From: e at 80x24.org (Eric Wong)
Subject: [PATCH] ui-ssdiff: get rid of strncat
Date: Wed, 2 Jan 2019 07:37:10 +0000 [thread overview]
Message-ID: <20190102073710.580-1-e@80x24.org> (raw)
strncat is slow and error-prone, use the git strbuf API instead.
We can steal much of our logic from git/pretty.c::strbuf_add_tabexpand,
but maybe keep the invalid characters for now *shrug*.
---
ui-ssdiff.c | 58 +++++++++++++++++++++++------------------------------
1 file changed, 25 insertions(+), 33 deletions(-)
diff --git a/ui-ssdiff.c b/ui-ssdiff.c
index c456033..a6b3861 100644
--- a/ui-ssdiff.c
+++ b/ui-ssdiff.c
@@ -109,44 +109,36 @@ static int line_from_hunk(char *line, char type)
return res;
}
-static char *replace_tabs(char *line)
+static char *replace_tabs(const char *line)
{
- char *prev_buf = line;
- char *cur_buf;
+ const size_t tabwidth = 8;
size_t linelen = strlen(line);
- int n_tabs = 0;
- int i;
- char *result;
- int result_len;
-
- if (linelen == 0) {
- result = xmalloc(1);
- result[0] = '\0';
- return result;
+ struct strbuf sb;
+ const char *tab;
+ size_t tab_extra = 0;
+
+ while ((tab = memchr(line, '\t', linelen)) != NULL) {
+ tab_extra += tabwidth - 1;
+ linelen -= tab + 1 - line;
+ line = tab + 1;
}
- for (i = 0; i < linelen; i++) {
- if (line[i] == '\t')
- n_tabs += 1;
- }
- result_len = linelen + n_tabs * 8;
- result = xmalloc(result_len + 1);
- result[0] = '\0';
-
- for (;;) {
- cur_buf = strchr(prev_buf, '\t');
- if (!cur_buf) {
- strncat(result, prev_buf, result_len);
- break;
- } else {
- strncat(result, prev_buf, cur_buf - prev_buf);
- linelen = strlen(result);
- memset(&result[linelen], ' ', 8 - (linelen % 8));
- result[linelen + 8 - (linelen % 8)] = '\0';
- }
- prev_buf = cur_buf + 1;
+ strbuf_init(&sb, linelen + tab_extra + 1);
+
+ /* based on git/pretty.c::strbuf_add_tabexpand: */
+ while ((tab = memchr(line, '\t', linelen)) != NULL) {
+ /* Output the data .. */
+ strbuf_add(&sb, line, tab - line);
+
+ /* .. and the de-tabified tab */
+ strbuf_addchars(&sb, ' ', tabwidth);
+
+ /* Skip over the printed part .. */
+ linelen -= tab + 1 - line;
+ line = tab + 1;
}
- return result;
+
+ return strbuf_detach(&sb, NULL);
}
static int calc_deferred_lines(struct deferred_lines *start)
--
EW
next reply other threads:[~2019-01-02 7:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-02 7:37 e [this message]
2019-04-22 2:39 ` [PATCH v2] " e
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