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stack damage tracking

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This commit is contained in:
Alessandro Mauri 2023-03-04 14:33:22 +01:00
parent 4f2a7fbf18
commit 30510ab69a
3 changed files with 77 additions and 16 deletions
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48
text_rendering/stack.h
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@ -3,17 +3,38 @@
#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
#define 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; \
}
// TODO: add a rolling hash
#define STACK_DECL(stackname, type) \
struct stackname { \
type *items; \
int size, idx; \
int size, idx, old_idx; \
unsigned int hash, old_hash; \
}; \
\
\
struct stackname stackname##_init(void) { return (struct stackname){0}; } \
struct stackname stackname##_init(void) \
{ \
return (struct stackname){0, .hash = STACK_SALT}; \
} \
\
\
int stackname##_grow(struct stackname *stack, int step) \
@ -37,6 +58,7 @@ int stackname##_push(struct stackname *stack, type *e) \
if (stackname##_grow(stack, STACK_STEP)) \
return -1; \
stack->items[stack->idx++] = *e; \
HASH(e, sizeof(type), stack->hash); \
return 0; \
} \
\
@ -45,6 +67,8 @@ type stackname##_pop(struct stackname *stack) \
{ \
if (!stack || stack->idx == 0 || stack->size == 0) \
return (type){0}; \
stack->hash = STACK_SALT; \
HASH(stack->items, sizeof(type)*(stack->idx-1), stack->hash); \
return stack->items[stack->idx--]; \
} \
\
@ -53,11 +77,30 @@ 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) { \
@ -68,5 +111,4 @@ int stackname##_free(struct stackname *stack) \
return 0; \
} \
#endif