libxbps: change the epoch char to ':' to differentiate the starting char in pkgname.

Added xbps_get_pkg_epoch(), to get the epoch version string.

include/xbps_api.h

@@ -1124,6 +1124,16 @@ char *xbps_get_pkg_name(const char *pkg);
  */
 char *xbps_get_pkgpattern_name(const char *pattern);
 
+/**
+ * Gets the package epoch version in a package string, i.e <b>foo-2.0:epoch</b>.
+ *
+ * @param[in] pkg Package string.
+ * 
+ * @return A string with the epoch version string, NULL if it couldn't find
+ * the epoch component.
+ */
+const char *xbps_get_pkg_epoch(const char *pkg);
+
 /**
  * Gets the package version in a package string, i.e <b>foo-2.0</b>.
  * 

lib/cmpver.c

@@ -29,7 +29,7 @@
  * split_version(pkgname, endname, epoch, revision) returns a pointer to
  * the version portion of a package name and the two special components.
  *
- * Syntax is: ${PKGNAME}-${VERSION}[_${PKGREVISION}][-${EPOCH}]
+ * Syntax is: ${PKGNAME}-${VERSION}[_${PKGREVISION}][:${EPOCH}]
  *
  */
 static const char *
@@ -54,8 +54,8 @@ split_version(const char *pkgname, const char **endname, unsigned long *epoch,
     }
     endversionstr = ch;
 
-    /* Look for the last '-' in the remaining version string */
-    ch = strrchr(endversionstr ? endversionstr + 1 : versionstr, '-');
+    /* Look for the last ':' in the remaining version string */
+    ch = strrchr(endversionstr ? endversionstr + 1 : versionstr, ':');
     if (epoch != NULL) {
 	*epoch = ch ? strtoul(ch + 1, NULL, 10) : 0;
     }
@@ -216,7 +216,7 @@ get_component(const char *position, version_component *component)
  * comparison of the basenames is done.
  *
  * The port version is defined by:
- * ${VERSION}[_${PKGREVISION}][-${EPOCH}]
+ * ${VERSION}[_${PKGREVISION}][:${EPOCH}]
  * ${EPOCH} supersedes ${VERSION} supersedes ${PKGREVISION}.
  *
  * The epoch and revision are defined to be a single number, while the rest

lib/util.c

@@ -183,6 +183,20 @@ xbps_check_is_installed_pkgname(const char *pkgname)
 	return false;
 }
 
+const char *
+xbps_get_pkg_epoch(const char *pkg)
+{
+	const char *tmp;
+
+	assert(pkg != NULL);
+
+	tmp = strrchr(pkg, ':');
+	if (tmp == NULL)
+		return NULL;
+
+	return tmp + 1; /* skip first ':' */
+}
+
 const char *
 xbps_get_pkg_version(const char *pkg)
 {