commit ecd9d212f6a3947821c7c6beb5014efd5a2e49ec
Author:     Hiltjo Posthuma <hil...@codemadness.org>
AuthorDate: Sat Oct 5 13:06:55 2024 +0200
Commit:     Hiltjo Posthuma <hil...@codemadness.org>
CommitDate: Sat Oct 5 13:06:55 2024 +0200

    sync drw.{c,h} from dmenu
    
    - drw: minor improvement to the nomatches cache
    - overhaul utf8decoding and render invalid utf8 sequences as U+FFFD.
    
    Thanks NRK for these improvements!

diff --git a/drw.c b/drw.c
index a58a2b4..344de61 100644
--- a/drw.c
+++ b/drw.c
@@ -9,54 +9,40 @@
 #include "util.h"
 
 #define UTF_INVALID 0xFFFD
-#define UTF_SIZ     4
 
-static const unsigned char utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 
0xF0};
-static const unsigned char utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 
0xF8};
-static const long utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  
0x10000};
-static const long utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 
0x10FFFF};
-
-static long
-utf8decodebyte(const char c, size_t *i)
-{
-       for (*i = 0; *i < (UTF_SIZ + 1); ++(*i))
-               if (((unsigned char)c & utfmask[*i]) == utfbyte[*i])
-                       return (unsigned char)c & ~utfmask[*i];
-       return 0;
-}
-
-static size_t
-utf8validate(long *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 size_t
-utf8decode(const char *c, long *u, size_t clen)
+static int
+utf8decode(const char *s_in, long *u, int *err)
 {
-       size_t i, j, len, type;
-       long udecoded;
-
+       static const unsigned char lens[] = {
+               /* 0XXXX */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+               /* 10XXX */ 0, 0, 0, 0, 0, 0, 0, 0,  /* invalid */
+               /* 110XX */ 2, 2, 2, 2,
+               /* 1110X */ 3, 3,
+               /* 11110 */ 4,
+               /* 11111 */ 0,  /* invalid */
+       };
+       static const unsigned char leading_mask[] = { 0x7F, 0x1F, 0x0F, 0x07 };
+       static const unsigned int overlong[] = { 0x0, 0x80, 0x0800, 0x10000 };
+
+       const unsigned char *s = (const unsigned char *)s_in;
+       int len = lens[*s >> 3];
        *u = UTF_INVALID;
-       if (!clen)
-               return 0;
-       udecoded = utf8decodebyte(c[0], &len);
-       if (!BETWEEN(len, 1, UTF_SIZ))
+       *err = 1;
+       if (len == 0)
                return 1;
-       for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
-               udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
-               if (type)
-                       return j;
+
+       long cp = s[0] & leading_mask[len - 1];
+       for (int i = 1; i < len; ++i) {
+               if (s[i] == '\0' || (s[i] & 0xC0) != 0x80)
+                       return i;
+               cp = (cp << 6) | (s[i] & 0x3F);
        }
-       if (j < len)
-               return 0;
-       *u = udecoded;
-       utf8validate(u, len);
+       /* out of range, surrogate, overlong encoding */
+       if (cp > 0x10FFFF || (cp >> 11) == 0x1B || cp < overlong[len - 1])
+               return len;
 
+       *err = 0;
+       *u = cp;
        return len;
 }
 
@@ -238,11 +224,11 @@ drw_rect(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, int filled, int
 int
 drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int 
lpad, const char *text, int invert)
 {
-       int i, ty, ellipsis_x = 0;
-       unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len;
+       int ty, ellipsis_x = 0;
+       unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len, hash, h0, h1;
        XftDraw *d = NULL;
        Fnt *usedfont, *curfont, *nextfont;
-       int utf8strlen, utf8charlen, render = x || y || w || h;
+       int utf8strlen, utf8charlen, utf8err, render = x || y || w || h;
        long utf8codepoint = 0;
        const char *utf8str;
        FcCharSet *fccharset;
@@ -251,9 +237,8 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, unsigned int lp
        XftResult result;
        int charexists = 0, overflow = 0;
        /* keep track of a couple codepoints for which we have no match. */
-       enum { nomatches_len = 64 };
-       static struct { long codepoint[nomatches_len]; unsigned int idx; } 
nomatches;
-       static unsigned int ellipsis_width = 0;
+       static unsigned int nomatches[128], ellipsis_width, invalid_width;
+       static const char invalid[] = "�";
 
        if (!drw || (render && (!drw->scheme || !w)) || !text || !drw->fonts)
                return 0;
@@ -273,12 +258,14 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, unsigned int lp
        usedfont = drw->fonts;
        if (!ellipsis_width && render)
                ellipsis_width = drw_fontset_getwidth(drw, "...");
+       if (!invalid_width && render)
+               invalid_width = drw_fontset_getwidth(drw, invalid);
        while (1) {
-               ew = ellipsis_len = utf8strlen = 0;
+               ew = ellipsis_len = utf8err = utf8charlen = utf8strlen = 0;
                utf8str = text;
                nextfont = NULL;
                while (*text) {
-                       utf8charlen = utf8decode(text, &utf8codepoint, UTF_SIZ);
+                       utf8charlen = utf8decode(text, &utf8codepoint, 
&utf8err);
                        for (curfont = drw->fonts; curfont; curfont = 
curfont->next) {
                                charexists = charexists || 
XftCharExists(drw->dpy, curfont->xfont, utf8codepoint);
                                if (charexists) {
@@ -300,9 +287,9 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, unsigned int lp
                                                else
                                                        utf8strlen = 
ellipsis_len;
                                        } else if (curfont == usedfont) {
-                                               utf8strlen += utf8charlen;
                                                text += utf8charlen;
-                                               ew += tmpw;
+                                               utf8strlen += utf8err ? 0 : 
utf8charlen;
+                                               ew += utf8err ? 0 : tmpw;
                                        } else {
                                                nextfont = curfont;
                                        }
@@ -310,7 +297,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, unsigned int lp
                                }
                        }
 
-                       if (overflow || !charexists || nextfont)
+                       if (overflow || !charexists || nextfont || utf8err)
                                break;
                        else
                                charexists = 0;
@@ -325,6 +312,12 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, unsigned int lp
                        x += ew;
                        w -= ew;
                }
+               if (utf8err && (!render || invalid_width < w)) {
+                       if (render)
+                               drw_text(drw, x, y, w, h, 0, invalid, invert);
+                       x += invalid_width;
+                       w -= invalid_width;
+               }
                if (render && overflow)
                        drw_text(drw, ellipsis_x, y, ellipsis_w, h, 0, "...", 
invert);
 
@@ -338,11 +331,14 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, unsigned int lp
                         * character must be drawn. */
                        charexists = 1;
 
-                       for (i = 0; i < nomatches_len; ++i) {
-                               /* avoid calling XftFontMatch if we know we 
won't find a match */
-                               if (utf8codepoint == nomatches.codepoint[i])
-                                       goto no_match;
-                       }
+                       hash = (unsigned int)utf8codepoint;
+                       hash = ((hash >> 16) ^ hash) * 0x21F0AAAD;
+                       hash = ((hash >> 15) ^ hash) * 0xD35A2D97;
+                       h0 = ((hash >> 15) ^ hash) % LENGTH(nomatches);
+                       h1 = (hash >> 17) % LENGTH(nomatches);
+                       /* avoid expensive XftFontMatch call when we know we 
won't find a match */
+                       if (nomatches[h0] == utf8codepoint || nomatches[h1] == 
utf8codepoint)
+                               goto no_match;
 
                        fccharset = FcCharSetCreate();
                        FcCharSetAddChar(fccharset, utf8codepoint);
@@ -371,7 +367,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned 
int h, unsigned int lp
                                        curfont->next = usedfont;
                                } else {
                                        xfont_free(usedfont);
-                                       nomatches.codepoint[++nomatches.idx % 
nomatches_len] = utf8codepoint;
+                                       nomatches[nomatches[h0] ? h1 : h0] = 
utf8codepoint;
 no_match:
                                        usedfont = drw->fonts;
                                }
diff --git a/util.h b/util.h
index f633b51..c0a50d4 100644
--- a/util.h
+++ b/util.h
@@ -3,6 +3,7 @@
 #define MAX(A, B)               ((A) > (B) ? (A) : (B))
 #define MIN(A, B)               ((A) < (B) ? (A) : (B))
 #define BETWEEN(X, A, B)        ((A) <= (X) && (X) <= (B))
+#define LENGTH(X)               (sizeof (X) / sizeof (X)[0])
 
 void die(const char *fmt, ...);
 void *ecalloc(size_t nmemb, size_t size);

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