+/* The inverse of base64_encode */
+static const int8_t base64_decode[] = {
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, 0, -1, -1,
+ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
+ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
+ -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+
+int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len)
+{
+ size_t i;
+ int8_t a, b, c, d;
+ size_t orig_size = buf->size, new_size;
+
+ if (len % 4) {
+ giterr_set(GITERR_INVALID, "invalid base64 input");
+ return -1;
+ }
+
+ assert(len % 4 == 0);
+ GITERR_CHECK_ALLOC_ADD(&new_size, (len / 4 * 3), buf->size);
+ GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
+ ENSURE_SIZE(buf, new_size);
+
+ for (i = 0; i < len; i += 4) {
+ if ((a = base64_decode[(unsigned char)base64[i]]) < 0 ||
+ (b = base64_decode[(unsigned char)base64[i+1]]) < 0 ||
+ (c = base64_decode[(unsigned char)base64[i+2]]) < 0 ||
+ (d = base64_decode[(unsigned char)base64[i+3]]) < 0) {
+ buf->size = orig_size;
+ buf->ptr[buf->size] = '\0';
+
+ giterr_set(GITERR_INVALID, "invalid base64 input");
+ return -1;
+ }
+
+ buf->ptr[buf->size++] = ((a << 2) | (b & 0x30) >> 4);
+ buf->ptr[buf->size++] = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
+ buf->ptr[buf->size++] = (c & 0x03) << 6 | (d & 0x3f);
+ }
+
+ buf->ptr[buf->size] = '\0';
+ return 0;
+}
+
+static const char base85_encode[] =
+ "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
+
+int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
+{
+ size_t blocks = (len / 4) + !!(len % 4), alloclen;
+
+ GITERR_CHECK_ALLOC_MULTIPLY(&alloclen, blocks, 5);
+ GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, buf->size);
+ GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, 1);
+
+ ENSURE_SIZE(buf, alloclen);
+
+ while (len) {
+ uint32_t acc = 0;
+ char b85[5];
+ int i;
+
+ for (i = 24; i >= 0; i -= 8) {
+ uint8_t ch = *data++;
+ acc |= ch << i;
+
+ if (--len == 0)
+ break;
+ }
+
+ for (i = 4; i >= 0; i--) {
+ int val = acc % 85;
+ acc /= 85;
+
+ b85[i] = base85_encode[val];
+ }
+
+ for (i = 0; i < 5; i++)
+ buf->ptr[buf->size++] = b85[i];
+ }
+
+ buf->ptr[buf->size] = '\0';
+
+ return 0;
+}
+
+/* The inverse of base85_encode */
+static const int8_t base85_decode[] = {
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, 63, -1, 64, 65, 66, 67, -1, 68, 69, 70, 71, -1, 72, -1, -1,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, -1, 73, 74, 75, 76, 77,
+ 78, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
+ 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, -1, -1, -1, 79, 80,
+ 81, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 82, 83, 84, 85, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+
+int git_buf_decode_base85(
+ git_buf *buf,
+ const char *base85,
+ size_t base85_len,
+ size_t output_len)
+{
+ size_t orig_size = buf->size, new_size;
+
+ if (base85_len % 5 ||
+ output_len > base85_len * 4 / 5) {
+ giterr_set(GITERR_INVALID, "invalid base85 input");
+ return -1;
+ }
+
+ GITERR_CHECK_ALLOC_ADD(&new_size, output_len, buf->size);
+ GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
+ ENSURE_SIZE(buf, new_size);
+
+ while (output_len) {
+ unsigned acc = 0;
+ int de, cnt = 4;
+ unsigned char ch;
+ do {
+ ch = *base85++;
+ de = base85_decode[ch];
+ if (--de < 0)
+ goto on_error;
+
+ acc = acc * 85 + de;
+ } while (--cnt);
+ ch = *base85++;
+ de = base85_decode[ch];
+ if (--de < 0)
+ goto on_error;
+
+ /* Detect overflow. */
+ if (0xffffffff / 85 < acc ||
+ 0xffffffff - de < (acc *= 85))
+ goto on_error;
+
+ acc += de;
+
+ cnt = (output_len < 4) ? output_len : 4;
+ output_len -= cnt;
+ do {
+ acc = (acc << 8) | (acc >> 24);
+ buf->ptr[buf->size++] = acc;
+ } while (--cnt);
+ }
+
+ buf->ptr[buf->size] = 0;
+
+ return 0;
+
+on_error:
+ buf->size = orig_size;
+ buf->ptr[buf->size] = '\0';
+
+ giterr_set(GITERR_INVALID, "invalid base85 input");
+ return -1;
+}
+