+static uchar utfbyte[UTF_SIZ + 1] = {0x80, 0, 0xC0, 0xE0, 0xF0};
+static uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
+static Rune utfmin[UTF_SIZ + 1] = { 0, 0, 0x80, 0x800, 0x10000};
+static Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};
+
+ssize_t
+xwrite(int fd, const char *s, size_t len)
+{
+ size_t aux = len;
+ ssize_t r;
+
+ while (len > 0) {
+ r = write(fd, s, len);
+ if (r < 0)
+ return r;
+ len -= r;
+ s += r;
+ }
+
+ return aux;
+}
+
+void *
+xmalloc(size_t len)
+{
+ void *p;
+
+ if (!(p = malloc(len)))
+ die("malloc: %s\n", strerror(errno));
+
+ return p;
+}
+
+void *
+xrealloc(void *p, size_t len)
+{
+ if ((p = realloc(p, len)) == NULL)
+ die("realloc: %s\n", strerror(errno));
+
+ return p;
+}
+
+char *
+xstrdup(char *s)
+{
+ if ((s = strdup(s)) == NULL)
+ die("strdup: %s\n", strerror(errno));
+
+ return s;
+}
+
+size_t
+utf8decode(const char *c, Rune *u, size_t clen)
+{
+ size_t i, j, len, type;
+ Rune udecoded;
+
+ *u = UTF_INVALID;
+ if (!clen)
+ return 0;
+ udecoded = utf8decodebyte(c[0], &len);
+ if (!BETWEEN(len, 1, UTF_SIZ))
+ return 1;
+ for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
+ udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
+ if (type != 0)
+ return j;
+ }
+ if (j < len)
+ return 0;
+ *u = udecoded;
+ utf8validate(u, len);
+
+ return len;
+}
+
+Rune
+utf8decodebyte(char c, size_t *i)
+{
+ for (*i = 0; *i < LEN(utfmask); ++(*i))
+ if (((uchar)c & utfmask[*i]) == utfbyte[*i])
+ return (uchar)c & ~utfmask[*i];
+
+ return 0;
+}
+
+size_t
+utf8encode(Rune u, char *c)
+{
+ size_t len, i;
+
+ len = utf8validate(&u, 0);
+ if (len > UTF_SIZ)
+ return 0;
+
+ for (i = len - 1; i != 0; --i) {
+ c[i] = utf8encodebyte(u, 0);
+ u >>= 6;
+ }
+ c[0] = utf8encodebyte(u, len);
+
+ return len;
+}
+
+char
+utf8encodebyte(Rune u, size_t i)
+{
+ return utfbyte[i] | (u & ~utfmask[i]);
+}
+
+size_t
+utf8validate(Rune *u, size_t i)
+{
+ if (!BETWEEN(*u, utfmin[i], utfmax[i]) || BETWEEN(*u, 0xD800, 0xDFFF))
+ *u = UTF_INVALID;
+ for (i = 1; *u > utfmax[i]; ++i)
+ ;
+
+ return i;
+}
+
+static const char base64_digits[] = {
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0,
+ 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, -1, 0, 0, 0, 0, 1,
+ 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
+ 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, 29, 30, 31, 32, 33, 34,
+ 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+char
+base64dec_getc(const char **src)
+{
+ while (**src && !isprint(**src))
+ (*src)++;
+ return **src ? *((*src)++) : '='; /* emulate padding if string ends */
+}
+
+char *
+base64dec(const char *src)
+{
+ size_t in_len = strlen(src);
+ char *result, *dst;
+
+ if (in_len % 4)
+ in_len += 4 - (in_len % 4);
+ result = dst = xmalloc(in_len / 4 * 3 + 1);
+ while (*src) {
+ int a = base64_digits[(unsigned char) base64dec_getc(&src)];
+ int b = base64_digits[(unsigned char) base64dec_getc(&src)];
+ int c = base64_digits[(unsigned char) base64dec_getc(&src)];
+ int d = base64_digits[(unsigned char) base64dec_getc(&src)];
+
+ /* invalid input. 'a' can be -1, e.g. if src is "\n" (c-str) */
+ if (a == -1 || b == -1)
+ break;
+
+ *dst++ = (a << 2) | ((b & 0x30) >> 4);
+ if (c == -1)
+ break;
+ *dst++ = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
+ if (d == -1)
+ break;
+ *dst++ = ((c & 0x03) << 6) | d;
+ }
+ *dst = '\0';
+ return result;
+}
+
+void
+selinit(void)
+{
+ sel.mode = SEL_IDLE;
+ sel.snap = 0;
+ sel.ob.x = -1;
+}
+
+int
+tlinelen(int y)
+{
+ int i = term.col;
+
+ if (term.line[y][i - 1].mode & ATTR_WRAP)
+ return i;
+
+ while (i > 0 && term.line[y][i - 1].u == ' ')
+ --i;
+
+ return i;
+}
+
+void
+selstart(int col, int row, int snap)
+{
+ selclear();
+ sel.mode = SEL_EMPTY;
+ sel.type = SEL_REGULAR;
+ sel.alt = IS_SET(MODE_ALTSCREEN);
+ sel.snap = snap;
+ sel.oe.x = sel.ob.x = col;
+ sel.oe.y = sel.ob.y = row;
+ selnormalize();
+
+ if (sel.snap != 0)
+ sel.mode = SEL_READY;
+ tsetdirt(sel.nb.y, sel.ne.y);
+}
+
+void
+selextend(int col, int row, int type, int done)
+{
+ int oldey, oldex, oldsby, oldsey, oldtype;
+
+ if (sel.mode == SEL_IDLE)
+ return;
+ if (done && sel.mode == SEL_EMPTY) {
+ selclear();
+ return;
+ }
+
+ oldey = sel.oe.y;
+ oldex = sel.oe.x;
+ oldsby = sel.nb.y;
+ oldsey = sel.ne.y;
+ oldtype = sel.type;
+
+ sel.oe.x = col;
+ sel.oe.y = row;
+ selnormalize();
+ sel.type = type;
+
+ if (oldey != sel.oe.y || oldex != sel.oe.x || oldtype != sel.type || sel.mode == SEL_EMPTY)
+ tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));
+
+ sel.mode = done ? SEL_IDLE : SEL_READY;
+}
+