add strbuf_expand_dict_cb(), a helper for simple cases

The new callback function strbuf_expand_dict_cb() can be used together with strbuf_expand() if there is only a small number of placeholders for static replacement texts. It expects its dictionary as an array of placeholder+value pairs as context parameter, terminated by an entry with the placeholder member set to NULL. The new helper is intended to aid converting the remaining calls of interpolate(). strbuf_expand() is smaller, more flexible and can be used to go faster than interpolate(), so it should replace the latter. Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>

René Scharfe committed Nov 23, 2008 at 00:09 UTC 9b864e730bda0e028a85387fa568429724582f22

3 files changed +28

Documentation/technical/api-strbuf.txt

@@ -205,6 +205,13 @@ In order to facilitate caching and to make it possible to give

205 parameters to the callback, `strbuf_expand()` passes a context pointer,

206 which can be used by the programmer of the callback as she sees fit.

207

208 +`strbuf_expand_dict_cb`::

209 +

210 + Used as callback for `strbuf_expand()`, expects an array of

211 + struct strbuf_expand_dict_entry as context, i.e. pairs of

212 + placeholder and replacement string. The array needs to be

213 + terminated by an entry with placeholder set to NULL.

214 +

215 `strbuf_addf`::

216

217 Add a formatted string to the buffer.

strbuf.c

+16

@@ -237,6 +237,22 @@ void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,

237 }

238 }

239

240 +size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,

241 + void *context)

242 +{

243 + struct strbuf_expand_dict_entry *e = context;

244 + size_t len;

245 +

246 + for (; e->placeholder && (len = strlen(e->placeholder)); e++) {

247 + if (!strncmp(placeholder, e->placeholder, len)) {

248 + if (e->value)

249 + strbuf_addstr(sb, e->value);

250 + return len;

251 + }

252 + }

253 + return 0;

254 +}

255 +

256 size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)

257 {

258 size_t res;

strbuf.h

@@ -111,6 +111,11 @@ extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);

111

112 typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context);

113 extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context);

114 +struct strbuf_expand_dict_entry {

115 + const char *placeholder;

116 + const char *value;

117 +};

118 +extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context);

119

120 __attribute__((format(printf,2,3)))

121 extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);