patch 9.1.0980: no support for base64 en-/decoding functions in Vim Script
Problem: no support for base64 en-/decoding functions in Vim Script
(networkhermit)
Solution: Add the base64_encode() and base64_decode() functions
(Yegappan Lakshmanan)
fixes: #16291
closes: #16330
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/evalfunc.c b/src/evalfunc.c
index b2905da..ec108b0c 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -28,6 +28,8 @@
static void f_balloon_split(typval_T *argvars, typval_T *rettv);
# endif
#endif
+static void f_base64_encode(typval_T *argvars, typval_T *rettv);
+static void f_base64_decode(typval_T *argvars, typval_T *rettv);
static void f_bindtextdomain(typval_T *argvars, typval_T *rettv);
static void f_byte2line(typval_T *argvars, typval_T *rettv);
static void f_call(typval_T *argvars, typval_T *rettv);
@@ -1834,6 +1836,10 @@
NULL
#endif
},
+ {"base64_decode", 1, 1, FEARG_1, arg1_string,
+ ret_blob, f_base64_decode},
+ {"base64_encode", 1, 1, FEARG_1, arg1_blob,
+ ret_string, f_base64_encode},
{"bindtextdomain", 2, 2, 0, arg2_string,
ret_bool, f_bindtextdomain},
{"blob2list", 1, 1, FEARG_1, arg1_blob,
@@ -3479,6 +3485,182 @@
# endif
#endif
+// Base64 character set
+static const char_u base64_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+// Base64 decoding table (initialized in init_base64_dec_table() below)
+static char_u base64_dec_table[256];
+
+/*
+ * Initialize the base64 decoding table
+ */
+ static void
+init_base64_dec_table(void)
+{
+ static int base64_dec_tbl_initialized = FALSE;
+
+ if (base64_dec_tbl_initialized)
+ return;
+
+ // Unsupported characters are set to 0xFF
+ vim_memset(base64_dec_table, 0xFF, sizeof(base64_dec_table));
+
+ // Initialize the index for the base64 alphabets
+ for (size_t i = 0; i < sizeof(base64_table) - 1; i++)
+ base64_dec_table[(char_u)base64_table[i]] = (char_u)i;
+
+ // base64 padding character
+ base64_dec_table['='] = 0;
+
+ base64_dec_tbl_initialized = TRUE;
+}
+
+/*
+ * Encode the bytes in "blob" using base-64 encoding.
+ */
+ static char_u *
+base64_encode(blob_T *blob)
+{
+ size_t input_len = blob->bv_ga.ga_len;
+ size_t encoded_len = ((input_len + 2) / 3) * 4;
+ char_u *data = blob->bv_ga.ga_data;
+
+ char_u *encoded = alloc(encoded_len + 1);
+ if (encoded == NULL)
+ return NULL;
+
+ size_t i, j;
+ for (i = 0, j = 0; i < input_len;)
+ {
+ int_u octet_a = i < input_len ? data[i++] : 0;
+ int_u octet_b = i < input_len ? data[i++] : 0;
+ int_u octet_c = i < input_len ? data[i++] : 0;
+
+ int_u triple = (octet_a << 16) | (octet_b << 8) | octet_c;
+
+ encoded[j++] = base64_table[(triple >> 18) & 0x3F];
+ encoded[j++] = base64_table[(triple >> 12) & 0x3F];
+ encoded[j++] = (!octet_b && i >= input_len) ? '='
+ : base64_table[(triple >> 6) & 0x3F];
+ encoded[j++] = (!octet_c && i >= input_len) ? '='
+ : base64_table[triple & 0x3F];
+ }
+ encoded[j] = NUL;
+
+ return encoded;
+}
+
+/*
+ * Decode the string "data" using base-64 encoding.
+ */
+ static void
+base64_decode(const char_u *data, blob_T *blob)
+{
+ size_t input_len = STRLEN(data);
+
+ if (input_len == 0)
+ return;
+
+ if (input_len % 4 != 0)
+ {
+ // Invalid input length
+ semsg(_(e_invalid_argument_str), data);
+ return;
+ }
+
+ init_base64_dec_table();
+
+ size_t decoded_len = (input_len / 4) * 3;
+ if (data[input_len - 1] == '=')
+ decoded_len--;
+ if (data[input_len - 2] == '=')
+ decoded_len--;
+
+ size_t i, j;
+ for (i = 0, j = 0; i < input_len;)
+ {
+ int_u sextet_a = base64_dec_table[(char_u)data[i++]];
+ int_u sextet_b = base64_dec_table[(char_u)data[i++]];
+ int_u sextet_c = base64_dec_table[(char_u)data[i++]];
+ int_u sextet_d = base64_dec_table[(char_u)data[i++]];
+
+ if (sextet_a == 0xFF || sextet_b == 0xFF || sextet_c == 0xFF
+ || sextet_d == 0xFF)
+ {
+ // Invalid character
+ semsg(_(e_invalid_argument_str), data);
+ ga_clear(&blob->bv_ga);
+ return;
+ }
+
+ int_u triple = (sextet_a << 18) | (sextet_b << 12)
+ | (sextet_c << 6) | sextet_d;
+
+ if (j < decoded_len)
+ {
+ ga_append(&blob->bv_ga, (triple >> 16) & 0xFF);
+ j++;
+ }
+ if (j < decoded_len)
+ {
+ ga_append(&blob->bv_ga, (triple >> 8) & 0xFF);
+ j++;
+ }
+ if (j < decoded_len)
+ {
+ ga_append(&blob->bv_ga, triple & 0xFF);
+ j++;
+ }
+
+ if (j == decoded_len)
+ {
+ // Check for invalid padding bytes (based on the
+ // "Base64 Malleability in Practice" ACM paper).
+ if ((data[input_len - 2] == '=' && ((sextet_b & 0xF) != 0))
+ || ((data[input_len - 1] == '=') && ((sextet_c & 0x3) != 0)))
+ {
+ semsg(_(e_invalid_argument_str), data);
+ ga_clear(&blob->bv_ga);
+ return;
+ }
+ }
+ }
+}
+
+/*
+ * "base64_decode(string)" function
+ */
+ static void
+f_base64_decode(typval_T *argvars, typval_T *rettv)
+{
+ if (check_for_string_arg(argvars, 0) == FAIL)
+ return;
+
+ if (rettv_blob_alloc(rettv) == FAIL)
+ return;
+
+ char_u *str = tv_get_string_chk(&argvars[0]);
+ if (str != NULL)
+ base64_decode(str, rettv->vval.v_blob);
+}
+
+/*
+ * "base64_encode(blob)" function
+ */
+ static void
+f_base64_encode(typval_T *argvars, typval_T *rettv)
+{
+ if (check_for_blob_arg(argvars, 0) == FAIL)
+ return;
+
+ rettv->v_type = VAR_STRING;
+ rettv->vval.v_string = NULL;
+
+ blob_T *blob = argvars->vval.v_blob;
+ if (blob != NULL)
+ rettv->vval.v_string = base64_encode(blob);
+}
+
/*
* Get the buffer from "arg" and give an error and return NULL if it is not
* valid.