strbuf: introduce strbuf_addstrings() to repeatedly add a string

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.

Helped-by: Junio C Hamano <gitster@pobox.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Co-authored-by: Achu Luma <ach.lumap@gmail.com>
Signed-off-by: Achu Luma <ach.lumap@gmail.com>
Signed-off-by: Ghanshyam Thakkar <shyamthakkar001@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index e4e18adb575ca2b5d180aa4ec420066e7455f4ce..9a1ea9b4eaf1274b855cf65ddfdb36d896811a88 100644 (file)
--- 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 005c820aa42e1f3c98bd2c1a376bd3a52bfc32a2..25b9201f9c0bce3c7f268301250cbe42f630fdd1 100644 (file)
--- 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 0d929e4e195fa3db65257142e558938471e7c141..e3ca9b1ee99ac8c5fa6c989293d34bde8cfdecbf 100644 (file)
--- a/strbuf.c
+++ b/strbuf.c
@@ -313,6 +313,15 @@ 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);
+
+       strbuf_grow(sb, st_mult(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 97fa4a3d01c04d1a591eec8dc479b701b962e62a..003f880ff7d61cf9a65ac2cec09ba8cd8091e82d 100644 (file)
--- 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.
  */