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"struct-array-on" word to easily promote a struct over memory to a struct-array over the same memory. buff up the struct-arrays docs

db4
Joe Groff 2009-08-31 17:49:45 -05:00
parent bce748ee81
commit 84adb4cb55
2 changed files with 33 additions and 2 deletions
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32
basis/struct-arrays/struct-arrays-docs.factor
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@ -1,5 +1,5 @@
IN: struct-arrays
USING: help.markup help.syntax alien strings math ;
USING: classes.struct help.markup help.syntax alien strings math multiline ;
HELP: struct-array
{ $class-description "The class of C struct and union arrays."
@ -14,10 +14,38 @@ HELP: <direct-struct-array>
{ $values { "alien" c-ptr } { "length" integer } { "c-type" string } { "struct-array" struct-array } }
{ $description "Creates a new array for holding values of the specified C type, backed by the memory at " { $snippet "alien" } "." } ;
HELP: struct-array-on
{ $value { "struct" struct } { "length" integer } }
{ $description "Create a new array for holding values of " { $snippet "struct" } "'s C type, backed by the memory starting at " { $snippet "struct" } "'s address." }
{ $examples
"This word is useful with the FFI. When a C function has a pointer to a struct as its return type (or a C callback has a struct pointer as an argument type), Factor automatically wraps the pointer in a " { $link struct } " object. If the pointer actually references an array of objects, this word will convert the struct object to a struct array object:"
{ $code <" USING: alien.syntax classes.struct struct-arrays ;
IN: scratchpad
STRUCT: zim { zang int } { zung int } ;
FUNCTION: zim* zingle ( ) ; ! Returns a pointer to 20 zims
zingle 20 struct-array-on "> }
} ;
HELP: struct-array{
{ $syntax "struct-array{ class value value value ... }" }
{ $description "Literal syntax for a " { $link struct-array } " containing structs of the given " { $link struct } " class." } ;
HELP: struct-array@
{ $syntax "struct-array@ class alien length" }
{ $description "Literal syntax for a " { $link struct-array } " at a particular memory address. The prettyprinter uses this syntax when the memory backing a struct array object is invalid. This syntax should not generally be used in source code." } ;
{ POSTPONE: struct-array{ POSTPONE: struct-array@ } related-words
ARTICLE: "struct-arrays" "C struct and union arrays"
"The " { $vocab-link "struct-arrays" } " vocabulary implements arrays specialized for holding C struct and union values."
{ $subsection struct-array }
{ $subsection <struct-array> }
{ $subsection <direct-struct-array> } ;
{ $subsection <direct-struct-array> }
{ $subsection struct-array-on }
"Struct arrays have literal syntax:"
{ $subsection POSTPONE: struct-array{ } ;
ABOUT: "struct-arrays"

3
basis/struct-arrays/struct-arrays.factor
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@ -49,6 +49,9 @@ ERROR: bad-byte-array-length byte-array ;
: <direct-struct-array> ( alien length c-type -- struct-array )
[ heap-size ] [ c-type-struct-class ] bi struct-array boa ; inline
: struct-array-on ( struct length -- struct-array )
[ [ >c-ptr ] [ class ] bi ] dip swap <direct-struct-array> ; inline
: malloc-struct-array ( length c-type -- struct-array )
[ heap-size calloc ] 2keep <direct-struct-array> ; inline