Fix yaz_base64decode to use proper signed var YAZ-656

[yaz-moved-to-github.git] / src / base64.c

diff --git a/src/base64.c b/src/base64.c
index d007a34..a8eb203 100644 (file)
--- a/src/base64.c
+++ b/src/base64.c
@@ -1,5 +1,5 @@
 /* This file is part of the YAZ toolkit.
- * Copyright (C) 1995-2011 Index Data
+ * Copyright (C) 1995-2013 Index Data
  * See the file LICENSE for details.
  */
 /**
@@ -58,44 +58,55 @@ void yaz_base64encode(const char *in, char *out)
     *out++ = 0;
 }
 
-int yaz_base64decode(const char *in, char *out)
+static int next_char(const char **in, size_t *len)
 {
     const char *map = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefghijklmnopqrstuvwxyz0123456789+/";
-    int len = strlen(in);
+    const char *p;
+    while (*len > 0 && strchr("\r\n\t\f ", **in))
+    {
+        (*len)--;
+        (*in)++;
+    }
+    if (*len > 0 && **in == '=')
+        return -2;
+    if (*len > 0 && (p = strchr(map, **in)))
+    {
+        (*len)--;
+        (*in)++;
+        return p - map;
+    }
+    return -1;
+}
+
+int yaz_base64decode(const char *in, char *out)
+{
+    size_t len = strlen(in);
 
     while (len >= 4)
     {
-       char i0, i1, i2, i3;
-       char *p;
+       int i0, i1, i2, i3;
 
-       if (!(p = strchr(map, in[0])))
-           return -1;
-       i0 = p - map;
-       len--;
-       if (!(p = strchr(map, in[1])))
-           return -1;
-       i1 = p - map;
-       len--;
+       i0 = next_char(&in, &len);
+        if (i0 < 0)
+            return -1;
+       i1 = next_char(&in, &len);
+        if (i1 < 0)
+            return -1;
        *(out++) = i0 << 2 | i1 >> 4;
-       if (in[2] == '=')
-           break;
-       if (!(p = strchr(map, in[2])))
-           return -1;
-       i2 = p - map;
-       len--;
+        i2 = next_char(&in, &len);
+        if (i2 == -2)
+            break;
+        if (i2 == -1)
+            return -1;
        *(out++) = i1 << 4 | i2 >> 2;
-       if (in[3] == '=')
-           break;
-       if (!(p = strchr(map, in[3])))
-           return -1;
-       i3 = p - map;
-       len--;
+        i3 = next_char(&in, &len);
+        if (i3 == -2)
+            break;
+        if (i3 == -1)
+            return -1;
        *(out++) = i2 << 6 | i3;
-
-       in += 4;
     }
-
     *out = '\0';
     return 0;
 }