Consolidate fast CSI color component parsing into inlined byte delimiter helper

1 files changed, 36 insertions, 105 deletions

diff --git a/src/fastcsi.c b/src/fastcsi.c
index 6cae7a3..2e0f004 100644
--- a/src/fastcsi.c
+++ b/src/fastcsi.c
@@ -10,121 +10,52 @@
 #include <string.h>
 
 TERM_ALWAYS_INLINE
-static inline const char *parse_color_sequence(const char *p, const char *end, uint32_t *color)
+static inline const char *parse_byte_delim(const char *s, const char *end, char delim, uint32_t *val)
 {
-    const char *s = p + 5;
-    uint32_t r, g, b;
-
-    if (TERM_EXPECT(s >= end, 0)) return NULL;
-    unsigned char c0 = (unsigned char)*s++;
-    unsigned char d0 = (unsigned char)(c0 - '0');
-    if (TERM_EXPECT(d0 > 9, 0)) return NULL;
-    if (TERM_EXPECT(s >= end, 0)) return NULL;
-    unsigned char c1 = (unsigned char)*s++;
-    if (c1 == ';') {
-        r = d0;
-    } else {
-        unsigned char d1 = (unsigned char)(c1 - '0');
-        if (TERM_EXPECT(d1 > 9, 0)) return NULL;
-        if (TERM_EXPECT(s >= end, 0)) return NULL;
-        unsigned char c2 = (unsigned char)*s++;
-        if (c2 == ';') {
-            r = d0 * 10 + d1;
-        } else {
-            unsigned char d2 = (unsigned char)(c2 - '0');
-            if (TERM_EXPECT(d2 > 9 || s >= end || *s++ != ';', 0)) return NULL;
-            r = d0 * 100 + d1 * 10 + d2;
-            if (TERM_EXPECT(r > 255, 0)) return NULL;
-        }
+    if (s >= end) return NULL;
+    unsigned char d0 = (unsigned char)(*s++ - '0');
+    if (d0 > 9) return NULL;
+    if (s < end && *s == delim) {
+        *val = d0;
+        return s + 1;
     }
-
-    if (TERM_EXPECT(s >= end, 0)) return NULL;
-    c0 = (unsigned char)*s++;
-    d0 = (unsigned char)(c0 - '0');
-    if (TERM_EXPECT(d0 > 9, 0)) return NULL;
-    if (TERM_EXPECT(s >= end, 0)) return NULL;
-    c1 = (unsigned char)*s++;
-    if (c1 == ';') {
-        g = d0;
-    } else {
-        unsigned char d1 = (unsigned char)(c1 - '0');
-        if (TERM_EXPECT(d1 > 9, 0)) return NULL;
-        if (TERM_EXPECT(s >= end, 0)) return NULL;
-        unsigned char c2 = (unsigned char)*s++;
-        if (c2 == ';') {
-            g = d0 * 10 + d1;
-        } else {
-            unsigned char d2 = (unsigned char)(c2 - '0');
-            if (TERM_EXPECT(d2 > 9 || s >= end || *s++ != ';', 0)) return NULL;
-            g = d0 * 100 + d1 * 10 + d2;
-            if (TERM_EXPECT(g > 255, 0)) return NULL;
-        }
-    }
-
-    if (TERM_EXPECT(s >= end, 0)) return NULL;
-    c0 = (unsigned char)*s++;
-    d0 = (unsigned char)(c0 - '0');
-    if (TERM_EXPECT(d0 > 9, 0)) return NULL;
-    if (TERM_EXPECT(s >= end, 0)) return NULL;
-    c1 = (unsigned char)*s++;
-    if (c1 == 'm') {
-        b = d0;
-    } else {
-        unsigned char d1 = (unsigned char)(c1 - '0');
-        if (TERM_EXPECT(d1 > 9, 0)) return NULL;
-        if (TERM_EXPECT(s >= end, 0)) return NULL;
-        unsigned char c2 = (unsigned char)*s++;
-        if (c2 == 'm') {
-            b = d0 * 10 + d1;
-        } else {
-            unsigned char d2 = (unsigned char)(c2 - '0');
-            if (TERM_EXPECT(d2 > 9 || s >= end || *s++ != 'm', 0)) return NULL;
-            b = d0 * 100 + d1 * 10 + d2;
-            if (TERM_EXPECT(b > 255, 0)) return NULL;
-        }
+    if (s >= end) return NULL;
+    unsigned char d1 = (unsigned char)(*s++ - '0');
+    if (d1 > 9) return NULL;
+    if (s < end && *s == delim) {
+        *val = d0 * 10 + d1;
+        return s + 1;
     }
+    if (s >= end) return NULL;
+    unsigned char d2 = (unsigned char)(*s++ - '0');
+    if (d2 > 9 || s >= end || *s++ != delim) return NULL;
+    unsigned v = d0 * 100 + d1 * 10 + d2;
+    if (v > 255) return NULL;
+    *val = v;
+    return s;
+}
 
+static inline const char *parse_color_sequence(const char *p, const char *end, uint32_t *color)
+{
+    const char *s = p + 5;
+    uint32_t r, g, b;
+    s = parse_byte_delim(s, end, ';', &r);
+    if (!s) return NULL;
+    s = parse_byte_delim(s, end, ';', &g);
+    if (!s) return NULL;
+    s = parse_byte_delim(s, end, 'm', &b);
+    if (!s) return NULL;
     *color = term_rgb((int)r, (int)g, (int)b);
     return s;
 }
 
 static const char *parse_256color(const char *p, const char *end, uint32_t *color)
 {
-    const char *q = p + 2;
-    if (q >= end)
-        return NULL;
-    unsigned char d0 = (unsigned char)(*q - '0');
-    if (d0 > 9)
-        return NULL;
-    q++;
-    if (q < end && *q == 'm') {
-        *color = term_color_index(d0);
-        return q + 1;
-    }
-    if (q >= end)
-        return NULL;
-    unsigned char d1 = (unsigned char)(*q - '0');
-    if (d1 > 9)
-        return NULL;
-    q++;
-    if (q < end && *q == 'm') {
-        *color = term_color_index(d0 * 10 + d1);
-        return q + 1;
-    }
-    if (q >= end)
-        return NULL;
-    unsigned char d2 = (unsigned char)(*q - '0');
-    if (d2 > 9)
-        return NULL;
-    q++;
-    if (q < end && *q == 'm') {
-        unsigned v = d0 * 100 + d1 * 10 + d2;
-        if (v <= 255) {
-            *color = term_color_index(v);
-            return q + 1;
-        }
-    }
-    return NULL;
+    uint32_t v;
+    const char *s = parse_byte_delim(p + 2, end, 'm', &v);
+    if (!s) return NULL;
+    *color = term_color_index(v);
+    return s;
 }
 
 TERM_NOINLINE