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git_buf: decode base85 inputs
This commit is contained in:
Edward Thomson
Edward Thomson
parent
3149ff6f66
commit
5b78dbdbf3
131
src/buffer.c
131
src/buffer.c
@ -273,42 +273,51 @@ int git_buf_encode_base64(git_buf *buf, const char *data, size_t len)
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return 0;
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}
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/* The inverse of base64_encode, offset by '+' == 43. */
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/* The inverse of base64_encode */
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static const int8_t base64_decode[] = {
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62,
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-1, -1, -1,
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63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
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-1, -1, -1, 0, -1, -1, -1,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
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13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
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-1, -1, -1, -1, -1, -1,
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26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
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39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, 0, -1, -1,
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
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-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
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};
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#define BASE64_DECODE_VALUE(c) (((c) < 43 || (c) > 122) ? -1 : base64_decode[c - 43])
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int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len)
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{
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size_t i;
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int8_t a, b, c, d;
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size_t orig_size = buf->size, new_size;
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if (len % 4) {
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giterr_set(GITERR_INVALID, "invalid base64 input");
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return -1;
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}
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assert(len % 4 == 0);
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GITERR_CHECK_ALLOC_ADD(&new_size, (len / 4 * 3), buf->size);
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GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
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ENSURE_SIZE(buf, new_size);
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for (i = 0; i < len; i += 4) {
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if ((a = BASE64_DECODE_VALUE(base64[i])) < 0 ||
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(b = BASE64_DECODE_VALUE(base64[i+1])) < 0 ||
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(c = BASE64_DECODE_VALUE(base64[i+2])) < 0 ||
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(d = BASE64_DECODE_VALUE(base64[i+3])) < 0) {
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if ((a = base64_decode[(unsigned char)base64[i]]) < 0 ||
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(b = base64_decode[(unsigned char)base64[i+1]]) < 0 ||
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(c = base64_decode[(unsigned char)base64[i+2]]) < 0 ||
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(d = base64_decode[(unsigned char)base64[i+3]]) < 0) {
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buf->size = orig_size;
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buf->ptr[buf->size] = '\0';
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giterr_set(GITERR_INVALID, "Invalid base64 input");
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giterr_set(GITERR_INVALID, "invalid base64 input");
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return -1;
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}
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@ -321,7 +330,7 @@ int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len)
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return 0;
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}
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static const char b85str[] =
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static const char base85_encode[] =
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"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
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int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
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@ -351,7 +360,7 @@ int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
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int val = acc % 85;
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acc /= 85;
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b85[i] = b85str[val];
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b85[i] = base85_encode[val];
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}
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for (i = 0; i < 5; i++)
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@ -363,6 +372,88 @@ int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
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return 0;
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}
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/* The inverse of base85_encode */
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static const int8_t base85_decode[] = {
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, 63, -1, 64, 65, 66, 67, -1, 68, 69, 70, 71, -1, 72, -1, -1,
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1, 2, 3, 4, 5, 6, 7, 8, 9, 10, -1, 73, 74, 75, 76, 77,
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78, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
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26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, -1, -1, -1, 79, 80,
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81, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 82, 83, 84, 85, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
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};
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int git_buf_decode_base85(
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git_buf *buf,
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const char *base85,
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size_t base85_len,
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size_t output_len)
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{
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size_t orig_size = buf->size, new_size;
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if (base85_len % 5 ||
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output_len > base85_len * 4 / 5) {
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giterr_set(GITERR_INVALID, "invalid base85 input");
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return -1;
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}
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GITERR_CHECK_ALLOC_ADD(&new_size, output_len, buf->size);
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GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
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ENSURE_SIZE(buf, new_size);
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while (output_len) {
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unsigned acc = 0;
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int de, cnt = 4;
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unsigned char ch;
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do {
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ch = *base85++;
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de = base85_decode[ch];
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if (--de < 0)
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goto on_error;
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acc = acc * 85 + de;
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} while (--cnt);
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ch = *base85++;
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de = base85_decode[ch];
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if (--de < 0)
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goto on_error;
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/* Detect overflow. */
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if (0xffffffff / 85 < acc ||
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0xffffffff - de < (acc *= 85))
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goto on_error;
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acc += de;
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cnt = (output_len < 4) ? output_len : 4;
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output_len -= cnt;
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do {
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acc = (acc << 8) | (acc >> 24);
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buf->ptr[buf->size++] = acc;
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} while (--cnt);
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}
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buf->ptr[buf->size] = 0;
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return 0;
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on_error:
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buf->size = orig_size;
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buf->ptr[buf->size] = '\0';
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giterr_set(GITERR_INVALID, "invalid base85 input");
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return -1;
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}
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int git_buf_vprintf(git_buf *buf, const char *format, va_list ap)
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{
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size_t expected_size, new_size;
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@ -185,6 +185,8 @@ int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len);
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/* Write data as "base85" encoded in buffer */
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int git_buf_encode_base85(git_buf *buf, const char *data, size_t len);
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/* Decode the given "base85" and write the result to the buffer */
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int git_buf_decode_base85(git_buf *buf, const char *base64, size_t len, size_t output_len);
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/*
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* Insert, remove or replace a portion of the buffer.
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@ -813,6 +813,42 @@ void test_core_buffer__encode_base85(void)
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git_buf_free(&buf);
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}
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void test_core_buffer__decode_base85(void)
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{
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git_buf buf = GIT_BUF_INIT;
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cl_git_pass(git_buf_decode_base85(&buf, "bZBXF", 5, 4));
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cl_assert_equal_sz(4, buf.size);
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cl_assert_equal_s("this", buf.ptr);
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git_buf_clear(&buf);
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cl_git_pass(git_buf_decode_base85(&buf, "ba!tca&BaE", 10, 8));
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cl_assert_equal_sz(8, buf.size);
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cl_assert_equal_s("two rnds", buf.ptr);
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git_buf_clear(&buf);
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cl_git_pass(git_buf_decode_base85(&buf, "bZBXFAZc?TVqtS-AUHK3Wo~0{WMyOk", 30, 23));
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cl_assert_equal_sz(23, buf.size);
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cl_assert_equal_s("this is base 85 encoded", buf.ptr);
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git_buf_clear(&buf);
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git_buf_free(&buf);
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}
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void test_core_buffer__decode_base85_fails_gracefully(void)
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{
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git_buf buf = GIT_BUF_INIT;
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git_buf_puts(&buf, "foobar");
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cl_git_fail(git_buf_decode_base85(&buf, "invalid charsZZ", 15, 42));
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cl_git_fail(git_buf_decode_base85(&buf, "invalidchars__ ", 15, 42));
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cl_git_fail(git_buf_decode_base85(&buf, "overflowZZ~~~~~", 15, 42));
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cl_git_fail(git_buf_decode_base85(&buf, "truncated", 9, 42));
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cl_assert_equal_sz(6, buf.size);
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cl_assert_equal_s("foobar", buf.ptr);
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}
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void test_core_buffer__classify_with_utf8(void)
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{
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char *data0 = "Simple text\n";
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