From: Andre Noll <maan@systemlinux.org>
Date: Sun, 31 Jul 2011 23:08:20 +0000 (+0200)
Subject: Make vorbis comment helper functions generic.
X-Git-Tag: v0.4.9~2^2~5
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=1b218c4cde1c14c5bfbd8f52321ceb16b006de52

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 e693c415..a95f234c 100644
--- 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 cefb45d6..f7d70353 100644
--- 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 06f4d3e6..403b9c6f 100644
--- 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);