moved code from header to source files

src/string.c

@@ -0,0 +1,108 @@
+#include "tim.h"
+
+i32 tim_ztrlen(cstr s) {
+    if(s == NULL)
+        return 0;
+    i32 n = strlen(s);
+    if(n < 0)
+        n = 0;
+    return n;
+}
+
+i32 tim_bsr8(u8 x) {
+#if defined __GNUC__ || defined __clang__
+    unsigned int b = x;
+    b <<= sizeof(b) * CHAR_BIT - 8;
+    b  |= 1 << (sizeof(b) * CHAR_BIT - 9);
+    return __builtin_clz(b);
+#elif defined _MSC_VER
+    unsigned long n = 0;
+    unsigned long b = x;
+    b <<= sizeof(b) * CHAR_BIT - 8;
+    b  |= 1 << (sizeof(b) * CHAR_BIT - 9);
+    _BitScanReverse(&n, b);
+    return n;
+#else
+    i32 n = 0;
+    for (; n < 8 && !(x & 128); n++, x <<= 1) {}
+    return n;
+#endif
+}
+
+
+i32 tim_utf8_to_i32(cstr s) {
+    s = s ? s : "";
+    // use bit magic to mask out leading utf8 1s
+    u32 c = s[0] & ((1 << (8 - tim_bsr8(~s[0]))) - 1);
+    for (i32 i = 1; s[0] && s[i] && i < 4; i++) {
+        c = (c << 6) | (s[i] & 63);
+    }
+    return (i32)c;
+}
+
+i32 tim_utf8_len(cstr s) {
+    i32 n = 0;
+    for (i32 i = 0; s && s[i]; i++) {
+        n += (s[i] & 192) != 128;
+    }
+    return n;
+}
+
+i32 tim_utf8_pos(cstr s, i32 pos) {
+    i32 i = 0;
+    for (i32 n = 0; pos >= 0 && s && s[i]; i++) {
+        n += (s[i] & 192) != 128;
+        if (n == pos + 1) {
+            return i;
+        }
+    }
+    return i;
+}
+
+bool tim_utf8_is_wide_perhaps(const u8* s, i32 n) {
+    // Character width depends on character, terminal and font. There is no
+    // reliable method, however most frequently used characters are narrow.
+    // Zero with characters are ignored, and hope that user input is benign.
+    if (n < 3 || s[0] < 225) {
+        // u+0000 - u+1000, basic latin - tibetan
+        return false;
+    } else if (s[0] == 226 && s[1] >= 148 && s[1] < 152) {
+        // u+2500 - u+2600 box drawing, block elements, geometric shapes
+        return false;
+    }
+    return true;
+}
+
+TimText tim_scan_str(cstr s) {
+    if(s == NULL)
+        s = "";
+    TimText t = {
+        .width = 0,
+        .lines = (s[0] != 0),
+    };
+    i32 width = 0;
+    for (t.size = 0; s[t.size]; t.size++) {
+        char ch      = s[t.size];
+        i32  newline = (ch == '\n');
+        width = newline ? 0 : width;
+        width += (ch & 192) != 128 && (u8)ch > 31;
+        t.lines += newline;
+        t.width = MAX(t.width, width);
+    }
+    return t;
+}
+
+bool tim_next_line(TimLine* l) {
+    if (!l->s || !l->s[0]) {
+        return false;
+    }
+    l->line  = l->s;
+    l->size  = 0;
+    l->width = 0;
+    for (cstr s = l->s; s[0] && s[0] != '\n'; s++) {
+        l->size  += 1;
+        l->width += (s[0] & 192) != 128 && (u8)s[0] > 31;
+    }
+    l->s += l->size + !!l->s[l->size];
+    return true;
+}