From 722a64a265cb1a7451997e440721459ead394f99 Mon Sep 17 00:00:00 2001
From: Oleg Oshmyan <chortos@inbox.lv>
Date: Thu, 1 May 2014 02:47:43 +0100
Subject: [PATCH] [WIP] Parse override tag arguments exactly like VSFilter

---
 libass/ass_parse.c | 403 ++++++++++++++++++++++-----------------------
 1 file changed, 201 insertions(+), 202 deletions(-)

diff --git a/libass/ass_parse.c b/libass/ass_parse.c
index d6b26271a..8ec0c64e3 100644
--- a/libass/ass_parse.c
+++ b/libass/ass_parse.c
@@ -236,11 +236,59 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
 {
     skip_to('\\');
     skip('\\');
-    if ((*p == '}') || (*p == 0))
+    while (isspace(*p))
+        ++p;
+
+    char *q = p;
+    while (*q != '(' && *q != '\\' && *q != '}' && *q != 0)
+        ++q;
+    if (q == p)
         return p;
 
+    char *name = p;
+    char *end = q;
+    while (isspace(end[-1]))
+        --end;
+
+    vector<char *> args;
+
+    // Do this for all tags and before non-bracketed
+    // arguments because that's what VSFilter does
+    if (*q == '(') {
+        ++q;
+        while (1) {
+            while (isspace(*q))
+                ++q;
+
+            char *r = q;
+            while (*r != ',' && *r != '\\' && *r != ')' && *r != '}' && *r != 0)
+                ++r;
+
+            // r > q because VSFilter
+            if (r > q && *r == ',') {
+                args << (q, r.rtrim);
+                q = r + 1;
+            } else {
+                while (*r != ')' && *r != '}' && *r != 0)
+                    ++r;
+                if (r > q) {
+                    char *s = r;
+                    while (isspace(s[-1]))
+                        --s;
+                    if (s > q)
+                        args << (q, s);
+                }
+                q = r;
+                break;
+            }
+        }
+    }
+
+#define tag(name) (mystrcmp(&p, (name)) && (args << (p, end), p = args[0].begin))
+#define complex_tag(name) mystrcmp(&p, (name))
+
     // New tags introduced in vsfilter 2.39
-    if (mystrcmp(&p, "xbord")) {
+    if (tag("xbord")) {
         double val;
         if (mystrtod(&p, &val)) {
             val = render_priv->state.border_x * (1 - pwr) + val * pwr;
@@ -248,7 +296,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         } else
             val = render_priv->state.style->Outline;
         render_priv->state.border_x = val;
-    } else if (mystrcmp(&p, "ybord")) {
+    } else if (tag("ybord")) {
         double val;
         if (mystrtod(&p, &val)) {
             val = render_priv->state.border_y * (1 - pwr) + val * pwr;
@@ -256,48 +304,41 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         } else
             val = render_priv->state.style->Outline;
         render_priv->state.border_y = val;
-    } else if (mystrcmp(&p, "xshad")) {
+    } else if (tag("xshad")) {
         double val;
         if (mystrtod(&p, &val))
             val = render_priv->state.shadow_x * (1 - pwr) + val * pwr;
         else
             val = render_priv->state.style->Shadow;
         render_priv->state.shadow_x = val;
-    } else if (mystrcmp(&p, "yshad")) {
+    } else if (tag("yshad")) {
         double val;
         if (mystrtod(&p, &val))
             val = render_priv->state.shadow_y * (1 - pwr) + val * pwr;
         else
             val = render_priv->state.style->Shadow;
         render_priv->state.shadow_y = val;
-    } else if (mystrcmp(&p, "fax")) {
+    } else if (tag("fax")) {
         double val;
         if (mystrtod(&p, &val))
             render_priv->state.fax =
                 val * pwr + render_priv->state.fax * (1 - pwr);
         else
             render_priv->state.fax = 0.;
-    } else if (mystrcmp(&p, "fay")) {
+    } else if (tag("fay")) {
         double val;
         if (mystrtod(&p, &val))
             render_priv->state.fay =
                 val * pwr + render_priv->state.fay * (1 - pwr);
         else
             render_priv->state.fay = 0.;
-    } else if (mystrcmp(&p, "iclip")) {
-        int x0, y0, x1, y1;
-        int res = 1;
-        char *start = p;
-        skip('(');
-        res &= mystrtoi(&p, &x0);
-        skipopt(',');
-        res &= mystrtoi(&p, &y0);
-        skipopt(',');
-        res &= mystrtoi(&p, &x1);
-        skipopt(',');
-        res &= mystrtoi(&p, &y1);
-        skipopt(')');
-        if (res) {
+    } else if (complex_tag("iclip")) {
+        if (args.size == 4) {
+            int x0, y0, x1, y1;
+            mystrtoi(&args[0], &x0);
+            mystrtoi(&args[1], &y0);
+            mystrtoi(&args[2], &x1);
+            mystrtoi(&args[3], &y1);
             render_priv->state.clip_x0 =
                 render_priv->state.clip_x0 * (1 - pwr) + x0 * pwr;
             render_priv->state.clip_x1 =
@@ -307,11 +348,12 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.clip_y1 =
                 render_priv->state.clip_y1 * (1 - pwr) + y1 * pwr;
             render_priv->state.clip_mode = 1;
-        } else if (!render_priv->state.clip_drawing) {
-            p = parse_vector_clip(render_priv, start);
+        // FIXME: make this code nice
+        } else if (args.size >= 1 && args.size <= 2 && !render_priv->state.clip_drawing) {
+            parse_vector_clip(render_priv, args, args.size);
             render_priv->state.clip_drawing_mode = 1;
         }
-    } else if (mystrcmp(&p, "blur")) {
+    } else if (tag("blur")) {
         double val;
         if (mystrtod(&p, &val)) {
             val = render_priv->state.blur * (1 - pwr) + val * pwr;
@@ -321,62 +363,48 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         } else
             render_priv->state.blur = 0.0;
         // ASS standard tags
-    } else if (mystrcmp(&p, "fsc")) {
-        char tp = *p++;
+    } else if (tag("fscx")) {
         double val;
-        if (tp == 'x') {
-            if (mystrtod(&p, &val)) {
-                val /= 100;
-                val = render_priv->state.scale_x * (1 - pwr) + val * pwr;
-                val = (val < 0) ? 0 : val;
-            } else
-                val = render_priv->state.style->ScaleX;
-            render_priv->state.scale_x = val;
-        } else if (tp == 'y') {
-            if (mystrtod(&p, &val)) {
-                val /= 100;
-                val = render_priv->state.scale_y * (1 - pwr) + val * pwr;
-                val = (val < 0) ? 0 : val;
-            } else
-                val = render_priv->state.style->ScaleY;
-            render_priv->state.scale_y = val;
-        } else {
-            --p;
-            render_priv->state.scale_x = render_priv->state.style->ScaleX;
-            render_priv->state.scale_y = render_priv->state.style->ScaleY;
-        }
-    } else if (mystrcmp(&p, "fsp")) {
+        if (mystrtod(&p, &val)) {
+            val /= 100;
+            val = render_priv->state.scale_x * (1 - pwr) + val * pwr;
+            val = (val < 0) ? 0 : val;
+        } else
+            val = render_priv->state.style->ScaleX;
+        render_priv->state.scale_x = val;
+    } else if (tag("fscy")) {
+        double val;
+        if (mystrtod(&p, &val)) {
+            val /= 100;
+            val = render_priv->state.scale_y * (1 - pwr) + val * pwr;
+            val = (val < 0) ? 0 : val;
+        } else
+            val = render_priv->state.style->ScaleY;
+        render_priv->state.scale_y = val;
+    } else if (tag("fsc")) {
+        render_priv->state.scale_x = render_priv->state.style->ScaleX;
+        render_priv->state.scale_y = render_priv->state.style->ScaleY;
+    } else if (tag("fsp")) {
         double val;
         if (mystrtod(&p, &val))
             render_priv->state.hspacing =
                 render_priv->state.hspacing * (1 - pwr) + val * pwr;
         else
             render_priv->state.hspacing = render_priv->state.style->Spacing;
-    } else if (mystrcmp(&p, "fs+")) {
+    } else if (tag("fs")) {
         double val;
-        mystrtod(&p, &val);
-        val = render_priv->state.font_size * (1 + pwr * val / 10);
-        if (val <= 0)
-            val = render_priv->state.style->FontSize;
-        if (render_priv->state.font)
-            change_font_size(render_priv, val);
-    } else if (mystrcmp(&p, "fs-")) {
-        double val;
-        mystrtod(&p, &val);
-        val = render_priv->state.font_size * (1 - pwr * val / 10);
-        if (val <= 0)
-            val = render_priv->state.style->FontSize;
-        if (render_priv->state.font)
-            change_font_size(render_priv, val);
-    } else if (mystrcmp(&p, "fs")) {
-        double val;
-        if (mystrtod(&p, &val))
-            val = render_priv->state.font_size * (1 - pwr) + val * pwr;
+        if (mystrtod(&p, &val)) {
+            // FIXME: p vs args[0], make this code clean
+            if (*args[0] == '+' || *args[0] == '-')
+                val = render_priv->state.font_size * (1 + pwr * val / 10);
+            else
+                val = render_priv->state.font_size * (1 - pwr) + val * pwr;
+        }
         if (val <= 0)
             val = render_priv->state.style->FontSize;
         if (render_priv->state.font)
             change_font_size(render_priv, val);
-    } else if (mystrcmp(&p, "bord")) {
+    } else if (tag("bord")) {
         double val, xval, yval;
         if (mystrtod(&p, &val)) {
             xval = render_priv->state.border_x * (1 - pwr) + val * pwr;
@@ -387,37 +415,32 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             xval = yval = render_priv->state.style->Outline;
         render_priv->state.border_x = xval;
         render_priv->state.border_y = yval;
-    } else if (mystrcmp(&p, "move")) {
+    } else if (complex_tag("move")) {
         double x1, x2, y1, y2;
         long long t1, t2, delta_t, t;
         double x, y;
         double k;
-        skip('(');
-        mystrtod(&p, &x1);
-        skip(',');
-        mystrtod(&p, &y1);
-        skip(',');
-        mystrtod(&p, &x2);
-        skip(',');
-        mystrtod(&p, &y2);
-        t1 = t2 = 0;
-        if (*p == ',') {
-            skip(',');
-            mystrtoll(&p, &t1);
-            skip(',');
-            mystrtoll(&p, &t2);
-            // VSFilter
-            if (t1 > t2) {
-                double tmp = t2;
-                t2 = t1;
-                t1 = tmp;
+        if (args.size == 4 || args.size == 6) {
+            mystrtod(&args[0], &x1);
+            mystrtod(&args[1], &y1);
+            mystrtod(&args[2], &x2);
+            mystrtod(&args[3], &y2);
+            t1 = t2 = 0;
+            if (args.size == 6) {
+                mystrtoll(&args[4], &t1);
+                mystrtoll(&args[5], &t2);
+                if (t1 > t2) {
+                    long long tmp = t2;
+                    t2 = t1;
+                    t1 = tmp;
+                }
             }
-        }
+        } else
+            return p;
         if (t1 <= 0 && t2 <= 0) {
             t1 = 0;
             t2 = render_priv->state.event->Duration;
         }
-        skipopt(')');
         delta_t = t2 - t1;
         t = render_priv->time - render_priv->state.event->Start;
         if (t <= t1)
@@ -434,7 +457,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.detect_collisions = 0;
             render_priv->state.evt_type = EVENT_POSITIONED;
         }
-    } else if (mystrcmp(&p, "frx")) {
+    } else if (tag("frx")) {
         double val;
         if (mystrtod(&p, &val)) {
             val *= M_PI / 180;
@@ -442,7 +465,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                 val * pwr + render_priv->state.frx * (1 - pwr);
         } else
             render_priv->state.frx = 0.;
-    } else if (mystrcmp(&p, "fry")) {
+    } else if (tag("fry")) {
         double val;
         if (mystrtod(&p, &val)) {
             val *= M_PI / 180;
@@ -450,7 +473,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                 val * pwr + render_priv->state.fry * (1 - pwr);
         } else
             render_priv->state.fry = 0.;
-    } else if (mystrcmp(&p, "frz") || mystrcmp(&p, "fr")) {
+    } else if (tag("frz") || tag("fr")) {
         double val;
         if (mystrtod(&p, &val)) {
             val *= M_PI / 180;
@@ -459,20 +482,21 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
         } else
             render_priv->state.frz =
                 M_PI * render_priv->state.style->Angle / 180.;
-    } else if (mystrcmp(&p, "fn")) {
-        char *start = p;
+    } else if (tag("fn")) {
         char *family;
-        skip_to('\\');
-        if (p > start && strncmp(start, "0", p - start)) {
-            family = malloc(p - start + 1);
-            strncpy(family, start, p - start);
-            family[p - start] = '\0';
+        end = args[0].end;
+        if (end > p && strncmp(p, "0", end - p)) {
+            while (isspace(*p))
+                ++p;
+            family = malloc(end - p + 1);
+            strncpy(family, p, end - p);
+            family[end - p] = '\0';
         } else
             family = strdup(render_priv->state.style->FontName);
         free(render_priv->state.family);
         render_priv->state.family = family;
         update_font(render_priv);
-    } else if (mystrcmp(&p, "alpha")) {
+    } else if (tag("alpha")) {
         uint32_t val;
         int i;
         int hex = render_priv->track->track_type == TRACK_TYPE_ASS;
@@ -491,7 +515,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                          render_priv->state.style->BackColour, 1);
         }
         // FIXME: simplify
-    } else if (mystrcmp(&p, "an")) {
+    } else if (tag("an")) {
         int val;
         mystrtoi(&p, &val);
         if ((render_priv->state.parsed_tags & PARSED_A) == 0) {
@@ -507,7 +531,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                     render_priv->state.style->Alignment;
             render_priv->state.parsed_tags |= PARSED_A;
         }
-    } else if (mystrcmp(&p, "a")) {
+    } else if (tag("a")) {
         int val;
         mystrtoi(&p, &val);
         if ((render_priv->state.parsed_tags & PARSED_A) == 0) {
@@ -520,13 +544,13 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                     render_priv->state.style->Alignment;
             render_priv->state.parsed_tags |= PARSED_A;
         }
-    } else if (mystrcmp(&p, "pos")) {
+    } else if (complex_tag("pos")) {
         double v1, v2;
-        skip('(');
-        mystrtod(&p, &v1);
-        skip(',');
-        mystrtod(&p, &v2);
-        skipopt(')');
+        if (args.size == 2) {
+            mystrtod(&args[0], &v1);
+            mystrtod(&args[1], &v2);
+        } else
+            return p;
         if (render_priv->state.evt_type == EVENT_POSITIONED) {
             ass_msg(render_priv->library, MSGL_V, "Subtitle has a new \\pos "
                    "after \\move or \\pos, ignoring");
@@ -536,40 +560,29 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.pos_x = v1;
             render_priv->state.pos_y = v2;
         }
-    } else if (mystrcmp(&p, "fad")) {
+    } else if (complex_tag("fade") || complex_tag("fad")) {
         int a1, a2, a3;
         long long t1, t2, t3, t4;
-        if (*p == 'e')
-            ++p;                // either \fad or \fade
-        skip('(');
-        mystrtoi(&p, &a1);
-        skip(',');
-        mystrtoi(&p, &a2);
-        if (*p == ')') {
+        if (args.size == 2) {
             // 2-argument version (\fad, according to specs)
-            // a1 and a2 are fade-in and fade-out durations
-            t1 = -1;
-            t2 = a1;
-            t3 = a2;
-            t4 = -1;
             a1 = 0xFF;
             a2 = 0;
             a3 = 0xFF;
-        } else {
+            t1 = -1;
+            mystrtoi(&args[0], &t2);
+            mystrtoi(&args[1], &t3);
+            t4 = -1;
+        } else if (args.size == 7) {
             // 7-argument version (\fade)
-            // a1 and a2 (and a3) are opacity values
-            skip(',');
-            mystrtoi(&p, &a3);
-            skip(',');
-            mystrtoll(&p, &t1);
-            skip(',');
-            mystrtoll(&p, &t2);
-            skip(',');
-            mystrtoll(&p, &t3);
-            skip(',');
-            mystrtoll(&p, &t4);
-        }
-        skipopt(')');
+            mystrtoi(&args[0], &a2);
+            mystrtoi(&args[1], &a3);
+            mystrtoi(&args[2], &a3);
+            mystrtoll(&args[3], &t1);
+            mystrtoll(&args[4], &t2);
+            mystrtoll(&args[5], &t3);
+            mystrtoll(&args[6], &t4);
+        } else
+            return p;
         if (t1 == -1 && t4 == -1) {
             t1 = 0;
             t4 = render_priv->state.event->Duration;
@@ -582,48 +595,43 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                         t3, t4, a1, a2, a3);
             render_priv->state.parsed_tags |= PARSED_FADE;
         }
-    } else if (mystrcmp(&p, "org")) {
+    } else if (complex_tag("org")) {
         double v1, v2;
-        skip('(');
-        mystrtod(&p, &v1);
-        skip(',');
-        mystrtod(&p, &v2);
-        skipopt(')');
+        if (args.size == 2) {
+            mystrtod(&args[0], &v1);
+            mystrtod(&args[1], &v2);
+        } else
+            return p;
         if (!render_priv->state.have_origin) {
             render_priv->state.org_x = v1;
             render_priv->state.org_y = v2;
             render_priv->state.have_origin = 1;
             render_priv->state.detect_collisions = 0;
         }
-    } else if (mystrcmp(&p, "t")) {
+    } else if (complex_tag("t")) {
         double v[3];
         double accel;
-        int cnt;
+        int cnt = args.size - 1;
         long long t1, t2, t, delta_t;
         double k;
-        skip('(');
-        for (cnt = 0; cnt < 3; ++cnt) {
-            if (!mystrtod(&p, &v[cnt]))
-                break;
-            skip(',');
-        }
         if (cnt == 3) {
-            t1 = v[0];
-            t2 = v[1];
-            accel = v[2];
+            mystrtoll(&args[0], &t1);
+            mystrtoll(&args[1], &t2);
+            mystrtod(&args[2], &accel);
         } else if (cnt == 2) {
-            t1 = v[0];
-            t2 = v[1];
+            mystrtoll(&args[0], &t1);
+            mystrtoll(&args[1], &t2);
             accel = 1.;
         } else if (cnt == 1) {
             t1 = 0;
             t2 = 0;
-            accel = v[0];
-        } else {                // cnt == 0
+            mystrtod(&args[0], &accel);
+        } else if (cnt == 0) {
             t1 = 0;
             t2 = 0;
             accel = 1.;
-        }
+        } else
+            return p;
         render_priv->state.detect_collisions = 0;
         if (t2 == 0)
             t2 = render_priv->state.event->Duration;
@@ -637,24 +645,16 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             assert(delta_t != 0.);
             k = pow(((double) (t - t1)) / delta_t, accel);
         }
+        p = args[cnt];
         while (*p != ')' && *p != '}' && *p != '\0')
             p = parse_tag(render_priv, p, k);   // maybe k*pwr ? no, specs forbid nested \t's
-        skip_to(')');           // in case there is some unknown tag or a comment
-        skipopt(')');
-    } else if (mystrcmp(&p, "clip")) {
-        char *start = p;
-        int x0, y0, x1, y1;
-        int res = 1;
-        skip('(');
-        res &= mystrtoi(&p, &x0);
-        skipopt(',');
-        res &= mystrtoi(&p, &y0);
-        skipopt(',');
-        res &= mystrtoi(&p, &x1);
-        skipopt(',');
-        res &= mystrtoi(&p, &y1);
-        skipopt(')');
-        if (res) {
+    } else if (complex_tag("clip")) {
+        if (args.size == 4) {
+            int x0, y0, x1, y1;
+            mystrtoi(&args[0], &x0);
+            mystrtoi(&args[1], &y0);
+            mystrtoi(&args[2], &x1);
+            mystrtoi(&args[3], &y1);
             render_priv->state.clip_x0 =
                 render_priv->state.clip_x0 * (1 - pwr) + x0 * pwr;
             render_priv->state.clip_x1 =
@@ -664,12 +664,12 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.clip_y1 =
                 render_priv->state.clip_y1 * (1 - pwr) + y1 * pwr;
             render_priv->state.clip_mode = 0;
-        // Might be a vector clip
-        } else if (!render_priv->state.clip_drawing) {
-            p = parse_vector_clip(render_priv, start);
+        // FIXME: make this code nice
+        } else if (args.size >= 1 && args.size <= 2 && !render_priv->state.clip_drawing) {
+            parse_vector_clip(render_priv, args, args.size);
             render_priv->state.clip_drawing_mode = 0;
         }
-    } else if (mystrcmp(&p, "c")) {
+    } else if (tag("c")) {
         uint32_t val;
         int hex = render_priv->track->track_type == TRACK_TYPE_ASS;
         if (strtocolor(render_priv->library, &p, &val, hex))
@@ -678,10 +678,10 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             change_color(&render_priv->state.c[0],
                          render_priv->state.style->PrimaryColour, 1);
     } else if ((*p >= '1') && (*p <= '4') && (++p)
-               && (mystrcmp(&p, "c") || mystrcmp(&p, "a"))) {
-        char n = *(p - 2);
+               && (tag("c") || tag("a"))) {
+        char n = *name;
         int cidx = n - '1';
-        char cmd = *(p - 1);
+        char cmd = *(name + 1);
         uint32_t val;
         int hex = render_priv->track->track_type == TRACK_TYPE_ASS;
         assert((n >= '1') && (n <= '4'));
@@ -719,20 +719,19 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
                     n, cmd);
             break;
         }
-    } else if (mystrcmp(&p, "r")) {
-        char *start = p;
+    } else if (tag("r")) {
         char *style;
-        skip_to('\\');
-        if (p > start) {
-            style = malloc(p - start + 1);
-            strncpy(style, start, p - start);
-            style[p - start] = '\0';
+        end = args[0].end;
+        if (end > p) {
+            style = malloc(end - p + 1);
+            strncpy(style, p, end - p);
+            style[end - p] = '\0';
             reset_render_context(render_priv,
                     lookup_style_strict(render_priv->track, style));
             free(style);
         } else
             reset_render_context(render_priv, NULL);
-    } else if (mystrcmp(&p, "be")) {
+    } else if (tag("be")) {
         double dval;
         if (mystrtod(&p, &dval)) {
             int val;
@@ -744,19 +743,19 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.be = val;
         } else
             render_priv->state.be = 0;
-    } else if (mystrcmp(&p, "b")) {
+    } else if (tag("b")) {
         int val;
         if (!mystrtoi(&p, &val) || !(val == 0 || val == 1 || val >= 100))
             val = render_priv->state.style->Bold;
         render_priv->state.bold = val;
         update_font(render_priv);
-    } else if (mystrcmp(&p, "i")) {
+    } else if (tag("i")) {
         int val;
         if (!mystrtoi(&p, &val) || !(val == 0 || val == 1))
             val = render_priv->state.style->Italic;
         render_priv->state.italic = val;
         update_font(render_priv);
-    } else if (mystrcmp(&p, "kf") || mystrcmp(&p, "K")) {
+    } else if (tag("kf") || tag("K")) {
         double val;
         if (!mystrtod(&p, &val))
             val = 100;
@@ -765,7 +764,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.effect_skip_timing +=
                 render_priv->state.effect_timing;
         render_priv->state.effect_timing = val * 10;
-    } else if (mystrcmp(&p, "ko")) {
+    } else if (tag("ko")) {
         double val;
         if (!mystrtod(&p, &val))
             val = 100;
@@ -774,7 +773,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.effect_skip_timing +=
                 render_priv->state.effect_timing;
         render_priv->state.effect_timing = val * 10;
-    } else if (mystrcmp(&p, "k")) {
+    } else if (tag("k")) {
         double val;
         if (!mystrtod(&p, &val))
             val = 100;
@@ -783,7 +782,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.effect_skip_timing +=
                 render_priv->state.effect_timing;
         render_priv->state.effect_timing = val * 10;
-    } else if (mystrcmp(&p, "shad")) {
+    } else if (tag("shad")) {
         double val, xval, yval;
         if (mystrtod(&p, &val)) {
             xval = render_priv->state.shadow_x * (1 - pwr) + val * pwr;
@@ -795,7 +794,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             xval = yval = render_priv->state.style->Shadow;
         render_priv->state.shadow_x = xval;
         render_priv->state.shadow_y = yval;
-    } else if (mystrcmp(&p, "s")) {
+    } else if (tag("s")) {
         int val;
         if (!mystrtoi(&p, &val) || !(val == 0 || val == 1))
             val = render_priv->state.style->StrikeOut;
@@ -803,7 +802,7 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.flags |= DECO_STRIKETHROUGH;
         else
             render_priv->state.flags &= ~DECO_STRIKETHROUGH;
-    } else if (mystrcmp(&p, "u")) {
+    } else if (tag("u")) {
         int val;
         if (!mystrtoi(&p, &val) || !(val == 0 || val == 1))
             val = render_priv->state.style->Underline;
@@ -811,28 +810,28 @@ char *parse_tag(ASS_Renderer *render_priv, char *p, double pwr)
             render_priv->state.flags |= DECO_UNDERLINE;
         else
             render_priv->state.flags &= ~DECO_UNDERLINE;
-    } else if (mystrcmp(&p, "pbo")) {
+    } else if (tag("pbo")) {
         double val;
         mystrtod(&p, &val);
         render_priv->state.pbo = val;
-    } else if (mystrcmp(&p, "p")) {
+    } else if (tag("p")) {
         int val;
         mystrtoi(&p, &val);
         val = (val < 0) ? 0 : val;
         render_priv->state.drawing_scale = val;
-    } else if (mystrcmp(&p, "q")) {
+    } else if (tag("q")) {
         int val;
         if (!mystrtoi(&p, &val) || !(val >= 0 && val <= 3))
             val = render_priv->track->WrapStyle;
         render_priv->state.wrap_style = val;
-    } else if (mystrcmp(&p, "fe")) {
+    } else if (tag("fe")) {
         int val;
         if (!mystrtoi(&p, &val))
             val = render_priv->state.style->Encoding;
         render_priv->state.font_encoding = val;
     }
 
-    return p;
+    return q;
 }
 
 void apply_transition_effects(ASS_Renderer *render_priv, ASS_Event *event)