Add base64 encoding and decoding routines

Patch Ryan Martell % rdm4 A martellventures P com %
Original thread:
Date: Oct 27, 2006 6:49 PM
Subject: [Ffmpeg-devel] [PATCH] Base64 code

Originally committed as revision 6816 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/base64.c

+/*
+ * Base64.c
+ * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+* @file base64.c
+ * @brief Base64 Encode/Decode
+ * @author Ryan Martell <rdm4@martellventures.com> (with lots of Michael)
+ */
+
+#include "common.h"
+#include "base64.h"
+
+/* ---------------- private code */
+static uint8_t map2[] =
+{
+    0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
+    0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01,
+    0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
+    0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
+    0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
+    0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
+    0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
+    0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33
+};
+
+int av_base64_decode(uint8_t * out, const char *in, int out_length)
+{
+    int i, v;
+    uint8_t *dst = out;
+
+    v = 0;
+    for (i = 0; in[i] && in[i] != '='; i++) {
+        unsigned int index= in[i]-43;
+        if (index>=(sizeof(map2)/sizeof(map2[0])) || map2[index] == 0xff)
+            return -1;
+        v = (v << 6) + map2[index];
+        if (i & 3) {
+            if (dst - out < out_length) {
+                *dst++ = v >> (6 - 2 * (i & 3));
+            }
+        }
+    }
+
+    return (dst - out);
+}
+
+/*****************************************************************************
+* b64_encode: stolen from VLC's http.c
+* simplified by michael
+* fixed edge cases and made it work from data (vs. strings) by ryan.
+*****************************************************************************/
+
+char *av_base64_encode(uint8_t * src, int len)
+{
+    static const char b64[] =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    char *ret, *dst;
+    unsigned i_bits = 0;
+    int i_shift = 0;
+    int bytes_remaining = len;
+
+    if (len < UINT_MAX / 4) {
+        ret = dst = av_malloc(len * 4 / 3 + 12);
+    } else
+        return NULL;
+
+    if (len) {                  // special edge case, what should we really do here?
+        while (bytes_remaining) {
+            i_bits = (i_bits << 8) + *src++;
+            bytes_remaining--;
+            i_shift += 8;
+
+            do {
+                *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
+                i_shift -= 6;
+            } while (i_shift > 6 || (bytes_remaining == 0 && i_shift > 0));
+        }
+        while ((dst - ret) & 3)
+            *dst++ = '=';
+    }
+    *dst = '\0';
+
+    return ret;
+}
+
+// #define TEST_BASE64
+
+#ifdef TEST_BASE64
+#include "avutil.h"
+
+int b64test()
+{
+    int numerr = 0;
+    int len;
+    int numtest = 1;
+    uint8_t decode[1000];
+    struct test {
+        void *data;
+        int len;
+        const char *result;
+    } *t, tests[] = {
+        {
+        "", 0, ""}, {
+        "1", 1, "MQ=="}, {
+        "22", 2, "MjI="}, {
+        "333", 3, "MzMz"}, {
+        "4444", 4, "NDQ0NA=="}, {
+        "55555", 5, "NTU1NTU="}, {
+        "abc:def", 7, "YWJjOmRlZg=="}, {
+        NULL}
+    };
+    for (t = tests; t->data; t++) {
+        char *str;
+
+        av_log(NULL, AV_LOG_ERROR, "Encoding %s...\n", (char *) t->data);
+        str = av_base64_encode(t->data, t->len);
+        if (str) {
+            av_log(NULL, AV_LOG_ERROR, "Encoded to %s...\n", str);
+            if (strcmp(str, t->result) != 0) {
+                av_log(NULL, AV_LOG_ERROR, "failed test %d: %s != %s\n",
+                       numtest, str, t->result);
+                numerr++;
+            }
+            av_free(str);
+        }
+
+        av_log(NULL, AV_LOG_ERROR, "Done encoding, about to decode...\n");
+        len = av_base64_decode(decode, t->result, sizeof(decode));
+        if (len != t->len) {
+            av_log(NULL, AV_LOG_ERROR, "failed test %d: len %d != %d\n",
+                   numtest, len, t->len);
+            numerr++;
+        } else if (memcmp(decode, t->data, t->len) != 0) {
+            av_log(NULL, AV_LOG_ERROR, "failed test %d: data\n", numtest);
+            numerr++;
+        } else {
+            av_log(NULL, AV_LOG_ERROR, "Decoded to %s\n",
+                   (char *) t->data);
+        }
+        numtest++;
+    }
+
+#undef srand
+#undef rand
+
+    {
+        int test_count;
+        srand(123141);          // time(NULL));
+        for (test_count = 0; test_count < 100; test_count++) {
+            int size = rand() % 1024;
+            int ii;
+            uint8_t *data;
+            char *encoded_result;
+
+            av_log(NULL, AV_LOG_ERROR, "Test %d: Size %d bytes...",
+                   test_count, size);
+            data = (uint8_t *) av_malloc(size);
+            for (ii = 0; ii < size; ii++) {
+                data[ii] = rand() % 255;
+            }
+
+            encoded_result = av_base64_encode(data, size);
+            if (encoded_result) {
+                int decode_buffer_size = size + 10;     // try without 10 as well
+                uint8_t *decode_buffer = av_malloc(decode_buffer_size);
+                if (decode_buffer) {
+                    int decoded_size =
+                        av_base64_decode(decode_buffer, encoded_result,
+                                   decode_buffer_size);
+
+                    if (decoded_size != size) {
+                        av_log(NULL, AV_LOG_ERROR,
+                               "Decoded/Encoded size mismatch (%d != %d)\n",
+                               decoded_size, size);
+                    } else {
+                        if (memcmp(decode_buffer, data, decoded_size) == 0) {
+                            av_log(NULL, AV_LOG_ERROR, "Passed!\n");
+                        } else {
+                            av_log(NULL, AV_LOG_ERROR,
+                                   "Failed (Data differs)!\n");
+                        }
+                    }
+                    av_free(decode_buffer);
+                }
+
+                av_free(encoded_result);
+            }
+        }
+    }
+
+    // these are invalid strings, that it currently decodes (which it probably shouldn't?)
+    {
+        uint8_t str[32];
+        if (av_base64_decode(str, "M=M=", sizeof(str)) != -1) {
+            av_log(NULL, AV_LOG_ERROR,
+                   "failed test %d: successful decode of `M=M='\n",
+                   numtest++);
+            numerr++;
+        }
+        if (av_base64_decode(str, "MQ===", sizeof(str)) != -1) {
+            av_log(NULL, AV_LOG_ERROR,
+                   "failed test %d: successful decode of `MQ==='\n",
+                   numtest++);
+            numerr++;
+        }
+    }
+
+    return numerr;
+}
+#endif
+

libavformat/base64.h

+/*
+ * Base64.c
+ * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+int av_base64_decode(uint8_t * out, const char *in, int out_length);  // param order as strncpy()
+char *av_base64_encode(uint8_t * src, int len);       // src is not a string, it's data.
+