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| author | Denys Vlasenko | 2020-11-27 15:39:23 +0100 |
|---|---|---|
| committer | Denys Vlasenko | 2020-11-27 15:39:23 +0100 |
| commit | cdab3c4fac76bcf941e55e309b061ac97925f9b0 (patch) | |
| tree | aa7c3895c8cfc09140c6e7f3d79ca9e8a3a21059 | |
| parent | c8b3d9a145d2db95869f0ae8081d85c0378f0aef (diff) | |
| download | busybox-cdab3c4fac76bcf941e55e309b061ac97925f9b0.zip busybox-cdab3c4fac76bcf941e55e309b061ac97925f9b0.tar.gz | |
base32/64: decode in-place
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | coreutils/uudecode.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/coreutils/uudecode.c b/coreutils/uudecode.c index 751976a..10e5a55 100644 --- a/coreutils/uudecode.c +++ b/coreutils/uudecode.c @@ -286,13 +286,19 @@ int baseNUM_main(int argc UNUSED_PARAM, char **argv) } else { enum { SRC_BUF_SIZE = 3 * 5 * 32, /* this *MUST* be a multiple of 3 and 5 */ - DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3), + DST_BUF_SIZE = 8 * ((SRC_BUF_SIZE + 4) / 5), /* max growth on decode (base32 case) */ }; - char src_buf[SRC_BUF_SIZE]; - char dst_buf[DST_BUF_SIZE + 1]; - int src_fd = fileno(src_stream); - int rem = 0; + /* Use one buffer for both input and output: + * decoding reads input "left-to-right", + * it's safe to place source at the end of the buffer and + * overwrite it while decoding, just be careful to have a gap. + */ + char dst_buf[((DST_BUF_SIZE + /*gap:*/ 16) /*round up to 16:*/ | 0xf) + 1]; +#define src_buf (dst_buf + sizeof(dst_buf) - SRC_BUF_SIZE) + int src_fd, rem; + src_fd = fileno(src_stream); + rem = 0; while (1) { size_t size = full_read(src_fd, src_buf, SRC_BUF_SIZE); if ((ssize_t)size < 0) @@ -331,6 +337,7 @@ int baseNUM_main(int argc UNUSED_PARAM, char **argv) } } } +#undef src_buf } fflush_stdout_and_exit(EXIT_SUCCESS); |