W2 (that is, the sequence ends with W1), [Terminate]"
+
+ // "... or if W2 is not between 0xDC00 and 0xDFFF, the sequence
+ // is in error. Terminate."
+ bool between2 = (W2 >= 0xDC00) && (W2 <= 0xDFFF);
+ if (!between2) {
+ return false;
+ }
+ // "4) Construct a 20-bit unsigned integer U', taking the 10 low-order
+ // bits of W1 as its 10 high-order bits and the 10 low-order bits of
+ // W2 as its 10 low-order bits."
+ code_point = ((W1 & 0x3FF) << 10) |
+ (W2 & 0x3FF);
+ // "5) Add 0x10000 to U' to obtain the character value U. Terminate."
+ code_point += 0x10000;
+ p += 2;
+ }
+ utf_string = p;
+ return true;
+}
+
+static size_t bytesOfSequence(GLsizei count, GLenum type, const GLvoid *sequence)
+{
+ GLsizei bytes_per_element;
+ switch (type) {
+ case GL_BYTE:
+ bytes_per_element = sizeof(GLbyte);
+ break;
+ case GL_UNSIGNED_BYTE:
+ bytes_per_element = sizeof(GLubyte);
+ break;
+ case GL_SHORT:
+ bytes_per_element = sizeof(GLshort);
+ break;
+ case GL_UNSIGNED_SHORT:
+ bytes_per_element = sizeof(GLushort);
+ break;
+ case GL_INT:
+ bytes_per_element = sizeof(GLint);
+ break;
+ case GL_UNSIGNED_INT:
+ bytes_per_element = sizeof(GLuint);
+ break;
+ case GL_FLOAT:
+ bytes_per_element = sizeof(GLfloat);
+ break;
+ case GL_2_BYTES:
+ bytes_per_element = 2*sizeof(GLubyte);
+ break;
+ case GL_3_BYTES:
+ bytes_per_element = 3*sizeof(GLubyte);
+ break;
+ case GL_4_BYTES:
+ bytes_per_element = 4*sizeof(GLubyte);
+ break;
+ case GL_UTF8_NV:
+ {
+ const void *utf_string = sequence;
+ for (GLsizei i=0; i<count; i++) {
+ GLuint code_point; // ignored
+ bool ok = __glPathGetCodePointUTF8(utf_string, code_point);
+ if (!ok) {
+ break;
+ }
+ }
+ const char *start = reinterpret_cast<const char*>(sequence);
+ const char *end = reinterpret_cast<const char*>(utf_string);
+ return end - start;
+ }
+ case GL_UTF16_NV:
+ {
+ const void *utf_string = sequence;
+ for (GLsizei i=0; i<count; i++) {
+ GLuint code_point; // ignored
+ bool ok = __glPathGetCodePointUTF16(utf_string, code_point);
+ if (!ok) {
+ break;
+ }
+ }
+ const char *start = reinterpret_cast<const char*>(sequence);
+ const char *end = reinterpret_cast<const char*>(utf_string);
+ return end - start;
+ }
+ default: // generate INVALID_ENUM
+ return 0;
+ }
+ if (count > 0) {
+ return count * bytes_per_element;
+ } else {
+ return 0;