diff options
| -rw-r--r-- | libbb/uuencode.c | 75 |
1 files changed, 43 insertions, 32 deletions
diff --git a/libbb/uuencode.c b/libbb/uuencode.c index 7c7f1cf..0e6fc8a 100644 --- a/libbb/uuencode.c +++ b/libbb/uuencode.c @@ -93,9 +93,10 @@ const char* FAST_FUNC decode_base64(char **pp_dst, const char *src) char *dst = *pp_dst; unsigned ch = 0; int i = 0; + int t; - while (*src) { - int t = (unsigned char)*src++; + while ((t = (unsigned char)*src) != '\0') { + src++; /* "if" forest is faster than strchr(bb_uuenc_tbl_base64, t) */ if (t >= '0' && t <= '9') @@ -131,7 +132,7 @@ const char* FAST_FUNC decode_base64(char **pp_dst, const char *src) } } *pp_dst = dst; - /* i should be zero here if full 4-char block was decoded */ + /* i is zero here if full 4-char block was decoded */ return src - i; /* -i rejects truncations: e.g. "MQ" and "MQ=" (correct encoding is "MQ==" -> "1") */ } @@ -141,9 +142,10 @@ const char* FAST_FUNC decode_base32(char **pp_dst, const char *src) char *dst = *pp_dst; uint64_t ch = 0; int i = 0; + int t; - while (*src) { - int t = (unsigned char)*src++; + while ((t = (unsigned char)*src) != '\0') { + src++; /* "if" forest is faster than strchr(bb_uuenc_tbl_base32, t) */ if (t >= '2' && t <= '7') @@ -156,27 +158,35 @@ const char* FAST_FUNC decode_base32(char **pp_dst, const char *src) //TODO: add BASE64_FLAG_foo to die on bad char? continue; - ch = (ch << 5) | t; + ch = (ch << 5) | (unsigned)t; /* cast prevents pointless sign-extension of t */ if (++i == 8) { + /* testcase: + * echo ' 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18' | base32 | base32 -d + * IOW, decoding of + * EAYSAMRAGMQDIIBVEA3CANZAHAQDSIBRGAQDCMJAGEZCAMJTEAYTIIBRGUQDCNRAGE3SAMJYBI== + * ==== + * should correctly stitch together the tail. + */ + if (t == 0) { + const char *s = src; + while (*--s == '=') + t--; + } *dst++ = (char) (ch >> 32); *dst++ = (char) (ch >> 24); *dst++ = (char) (ch >> 16); *dst++ = (char) (ch >> 8); *dst++ = (char) ch; - if (t == 0 && src[-1] == '=') { /* was last input char '='? */ - const char *s = src; - while (*--s == '=' && --i != 0) - continue; - i = 8 - i; /* count of =, must be 1, 3, 4 or 6 */ - dst -= (i+1) * 2 / 3; /* discard last 1, 2, 3 or 4 bytes */ - i = 0; - break; - } i = 0; + if (t < 0) /* was last input char '='? */ + break; } } + if (t < 0) /* was last input char '='? */ + /* -t is the count of =, must be 1, 3, 4 or 6 */ + dst -= (-t + 1) * 2 / 3; /* discard last 1, 2, 3 or 4 bytes */ *pp_dst = dst; - /* i should be zero here if full 8-char block was decoded */ + /* i is zero here if full 8-char block was decoded */ return src - i; } #endif @@ -193,19 +203,20 @@ void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags) #define uu_style_end (flags & BASE64_FLAG_UU_STOP) #define base32 (flags & BASE64_32) - /* uuencoded files have 61 byte lines. Use 64 byte buffer - * to process line at a time. + /* uuencoded files have 61 byte lines. + * base32/64 have 76 byte lines by default. + * Use 80 byte buffer to process one line at a time. */ - enum { BUFFER_SIZE = 64 }; - - char in_buf[BUFFER_SIZE + 2]; - char out_buf[BUFFER_SIZE / 4 * 3 + 2]; - char *out_tail; - const char *in_tail; + enum { BUFFER_SIZE = 80 }; + /* decoded data is shorter than input, can use single buffer for both */ + char buf[BUFFER_SIZE + 2]; int term_seen = 0; int in_count = 0; while (1) { + char *out_tail; + const char *in_tail; + while (in_count < BUFFER_SIZE) { int ch = fgetc(src_stream); if (ch == exit_char) { @@ -224,23 +235,23 @@ void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags) */ if (ch <= ' ') break; - in_buf[in_count++] = ch; + buf[in_count++] = ch; } - in_buf[in_count] = '\0'; + buf[in_count] = '\0'; /* Did we encounter "====" line? */ - if (uu_style_end && strcmp(in_buf, "====") == 0) + if (uu_style_end && strcmp(buf, "====") == 0) return; - out_tail = out_buf; + out_tail = buf; #if ENABLE_BASE32 if (base32) - in_tail = decode_base32(&out_tail, in_buf); + in_tail = decode_base32(&out_tail, buf); else #endif - in_tail = decode_base64(&out_tail, in_buf); + in_tail = decode_base64(&out_tail, buf); - fwrite(out_buf, (out_tail - out_buf), 1, dst_stream); + fwrite(buf, (out_tail - buf), 1, dst_stream); if (term_seen) { /* Did we consume ALL characters? */ @@ -252,6 +263,6 @@ void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags) /* It was partial decode */ in_count = strlen(in_tail); - memmove(in_buf, in_tail, in_count); + memmove(buf, in_tail, in_count); } } |