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-rw-r--r--fitz/base_rune.c168
1 files changed, 168 insertions, 0 deletions
diff --git a/fitz/base_rune.c b/fitz/base_rune.c
new file mode 100644
index 00000000..4aa81df3
--- /dev/null
+++ b/fitz/base_rune.c
@@ -0,0 +1,168 @@
+enum
+{
+ UTFmax = 3, /* maximum bytes per rune */
+ Runesync = 0x80, /* cannot represent part of a UTF sequence (<) */
+ Runeself = 0x80, /* rune and UTF sequences are the same (<) */
+ Runeerror = 0x80 /* decoding error in UTF */
+};
+
+enum
+{
+ Bit1 = 7,
+ Bitx = 6,
+ Bit2 = 5,
+ Bit3 = 4,
+ Bit4 = 3,
+
+ T1 = ((1<<(Bit1+1))-1) ^ 0xFF, /* 0000 0000 */
+ Tx = ((1<<(Bitx+1))-1) ^ 0xFF, /* 1000 0000 */
+ T2 = ((1<<(Bit2+1))-1) ^ 0xFF, /* 1100 0000 */
+ T3 = ((1<<(Bit3+1))-1) ^ 0xFF, /* 1110 0000 */
+ T4 = ((1<<(Bit4+1))-1) ^ 0xFF, /* 1111 0000 */
+
+ Rune1 = (1<<(Bit1+0*Bitx))-1, /* 0000 0000 0111 1111 */
+ Rune2 = (1<<(Bit2+1*Bitx))-1, /* 0000 0111 1111 1111 */
+ Rune3 = (1<<(Bit3+2*Bitx))-1, /* 1111 1111 1111 1111 */
+
+ Maskx = (1<<Bitx)-1, /* 0011 1111 */
+ Testx = Maskx ^ 0xFF, /* 1100 0000 */
+
+ Bad = Runeerror
+};
+
+int
+chartorune(int *rune, char *str)
+{
+ int c, c1, c2;
+ int l;
+
+ /*
+ * one character sequence
+ * 00000-0007F => T1
+ */
+ c = *(unsigned char*)str;
+ if(c < Tx) {
+ *rune = c;
+ return 1;
+ }
+
+ /*
+ * two character sequence
+ * 0080-07FF => T2 Tx
+ */
+ c1 = *(unsigned char*)(str+1) ^ Tx;
+ if(c1 & Testx)
+ goto bad;
+ if(c < T3) {
+ if(c < T2)
+ goto bad;
+ l = ((c << Bitx) | c1) & Rune2;
+ if(l <= Rune1)
+ goto bad;
+ *rune = l;
+ return 2;
+ }
+
+ /*
+ * three character sequence
+ * 0800-FFFF => T3 Tx Tx
+ */
+ c2 = *(unsigned char*)(str+2) ^ Tx;
+ if(c2 & Testx)
+ goto bad;
+ if(c < T4) {
+ l = ((((c << Bitx) | c1) << Bitx) | c2) & Rune3;
+ if(l <= Rune2)
+ goto bad;
+ *rune = l;
+ return 3;
+ }
+
+ /*
+ * bad decoding
+ */
+bad:
+ *rune = Bad;
+ return 1;
+}
+
+int
+runetochar(char *str, int *rune)
+{
+ int c;
+
+ /*
+ * one character sequence
+ * 00000-0007F => 00-7F
+ */
+ c = *rune;
+ if(c <= Rune1) {
+ str[0] = c;
+ return 1;
+ }
+
+ /*
+ * two character sequence
+ * 0080-07FF => T2 Tx
+ */
+ if(c <= Rune2) {
+ str[0] = T2 | (c >> 1*Bitx);
+ str[1] = Tx | (c & Maskx);
+ return 2;
+ }
+
+ /*
+ * three character sequence
+ * 0800-FFFF => T3 Tx Tx
+ */
+ str[0] = T3 | (c >> 2*Bitx);
+ str[1] = Tx | ((c >> 1*Bitx) & Maskx);
+ str[2] = Tx | (c & Maskx);
+ return 3;
+}
+
+int
+runelen(int c)
+{
+ int rune;
+ char str[10];
+
+ rune = c;
+ return runetochar(str, &rune);
+}
+
+int
+runenlen(int *r, int nrune)
+{
+ int nb, c;
+
+ nb = 0;
+ while(nrune--) {
+ c = *r++;
+ if(c <= Rune1)
+ nb++;
+ else
+ if(c <= Rune2)
+ nb += 2;
+ else
+ nb += 3;
+ }
+ return nb;
+}
+
+int
+fullrune(char *str, int n)
+{
+ int c;
+
+ if(n > 0) {
+ c = *(unsigned char*)str;
+ if(c < Tx)
+ return 1;
+ if(n > 1)
+ if(c < T3 || n > 2)
+ return 1;
+ }
+ return 0;
+}
+