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vector: grow exponentially to reduce number of reallocs #2

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Merged
tlsa merged 1 commit into from
Nov 19, 2025
Merged

vector: grow exponentially to reduce number of reallocs #2

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19 changes: 15 additions & 4 deletions src/utils/vector.c
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Original file line number Diff line number Diff line change
Expand Up @@ -99,14 +99,25 @@ parserutils_error parserutils_vector_append(parserutils_vector *vector,
slot = vector->current_item + 1;

if ((size_t) slot >= vector->items_allocated) {
void *temp = realloc(vector->items,
(vector->items_allocated + vector->chunk_size) *
vector->item_size);
/* Exponential growth: double current allocation,
but at least add chunk_size */
size_t new_allocated = vector->items_allocated * 2;
void *temp;

if (new_allocated < vector->items_allocated + vector->chunk_size)
new_allocated = vector->items_allocated + vector->chunk_size;

/* Overflow check */
if (new_allocated < vector->items_allocated ||
new_allocated > SIZE_MAX / vector->item_size)
return PARSERUTILS_NOMEM;

temp = realloc(vector->items, new_allocated * vector->item_size);
if (temp == NULL)
return PARSERUTILS_NOMEM;

vector->items = temp;
vector->items_allocated += vector->chunk_size;
vector->items_allocated = new_allocated;
}

memcpy((uint8_t *) vector->items + (slot * vector->item_size),
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