In a following commit we are going to port code from
"t/helper/test-sha256.c", t/helper/test-hash.c and "t/t0015-hash.sh" to
a new "t/unit-tests/t-hash.c" file using the recently added unit test
framework.
To port code like: perl -e "$| = 1; print q{aaaaaaaaaa} for 1..100000;"
we are going to need a new strbuf_addstrings() function that repeatedly
adds the same string a number of times to a buffer.
Such a strbuf_addstrings() function would already be useful in
"json-writer.c" and "builtin/submodule-helper.c" as both of these files
already have code that repeatedly adds the same string. So let's
introduce such a strbuf_addstrings() function in "strbuf.{c,h}" and use
it in both "json-writer.c" and "builtin/submodule-helper.c".
We use the "strbuf_addstrings" name as this way strbuf_addstr() and
strbuf_addstrings() would be similar for strings as strbuf_addch() and
strbuf_addchars() for characters.
Mentored-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
Signed-off-by: Achu Luma <ach.lumap@xxxxxxxxx>
---
The changes between version 1 and version 2 are the following:
- Remove memcpy() that involves manual offset computation
- Use strbuf_add() repeatedly after calling strbuf_grow() once to avoid
repeated allocation.
Thanks to Junio for pointing this out.
Here is a diff between v1 and v2:
- size_t len = strlen(s);
- if (unsigned_mult_overflows(len, n))
- die("you want to use way too much memory");
- strbuf_grow(sb, len * n);
- for (size_t i = 0; i < n; i++)
- memcpy(sb->buf + sb->len + len * i, s, len);
- strbuf_setlen(sb, sb->len + len * n);
+ size_t len = strlen(s);
+
+ if (unsigned_mult_overflows(len, n))
+ die("you want to use way too much memory");
+ strbuf_grow(sb, len * n);
+ for (size_t i = 0; i < n; i++)
+ strbuf_add(sb, s, len);
builtin/submodule--helper.c | 4 +---
json-writer.c | 5 +----
strbuf.c | 10 ++++++++++
strbuf.h | 5 +++++
4 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index fda50f2af1..bed08af410 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -257,11 +257,9 @@ static void module_list_active(struct module_list *list)
static char *get_up_path(const char *path)
{
- int i;
struct strbuf sb = STRBUF_INIT;
- for (i = count_slashes(path); i; i--)
- strbuf_addstr(&sb, "../");
+ strbuf_addstrings(&sb, "../", count_slashes(path));
/*
* Check if 'path' ends with slash or not
diff --git a/json-writer.c b/json-writer.c
index 005c820aa4..25b9201f9c 100644
--- a/json-writer.c
+++ b/json-writer.c
@@ -46,10 +46,7 @@ static void append_quoted_string(struct strbuf *out, const char *in)
static void indent_pretty(struct json_writer *jw)
{
- int k;
-
- for (k = 0; k < jw->open_stack.len; k++)
- strbuf_addstr(&jw->json, " ");
+ strbuf_addstrings(&jw->json, " ", jw->open_stack.len);
}
/*
diff --git a/strbuf.c b/strbuf.c
index 7827178d8e..f4282b70ad 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -302,6 +302,16 @@ void strbuf_add(struct strbuf *sb, const void *data, size_t len)
strbuf_setlen(sb, sb->len + len);
}
+void strbuf_addstrings(struct strbuf *sb, const char *s, size_t n)
+{
+ size_t len = strlen(s);
+
+ if (unsigned_mult_overflows(len, n))
+ die("you want to use way too much memory");
+ strbuf_grow(sb, len * n);
+ for (size_t i = 0; i < n; i++)
+ strbuf_add(sb, s, len);
+}
+
void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
{
strbuf_grow(sb, sb2->len);
diff --git a/strbuf.h b/strbuf.h
index e959caca87..0fb1b5e81e 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -310,6 +310,11 @@ static inline void strbuf_addstr(struct strbuf *sb, const char *s)
strbuf_add(sb, s, strlen(s));
}
+/**
+ * Add a NUL-terminated string the specified number of times to the buffer.
+ */
+void strbuf_addstrings(struct strbuf *sb, const char *s, size_t n);
+
/**
* Copy the contents of another buffer at the end of the current one.
*/
--
2.43.0.windows.1
