More benchmarks and add shortcircuiting logic to validate_ascii_fast

Author: byroot

benchmark/string_coderange_scan.yml

@@ -0,0 +1,26 @@
+prelude: |
+  ascii1 = [*"a".."m",*"N".."Z",*"0".."9"].join("")
+  ascii10 = ascii1 * 10
+  ascii100 = ascii10 * 10
+  ascii1000 = ascii100 * 10
+
+  utf81 = [*"a".."m",*"N".."Z", "éà€‹›Ç☃"].join("")
+  utf810 = utf81 * 10
+  utf8100 = utf810 * 10
+  utf81000 = utf8100 * 10
+
+  invalid_ascii_last = ascii1000 + "☃"
+  invalid_ascii_first = "☃" + ascii1000
+benchmark:
+  ascii-coderange-scan-1: ascii1.force_encoding(Encoding::UTF_8).valid_encoding?
+  ascii-coderange-scan-10: ascii10.force_encoding(Encoding::UTF_8).valid_encoding?
+  ascii-coderange-scan-100: ascii100.force_encoding(Encoding::UTF_8).valid_encoding?
+  ascii-coderange-scan-1000: ascii1000.force_encoding(Encoding::UTF_8).valid_encoding?
+  
+  utf8-coderange-scan-1: utf81.force_encoding(Encoding::UTF_8).valid_encoding?
+  utf8-coderange-scan-10: utf810.force_encoding(Encoding::UTF_8).valid_encoding?
+  utf8-coderange-scan-100: utf8100.force_encoding(Encoding::UTF_8).valid_encoding?
+  utf8-coderange-scan-1000: utf81000.force_encoding(Encoding::UTF_8).valid_encoding?
+
+  ascii-coderange-scan-first-1: invalid_ascii_first.force_encoding(Encoding::ASCII).valid_encoding?
+  ascii-coderange-scan-last-1: invalid_ascii_last.force_encoding(Encoding::ASCII).valid_encoding?

benchmark/string_coderange_scan_ascii.rb

@@ -23,17 +23,22 @@ static bool validate_ascii_fast(const char *src, size_t len) {
     for (; i <= len - 32; i += 32) {
       __m256i current_bytes = _mm256_loadu_si256((const __m256i *)(src + i));
       has_error = _mm256_or_si256(has_error, current_bytes);
+      if (_mm256_movemask_epi8(has_error)) {
+          return false;
+      }
     }
   }
   int error_mask = _mm256_movemask_epi8(has_error);
 
   char tail_has_error = 0;
   for (; i < len; i++) {
+    if (src[i] & 0x80) {
+      return false;
+    }
     tail_has_error |= src[i];
   }
-  error_mask |= (tail_has_error & 0x80);
 
-  return !error_mask;
+  return true;
 }
 
 
@@ -242,17 +247,21 @@ static bool validate_ascii_fast(const char *src, size_t len) {
     for (; i <= len - 16; i += 16) {
       __m128i current_bytes = _mm_loadu_si128((const __m128i *)(src + i));
       has_error = _mm_or_si128(has_error, current_bytes);
+      if (_mm_movemask_epi8(has_error)) {
+        return false;
+      }
     }
   }
-  int error_mask = _mm_movemask_epi8(has_error);
 
   char tail_has_error = 0;
   for (; i < len; i++) {
+    if (src[i] & 0x80) {
+      return false;
+    }
     tail_has_error |= src[i];
   }
-  error_mask |= (tail_has_error & 0x80);
 
-  return !error_mask;
+  return true;
 }
 
 /*