pm_newline_list.c

#include "prism/util/pm_newline_list.h"
 
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;
}
 
void
pm_newline_list_clear(pm_newline_list_t *list) {
    list->size = 1;
}
 
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;
}
 
int32_t
pm_newline_list_line(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 ((int32_t) mid) + start_line;
        }
 
        if (list->offsets[mid] < offset) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }
 
    return ((int32_t) left) + start_line - 1;
}
 
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])
    });
}
 
void
pm_newline_list_free(pm_newline_list_t *list) {
    xfree(list->offsets);
}