Abandonment of the project

base64.c

@@ -0,0 +1,83 @@
+#include "base64.h"
+
+// Thanks, ryyst https://stackoverflow.com/questions/342409/how-do-i-base64-encode-decode-in-c
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * Data
+ */
+static const int mod_table[] = {0, 2, 1};
+static const char *encoding_table =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+static char decoding_table[256] = {};
+
+/*
+ * Private API
+ */
+static void build_decoding_table() {
+    for (int i = 0; i < 64; ++i) {
+        decoding_table[(uint8_t)encoding_table[i]] = i;
+    }
+}
+
+/*
+ * Public API
+ */
+char *base64_encode(const void *_data, uint32_t size) {
+    uint32_t out_size = 4 * ((size + 2) / 3) + 1;
+    char *out_data = malloc(out_size);
+    if (!out_size) {
+        return NULL;
+    }
+    const char *data = _data;
+    for (int i = 0, j = 0; i < size;) {
+        uint32_t octet_a = i < size ? (uint8_t)data[i++] : 0;
+        uint32_t octet_b = i < size ? (uint8_t)data[i++] : 0;
+        uint32_t octet_c = i < size ? (uint8_t)data[i++] : 0;
+
+        uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
+
+        out_data[j++] = encoding_table[(triple >> 3 * 6) & 0x3F];
+        out_data[j++] = encoding_table[(triple >> 2 * 6) & 0x3F];
+        out_data[j++] = encoding_table[(triple >> 1 * 6) & 0x3F];
+        out_data[j++] = encoding_table[(triple >> 0 * 6) & 0x3F];
+    }
+    for (int i = 0; i < mod_table[size % 3]; i++)
+        out_data[out_size - 2 - i] = '=';
+    out_data[out_size - 1] = '\0';
+    return out_data;
+}
+
+void *base64_decode(const char *data, uint32_t *out_size) {
+    if (decoding_table[0] == 0)
+        build_decoding_table();
+    uint32_t size = strlen(data);
+    if (size % 4 != 0) return NULL;
+
+    *out_size = size / 4 * 3;
+    if (data[size - 1] == '=') (*out_size)--;
+    if (data[size - 2] == '=') (*out_size)--;
+
+    uint8_t *decoded_data = malloc(*out_size);
+    if (decoded_data == NULL) return NULL;
+
+    for (int i = 0, j = 0; i < size;) {
+        uint32_t sextet_a = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+        uint32_t sextet_b = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+        uint32_t sextet_c = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+        uint32_t sextet_d = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
+
+        uint32_t triple = (sextet_a << 3 * 6)
+            + (sextet_b << 2 * 6)
+            + (sextet_c << 1 * 6)
+            + (sextet_d << 0 * 6);
+
+        if (j < *out_size) decoded_data[j++] = (triple >> 2 * 8) & 0xFF;
+        if (j < *out_size) decoded_data[j++] = (triple >> 1 * 8) & 0xFF;
+        if (j < *out_size) decoded_data[j++] = (triple >> 0 * 8) & 0xFF;
+    }
+    return decoded_data;
+}