[libvirt] [PATCH v3 1/3] vsh: Add API for printing tables.
Daniel P. Berrangé
berrange at redhat.com
Thu Aug 16 11:28:45 UTC 2018
On Thu, Aug 16, 2018 at 12:56:24PM +0200, Simon Kobyda wrote:
> It solves problems with alignment of columns. Width of each column
> is calculated by its biggest cell. Should solve unicode bug.
> In future, it may be implemented in virsh, virt-admin...
>
> This API has 5 public functions:
> - vshTableNew - adds new table and defines its header
> - vshTableRowAppend - appends new row (for same number of columns as in
> header)
> - vshTablePrintToStdout
> - vshTablePrintToString
> - vshTableFree
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1574624
> https://bugzilla.redhat.com/show_bug.cgi?id=1584630
>
> Signed-off-by: Simon Kobyda <skobyda at redhat.com>
> ---
> tools/Makefile.am | 4 +-
> tools/vsh-table.c | 413 ++++++++++++++++++++++++++++++++++++++++++++++
> tools/vsh-table.h | 42 +++++
> 3 files changed, 458 insertions(+), 1 deletion(-)
> create mode 100644 tools/vsh-table.c
> create mode 100644 tools/vsh-table.h
>
> +/**
> + * vshTableGetColumnsWidths:
> + * @table: table
> + * @maxwidths: maximum count of characters for each columns
> + * @widths: count of characters for each cell in the table
> + *
> + * Fill passed @maxwidths and @widths arrays with maximum number
> + * of characters for columns and number of character per each
> + * table cell, respectively.
> + *
> + * Handle unicode strings (user must have multibyte locale)
> + */
> +static int
> +vshTableGetColumnsWidths(vshTablePtr table,
> + size_t *maxwidths,
> + size_t **widths,
> + bool header)
> +{
> + int ret = -1;
> + size_t i = 1;
> + size_t j;
> + size_t len;
> + int tmp;
> + wchar_t *wstr = NULL;
> + size_t wstrlen;
> +
> + if (header)
> + i = 0;
> + else
> + i = 1;
> + for (; i < table->nrows; i++) {
> + vshTableRowPtr row = table->rows[i];
> +
> + for (j = 0; j < row->ncells; j++) {
> + /* strlen should return maximum possible length needed */
> + wstrlen = strlen(row->cells[j]);
> + VIR_FREE(wstr);
> + if (VIR_ALLOC_N(wstr, wstrlen) < 0)
> + goto cleanup;
> + /* mbstowcs fails if machine is using singlebyte locale
> + * and user tries to convert unicode(multibyte)
> + * */
> + if (mbstowcs(wstr, row->cells[j], wstrlen) ==
> + (size_t) -1) {
> + len = wstrlen;
> + } else {
> + tmp = wcswidth(wstr, wstrlen);
> + if (tmp < 0)
> + goto cleanup;
> + len = (size_t)((unsigned)tmp);
> + }
> + widths[i][j] = len;
> + if (len > maxwidths[j])
> + maxwidths[j] = len;
After asking around I have found the right solution that we need to use
for measuring string width. mbstowcs()/wcswidth() will get the answer
wrong wrt zero-width characters, combining characters, non-printable
characters, etc. We need to use the libunistring library:
https://www.gnu.org/software/libunistring/manual/libunistring.html#uniwidth_002eh
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
More information about the libvir-list
mailing list