Make vorbis comment helper functions generic.

copy_comment() and copy_if_tag_type() are useful also to the new flac
audio format handler, so move these functions to string.c and make
them public.

Rename them to safe_strdup() and key_value_copy() respectively,
as this is more to the point.

diff --git a/spx_afh.c b/spx_afh.c
index e693c4150e03b7dae9b991c343ec7abbfe980db0..a95f234c5e318322a436ad07d74dd78acf169d05 100644 (file)
--- a/spx_afh.c
+++ b/spx_afh.c
@@ -57,31 +57,14 @@ struct private_spx_data {
        struct spx_header_info shi;
 };
 
-
-static char *copy_comment(const char *src, int len)
-{
-       char *p = para_malloc(len + 1);
-
-       if (len > 0)
-               memcpy(p, src, len);
-       p[len] = '\0';
-       PARA_DEBUG_LOG("%s\n", p);
-       return p;
-}
-
 static bool copy_if_tag_type(const char *tag, int taglen, const char *type,
                char **p)
 {
-       int len = strlen(type);
-
-       if (taglen <= len)
-               return false;
-       if (strncasecmp(tag, type, len))
-               return false;
-       if (tag[len] != '=')
+       char *q = key_value_copy(tag, taglen, type);
+       if (!q)
                return false;
        free(*p);
-       *p = copy_comment(tag + len + 1, taglen - len - 1);
+       *p = q;
        return true;
 }
 
@@ -100,7 +83,7 @@ static int spx_get_comments(unsigned char *comments, int length,
        c += 4;
        if (c + len > end)
                return -E_SPX_COMMENT;
-       tags->comment = copy_comment(c, len);
+       tags->comment = safe_strdup(c, len);
 
        c += len;
        if (c + 4 > end)
@@ -129,7 +112,7 @@ static int spx_get_comments(unsigned char *comments, int length,
                        continue;
                if (copy_if_tag_type(c, len, "comment", &tags->comment))
                        continue;
-               tag = copy_comment(c, len);
+               tag = safe_strdup(c, len);
                PARA_NOTICE_LOG("unrecognized comment: %s\n", tag);
                free(tag);
        }

diff --git a/string.c b/string.c
index cefb45d674075cf1fcb2e42b42e5b0a929a52c16..f7d70353db977d6543055c19c7bd68a17b83a3ce 100644 (file)
--- a/string.c
+++ b/string.c
@@ -793,3 +793,56 @@ int para_regcomp(regex_t *preg, const char *regex, int cflags)
        free(buf);
        return -E_REGEX;
 }
+
+/**
+ * strdup() for not necessarily zero-terminated strings.
+ *
+ * \param src The source buffer.
+ * \param len The number of bytes to be copied.
+ *
+ * \return A 0-terminated buffer of length \a len + 1.
+ *
+ * This is similar to strndup(), which is a GNU extension. However, one
+ * difference is that strndup() returns \p NULL if insufficient memory was
+ * available while this function aborts in this case.
+ *
+ * \sa strdup(), \ref para_strdup().
+ */
+char *safe_strdup(const char *src, size_t len)
+{
+       char *p;
+
+       assert(len < (size_t)-1);
+       p = para_malloc(len + 1);
+       if (len > 0)
+               memcpy(p, src, len);
+       p[len] = '\0';
+       return p;
+}
+
+/**
+ * Copy the value of a key=value pair.
+ *
+ * This checks whether the given buffer starts with "key=", ignoring case. If
+ * yes, a copy of the value is returned. The source buffer may not be
+ * zero-terminated.
+ *
+ * \param src The source buffer.
+ * \param len The number of bytes of the tag.
+ * \param key Only copy if it is the value of this key.
+ *
+ * \return A zero-terminated buffer, or \p NULL if the key was
+ * not of the given type.
+ */
+char *key_value_copy(const char *src, size_t len, const char *key)
+{
+       int keylen = strlen(key);
+
+       if (len <= keylen)
+               return NULL;
+       if (strncasecmp(src, key, keylen))
+               return NULL;
+       if (src[keylen] != '=')
+               return NULL;
+       return safe_strdup(src + keylen + 1, len - keylen - 1);
+}

diff --git a/string.h b/string.h
index 06f4d3e6ca88646fbe531b42af49089be23680ba..403b9c6f15d15404076eeed7ea641b8b22ed600f 100644 (file)
--- a/string.h
+++ b/string.h
@@ -83,3 +83,5 @@ int create_argv(const char *buf, const char *delim, char ***result);
 void free_argv(char **argv);
 int para_regcomp(regex_t *preg, const char *regex, int cflags);
 void freep(void *arg);
+char *safe_strdup(const char *src, size_t len);
+char *key_value_copy(const char *src, size_t len, const char *key);