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ugui/generic_stack.h

118 lines
6.4 KiB

#ifndef _STACK_GENERIC_H
#define _STACK_GENERIC_H
#define STACK_STEP 8
#define STACK_SALT 0xbabb0cac
// FIXME: find a way to not re-hash the whole stack when removing one item
// incremental hash for every grow
#if STACK_DISABLE_HASH
#define STACK_HASH(p, s, h) {}
#else
#define STACK_HASH(p, s, h) \
{ \
unsigned char *v = (unsigned char *)(p); \
for (int x = (s); x; x--) { \
(h) += v[x-1]; \
(h) += (h) << 10; \
(h) ^= (h) >> 6; \
} \
(h) += (h) << 3; \
(h) ^= (h) >> 11; \
(h) += (h) << 15; \
}
#endif
// TODO: add a rolling hash
#define STACK_DECL(stackname, type) \
struct stackname { \
type *items; \
int size, idx, old_idx; \
unsigned int hash, old_hash; \
}; \
\
\
struct stackname stackname##_init(void) \
{ \
return (struct stackname){0, .hash = STACK_SALT}; \
} \
\
\
int stackname##_grow(struct stackname *stack, int step) \
{ \
if (!stack) \
return -1; \
stack->items = realloc(stack->items, (stack->size+step)*sizeof(type)); \
if(!stack->items) \
return -1; \
memset(&(stack->items[stack->size]), 0, step*sizeof(*(stack->items))); \
stack->size += step; \
return 0; \
} \
\
\
int stackname##_push(struct stackname *stack, type *e) \
{ \
if (!stack || !e) \
return -1; \
if (stack->idx >= stack->size) \
if (stackname##_grow(stack, STACK_STEP)) \
return -1; \
stack->items[stack->idx++] = *e; \
STACK_HASH(e, sizeof(type), stack->hash); \
return 0; \
} \
\
\
type stackname##_pop(struct stackname *stack) \
{ \
if (!stack || stack->idx == 0 || stack->size == 0) \
return (type){0}; \
stack->hash = STACK_SALT; \
STACK_HASH(stack->items, sizeof(type)*(stack->idx-1), stack->hash); \
return stack->items[stack->idx--]; \
} \
\
\
int stackname##_clear(struct stackname *stack) \
{ \
if (!stack) \
return -1; \
stack->old_idx = stack->idx; \
stack->old_hash = stack->hash; \
stack->hash = STACK_SALT; \
stack->idx = 0; \
return 0; \
} \
\
\
int stackname##_changed(struct stackname *stack) \
{ \
if (!stack) \
return -1; \
return stack->hash != stack->old_hash; \
} \
\
\
int stackname##_size_changed(struct stackname *stack) \
{ \
if (!stack) \
return -1; \
return stack->size != stack->old_idx; \
} \
\
\
int stackname##_free(struct stackname *stack) \
{ \
if (stack) { \
stackname##_clear(stack); \
if (stack->items) \
free(stack->items); \
} \
return 0; \
} \
#endif