Rename YARP filepaths to prism filepaths

1 files changed, 66 insertions, 0 deletions

diff --git a/prism/util/pm_strpbrk.c b/prism/util/pm_strpbrk.c
new file mode 100644
index 0000000000..7c0015d289
--- /dev/null
+++ b/prism/util/pm_strpbrk.c
@@ -0,0 +1,66 @@
+#include "yarp/util/yp_strpbrk.h"
+
+// This is the slow path that does care about the encoding.
+static inline const uint8_t *
+yp_strpbrk_multi_byte(yp_parser_t *parser, const uint8_t *source, const uint8_t *charset, size_t maximum) {
+    size_t index = 0;
+
+    while (index < maximum) {
+        if (strchr((const char *) charset, source[index]) != NULL) {
+            return source + index;
+        }
+
+        size_t width = parser->encoding.char_width(source + index, (ptrdiff_t) (maximum - index));
+        if (width == 0) {
+            return NULL;
+        }
+
+        index += width;
+    }
+
+    return NULL;
+}
+
+// This is the fast path that does not care about the encoding.
+static inline const uint8_t *
+yp_strpbrk_single_byte(const uint8_t *source, const uint8_t *charset, size_t maximum) {
+    size_t index = 0;
+
+    while (index < maximum) {
+        if (strchr((const char *) charset, source[index]) != NULL) {
+            return source + index;
+        }
+
+        index++;
+    }
+
+    return NULL;
+}
+
+// Here we have rolled our own version of strpbrk. The standard library strpbrk
+// has undefined behavior when the source string is not null-terminated. We want
+// to support strings that are not null-terminated because yp_parse does not
+// have the contract that the string is null-terminated. (This is desirable
+// because it means the extension can call yp_parse with the result of a call to
+// mmap).
+//
+// The standard library strpbrk also does not support passing a maximum length
+// to search. We want to support this for the reason mentioned above, but we
+// also don't want it to stop on null bytes. Ruby actually allows null bytes
+// within strings, comments, regular expressions, etc. So we need to be able to
+// skip past them.
+//
+// Finally, we want to support encodings wherein the charset could contain
+// characters that are trailing bytes of multi-byte characters. For example, in
+// Shift-JIS, the backslash character can be a trailing byte. In that case we
+// need to take a slower path and iterate one multi-byte character at a time.
+const uint8_t *
+yp_strpbrk(yp_parser_t *parser, const uint8_t *source, const uint8_t *charset, ptrdiff_t length) {
+    if (length <= 0) {
+        return NULL;
+    } else if (parser->encoding_changed && parser->encoding.multibyte) {
+        return yp_strpbrk_multi_byte(parser, source, charset, (size_t) length);
+    } else {
+        return yp_strpbrk_single_byte(source, charset, (size_t) length);
+    }
+}