14 The optional Memory-Allocation word set

14.6.1.2145 RESIZE MEMORY

( a-addr1 u -- a-addr2 ior )

Change the allocation of the contiguous data space starting at the address a-addr1, previously allocated by ALLOCATE or RESIZE, to u address units. u may be either larger or smaller than the current size of the region. The data-space pointer is unaffected by this operation.

If the operation succeeds, a-addr2 is the aligned starting address of u address units of allocated memory and ior is zero. a-addr2 may be, but need not be, the same as a-addr1. If they are not the same, the values contained in the region at a-addr1 are copied to a-addr2, up to the minimum size of either of the two regions. If they are the same, the values contained in the region are preserved to the minimum of u or the original size. If a-addr2 is not the same as a-addr1, the region of memory at a-addr1 is returned to the system according to the operation of FREE.

If the operation fails, a-addr2 equals a-addr1, the region of memory at a-addr1 is unaffected, and ior is the implementation-defined I/O result code.

See:

Testing:

T{ 50 CHARS ALLOCATE SWAP addr ! -> 0 }T
addr @ 50 write-char-mem addr @ 50 check-char-mem

\ Resize smaller does not change content.
T{ addr @ 28 CHARS RESIZE SWAP addr ! -> 0 }T
addr @ 28 check-char-mem

\ Resize larger does not change original content.
T{ addr @ 100 CHARS RESIZE SWAP addr ! -> 0 }T
addr @ 28 check-char-mem

\ Resize error does not change addr
T{ addr @ -1 RESIZE 0= -> addr @ <FALSE> }T

T{ addr @ FREE -> 0 }T
T{ HERE -> datsp @ }T    \ Data space pointer is unaffected

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