Add line wrapper

Add a tool to wrap lines at words boundaries (spaces) to fit in a
specified number of columns, left-indented by a specified number of
spaces.
This commit is contained in:
Romain Vimont 2021-11-06 20:26:35 +01:00
parent 6dba1922c1
commit 9ec3406568
4 changed files with 130 additions and 0 deletions

View file

@ -187,6 +187,7 @@ if get_option('buildtype') == 'debug'
'tests/test_cli.c', 'tests/test_cli.c',
'src/cli.c', 'src/cli.c',
'src/options.c', 'src/options.c',
'src/util/strbuf.c',
'src/util/str_util.c', 'src/util/str_util.c',
]], ]],
['test_clock', [ ['test_clock', [
@ -196,6 +197,7 @@ if get_option('buildtype') == 'debug'
['test_control_msg_serialize', [ ['test_control_msg_serialize', [
'tests/test_control_msg_serialize.c', 'tests/test_control_msg_serialize.c',
'src/control_msg.c', 'src/control_msg.c',
'src/util/strbuf.c',
'src/util/str_util.c', 'src/util/str_util.c',
]], ]],
['test_device_msg_deserialize', [ ['test_device_msg_deserialize', [
@ -211,6 +213,7 @@ if get_option('buildtype') == 'debug'
]], ]],
['test_strutil', [ ['test_strutil', [
'tests/test_strutil.c', 'tests/test_strutil.c',
'src/util/strbuf.c',
'src/util/str_util.c', 'src/util/str_util.c',
]], ]],
] ]

View file

@ -1,9 +1,11 @@
#include "str_util.h" #include "str_util.h"
#include <assert.h>
#include <errno.h> #include <errno.h>
#include <limits.h> #include <limits.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
#include "util/strbuf.h"
#ifdef _WIN32 #ifdef _WIN32
# include <windows.h> # include <windows.h>
@ -209,3 +211,81 @@ utf8_from_wide_char(const wchar_t *ws) {
} }
#endif #endif
char *sc_str_wrap_lines(const char *input, unsigned columns, unsigned indent) {
assert(indent < columns);
struct sc_strbuf buf;
// The output string should not be much longer than the input string (just
// a few '\n' added), so this initial capacity should hopefully almost
// always avoid internal realloc() in string buffer
size_t cap = strlen(input) * 3 / 2;
if (!sc_strbuf_init(&buf, cap)) {
return false;
}
#define APPEND(S,N) if (!sc_strbuf_append(&buf, S, N)) goto error
#define APPEND_CHAR(C) if (!sc_strbuf_append_char(&buf, C)) goto error
#define APPEND_N(C,N) if (!sc_strbuf_append_n(&buf, C, N)) goto error
#define APPEND_INDENT() if (indent) APPEND_N(' ', indent)
APPEND_INDENT();
// The last separator encountered, it must be inserted only conditionnaly,
// depending on the next token
char pending = 0;
// col tracks the current column in the current line
size_t col = indent;
while (*input) {
size_t sep_idx = strcspn(input, "\n ");
size_t new_col = col + sep_idx;
if (pending == ' ') {
// The pending space counts
++new_col;
}
bool wrap = new_col > columns;
char sep = input[sep_idx];
if (sep == ' ')
sep = ' ';
if (wrap) {
APPEND_CHAR('\n');
APPEND_INDENT();
col = indent;
} else if (pending) {
APPEND_CHAR(pending);
++col;
if (pending == '\n')
{
APPEND_INDENT();
col = indent;
}
}
if (sep_idx) {
APPEND(input, sep_idx);
col += sep_idx;
}
pending = sep;
input += sep_idx;
if (*input != '\0') {
// Skip the separator
++input;
}
}
if (pending)
APPEND_CHAR(pending);
return buf.s;
error:
free(buf.s);
return NULL;
}

View file

@ -62,4 +62,12 @@ char *
utf8_from_wide_char(const wchar_t *s); utf8_from_wide_char(const wchar_t *s);
#endif #endif
/**
* Wrap input lines to fit in `columns` columns
*
* Break input lines at word boundaries (spaces) so that they fit in `columns`
* columns, left-indented by `indent` spaces.
*/
char *sc_str_wrap_lines(const char *input, unsigned columns, unsigned indent);
#endif #endif

View file

@ -299,6 +299,44 @@ static void test_strlist_contains(void) {
assert(strlist_contains("xyz", '\0', "xyz")); assert(strlist_contains("xyz", '\0', "xyz"));
} }
static void test_wrap_lines(void) {
const char *s = "This is a text to test line wrapping. The lines must be "
"wrapped at a space or a line break.\n"
"\n"
"This rectangle must remains a rectangle because it is "
"drawn in lines having lengths lower than the specified "
"number of columns:\n"
" +----+\n"
" | |\n"
" +----+\n";
// |---- 1 1 2 2|
// |0 5 0 5 0 3| <-- 24 columns
const char *expected = " This is a text to\n"
" test line wrapping.\n"
" The lines must be\n"
" wrapped at a space\n"
" or a line break.\n"
" \n"
" This rectangle must\n"
" remains a rectangle\n"
" because it is drawn\n"
" in lines having\n"
" lengths lower than\n"
" the specified number\n"
" of columns:\n"
" +----+\n"
" | |\n"
" +----+\n";
char *formatted = sc_str_wrap_lines(s, 24, 4);
assert(formatted);
assert(!strcmp(formatted, expected));
free(formatted);
}
int main(int argc, char *argv[]) { int main(int argc, char *argv[]) {
(void) argc; (void) argc;
(void) argv; (void) argv;
@ -317,5 +355,6 @@ int main(int argc, char *argv[]) {
test_parse_integers(); test_parse_integers();
test_parse_integer_with_suffix(); test_parse_integer_with_suffix();
test_strlist_contains(); test_strlist_contains();
test_wrap_lines();
return 0; return 0;
} }