diff options
Diffstat (limited to 'libgo/go/encoding/gob/doc.go')
| -rw-r--r-- | libgo/go/encoding/gob/doc.go | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/libgo/go/encoding/gob/doc.go b/libgo/go/encoding/gob/doc.go index 4d3d0076fbc..cf878f45029 100644 --- a/libgo/go/encoding/gob/doc.go +++ b/libgo/go/encoding/gob/doc.go @@ -82,6 +82,12 @@ slice has capacity the slice will be extended in place; if not, a new array is allocated. Regardless, the length of the resulting slice reports the number of elements decoded. +In general, if allocation is required, the decoder will allocate memory. If not, +it will update the destination variables with values read from the stream. It does +not initialize them first, so if the destination is a compound value such as a +map, struct, or slice, the decoded values will be merged elementwise into the +existing variables. + Functions and channels will not be sent in a gob. Attempting to encode such a value at the top level will fail. A struct field of chan or func type is treated exactly like an unexported field and is ignored. @@ -141,18 +147,21 @@ pairs. Empty but non-nil maps are sent, so if the receiver has not allocated one already, one will always be allocated on receipt unless the transmitted map is nil and not at the top level. +In slices and arrays, as well as maps, all elements, even zero-valued elements, +are transmitted, even if all the elements are zero. + Structs are sent as a sequence of (field number, field value) pairs. The field value is sent using the standard gob encoding for its type, recursively. If a -field has the zero value for its type, it is omitted from the transmission. The -field number is defined by the type of the encoded struct: the first field of the -encoded type is field 0, the second is field 1, etc. When encoding a value, the -field numbers are delta encoded for efficiency and the fields are always sent in -order of increasing field number; the deltas are therefore unsigned. The -initialization for the delta encoding sets the field number to -1, so an unsigned -integer field 0 with value 7 is transmitted as unsigned delta = 1, unsigned value -= 7 or (01 07). Finally, after all the fields have been sent a terminating mark -denotes the end of the struct. That mark is a delta=0 value, which has -representation (00). +field has the zero value for its type (except for arrays; see above), it is omitted +from the transmission. The field number is defined by the type of the encoded +struct: the first field of the encoded type is field 0, the second is field 1, +etc. When encoding a value, the field numbers are delta encoded for efficiency +and the fields are always sent in order of increasing field number; the deltas are +therefore unsigned. The initialization for the delta encoding sets the field +number to -1, so an unsigned integer field 0 with value 7 is transmitted as unsigned +delta = 1, unsigned value = 7 or (01 07). Finally, after all the fields have been +sent a terminating mark denotes the end of the struct. That mark is a delta=0 +value, which has representation (00). Interface types are not checked for compatibility; all interface types are treated, for transmission, as members of a single "interface" type, analogous to |