rstring.h

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#ifndef RBIMPL_RSTRING_H                             /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_RSTRING_H
#include "ruby/internal/config.h"
#include "ruby/internal/arithmetic/long.h"
#include "ruby/internal/attr/artificial.h"
#include "ruby/internal/attr/pure.h"
#include "ruby/internal/cast.h"
#include "ruby/internal/core/rbasic.h"
#include "ruby/internal/dllexport.h"
#include "ruby/internal/fl_type.h"
#include "ruby/internal/value_type.h"
#include "ruby/internal/warning_push.h"
#include "ruby/assert.h"

#define RSTRING(obj)            RBIMPL_CAST((struct RString *)(obj))

#define RSTRING_NOEMBED         RSTRING_NOEMBED
#define RSTRING_FSTR            RSTRING_FSTR
#define RSTRING_LEN       RSTRING_LEN
#define RSTRING_LENINT    RSTRING_LENINT
#define RSTRING_PTR       RSTRING_PTR
#define RSTRING_END       RSTRING_END


#define StringValue(v)     rb_string_value(&(v))

#define StringValuePtr(v)  rb_string_value_ptr(&(v))

#define StringValueCStr(v) rb_string_value_cstr(&(v))

#define SafeStringValue(v) StringValue(v)

#define ExportStringValue(v) do { \
    StringValue(v);               \
    (v) = rb_str_export(v);       \
} while (0)


enum ruby_rstring_flags {

    RSTRING_NOEMBED         = RUBY_FL_USER1,
 
    /* Actually,  string  encodings are  also  encoded  into the  flags,  using
     * remaining bits.*/

    RSTRING_FSTR            = RUBY_FL_USER17
};

struct RString {

    struct RBasic basic;

    long len;

    union {

        struct {
            char *ptr;

            union {

                long capa;

                VALUE shared;
            } aux;
        } heap;

        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;
};
 
RBIMPL_SYMBOL_EXPORT_BEGIN()
VALUE rb_str_to_str(VALUE obj);

VALUE rb_string_value(volatile VALUE *ptr);

char *rb_string_value_ptr(volatile VALUE *ptr);

char *rb_string_value_cstr(volatile VALUE *ptr);

VALUE rb_str_export(VALUE obj);

VALUE rb_str_export_locale(VALUE obj);
 
RBIMPL_ATTR_ERROR(("rb_check_safe_str() and Check_SafeStr() are obsolete; use StringValue() instead"))
void rb_check_safe_str(VALUE);

#define Check_SafeStr(v) rb_check_safe_str(RBIMPL_CAST((VALUE)(v)))

void rb_debug_rstring_null_ptr(const char *func);
RBIMPL_SYMBOL_EXPORT_END()
 
RBIMPL_ATTR_PURE_UNLESS_DEBUG()
RBIMPL_ATTR_ARTIFICIAL()
static inline long
RSTRING_LEN(VALUE str)
{
    return RSTRING(str)->len;
}
 
RBIMPL_ATTR_ARTIFICIAL()
static inline char *
RSTRING_PTR(VALUE str)
{
    char *ptr = RB_FL_TEST_RAW(str, RSTRING_NOEMBED) ?
        RSTRING(str)->as.heap.ptr :
        RSTRING(str)->as.embed.ary;
 
    if (RUBY_DEBUG && RB_UNLIKELY(! ptr)) {
        /* :BEWARE: @shyouhei thinks  that currently, there are  rooms for this
         * 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
         * Ruby objects.  That is not possible at this moment. */
        rb_debug_rstring_null_ptr("RSTRING_PTR");
    }
 
    return ptr;
}
 
RBIMPL_ATTR_ARTIFICIAL()
static inline char *
RSTRING_END(VALUE str)
{
    char *ptr = RB_FL_TEST_RAW(str, RSTRING_NOEMBED) ?
        RSTRING(str)->as.heap.ptr :
        RSTRING(str)->as.embed.ary;
    long len = RSTRING_LEN(str);
 
    if (RUBY_DEBUG && RB_UNLIKELY(!ptr)) {
        /* Ditto. */
        rb_debug_rstring_null_ptr("RSTRING_END");
    }
 
    return &ptr[len];
}
 
RBIMPL_ATTR_ARTIFICIAL()
static inline int
RSTRING_LENINT(VALUE str)
{
    return rb_long2int(RSTRING_LEN(str));
}

# define RSTRING_GETMEM(str, ptrvar, lenvar) \
    ((ptrvar) = RSTRING_PTR(str),           \
     (lenvar) = RSTRING_LEN(str))
#endif /* RBIMPL_RSTRING_H */