Add prefixcmp() (stol^H^H^H^Hborrowed from git)

This allows us to avoid the nasty repetition in strncmp(foo,
bar, strlen(foo)).  We'll miss out on the compiler optimizing
strlen() into sizeof() - 1 for string literals for this; but we
don't use this it for performance-critical functions anyways...

2 files changed, 12 insertions, 0 deletions

diff --git a/src/utils.c b/src/utils.c
index 332c73587..f23f8c1fa 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -268,3 +268,13 @@ void xpthread_cond_destroy(pthread_cond_t *cond)
 	if ((err = pthread_cond_destroy(cond)))
 		FATAL("failed to destroy cond: %s\n", strerror(err));
 }
+
+int prefixcmp(const char *str, const char *prefix)
+{
+	for (; ; str++, prefix++)
+		if (!*prefix)
+			return 0;
+		else if (*str != *prefix)
+			return (unsigned char)*prefix - (unsigned char)*str;
+}
+
diff --git a/src/utils.h b/src/utils.h
index 0001ba3c8..3958ac9a0 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -90,6 +90,8 @@ void xpthread_mutex_destroy(pthread_mutex_t *mutex);
 
 void xpthread_cond_destroy(pthread_cond_t *cond);
 
+int prefixcmp(const char *str, const char *prefix);
+
 /*
  * Work-arounds for braindead APIs that require non-const pointers:
  *   ao_play(), free(), vorbis_comment_add_tag(), iconv()