Merge json_decode_float_slice in json_decode_large_float

17 digits is already a pretty large float, we can consider it
as the slow path, so it's best not to inline it.

Author: byroot

ext/json/ext/parser/parser.c

@@ -791,15 +791,22 @@ static VALUE json_decode_large_integer(const char *start, long len)
 static inline VALUE
 json_decode_integer(const char *start, const char *end)
 {
-        long len = end - start;
-        if (RB_LIKELY(len < MAX_FAST_INTEGER_SIZE)) {
-            return fast_decode_integer(start, end);
-        }
-        return json_decode_large_integer(start, len);
+    long len = end - start;
+    if (RB_LIKELY(len < MAX_FAST_INTEGER_SIZE)) {
+        return fast_decode_integer(start, end);
+    }
+    return json_decode_large_integer(start, len);
 }
 
 static VALUE json_decode_large_float(const char *start, long len)
 {
+    if (RB_LIKELY(len < 64)) {
+        char buffer[64];
+        MEMCPY(buffer, start, char, len);
+        buffer[len] = '\0';
+        return DBL2NUM(rb_cstr_to_dbl(buffer, 1));
+    }
+
     VALUE buffer_v;
     char *buffer = RB_ALLOCV_N(char, buffer_v, len + 1);
     MEMCPY(buffer, start, char, len);
@@ -809,21 +816,6 @@ static VALUE json_decode_large_float(const char *start, long len)
     return number;
 }
 
-/* Helper: Parse float from string slice using rb_cstr_to_dbl
- * Handles small strings efficiently with stack buffer
- */
-static inline VALUE json_decode_float_slice(const char *start, long len)
-{
-    if (RB_LIKELY(len < 64)) {
-        char buffer[64];
-        MEMCPY(buffer, start, char, len);
-        buffer[len] = '\0';
-        return DBL2NUM(rb_cstr_to_dbl(buffer, 1));
-    } else {
-        return json_decode_large_float(start, len);
-    }
-}
-
 /* Ruby JSON optimized float decoder using vendored Ryu algorithm
  * Accepts pre-extracted mantissa and exponent from first-pass validation
  */
@@ -834,7 +826,7 @@ static inline VALUE json_ryu_parse_float(uint64_t m10, int m10digits, int32_t e1
     // Ryu has rounding issues with subnormals around 1e-310 (< 2.225e-308)
     if (m10digits + e10 < -307) {
         // Use original string directly via shared helper
-        return json_decode_float_slice(start, end - start);
+        return json_decode_large_float(start, end - start);
     }
 
     double result = ryu_s2d_from_parts(m10, m10digits, e10, signedM);
@@ -849,7 +841,7 @@ static VALUE json_decode_float(JSON_ParserConfig *config, const char *start, con
         VALUE text = rb_str_new(start, len);
         return rb_funcallv(config->decimal_class, config->decimal_method_id, 1, &text);
     } else {
-        return json_decode_float_slice(start, len);
+        return json_decode_large_float(start, len);
     }
 }