From 4a4fd4582feb9497e3ffd348a2fc019a7910d214 Mon Sep 17 00:00:00 2001
From: Alastair Stuart <alastair@muto.so>
Date: Fri, 3 May 2013 23:30:40 -0500
Subject: [PATCH] base64: Added base64

---
 base64.c | 171 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 base64.c

diff --git a/base64.c b/base64.c
new file mode 100644
index 0000000..28e733d
--- /dev/null
+++ b/base64.c
@@ -0,0 +1,171 @@
+/*  
+    Copyright © 2013 Alastair Stuart
+    
+    This program is open source software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+    
+    This program 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 General Public License for more details.
+*/
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include <getopt.h>
+
+#define VERSION "0.01"
+
+const char base64_table[]  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+const int  padding_table[] = {0, 2, 1};
+
+void base64_encode_block(uint8_t in[3], char out[5])
+{
+    uint8_t octet_a = in[0];
+    uint8_t octet_b = in[1];
+    uint8_t octet_c = in[2];
+
+    uint32_t combined = (octet_a << 16) + (octet_b << 8) + octet_c;
+
+    out[0] = base64_table[(combined >> 3 * 6) & 0x3F];
+    out[1] = base64_table[(combined >> 2 * 6) & 0x3F];
+    out[2] = base64_table[(combined >> 1 * 6) & 0x3F];
+    out[3] = base64_table[(combined >> 0 * 6) & 0x3F];
+    out[4] = '\0';
+}
+
+void usage(char* program)
+{
+    printf("Usage: %s [options] [file]\n", program);
+    printf("Encodes a file into base64..\n"
+           "\n"
+           "    -w, --wrap [num]   Wrap lines after [num] characters.\n"
+           "\n"
+           "    --help             Print this message.\n"
+           "    --version          Show version info.\n");
+}
+
+int main(int argc, char* argv[])
+{
+    size_t line_width = 0;
+    size_t wrap = 76;
+    static struct option long_options[] = {
+        {"wrap",    required_argument, NULL, 'w'},
+        {"help",    no_argument,       NULL,  1},
+        {"version", no_argument,       NULL,  2},
+        {NULL, 0, NULL, 0}
+    };
+
+    int c = 0;
+    while ((c = getopt_long(argc, argv, "w:",
+                            long_options, NULL)) != -1)
+    {
+        switch (c)
+        {
+            case 'w':
+                // check if wrap argument is a valid number
+                for (size_t i = 0; i < strlen(optarg); i++)
+                {
+                    if (!isdigit(optarg[i])) {
+                        fprintf(stderr, "%s: invalid wrap size: %s\n",
+                                         argv[0],               optarg);
+                        return 1;
+                    }
+                }
+                wrap = atoi(optarg);
+                break;
+            case 1:
+                usage(argv[0]);
+                return 0;
+            case 2:
+                printf("base64 (mutos) v"VERSION"\n");
+                return 0;
+            default:
+                printf("Run '%s --help' for usage.\n",
+                             argv[0]);
+                return 1;
+        }
+    }
+
+    FILE* input = NULL;
+    char* filename = NULL;
+
+    if ((argc - optind) > 1) {
+        fprintf(stderr, "%s: extra operand: %s\n",
+                         argv[0],           argv[optind+1]);
+        return 1;
+    } else if ((argc - optind) < 1) {
+        input = stdin;
+        filename = "stdin";
+    } else {
+        input = fopen(argv[optind], "rb");
+        filename = argv[optind];
+    }
+
+    if (!input) {
+        fprintf(stderr, "%s: %s: %s\n",
+                         argv[0], strerror(errno), filename);
+        return 1;
+    }
+    
+    bool last_block = false;
+
+    size_t length = 0;
+    while (!last_block)
+    {
+        int eof_count = 0;
+
+        int c = 0;
+
+        uint8_t block[3] = {0};
+        block[0] = (c = fgetc(input)) != EOF ? c : 0;
+        if (c != EOF) { length++; } else { eof_count++; }
+        block[1] = (c = fgetc(input)) != EOF ? c : 0;
+        if (c != EOF) { length++; } else { eof_count++; }
+        block[2] = (c = fgetc(input)) != EOF ? c : 0;
+        if (c != EOF) { length++; } else { eof_count++; }
+
+        if (feof(input)) {
+            last_block = true;
+        }
+
+        if (eof_count == 3) {
+            break;
+        }
+
+        char encoded[5] = {'\0'};
+        base64_encode_block(block, encoded);
+
+        if (last_block) {
+            for (int i = 0; i < padding_table[length % 3]; i++)
+            {
+                encoded[3-i] = '=';
+            }
+        }
+
+        for (size_t i = 0; i < 4; i++)
+        {
+            printf("%c", encoded[i]);
+            line_width++;
+            if (wrap != 0) {
+                if (line_width % wrap == 0) {
+                    printf("\n");
+                    line_width = 0;
+                }
+            }
+        }
+    }
+    printf("\n");
+
+    fclose(input);
+
+    return 0;
+}
-- 
2.11.4.GIT