SQL Programming Manual for Pascal

Examples of Dynamic NonStop SQL Programs
HP NonStop SQL Programming Manual for Pascal—528614-001
C-14
Detailed Dynamic SQL Program
197 0 {**********************************************************}
198 0 {* ALLOC_SPACE : Allocate the required number of bytes, nb, on
*}
199 0 {* the current heap if there is sufficient space. *}
200 0 {* Otherwise, allocate a heap of size HEAPSIZE. *}
201 0 {* Maintain a LIFO list of heaps anchored in pheap. *}
202 0 {**********************************************************}
203 0 function alloc_space(var pheap : P_HEAP_HDR; nb : longint) :
extaddr;
204 1 var
205 1 newp,oldp : P_ANY; { scratch pointer }
206 1 begin
207 2 if (pheap = NIL) or { heap has not been alloc'd }
208 3 (pheap^.off + nb > HEAPSIZE) then
{ space is insufficient }
209 3 begin { allocate a new heap ----1 }
210 4 newp.xa := MALLOC(HEAPSIZE);
211 4 if (newp.i > 0) then { successfully allocated ? }
212 5 begin { yes, it did ----2 }
213 6 oldp.hp := pheap; { load local pointer }
214 6 newp.hp^.nxt := oldp.xa; { 1st heap will become 2nd }
215 6 pheap := newp.hp; { new heap becomes 1st }
216 6 pheap^.off := sizeof(HEAP_HDR);
{ set offset to free space }
217 6 end { yes, it did ----2 }
218 5 else { allocation failed }
219 5 begin { report an error ----3 }
220 6 G_errcb.erc := ERC_NOHEAPSPACE;
221 6
222 6 alloc_space := RETYPE(0, EXTADDR);
{ return an EXTADDR 0 }
223 6 { if function fails }
224 6 return;
225 6 end { report an error ----3 }
226 5 end { allocate a new heap ----1 }
227 3 else newp.hp := pheap;
228 2 newp.i := newp.i + pheap^.off; { set ptr to free area }
229 2
230 2 { allocate space and round result to even number of bytes, to }
231 2 { accommodate values which must be word-aligned: }
232 2 pheap^.off := pheap^.off + nb + (nb mod 2);
233 2 alloc_space := newp.xa; { set return value }
234 2 end; { of proc alloc_space }
235 0
236 0 {**********************************************************}
237 0 {* DEALLOC_SPACE : Deallocate all of the storage on the heap *}
238 0 {* pointed to by pheap. *}
239 0 {**********************************************************}
240 0 procedure dealloc_space(var pheap : P_HEAP_HDR);
241 1 var
242 1 curp,nxtp : P_ANY; { scratch pointer }
243 1 begin
244 2 nxtp.hp := pheap; { next heap to free }
245 2 while (nxtp.hp <> NIL) do { while got some heap space }
246 3 begin
247 4 curp := nxtp; { set ptr to heap to free }
248 4 nxtp.xa := curp.hp^.nxt;{ remember ptr to neighbour }
249 4 FREE(curp.xa); { deallocate current heap }
250 4 end;
251 2 pheap := NIL; { heap storage deallocated }
252 2 end; { of proc dealloc_space }
253 0