[FFmpeg-devel] [PATCH] opt: implement av_opt_set_from_string().
Nicolas George
nicolas.george at normalesup.org
Sun Sep 16 11:18:19 CEST 2012
It is similar to av_set_options_string() but accepts a list
of options that can be in shorthand: if the key is omitted
on the first fields, the keys from the shorthand list are
assumed, in order.
Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
---
libavutil/opt.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
libavutil/opt.h | 30 ++++++++++++++
2 files changed, 146 insertions(+)
diff --git a/libavutil/opt.c b/libavutil/opt.c
index 0957281..d826b4b 100644
--- a/libavutil/opt.c
+++ b/libavutil/opt.c
@@ -790,6 +790,91 @@ int av_set_options_string(void *ctx, const char *opts,
return count;
}
+#define WHITESPACES " \n\t"
+
+static int is_key_char(char c)
+{
+ return (unsigned)((c | 32) - 'a') < 26 ||
+ (unsigned)(c - '0') < 10 ||
+ c == '-' || c == '_' || c == '/' || c == '.';
+}
+
+/**
+ * Read a key from a string. The key consists of is_key_char characters and
+ * must be terminated by a character from the delim string; spaces are
+ * ignored. The key buffer must be 4 bytes larger than the longest
+ * acceptable key. If the key is too long, an ellipsis will be written at
+ * the end. @return 0 for success (even with ellipsis), <0 for failure
+ */
+static int get_key(const char **ropts, const char *delim, char *key, unsigned key_size)
+{
+ unsigned key_pos = 0;
+ const char *opts = *ropts;
+
+ opts += strspn(opts, WHITESPACES);
+ while (is_key_char(*opts)) {
+ key[key_pos++] = *opts;
+ if (key_pos == key_size)
+ key_pos--;
+ (opts)++;
+ }
+ opts += strspn(opts, WHITESPACES);
+ if (!*opts || !strchr(delim, *opts))
+ return AVERROR(EINVAL);
+ opts++;
+ key[key_pos++] = 0;
+ if (key_pos == key_size)
+ key[key_pos - 4] = key[key_pos - 3] = key[key_pos - 2] = '.';
+ *ropts = opts;
+ return 0;
+}
+
+int av_opt_set_from_string(void *ctx, const char *opts,
+ const char *const *shorthand,
+ const char *key_val_sep, const char *pairs_sep)
+{
+ int ret, count = 0;
+ const char *dummy_shorthand = NULL;
+ char key_buf[68], *value;
+ const char *key;
+
+ if (!opts)
+ return 0;
+ if (!shorthand)
+ shorthand = &dummy_shorthand;
+
+ while (*opts) {
+ if ((ret = get_key(&opts, key_val_sep, key_buf, sizeof(key_buf))) < 0) {
+ if (*shorthand) {
+ key = *(shorthand++);
+ } else {
+ av_log(ctx, AV_LOG_ERROR, "No option name near '%s'\n", opts);
+ return AVERROR(EINVAL);
+ }
+ } else {
+ key = key_buf;
+ while (*shorthand) /* discard all remaining shorthand */
+ shorthand++;
+ }
+
+ if (!(value = av_get_token(&opts, pairs_sep)))
+ return AVERROR(ENOMEM);
+ if (*opts && strchr(pairs_sep, *opts))
+ opts++;
+
+ av_log(ctx, AV_LOG_DEBUG, "Setting '%s' to value '%s'\n", key, value);
+ if ((ret = av_opt_set(ctx, key, value, 0)) < 0) {
+ if (ret == AVERROR_OPTION_NOT_FOUND)
+ av_log(ctx, AV_LOG_ERROR, "Option '%s' not found\n", key);
+ return ret;
+ }
+
+ av_free(value);
+ count++;
+ }
+ return count;
+}
+
void av_opt_free(void *obj)
{
const AVOption *o = NULL;
@@ -986,6 +1071,37 @@ int main(void)
av_freep(&test_ctx.string);
}
+ printf("\nTesting av_opt_set_from_string()\n");
+ {
+ TestContext test_ctx = { 0 };
+ const char *options[] = {
+ "",
+ "5",
+ "5:hello",
+ "5:hello:size=pal",
+ "5:size=pal:hello",
+ ":",
+ "=",
+ " 5 : hello : size = pal ",
+ "a_very_long_option_name_that_will_need_to_be_ellipsized_around_here=42"
+ };
+ const char *shorthand[] = { "num", "string", NULL };
+
+ test_ctx.class = &test_class;
+ av_opt_set_defaults(&test_ctx);
+ test_ctx.string = av_strdup("default");
+
+ av_log_set_level(AV_LOG_DEBUG);
+
+ for (i=0; i < FF_ARRAY_ELEMS(options); i++) {
+ av_log(&test_ctx, AV_LOG_DEBUG, "Setting options string '%s'\n", options[i]);
+ if (av_opt_set_from_string(&test_ctx, options[i], shorthand, "=", ":") < 0)
+ av_log(&test_ctx, AV_LOG_ERROR, "Error setting options string: '%s'\n", options[i]);
+ printf("\n");
+ }
+ av_freep(&test_ctx.string);
+ }
+
return 0;
}
diff --git a/libavutil/opt.h b/libavutil/opt.h
index 285d854..3aa912a 100644
--- a/libavutil/opt.h
+++ b/libavutil/opt.h
@@ -394,6 +394,36 @@ int av_set_options_string(void *ctx, const char *opts,
const char *key_val_sep, const char *pairs_sep);
/**
+ * Parse the key=value pairs list in opts. For each key=value pair found,
+ * set the value of the corresponding option in ctx.
+ *
+ * @param ctx the AVClass object to set options on
+ * @param opts the options string, key-value pairs separated by a
+ * delimiter
+ * @param shorthand a NULL-terminated array of options names for shorthand
+ * notation: if the first field in opts has no key part,
+ * the key is taken from the first element of shorthand;
+ * then again for the second, etc., until either opts is
+ * finished, shorthand is finished or a named option is
+ * found; after that, all options must be named
+ * @param key_val_sep a 0-terminated list of characters used to separate
+ * key from value, for example '='
+ * @param pairs_sep a 0-terminated list of characters used to separate
+ * two pairs from each other, for example ':' or ','
+ * @return the number of successfully set key=value pairs, or a negative
+ * value corresponding to an AVERROR code in case of error:
+ * AVERROR(EINVAL) if opts cannot be parsed,
+ * the error code issued by av_set_string3() if a key/value pair
+ * cannot be set
+ *
+ * Options names must use only the following characters: a-z A-Z 0-9 - . / _
+ * Separators must use characters distinct from from options and from each
+ * other.
+ */
+int av_opt_set_from_string(void *ctx, const char *opts,
+ const char *const *shorthand,
+ const char *key_val_sep, const char *pairs_sep);
+/**
* Free all string and binary options in obj.
*/
void av_opt_free(void *obj);
--
1.7.10.4
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