1 files changed, 110 insertions, 0 deletions
diff --git a/src/common/impl/base64.c b/src/common/impl/base64.c
new file mode 100644
index 0000000..98a415f
--- /dev/null
+++ b/src/common/impl/base64.c
@@ -0,0 +1,110 @@
+#include "common/base64.h"
+
+// https://github.com/kostya/benchmarks/blob/master/base64/test-nolib.c#L145
+void ffBase64EncodeRaw(uint32_t size, const char* str, uint32_t* out_size, char* output) {
+    static const char chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    char* out = output;
+    const char* ends = str + (size - size % 3);
+    while (str != ends) {
+        uint32_t n = __builtin_bswap32(*(uint32_t*) str);
+        *out++ = chars[(n >> 26) & 63];
+        *out++ = chars[(n >> 20) & 63];
+        *out++ = chars[(n >> 14) & 63];
+        *out++ = chars[(n >> 8) & 63];
+        str += 3;
+    }
+
+    if (size % 3 == 1) {
+        uint64_t n = (uint64_t) *str << 16;
+        *out++ = chars[(n >> 18) & 63];
+        *out++ = chars[(n >> 12) & 63];
+        *out++ = '=';
+        *out++ = '=';
+    } else if (size % 3 == 2) {
+        uint64_t n = (uint64_t) *str++ << 16;
+        n |= (uint64_t) *str << 8;
+        *out++ = chars[(n >> 18) & 63];
+        *out++ = chars[(n >> 12) & 63];
+        *out++ = chars[(n >> 6) & 63];
+        *out++ = '=';
+    }
+    *out = '\0';
+    *out_size = (uint32_t) (out - output);
+}
+
+static uint8_t decode_table[256];
+
+static void init_decode_table() {
+    uint8_t ch = 0;
+    do {
+        int32_t code = -1;
+        if (ch >= 'A' && ch <= 'Z') {
+            code = ch - 0x41;
+        }
+        if (ch >= 'a' && ch <= 'z') {
+            code = ch - 0x47;
+        }
+        if (ch >= '0' && ch <= '9') {
+            code = ch + 0x04;
+        }
+        if (ch == '+' || ch == '-') {
+            code = 0x3E;
+        }
+        if (ch == '/' || ch == '_') {
+            code = 0x3F;
+        }
+        decode_table[ch] = (uint8_t) code;
+    } while (ch++ < 0xFF);
+}
+
+#define next_char(x) uint8_t x = decode_table[(uint8_t) *str++];
+
+bool ffBase64DecodeRaw(uint32_t size, const char* str, uint32_t* out_size, char* output) {
+    if (*(uint64_t*) decode_table == 0) {
+        init_decode_table();
+    }
+
+    char* out = output;
+    while (size > 0 && (str[size - 1] == '\n' || str[size - 1] == '\r' || str[size - 1] == '=')) {
+        size--;
+    }
+
+    const char* ends = str + size - 4;
+    while (true) {
+        if (str > ends) {
+            break;
+        }
+        while (*str == '\n' || *str == '\r') {
+            str++;
+        }
+
+        if (str > ends) {
+            break;
+        }
+        next_char(a);
+        next_char(b);
+        next_char(c);
+        next_char(d);
+
+        *out++ = (char) (a << 2 | b >> 4);
+        *out++ = (char) (b << 4 | c >> 2);
+        *out++ = (char) (c << 6 | d >> 0);
+    }
+
+    uint8_t mod = (uint8_t) (ends - str + 4) % 4;
+    if (mod == 2) {
+        next_char(a);
+        next_char(b);
+        *out++ = (char) (a << 2 | b >> 4);
+    } else if (mod == 3) {
+        next_char(a);
+        next_char(b);
+        next_char(c);
+        *out++ = (char) (a << 2 | b >> 4);
+        *out++ = (char) (b << 4 | c >> 2);
+    }
+
+    *out = '\0';
+    *out_size = (uint32_t) (out - output);
+    return true;
+}