Base64 utilities public

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

diff --git a/src/base64.c b/src/base64.c
new file mode 100644 (file)
index 0000000..d007a34
--- /dev/null
+++ b/src/base64.c
@@ -0,0 +1,111 @@
+/* This file is part of the YAZ toolkit.
+ * Copyright (C) 1995-2011 Index Data
+ * See the file LICENSE for details.
+ */
+/**
+ * \file base64.c
+ * \brief Base64 encode/decode utilities
+ */
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+#include <yaz/base64.h>
+
+void yaz_base64encode(const char *in, char *out)
+{
+    static char encoding[] =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    unsigned char buf[3];
+    long n;
+
+    while (*in != 0)
+    {
+       const char *pad = 0;
+        buf[0] = in[0];
+       buf[1] = in[1];
+       if (in[1] == 0)
+        {
+           buf[2] = 0;
+           pad = "==";
+       }
+        else
+        {
+           buf[2] = in[2];
+           if (in[2] == 0)
+               pad = "=";
+       }
+
+       /* Treat three eight-bit numbers as on 24-bit number */
+       n = (buf[0] << 16) + (buf[1] << 8) + buf[2];
+
+       /* Write the six-bit chunks out as four encoded characters */
+       *out++ = encoding[(n >> 18) & 63];
+       *out++ = encoding[(n >> 12) & 63];
+       if (in[1] != 0)
+           *out++ = encoding[(n >> 6) & 63];
+       if (in[1] != 0 && in[2] != 0)
+           *out++ = encoding[n & 63];
+
+       if (pad != 0) {
+           while (*pad != 0)
+               *out++ = *pad++;
+           break;
+       }
+       in += 3;
+    }
+    *out++ = 0;
+}
+
+int yaz_base64decode(const char *in, char *out)
+{
+    const char *map = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+       "abcdefghijklmnopqrstuvwxyz0123456789+/";
+    int len = strlen(in);
+
+    while (len >= 4)
+    {
+       char i0, i1, i2, i3;
+       char *p;
+
+       if (!(p = strchr(map, in[0])))
+           return -1;
+       i0 = p - map;
+       len--;
+       if (!(p = strchr(map, in[1])))
+           return -1;
+       i1 = p - map;
+       len--;
+       *(out++) = i0 << 2 | i1 >> 4;
+       if (in[2] == '=')
+           break;
+       if (!(p = strchr(map, in[2])))
+           return -1;
+       i2 = p - map;
+       len--;
+       *(out++) = i1 << 4 | i2 >> 2;
+       if (in[3] == '=')
+           break;
+       if (!(p = strchr(map, in[3])))
+           return -1;
+       i3 = p - map;
+       len--;
+       *(out++) = i2 << 6 | i3;
+
+       in += 4;
+    }
+
+    *out = '\0';
+    return 0;
+}
+
+/*
+ * Local variables:
+ * c-basic-offset: 4
+ * c-file-style: "Stroustrup"
+ * indent-tabs-mode: nil
+ * End:
+ * vim: shiftwidth=4 tabstop=8 expandtab
+ */
+