ceph/src/civetweb/src/third_party/duktape-1.5.2/src-separate/duk_hbufferobject.h

   1 /*
   2  *  Heap Buffer object representation.  Used for all Buffer variants.
   3  */
   4
   5 #ifndef DUK_HBUFFEROBJECT_H_INCLUDED
   6 #define DUK_HBUFFEROBJECT_H_INCLUDED
   7
   8 /* All element accessors are host endian now (driven by TypedArray spec). */
   9 #define DUK_HBUFFEROBJECT_ELEM_UINT8           0
  10 #define DUK_HBUFFEROBJECT_ELEM_UINT8CLAMPED    1
  11 #define DUK_HBUFFEROBJECT_ELEM_INT8            2
  12 #define DUK_HBUFFEROBJECT_ELEM_UINT16          3
  13 #define DUK_HBUFFEROBJECT_ELEM_INT16           4
  14 #define DUK_HBUFFEROBJECT_ELEM_UINT32          5
  15 #define DUK_HBUFFEROBJECT_ELEM_INT32           6
  16 #define DUK_HBUFFEROBJECT_ELEM_FLOAT32         7
  17 #define DUK_HBUFFEROBJECT_ELEM_FLOAT64         8
  18 #define DUK_HBUFFEROBJECT_ELEM_MAX             8
  19
  20 #define DUK_ASSERT_HBUFFEROBJECT_VALID(h) do { \
  21                 DUK_ASSERT((h) != NULL); \
  22                 DUK_ASSERT((h)->shift <= 3); \
  23                 DUK_ASSERT((h)->elem_type <= DUK_HBUFFEROBJECT_ELEM_MAX); \
  24                 DUK_ASSERT(((h)->shift == 0 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_UINT8) || \
  25                            ((h)->shift == 0 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_UINT8CLAMPED) || \
  26                            ((h)->shift == 0 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_INT8) || \
  27                            ((h)->shift == 1 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_UINT16) || \
  28                            ((h)->shift == 1 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_INT16) || \
  29                            ((h)->shift == 2 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_UINT32) || \
  30                            ((h)->shift == 2 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_INT32) || \
  31                            ((h)->shift == 2 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_FLOAT32) || \
  32                            ((h)->shift == 3 && (h)->elem_type == DUK_HBUFFEROBJECT_ELEM_FLOAT64)); \
  33                 DUK_ASSERT((h)->is_view == 0 || (h)->is_view == 1); \
  34                 DUK_ASSERT(DUK_HOBJECT_IS_BUFFEROBJECT((duk_hobject *) (h))); \
  35                 if ((h)->buf == NULL) { \
  36                         DUK_ASSERT((h)->offset == 0); \
  37                         DUK_ASSERT((h)->length == 0); \
  38                 } else { \
  39                         /* No assertions for offset or length; in particular, \
  40                          * it's OK for length to be longer than underlying \
  41                          * buffer.  Just ensure they don't wrap when added. \
  42                          */ \
  43                         DUK_ASSERT((h)->offset + (h)->length >= (h)->offset); \
  44                 } \
  45         } while (0)
  46
  47 /* Get the current data pointer (caller must ensure buf != NULL) as a
  48  * duk_uint8_t ptr.
  49  */
  50 #define DUK_HBUFFEROBJECT_GET_SLICE_BASE(heap,h) \
  51         (DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
  52         (((duk_uint8_t *) DUK_HBUFFER_GET_DATA_PTR((heap), (h)->buf)) + (h)->offset))
  53
  54 /* True if slice is full, i.e. offset is zero and length covers the entire
  55  * buffer.  This status may change independently of the duk_hbufferobject if
  56  * the underlying buffer is dynamic and changes without the hbufferobject
  57  * being changed.
  58  */
  59 #define DUK_HBUFFEROBJECT_FULL_SLICE(h) \
  60         (DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
  61         ((h)->offset == 0 && (h)->length == DUK_HBUFFER_GET_SIZE((h)->buf)))
  62
  63 /* Validate that the whole slice [0,length[ is contained in the underlying
  64  * buffer.  Caller must ensure 'buf' != NULL.
  65  */
  66 #define DUK_HBUFFEROBJECT_VALID_SLICE(h) \
  67         (DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
  68         ((h)->offset + (h)->length <= DUK_HBUFFER_GET_SIZE((h)->buf)))
  69
  70 /* Validate byte read/write for virtual 'offset', i.e. check that the
  71  * offset, taking into account h->offset, is within the underlying
  72  * buffer size.  This is a safety check which is needed to ensure
  73  * that even a misconfigured duk_hbufferobject never causes memory
  74  * unsafe behavior (e.g. if an underlying dynamic buffer changes
  75  * after being setup).  Caller must ensure 'buf' != NULL.
  76  */
  77 #define DUK_HBUFFEROBJECT_VALID_BYTEOFFSET_INCL(h,off) \
  78         (DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
  79         ((h)->offset + (off) < DUK_HBUFFER_GET_SIZE((h)->buf)))
  80
  81 #define DUK_HBUFFEROBJECT_VALID_BYTEOFFSET_EXCL(h,off) \
  82         (DUK_ASSERT_EXPR((h) != NULL), DUK_ASSERT_EXPR((h)->buf != NULL), \
  83         ((h)->offset + (off) <= DUK_HBUFFER_GET_SIZE((h)->buf)))
  84
  85 /* Clamp an input byte length (already assumed to be within the nominal
  86  * duk_hbufferobject 'length') to the current dynamic buffer limits to
  87  * yield a byte length limit that's safe for memory accesses.  This value
  88  * can be invalidated by any side effect because it may trigger a user
  89  * callback that resizes the underlying buffer.
  90  */
  91 #define DUK_HBUFFEROBJECT_CLAMP_BYTELENGTH(h,len) \
  92         (DUK_ASSERT_EXPR((h) != NULL), \
  93         duk_hbufferobject_clamp_bytelength((h), (len)))
  94
  95 struct duk_hbufferobject {
  96         /* Shared object part. */
  97         duk_hobject obj;
  98
  99         /* Underlying buffer (refcounted), may be NULL. */
 100         duk_hbuffer *buf;
 101
 102         /* Slice and accessor information.
 103          *
 104          * Because the underlying buffer may be dynamic, these may be
 105          * invalidated by the buffer being modified so that both offset
 106          * and length should be validated before every access.  Behavior
 107          * when the underlying buffer has changed doesn't need to be clean:
 108          * virtual 'length' doesn't need to be affected, reads can return
 109          * zero/NaN, and writes can be ignored.
 110          *
 111          * Note that a data pointer cannot be precomputed because 'buf' may
 112          * be dynamic and its pointer unstable.
 113          */
 114
 115         duk_uint_t offset;       /* byte offset to buf */
 116         duk_uint_t length;       /* byte index limit for element access, exclusive */
 117         duk_uint8_t shift;       /* element size shift:
 118                                   *   0 = u8/i8
 119                                   *   1 = u16/i16
 120                                   *   2 = u32/i32/float
 121                                   *   3 = double
 122                                   */
 123         duk_uint8_t elem_type;   /* element type */
 124         duk_uint8_t is_view;
 125 };
 126
 127 #if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
 128 DUK_INTERNAL_DECL duk_uint_t duk_hbufferobject_clamp_bytelength(duk_hbufferobject *h_bufobj, duk_uint_t len);
 129 #endif
 130 DUK_INTERNAL_DECL void duk_hbufferobject_push_validated_read(duk_context *ctx, duk_hbufferobject *h_bufobj, duk_uint8_t *p, duk_small_uint_t elem_size);
 131 DUK_INTERNAL_DECL void duk_hbufferobject_validated_write(duk_context *ctx, duk_hbufferobject *h_bufobj, duk_uint8_t *p, duk_small_uint_t elem_size);
 132
 133 #endif  /* DUK_HBUFFEROBJECT_H_INCLUDED */