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#include "prism/util/pm_newline_list.h"
/**
* Initialize a new newline list with the given capacity. Returns true if the
* allocation of the offsets succeeds, otherwise returns false.
*/
bool
pm_newline_list_init(pm_newline_list_t *list, const uint8_t *start, size_t capacity) {
list->offsets = (size_t *) xcalloc(capacity, sizeof(size_t));
if (list->offsets == NULL) return false;
list->start = start;
// This is 1 instead of 0 because we want to include the first line of the
// file as having offset 0, which is set because of calloc.
list->size = 1;
list->capacity = capacity;
return true;
}
/**
* Clear out the newlines that have been appended to the list.
*/
void
pm_newline_list_clear(pm_newline_list_t *list) {
list->size = 1;
}
/**
* Append a new offset to the newline list. Returns true if the reallocation of
* the offsets succeeds (if one was necessary), otherwise returns false.
*/
bool
pm_newline_list_append(pm_newline_list_t *list, const uint8_t *cursor) {
if (list->size == list->capacity) {
size_t *original_offsets = list->offsets;
list->capacity = (list->capacity * 3) / 2;
list->offsets = (size_t *) xcalloc(list->capacity, sizeof(size_t));
if (list->offsets == NULL) return false;
memcpy(list->offsets, original_offsets, list->size * sizeof(size_t));
xfree(original_offsets);
}
assert(*cursor == '\n');
assert(cursor >= list->start);
size_t newline_offset = (size_t) (cursor - list->start + 1);
assert(list->size == 0 || newline_offset > list->offsets[list->size - 1]);
list->offsets[list->size++] = newline_offset;
return true;
}
/**
* Returns the line and column of the given offset. If the offset is not in the
* list, the line and column of the closest offset less than the given offset
* are returned.
*/
pm_line_column_t
pm_newline_list_line_column(const pm_newline_list_t *list, const uint8_t *cursor, int32_t start_line) {
assert(cursor >= list->start);
size_t offset = (size_t) (cursor - list->start);
size_t left = 0;
size_t right = list->size - 1;
while (left <= right) {
size_t mid = left + (right - left) / 2;
if (list->offsets[mid] == offset) {
return ((pm_line_column_t) { ((int32_t) mid) + start_line, 0 });
}
if (list->offsets[mid] < offset) {
left = mid + 1;
} else {
right = mid - 1;
}
}
return ((pm_line_column_t) {
.line = ((int32_t) left) + start_line - 1,
.column = (uint32_t) (offset - list->offsets[left - 1])
});
}
/**
* Free the internal memory allocated for the newline list.
*/
void
pm_newline_list_free(pm_newline_list_t *list) {
xfree(list->offsets);
}
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