[thirdparty/systemd.git] / src / shared / format-table.c

/* SPDX-License-Identifier: LGPL-2.1+ */

#include <stdio_ext.h>

#include "alloc-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "format-table.h"
#include "gunicode.h"
#include "pager.h"
#include "parse-util.h"
#include "pretty-print.h"
#include "string-util.h"
#include "terminal-util.h"
#include "time-util.h"
#include "utf8.h"
#include "util.h"

#define DEFAULT_WEIGHT 100

/*
   A few notes on implementation details:

 - TableCell is a 'fake' structure, it's just used as data type to pass references to specific cell positions in the
   table. It can be easily converted to an index number and back.

 - TableData is where the actual data is stored: it encapsulates the data and formatting for a specific cell. It's
   'pseudo-immutable' and ref-counted. When a cell's data's formatting is to be changed, we duplicate the object if the
   ref-counting is larger than 1. Note that TableData and its ref-counting is mostly not visible to the outside. The
   outside only sees Table and TableCell.

 - The Table object stores a simple one-dimensional array of references to TableData objects, one row after the
   previous one.

 - There's no special concept of a "row" or "column" in the table, and no special concept of the "header" row. It's all
   derived from the cell index: we know how many cells are to be stored in a row, and can determine the rest from
   that. The first row is always the header row. If header display is turned off we simply skip outputting the first
   row. Also, when sorting rows we always leave the first row where it is, as the header shouldn't move.

 - Note because there's no row and no column object some properties that might be appropriate as row/column properties
   are exposed as cell properties instead. For example, the "weight" of a column (which is used to determine where to
   add/remove space preferable when expanding/compressing tables horizontally) is actually made the "weight" of a
   cell. Given that we usually need it per-column though we will calculate the average across every cell of the column
   instead.

 - To make things easy, when cells are added without any explicit configured formatting, then we'll copy the formatting
   from the same cell in the previous cell. This is particularly useful for the "weight" of the cell (see above), as
   this means setting the weight of the cells of the header row will nicely propagate to all cells in the other rows.
*/

typedef struct TableData {
        unsigned n_ref;
        TableDataType type;

        size_t minimum_width;       /* minimum width for the column */
        size_t maximum_width;       /* maximum width for the column */
        unsigned weight;            /* the horizontal weight for this column, in case the table is expanded/compressed */
        unsigned ellipsize_percent; /* 0 … 100, where to place the ellipsis when compression is needed */
        unsigned align_percent;     /* 0 … 100, where to pad with spaces when expanding is needed. 0: left-aligned, 100: right-aligned */

        const char *color;          /* ANSI color string to use for this cell. When written to terminal should not move cursor. Will automatically be reset after the cell */
        char *url;                  /* A URL to use for a clickable hyperlink */
        char *formatted;            /* A cached textual representation of the cell data, before ellipsation/alignment */

        union {
                uint8_t data[0];    /* data is generic array */
                bool boolean;
                usec_t timestamp;
                usec_t timespan;
                uint64_t size;
                char string[0];
                uint32_t uint32;
                uint64_t uint64;
                int percent;        /* we use 'int' as datatype for percent values in order to match the result of parse_percent() */
                /* … add more here as we start supporting more cell data types … */
        };
} TableData;

static size_t TABLE_CELL_TO_INDEX(TableCell *cell) {
        size_t i;

        assert(cell);

        i = PTR_TO_SIZE(cell);
        assert(i > 0);

        return i-1;
}

static TableCell* TABLE_INDEX_TO_CELL(size_t index) {
        assert(index != (size_t) -1);
        return SIZE_TO_PTR(index + 1);
}

struct Table {
        size_t n_columns;
        size_t n_cells;

        bool header;   /* Whether to show the header row? */
        size_t width;  /* If != (size_t) -1 the width to format this table in */

        TableData **data;
        size_t n_allocated;

        size_t *display_map;  /* List of columns to show (by their index). It's fine if columns are listed multiple times or not at all */
        size_t n_display_map;

        size_t *sort_map;     /* The columns to order rows by, in order of preference. */
        size_t n_sort_map;

        bool *reverse_map;
};

Table *table_new_raw(size_t n_columns) {
        _cleanup_(table_unrefp) Table *t = NULL;

        assert(n_columns > 0);

        t = new(Table, 1);
        if (!t)
                return NULL;

        *t = (struct Table) {
                .n_columns = n_columns,
                .header = true,
                .width = (size_t) -1,
        };

        return TAKE_PTR(t);
}

Table *table_new_internal(const char *first_header, ...) {
        _cleanup_(table_unrefp) Table *t = NULL;
        size_t n_columns = 1;
        va_list ap;
        int r;

        assert(first_header);

        va_start(ap, first_header);
        for (;;) {
                const char *h;

                h = va_arg(ap, const char*);
                if (!h)
                        break;

                n_columns++;
        }
        va_end(ap);

        t = table_new_raw(n_columns);
        if (!t)
                return NULL;

        r = table_add_cell(t, NULL, TABLE_STRING, first_header);
        if (r < 0)
                return NULL;

        va_start(ap, first_header);
        for (;;) {
                const char *h;

                h = va_arg(ap, const char*);
                if (!h)
                        break;

                r = table_add_cell(t, NULL, TABLE_STRING, h);
                if (r < 0) {
                        va_end(ap);
                        return NULL;
                }
        }
        va_end(ap);

        assert(t->n_columns == t->n_cells);
        return TAKE_PTR(t);
}

static TableData *table_data_free(TableData *d) {
        assert(d);

        free(d->formatted);
        free(d->url);

        return mfree(d);
}

DEFINE_PRIVATE_TRIVIAL_REF_UNREF_FUNC(TableData, table_data, table_data_free);
DEFINE_TRIVIAL_CLEANUP_FUNC(TableData*, table_data_unref);

Table *table_unref(Table *t) {
        size_t i;

        if (!t)
                return NULL;

        for (i = 0; i < t->n_cells; i++)
                table_data_unref(t->data[i]);

        free(t->data);
        free(t->display_map);
        free(t->sort_map);
        free(t->reverse_map);

        return mfree(t);
}

static size_t table_data_size(TableDataType type, const void *data) {

        switch (type) {

        case TABLE_EMPTY:
                return 0;

        case TABLE_STRING:
                return strlen(data) + 1;

        case TABLE_BOOLEAN:
                return sizeof(bool);

        case TABLE_TIMESTAMP:
        case TABLE_TIMESPAN:
                return sizeof(usec_t);

        case TABLE_SIZE:
        case TABLE_UINT64:
                return sizeof(uint64_t);

        case TABLE_UINT32:
                return sizeof(uint32_t);

        case TABLE_PERCENT:
                return sizeof(int);

        default:
                assert_not_reached("Uh? Unexpected cell type");
        }
}

static bool table_data_matches(
                TableData *d,
                TableDataType type,
                const void *data,
                size_t minimum_width,
                size_t maximum_width,
                unsigned weight,
                unsigned align_percent,
                unsigned ellipsize_percent) {

        size_t k, l;
        assert(d);

        if (d->type != type)
                return false;

        if (d->minimum_width != minimum_width)
                return false;

        if (d->maximum_width != maximum_width)
                return false;

        if (d->weight != weight)
                return false;

        if (d->align_percent != align_percent)
                return false;

        if (d->ellipsize_percent != ellipsize_percent)
                return false;

        k = table_data_size(type, data);
        l = table_data_size(d->type, d->data);

        if (k != l)
                return false;

        return memcmp(data, d->data, l) == 0;
}

static TableData *table_data_new(
                TableDataType type,
                const void *data,
                size_t minimum_width,
                size_t maximum_width,
                unsigned weight,
                unsigned align_percent,
                unsigned ellipsize_percent) {

        size_t data_size;
        TableData *d;

        data_size = table_data_size(type, data);

        d = malloc0(offsetof(TableData, data) + data_size);
        if (!d)
                return NULL;

        d->n_ref = 1;
        d->type = type;
        d->minimum_width = minimum_width;
        d->maximum_width = maximum_width;
        d->weight = weight;
        d->align_percent = align_percent;
        d->ellipsize_percent = ellipsize_percent;
        memcpy_safe(d->data, data, data_size);

        return d;
}

int table_add_cell_full(
                Table *t,
                TableCell **ret_cell,
                TableDataType type,
                const void *data,
                size_t minimum_width,
                size_t maximum_width,
                unsigned weight,
                unsigned align_percent,
                unsigned ellipsize_percent) {

        _cleanup_(table_data_unrefp) TableData *d = NULL;
        TableData *p;

        assert(t);
        assert(type >= 0);
        assert(type < _TABLE_DATA_TYPE_MAX);

        /* Determine the cell adjacent to the current one, but one row up */
        if (t->n_cells >= t->n_columns)
                assert_se(p = t->data[t->n_cells - t->n_columns]);
        else
                p = NULL;

        /* If formatting parameters are left unspecified, copy from the previous row */
        if (minimum_width == (size_t) -1)
                minimum_width = p ? p->minimum_width : 1;

        if (weight == (unsigned) -1)
                weight = p ? p->weight : DEFAULT_WEIGHT;

        if (align_percent == (unsigned) -1)
                align_percent = p ? p->align_percent : 0;

        if (ellipsize_percent == (unsigned) -1)
                ellipsize_percent = p ? p->ellipsize_percent : 100;

        assert(align_percent <= 100);
        assert(ellipsize_percent <= 100);

        /* Small optimization: Pretty often adjacent cells in two subsequent lines have the same data and
         * formatting. Let's see if we can reuse the cell data and ref it once more. */

        if (p && table_data_matches(p, type, data, minimum_width, maximum_width, weight, align_percent, ellipsize_percent))
                d = table_data_ref(p);
        else {
                d = table_data_new(type, data, minimum_width, maximum_width, weight, align_percent, ellipsize_percent);
                if (!d)
                        return -ENOMEM;
        }

        if (!GREEDY_REALLOC(t->data, t->n_allocated, MAX(t->n_cells + 1, t->n_columns)))
                return -ENOMEM;

        if (ret_cell)
                *ret_cell = TABLE_INDEX_TO_CELL(t->n_cells);

        t->data[t->n_cells++] = TAKE_PTR(d);

        return 0;
}

int table_dup_cell(Table *t, TableCell *cell) {
        size_t i;

        assert(t);

        /* Add the data of the specified cell a second time as a new cell to the end. */

        i = TABLE_CELL_TO_INDEX(cell);
        if (i >= t->n_cells)
                return -ENXIO;

        if (!GREEDY_REALLOC(t->data, t->n_allocated, MAX(t->n_cells + 1, t->n_columns)))
                return -ENOMEM;

        t->data[t->n_cells++] = table_data_ref(t->data[i]);
        return 0;
}

static int table_dedup_cell(Table *t, TableCell *cell) {
        _cleanup_free_ char *curl = NULL;
        TableData *nd, *od;
        size_t i;

        assert(t);

        /* Helper call that ensures the specified cell's data object has a ref count of 1, which we can use before
         * changing a cell's formatting without effecting every other cell's formatting that shares the same data */

        i = TABLE_CELL_TO_INDEX(cell);
        if (i >= t->n_cells)
                return -ENXIO;

        assert_se(od = t->data[i]);
        if (od->n_ref == 1)
                return 0;

        assert(od->n_ref > 1);

        if (od->url) {
                curl = strdup(od->url);
                if (!curl)
                        return -ENOMEM;
        }

        nd = table_data_new(
                        od->type,
                        od->data,
                        od->minimum_width,
                        od->maximum_width,
                        od->weight,
                        od->align_percent,
                        od->ellipsize_percent);
        if (!nd)
                return -ENOMEM;

        nd->color = od->color;
        nd->url = TAKE_PTR(curl);

        table_data_unref(od);
        t->data[i] = nd;

        assert(nd->n_ref == 1);

        return 1;
}

static TableData *table_get_data(Table *t, TableCell *cell) {
        size_t i;

        assert(t);
        assert(cell);

        /* Get the data object of the specified cell, or NULL if it doesn't exist */

        i = TABLE_CELL_TO_INDEX(cell);
        if (i >= t->n_cells)
                return NULL;

        assert(t->data[i]);
        assert(t->data[i]->n_ref > 0);

        return t->data[i];
}

int table_set_minimum_width(Table *t, TableCell *cell, size_t minimum_width) {
        int r;

        assert(t);
        assert(cell);

        if (minimum_width == (size_t) -1)
                minimum_width = 1;

        r = table_dedup_cell(t, cell);
        if (r < 0)
                return r;

        table_get_data(t, cell)->minimum_width = minimum_width;
        return 0;
}

int table_set_maximum_width(Table *t, TableCell *cell, size_t maximum_width) {
        int r;

        assert(t);
        assert(cell);

        r = table_dedup_cell(t, cell);
        if (r < 0)
                return r;

        table_get_data(t, cell)->maximum_width = maximum_width;
        return 0;
}

int table_set_weight(Table *t, TableCell *cell, unsigned weight) {
        int r;

        assert(t);
        assert(cell);

        if (weight == (unsigned) -1)
                weight = DEFAULT_WEIGHT;

        r = table_dedup_cell(t, cell);
        if (r < 0)
                return r;

        table_get_data(t, cell)->weight = weight;
        return 0;
}

int table_set_align_percent(Table *t, TableCell *cell, unsigned percent) {
        int r;

        assert(t);
        assert(cell);

        if (percent == (unsigned) -1)
                percent = 0;

        assert(percent <= 100);

        r = table_dedup_cell(t, cell);
        if (r < 0)
                return r;

        table_get_data(t, cell)->align_percent = percent;
        return 0;
}

int table_set_ellipsize_percent(Table *t, TableCell *cell, unsigned percent) {
        int r;

        assert(t);
        assert(cell);

        if (percent == (unsigned) -1)
                percent = 100;

        assert(percent <= 100);

        r = table_dedup_cell(t, cell);
        if (r < 0)
                return r;

        table_get_data(t, cell)->ellipsize_percent = percent;
        return 0;
}

int table_set_color(Table *t, TableCell *cell, const char *color) {
        int r;

        assert(t);
        assert(cell);

        r = table_dedup_cell(t, cell);
        if (r < 0)
                return r;

        table_get_data(t, cell)->color = empty_to_null(color);
        return 0;
}

int table_set_url(Table *t, TableCell *cell, const char *url) {
        _cleanup_free_ char *copy = NULL;
        int r;

        assert(t);
        assert(cell);

        if (url) {
                copy = strdup(url);
                if (!copy)
                        return -ENOMEM;
        }

        r = table_dedup_cell(t, cell);
        if (r < 0)
                return r;

        return free_and_replace(table_get_data(t, cell)->url, copy);
}

int table_add_many_internal(Table *t, TableDataType first_type, ...) {
        TableDataType type;
        va_list ap;
        int r;

        assert(t);
        assert(first_type >= 0);
        assert(first_type < _TABLE_DATA_TYPE_MAX);

        type = first_type;

        va_start(ap, first_type);
        for (;;) {
                const void *data;
                union {
                        uint64_t size;
                        usec_t usec;
                        uint32_t uint32;
                        uint64_t uint64;
                        int percent;
                        bool b;
                } buffer;

                switch (type) {

                case TABLE_EMPTY:
                        data = NULL;
                        break;

                case TABLE_STRING:
                        data = va_arg(ap, const char *);
                        break;

                case TABLE_BOOLEAN:
                        buffer.b = va_arg(ap, int);
                        data = &buffer.b;
                        break;

                case TABLE_TIMESTAMP:
                case TABLE_TIMESPAN:
                        buffer.usec = va_arg(ap, usec_t);
                        data = &buffer.usec;
                        break;

                case TABLE_SIZE:
                        buffer.size = va_arg(ap, uint64_t);
                        data = &buffer.size;
                        break;

                case TABLE_UINT32:
                        buffer.uint32 = va_arg(ap, uint32_t);
                        data = &buffer.uint32;
                        break;

                case TABLE_UINT64:
                        buffer.uint64 = va_arg(ap, uint64_t);
                        data = &buffer.uint64;
                        break;

                case TABLE_PERCENT:
                        buffer.percent = va_arg(ap, int);
                        data = &buffer.percent;
                        break;

                case _TABLE_DATA_TYPE_MAX:
                        /* Used as end marker */
                        va_end(ap);
                        return 0;

                default:
                        assert_not_reached("Uh? Unexpected data type.");
                }

                r = table_add_cell(t, NULL, type, data);
                if (r < 0) {
                        va_end(ap);
                        return r;
                }

                type = va_arg(ap, TableDataType);
        }
}

void table_set_header(Table *t, bool b) {
        assert(t);

        t->header = b;
}

void table_set_width(Table *t, size_t width) {
        assert(t);

        t->width = width;
}

int table_set_display(Table *t, size_t first_column, ...) {
        size_t allocated, column;
        va_list ap;

        assert(t);

        allocated = t->n_display_map;
        column = first_column;

        va_start(ap, first_column);
        for (;;) {
                assert(column < t->n_columns);

                if (!GREEDY_REALLOC(t->display_map, allocated, MAX(t->n_columns, t->n_display_map+1))) {
                        va_end(ap);
                        return -ENOMEM;
                }

                t->display_map[t->n_display_map++] = column;

                column = va_arg(ap, size_t);
                if (column == (size_t) -1)
                        break;

        }
        va_end(ap);

        return 0;
}

int table_set_sort(Table *t, size_t first_column, ...) {
        size_t allocated, column;
        va_list ap;

        assert(t);

        allocated = t->n_sort_map;
        column = first_column;

        va_start(ap, first_column);
        for (;;) {
                assert(column < t->n_columns);

                if (!GREEDY_REALLOC(t->sort_map, allocated, MAX(t->n_columns, t->n_sort_map+1))) {
                        va_end(ap);
                        return -ENOMEM;
                }

                t->sort_map[t->n_sort_map++] = column;

                column = va_arg(ap, size_t);
                if (column == (size_t) -1)
                        break;
        }
        va_end(ap);

        return 0;
}

static int cell_data_compare(TableData *a, size_t index_a, TableData *b, size_t index_b) {
        assert(a);
        assert(b);

        if (a->type == b->type) {

                /* We only define ordering for cells of the same data type. If cells with different data types are
                 * compared we follow the order the cells were originally added in */

                switch (a->type) {

                case TABLE_STRING:
                        return strcmp(a->string, b->string);

                case TABLE_BOOLEAN:
                        if (!a->boolean && b->boolean)
                                return -1;
                        if (a->boolean && !b->boolean)
                                return 1;
                        return 0;

                case TABLE_TIMESTAMP:
                        return CMP(a->timestamp, b->timestamp);

                case TABLE_TIMESPAN:
                        return CMP(a->timespan, b->timespan);

                case TABLE_SIZE:
                        return CMP(a->size, b->size);

                case TABLE_UINT32:
                        return CMP(a->uint32, b->uint32);

                case TABLE_UINT64:
                        return CMP(a->uint64, b->uint64);

                case TABLE_PERCENT:
                        return CMP(a->percent, b->percent);

                default:
                        ;
                }
        }

        /* Generic fallback using the orginal order in which the cells where added. */
        return CMP(index_a, index_b);
}

static int table_data_compare(const size_t *a, const size_t *b, Table *t) {
        size_t i;
        int r;

        assert(t);
        assert(t->sort_map);

        /* Make sure the header stays at the beginning */
        if (*a < t->n_columns && *b < t->n_columns)
                return 0;
        if (*a < t->n_columns)
                return -1;
        if (*b < t->n_columns)
                return 1;

        /* Order other lines by the sorting map */
        for (i = 0; i < t->n_sort_map; i++) {
                TableData *d, *dd;

                d = t->data[*a + t->sort_map[i]];
                dd = t->data[*b + t->sort_map[i]];

                r = cell_data_compare(d, *a, dd, *b);
                if (r != 0)
                        return t->reverse_map && t->reverse_map[t->sort_map[i]] ? -r : r;
        }

        /* Order identical lines by the order there were originally added in */
        return CMP(*a, *b);
}

static const char *table_data_format(TableData *d) {
        assert(d);

        if (d->formatted)
                return d->formatted;

        switch (d->type) {
        case TABLE_EMPTY:
                return "";

        case TABLE_STRING:
                return d->string;

        case TABLE_BOOLEAN:
                return yes_no(d->boolean);

        case TABLE_TIMESTAMP: {
                _cleanup_free_ char *p;

                p = new(char, FORMAT_TIMESTAMP_MAX);
                if (!p)
                        return NULL;

                if (!format_timestamp(p, FORMAT_TIMESTAMP_MAX, d->timestamp))
                        return "n/a";

                d->formatted = TAKE_PTR(p);
                break;
        }

        case TABLE_TIMESPAN: {
                _cleanup_free_ char *p;

                p = new(char, FORMAT_TIMESPAN_MAX);
                if (!p)
                        return NULL;

                if (!format_timespan(p, FORMAT_TIMESPAN_MAX, d->timestamp, 0))
                        return "n/a";

                d->formatted = TAKE_PTR(p);
                break;
        }

        case TABLE_SIZE: {
                _cleanup_free_ char *p;

                p = new(char, FORMAT_BYTES_MAX);
                if (!p)
                        return NULL;

                if (!format_bytes(p, FORMAT_BYTES_MAX, d->size))
                        return "n/a";

                d->formatted = TAKE_PTR(p);
                break;
        }

        case TABLE_UINT32: {
                _cleanup_free_ char *p;

                p = new(char, DECIMAL_STR_WIDTH(d->uint32) + 1);
                if (!p)
                        return NULL;

                sprintf(p, "%" PRIu32, d->uint32);
                d->formatted = TAKE_PTR(p);
                break;
        }

        case TABLE_UINT64: {
                _cleanup_free_ char *p;

                p = new(char, DECIMAL_STR_WIDTH(d->uint64) + 1);
                if (!p)
                        return NULL;

                sprintf(p, "%" PRIu64, d->uint64);
                d->formatted = TAKE_PTR(p);
                break;
        }

        case TABLE_PERCENT: {
                _cleanup_free_ char *p;

                p = new(char, DECIMAL_STR_WIDTH(d->percent) + 2);
                if (!p)
                        return NULL;

                sprintf(p, "%i%%" , d->percent);
                d->formatted = TAKE_PTR(p);
                break;
        }

        default:
                assert_not_reached("Unexpected type?");
        }

        return d->formatted;
}

static int table_data_requested_width(TableData *d, size_t *ret) {
        const char *t;
        size_t l;

        t = table_data_format(d);
        if (!t)
                return -ENOMEM;

        l = utf8_console_width(t);
        if (l == (size_t) -1)
                return -EINVAL;

        if (d->maximum_width != (size_t) -1 && l > d->maximum_width)
                l = d->maximum_width;

        if (l < d->minimum_width)
                l = d->minimum_width;

        *ret = l;
        return 0;
}

static char *align_string_mem(const char *str, const char *url, size_t new_length, unsigned percent) {
        size_t w = 0, space, lspace, old_length, clickable_length;
        _cleanup_free_ char *clickable = NULL;
        const char *p;
        char *ret;
        size_t i;
        int r;

        /* As with ellipsize_mem(), 'old_length' is a byte size while 'new_length' is a width in character cells */

        assert(str);
        assert(percent <= 100);

        old_length = strlen(str);

        if (url) {
                r = terminal_urlify(url, str, &clickable);
                if (r < 0)
                        return NULL;

                clickable_length = strlen(clickable);
        } else
                clickable_length = old_length;

        /* Determine current width on screen */
        p = str;
        while (p < str + old_length) {
                char32_t c;

                if (utf8_encoded_to_unichar(p, &c) < 0) {
                        p++, w++; /* count invalid chars as 1 */
                        continue;
                }

                p = utf8_next_char(p);
                w += unichar_iswide(c) ? 2 : 1;
        }

        /* Already wider than the target, if so, don't do anything */
        if (w >= new_length)
                return clickable ? TAKE_PTR(clickable) : strdup(str);

        /* How much spaces shall we add? An how much on the left side? */
        space = new_length - w;
        lspace = space * percent / 100U;

        ret = new(char, space + clickable_length + 1);
        if (!ret)
                return NULL;

        for (i = 0; i < lspace; i++)
                ret[i] = ' ';
        memcpy(ret + lspace, clickable ?: str, clickable_length);
        for (i = lspace + clickable_length; i < space + clickable_length; i++)
                ret[i] = ' ';

        ret[space + clickable_length] = 0;
        return ret;
}

int table_print(Table *t, FILE *f) {
        size_t n_rows, *minimum_width, *maximum_width, display_columns, *requested_width,
                i, j, table_minimum_width, table_maximum_width, table_requested_width, table_effective_width,
                *width;
        _cleanup_free_ size_t *sorted = NULL;
        uint64_t *column_weight, weight_sum;
        int r;

        assert(t);

        if (!f)
                f = stdout;

        /* Ensure we have no incomplete rows */
        assert(t->n_cells % t->n_columns == 0);

        n_rows = t->n_cells / t->n_columns;
        assert(n_rows > 0); /* at least the header row must be complete */

        if (t->sort_map) {
                /* If sorting is requested, let's calculate an index table we use to lookup the actual index to display with. */

                sorted = new(size_t, n_rows);
                if (!sorted)
                        return -ENOMEM;

                for (i = 0; i < n_rows; i++)
                        sorted[i] = i * t->n_columns;

                typesafe_qsort_r(sorted, n_rows, table_data_compare, t);
        }

        if (t->display_map)
                display_columns = t->n_display_map;
        else
                display_columns = t->n_columns;

        assert(display_columns > 0);

        minimum_width = newa(size_t, display_columns);
        maximum_width = newa(size_t, display_columns);
        requested_width = newa(size_t, display_columns);
        width = newa(size_t, display_columns);
        column_weight = newa0(uint64_t, display_columns);

        for (j = 0; j < display_columns; j++) {
                minimum_width[j] = 1;
                maximum_width[j] = (size_t) -1;
                requested_width[j] = (size_t) -1;
        }

        /* First pass: determine column sizes */
        for (i = t->header ? 0 : 1; i < n_rows; i++) {
                TableData **row;

                /* Note that we don't care about ordering at this time, as we just want to determine column sizes,
                 * hence we don't care for sorted[] during the first pass. */
                row = t->data + i * t->n_columns;

                for (j = 0; j < display_columns; j++) {
                        TableData *d;
                        size_t req;

                        assert_se(d = row[t->display_map ? t->display_map[j] : j]);

                        r = table_data_requested_width(d, &req);
                        if (r < 0)
                                return r;

                        /* Determine the biggest width that any cell in this column would like to have */
                        if (requested_width[j] == (size_t) -1 ||
                            requested_width[j] < req)
                                requested_width[j] = req;

                        /* Determine the minimum width any cell in this column needs */
                        if (minimum_width[j] < d->minimum_width)
                                minimum_width[j] = d->minimum_width;

                        /* Determine the maximum width any cell in this column needs */
                        if (d->maximum_width != (size_t) -1 &&
                            (maximum_width[j] == (size_t) -1 ||
                             maximum_width[j] > d->maximum_width))
                                maximum_width[j] = d->maximum_width;

                        /* Determine the full columns weight */
                        column_weight[j] += d->weight;
                }
        }

        /* One space between each column */
        table_requested_width = table_minimum_width = table_maximum_width = display_columns - 1;

        /* Calculate the total weight for all columns, plus the minimum, maximum and requested width for the table. */
        weight_sum = 0;
        for (j = 0; j < display_columns; j++) {
                weight_sum += column_weight[j];

                table_minimum_width += minimum_width[j];

                if (maximum_width[j] == (size_t) -1)
                        table_maximum_width = (size_t) -1;
                else
                        table_maximum_width += maximum_width[j];

                table_requested_width += requested_width[j];
        }

        /* Calculate effective table width */
        if (t->width == (size_t) -1)
                table_effective_width = pager_have() ? table_requested_width : MIN(table_requested_width, columns());
        else
                table_effective_width = t->width;

        if (table_maximum_width != (size_t) -1 && table_effective_width > table_maximum_width)
                table_effective_width = table_maximum_width;

        if (table_effective_width < table_minimum_width)
                table_effective_width = table_minimum_width;

        if (table_effective_width >= table_requested_width) {
                size_t extra;

                /* We have extra room, let's distribute it among columns according to their weights. We first provide
                 * each column with what it asked for and the distribute the rest.  */

                extra = table_effective_width - table_requested_width;

                for (j = 0; j < display_columns; j++) {
                        size_t delta;

                        if (weight_sum == 0)
                                width[j] = requested_width[j] + extra / (display_columns - j); /* Avoid division by zero */
                        else
                                width[j] = requested_width[j] + (extra * column_weight[j]) / weight_sum;

                        if (maximum_width[j] != (size_t) -1 && width[j] > maximum_width[j])
                                width[j] = maximum_width[j];

                        if (width[j] < minimum_width[j])
                                width[j] = minimum_width[j];

                        assert(width[j] >= requested_width[j]);
                        delta = width[j] - requested_width[j];

                        /* Subtract what we just added from the rest */
                        if (extra > delta)
                                extra -= delta;
                        else
                                extra = 0;

                        assert(weight_sum >= column_weight[j]);
                        weight_sum -= column_weight[j];
                }

        } else {
                /* We need to compress the table, columns can't get what they asked for. We first provide each column
                 * with the minimum they need, and then distribute anything left. */
                bool finalize = false;
                size_t extra;

                extra = table_effective_width - table_minimum_width;

                for (j = 0; j < display_columns; j++)
                        width[j] = (size_t) -1;

                for (;;) {
                        bool restart = false;

                        for (j = 0; j < display_columns; j++) {
                                size_t delta, w;

                                /* Did this column already get something assigned? If so, let's skip to the next */
                                if (width[j] != (size_t) -1)
                                        continue;

                                if (weight_sum == 0)
                                        w = minimum_width[j] + extra / (display_columns - j); /* avoid division by zero */
                                else
                                        w = minimum_width[j] + (extra * column_weight[j]) / weight_sum;

                                if (w >= requested_width[j]) {
                                        /* Never give more than requested. If we hit a column like this, there's more
                                         * space to allocate to other columns which means we need to restart the
                                         * iteration. However, if we hit a column like this, let's assign it the space
                                         * it wanted for good early.*/

                                        w = requested_width[j];
                                        restart = true;

                                } else if (!finalize)
                                        continue;

                                width[j] = w;

                                assert(w >= minimum_width[j]);
                                delta = w - minimum_width[j];

                                assert(delta <= extra);
                                extra -= delta;

                                assert(weight_sum >= column_weight[j]);
                                weight_sum -= column_weight[j];

                                if (restart && !finalize)
                                        break;
                        }

                        if (finalize)
                                break;

                        if (!restart)
                                finalize = true;
                }
        }

        /* Second pass: show output */
        for (i = t->header ? 0 : 1; i < n_rows; i++) {
                TableData **row;

                if (sorted)
                        row = t->data + sorted[i];
                else
                        row = t->data + i * t->n_columns;

                for (j = 0; j < display_columns; j++) {
                        _cleanup_free_ char *buffer = NULL;
                        const char *field;
                        TableData *d;
                        size_t l;

                        assert_se(d = row[t->display_map ? t->display_map[j] : j]);

                        field = table_data_format(d);
                        if (!field)
                                return -ENOMEM;

                        l = utf8_console_width(field);
                        if (l > width[j]) {
                                /* Field is wider than allocated space. Let's ellipsize */

                                buffer = ellipsize(field, width[j], d->ellipsize_percent);
                                if (!buffer)
                                        return -ENOMEM;

                                field = buffer;

                        } else if (l < width[j]) {
                                /* Field is shorter than allocated space. Let's align with spaces */

                                buffer = align_string_mem(field, d->url, width[j], d->align_percent);
                                if (!buffer)
                                        return -ENOMEM;

                                field = buffer;
                        }

                        if (l >= width[j] && d->url) {
                                _cleanup_free_ char *clickable = NULL;

                                r = terminal_urlify(d->url, field, &clickable);
                                if (r < 0)
                                        return r;

                                free_and_replace(buffer, clickable);
                                field = buffer;
                        }

                        if (j > 0)
                                fputc(' ', f); /* column separator */

                        if (d->color && colors_enabled())
                                fputs(d->color, f);

                        fputs(field, f);

                        if (d->color && colors_enabled())
                                fputs(ANSI_NORMAL, f);
                }

                fputc('\n', f);
        }

        return fflush_and_check(f);
}

int table_format(Table *t, char **ret) {
        _cleanup_fclose_ FILE *f = NULL;
        char *buf = NULL;
        size_t sz = 0;
        int r;

        f = open_memstream(&buf, &sz);
        if (!f)
                return -ENOMEM;

        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);

        r = table_print(t, f);
        if (r < 0)
                return r;

        f = safe_fclose(f);

        *ret = buf;

        return 0;
}

size_t table_get_rows(Table *t) {
        if (!t)
                return 0;

        assert(t->n_columns > 0);
        return t->n_cells / t->n_columns;
}

size_t table_get_columns(Table *t) {
        if (!t)
                return 0;

        assert(t->n_columns > 0);
        return t->n_columns;
}

int table_set_reverse(Table *t, size_t column, bool b) {
        assert(t);
        assert(column < t->n_columns);

        if (!t->reverse_map) {
                if (!b)
                        return 0;

                t->reverse_map = new0(bool, t->n_columns);
                if (!t->reverse_map)
                        return -ENOMEM;
        }

        t->reverse_map[column] = b;
        return 0;
}