diff options
Diffstat (limited to 'include/ruby/internal/core/rstring.h')
| -rw-r--r-- | include/ruby/internal/core/rstring.h | 114 |
1 files changed, 26 insertions, 88 deletions
diff --git a/include/ruby/internal/core/rstring.h b/include/ruby/internal/core/rstring.h index d16a57b1c4..0bca74e688 100644 --- a/include/ruby/internal/core/rstring.h +++ b/include/ruby/internal/core/rstring.h @@ -42,11 +42,7 @@ /** @cond INTERNAL_MACRO */ #define RSTRING_NOEMBED RSTRING_NOEMBED -#define RSTRING_EMBED_LEN_MASK RSTRING_EMBED_LEN_MASK -#define RSTRING_EMBED_LEN_SHIFT RSTRING_EMBED_LEN_SHIFT -#define RSTRING_EMBED_LEN_MAX RSTRING_EMBED_LEN_MAX #define RSTRING_FSTR RSTRING_FSTR -#define RSTRING_EMBED_LEN RSTRING_EMBED_LEN #define RSTRING_LEN RSTRING_LEN #define RSTRING_LENINT RSTRING_LENINT #define RSTRING_PTR RSTRING_PTR @@ -160,19 +156,6 @@ enum ruby_rstring_flags { */ RSTRING_NOEMBED = RUBY_FL_USER1, - /** - * When a string employs embedded strategy (see ::RSTRING_NOEMBED), these - * bits are used to store the number of bytes actually filled into - * ::RString::ary. - * - * @internal - * - * 3rd parties must not be aware that there even is more than one way to - * store a string. Might better be hidden. - */ - RSTRING_EMBED_LEN_MASK = RUBY_FL_USER2 | RUBY_FL_USER3 | RUBY_FL_USER4 | - RUBY_FL_USER5 | RUBY_FL_USER6, - /* Actually, string encodings are also encoded into the flags, using * remaining bits.*/ @@ -199,18 +182,6 @@ enum ruby_rstring_flags { }; /** - * This is an enum because GDB wants it (rather than a macro). People need not - * bother. - */ -enum ruby_rstring_consts { - /** Where ::RSTRING_EMBED_LEN_MASK resides. */ - RSTRING_EMBED_LEN_SHIFT = RUBY_FL_USHIFT + 2, - - /** Max possible number of characters that can be embedded. */ - RSTRING_EMBED_LEN_MAX = RBIMPL_EMBED_LEN_MAX_OF(char) - 1 -}; - -/** * Ruby's String. A string in ruby conceptually has these information: * * - Encoding of the string. @@ -227,6 +198,13 @@ struct RString { /** Basic part, including flags and class. */ struct RBasic basic; + /** + * Length of the string, not including terminating NUL character. + * + * @note This is in bytes. + */ + long len; + /** String's specific fields. */ union { @@ -235,14 +213,6 @@ struct RString { * pattern. */ struct { - - /** - * Length of the string, not including terminating NUL character. - * - * @note This is in bytes. - */ - long len; - /** * Pointer to the contents of the string. In the old days each * string had dedicated memory regions. That is no longer true @@ -271,14 +241,15 @@ struct RString { } aux; } heap; - /** - * Embedded contents. When a string is short enough, it uses this area - * to store the contents themselves. This was impractical in the 20th - * century, but these days 64 bit machines can typically hold 48 bytes - * here. Could be sufficiently large. In this case the length is - * encoded into the flags. - */ - char ary[RSTRING_EMBED_LEN_MAX + 1]; + /** Embedded contents. */ + struct { + /* This is a length 1 array because: + * 1. GCC has a bug that does not optimize C flexible array members + * (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102452) + * 2. Zero length arrays are not supported by all compilers + */ + char ary[1]; + } embed; } as; }; @@ -390,26 +361,12 @@ RBIMPL_ATTR_ARTIFICIAL() * * @param[in] str String in question. * @return Its length, in bytes. - * @pre `str` must be an instance of ::RString, and must has its - * ::RSTRING_NOEMBED flag off. - * - * @internal - * - * This was a macro before. It was inevitable to be public, since macros are - * global constructs. But should it be forever? Now that it is a function, - * @shyouhei thinks it could just be eliminated, hidden into implementation - * details. + * @pre `str` must be an instance of ::RString. */ static inline long -RSTRING_EMBED_LEN(VALUE str) +RSTRING_LEN(VALUE str) { - RBIMPL_ASSERT_TYPE(str, RUBY_T_STRING); - RBIMPL_ASSERT_OR_ASSUME(! RB_FL_ANY_RAW(str, RSTRING_NOEMBED)); - - VALUE f = RBASIC(str)->flags; - f &= RSTRING_EMBED_LEN_MASK; - f >>= RSTRING_EMBED_LEN_SHIFT; - return RBIMPL_CAST((long)f); + return RSTRING(str)->len; } RBIMPL_WARNING_PUSH() @@ -439,29 +396,14 @@ rbimpl_rstring_getmem(VALUE str) else { /* Expecting compilers to optimize this on-stack struct away. */ struct RString retval; - retval.as.heap.len = RSTRING_EMBED_LEN(str); - retval.as.heap.ptr = RSTRING(str)->as.ary; + retval.len = RSTRING_LEN(str); + retval.as.heap.ptr = RSTRING(str)->as.embed.ary; return retval; } } RBIMPL_WARNING_POP() -RBIMPL_ATTR_PURE_UNLESS_DEBUG() -RBIMPL_ATTR_ARTIFICIAL() -/** - * Queries the length of the string. - * - * @param[in] str String in question. - * @return Its length, in bytes. - * @pre `str` must be an instance of ::RString. - */ -static inline long -RSTRING_LEN(VALUE str) -{ - return rbimpl_rstring_getmem(str).as.heap.len; -} - RBIMPL_ATTR_ARTIFICIAL() /** * Queries the contents pointer of the string. @@ -475,13 +417,9 @@ RSTRING_PTR(VALUE str) { char *ptr = rbimpl_rstring_getmem(str).as.heap.ptr; - if (RB_UNLIKELY(! ptr)) { + if (RUBY_DEBUG && RB_UNLIKELY(! ptr)) { /* :BEWARE: @shyouhei thinks that currently, there are rooms for this - * function to return NULL. In the 20th century that was a pointless - * concern. However struct RString can hold fake strings nowadays. It - * seems no check against NULL are exercised around handling of them - * (one of such usages is located in marshal.c, which scares - * @shyouhei). Better check here for maximum safety. + * function to return NULL. Better check here for maximum safety. * * Also, this is not rb_warn() because RSTRING_PTR() can be called * during GC (see what obj_info() does). rb_warn() needs to allocate @@ -505,12 +443,12 @@ RSTRING_END(VALUE str) { struct RString buf = rbimpl_rstring_getmem(str); - if (RB_UNLIKELY(! buf.as.heap.ptr)) { + if (RUBY_DEBUG && RB_UNLIKELY(! buf.as.heap.ptr)) { /* Ditto. */ rb_debug_rstring_null_ptr("RSTRING_END"); } - return &buf.as.heap.ptr[buf.as.heap.len]; + return &buf.as.heap.ptr[buf.len]; } RBIMPL_ATTR_ARTIFICIAL() @@ -544,7 +482,7 @@ RSTRING_LENINT(VALUE str) __extension__ ({ \ struct RString rbimpl_str = rbimpl_rstring_getmem(str); \ (ptrvar) = rbimpl_str.as.heap.ptr; \ - (lenvar) = rbimpl_str.as.heap.len; \ + (lenvar) = rbimpl_str.len; \ }) #else # define RSTRING_GETMEM(str, ptrvar, lenvar) \ |