xzcat: more cleanup and some shrinking.
-drop __always_inline (c. 1.5k of binary size),
-remove the xz_dec_bcj_end and memzero macros
(memeq is left because of negative returns),
-disable XZ_DEC_SINGLE and XZ_DEC_PREALLOC, since we aren't using them.
(160 bytes)
-Merge xz_dec_lzma2_end into xz_dec_end
-Move xz_crc32 to where it's defined.
(That does not seem to be duplicated elsewhere in toybox.)
On Thu, 11 Apr 2013 12:03:54 -0500
Rob Landley <[email protected]> wrote:
> > *I don't know C very well. Really, I went through the first few
> > chapters of "Using
> > Turbo C" and a couple other books of similar age,
>
> By Herbert Schildt?
Yes. Also looked at "Writing Portable C" and whatever book on that topic it
was that Eric S. Raymond wrote...
> (Everybody makes fun of the guy because he wrote like the Hitchhiker's
> Guide to the Galaxy. "Although it contains much that is apocryphal, or
> at least wildly inaccurate..." But his "How to Program in Turbo C" was
> better and more complete than the other book I had access to ("From
> Basic to C", from my community college's library). And moving from DOS
> to Unix was way bigger a change than anything Schildt got wrong. (Fork!
> Signal handling! No more near/far pointers! Cooked tty mode! mknod!
> setuid vs seteuid vs setfsuid...))
>
> People don't teach C these days. They teach C++, which is not C. (A
> swimming pool full of jello may be mostly water, but flailing around in
> it is not gonna teach you how to swim. It's different, less general
> purpose, less generally useful, and who thought doing that was a good
> idea?)
Agreed.
> > and then picked up what I needed to get things building over the last
> > 4-5 years.
>
> Best way. :)
>
--
Isaac Dunham <[email protected]>
diff --git a/toys/pending/xzcat.c b/toys/pending/xzcat.c
index 8ed36ec..5e96cf6 100644
--- a/toys/pending/xzcat.c
+++ b/toys/pending/xzcat.c
@@ -43,9 +43,8 @@ config XZCAT
*
* It is possible to enable support only for a subset of the above
* modes at compile time by defining XZ_DEC_SINGLE, XZ_DEC_PREALLOC,
- * or XZ_DEC_DYNALLOC. The xz_dec kernel module is always compiled
- * with support for all operation modes, but the preboot code may
- * be built with fewer features to minimize code size.
+ * or XZ_DEC_DYNALLOC. xzcat uses only XZ_DEC_DYNALLOC,
+ * so that is the default.
*/
enum xz_mode {
XZ_SINGLE,
@@ -236,7 +235,19 @@ void xz_dec_end(struct xz_dec *s);
* calculation, the third argument must be zero. To continue the calculation,
* the previously returned value is passed as the third argument.
*/
-uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc);
+static uint32_t xz_crc32_table[256];
+
+uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
+{
+ crc = ~crc;
+
+ while (size != 0) {
+ crc = xz_crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
+ --size;
+ }
+
+ return ~crc;
+}
/*
* This must be called before any other xz_* function (but after crc_init())
@@ -281,7 +292,6 @@ uint64_t xz_crc64(const uint8_t *buf, size_t size, uint64_t crc)
}
// END xz.h
-static uint32_t xz_crc32_table[256];
static uint8_t in[BUFSIZ];
static uint8_t out[BUFSIZ];
@@ -395,31 +405,12 @@ error:
#define memeq(a, b, size) (memcmp(a, b, size) == 0)
-#define memzero(buf, size) memset(buf, 0, size)
#ifndef min
# define min(x, y) ((x) < (y) ? (x) : (y))
#endif
#define min_t(type, x, y) min(x, y)
-/*
- * Some functions have been marked with __always_inline to keep the
- * performance reasonable even when the compiler is optimizing for
- * small code size. You may be able to save a few bytes by #defining
- * __always_inline to plain inline, but don't complain if the code
- * becomes slow.
- *
- * NOTE: System headers on GNU/Linux may #define this macro already,
- * so if you want to change it, you need to #undef it first.
- */
-#ifndef __always_inline
-# ifdef __GNUC__
-# define __always_inline \
- inline __attribute__((__always_inline__))
-# else
-# define __always_inline inline
-# endif
-#endif
/* Inline functions to access unaligned unsigned 32-bit integers */
#ifndef get_unaligned_le32
@@ -471,13 +462,12 @@ static inline void put_unaligned_be32(uint32_t val, uint8_t *buf)
# define get_le32 get_unaligned_le32
#endif
-/* If no specific decoding mode is requested, enable support for all modes. */
-#if !defined(XZ_DEC_SINGLE) && !defined(XZ_DEC_PREALLOC) \
- && !defined(XZ_DEC_DYNALLOC)
-# define XZ_DEC_SINGLE
-# define XZ_DEC_PREALLOC
-# define XZ_DEC_DYNALLOC
-#endif
+
+#define XZ_DEC_DYNALLOC
+/* DYNALLOC is what we use, but we may want these later.
+#define XZ_DEC_SINGLE
+#define XZ_DEC_PREALLOC
+*/
/*
* The DEC_IS_foo(mode) macros are used in "if" statements. If only some
@@ -543,9 +533,6 @@ enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s,
enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
struct xz_buf *b);
-/* Free the memory allocated for the LZMA2 decoder. */
-void xz_dec_lzma2_end(struct xz_dec_lzma2 *s);
-
#ifdef XZ_DEC_BCJ
/*
* Allocate memory for BCJ decoders. xz_dec_bcj_reset() must be used before
@@ -569,24 +556,10 @@ enum xz_ret xz_dec_bcj_reset(struct xz_dec_bcj *s, uint8_t id);
enum xz_ret xz_dec_bcj_run(struct xz_dec_bcj *s,
struct xz_dec_lzma2 *lzma2,
struct xz_buf *b);
-
-/* Free the memory allocated for the BCJ filters. */
-#define xz_dec_bcj_end(s) free(s)
#endif
// END "xz_private.h"
-uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
-{
- crc = ~crc;
-
- while (size != 0) {
- crc = xz_crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
- --size;
- }
-
- return ~crc;
-}
@@ -1820,7 +1793,7 @@ static inline int rc_is_finished(const struct rc_dec *rc)
}
/* Read the next input byte if needed. */
-static __always_inline void rc_normalize(struct rc_dec *rc)
+static inline void rc_normalize(struct rc_dec *rc)
{
if (rc->range < RC_TOP_VALUE) {
rc->range <<= RC_SHIFT_BITS;
@@ -1839,7 +1812,7 @@ static __always_inline void rc_normalize(struct rc_dec *rc)
* of the code generated by GCC 3.x decreases 10-15 %. (GCC 4.3 doesn't care,
* and it generates 10-20 % faster code than GCC 3.x from this file anyway.)
*/
-static __always_inline int rc_bit(struct rc_dec *rc, uint16_t *prob)
+static inline int rc_bit(struct rc_dec *rc, uint16_t *prob)
{
uint32_t bound;
int bit;
@@ -1861,7 +1834,7 @@ static __always_inline int rc_bit(struct rc_dec *rc, uint16_t *prob)
}
/* Decode a bittree starting from the most significant bit. */
-static __always_inline uint32_t rc_bittree(struct rc_dec *rc,
+static inline uint32_t rc_bittree(struct rc_dec *rc,
uint16_t *probs, uint32_t limit)
{
uint32_t symbol = 1;
@@ -1877,7 +1850,7 @@ static __always_inline uint32_t rc_bittree(struct rc_dec *rc,
}
/* Decode a bittree starting from the least significant bit. */
-static __always_inline void rc_bittree_reverse(struct rc_dec *rc,
+static inline void rc_bittree_reverse(struct rc_dec *rc,
uint16_t *probs,
uint32_t *dest, uint32_t limit)
{
@@ -2204,7 +2177,7 @@ static int lzma2_lzma(struct xz_dec_lzma2 *s, struct xz_buf *b)
memcpy(s->temp.buf + s->temp.size, b->in + b->in_pos, tmp);
if (s->temp.size + tmp == s->lzma2.compressed) {
- memzero(s->temp.buf + s->temp.size + tmp,
+ memset(s->temp.buf + s->temp.size + tmp, 0,
sizeof(s->temp.buf)
- s->temp.size - tmp);
s->rc.in_limit = s->temp.size + tmp;
@@ -2506,13 +2479,6 @@ enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s, uint8_t props)
return XZ_OK;
}
-void xz_dec_lzma2_end(struct xz_dec_lzma2 *s)
-{
- if (DEC_IS_MULTI(s->dict.mode))
- free(s->dict.buf);
-
- free(s);
-}
/*
* .xz Stream decoder
*/
@@ -3342,7 +3308,7 @@ struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max)
error_lzma2:
#ifdef XZ_DEC_BCJ
- xz_dec_bcj_end(s->bcj);
+ free(s->bcj);
error_bcj:
#endif
free(s);
@@ -3355,8 +3321,8 @@ void xz_dec_reset(struct xz_dec *s)
s->allow_buf_error = 0;
s->pos = 0;
s->crc = 0;
- memzero(&s->block, sizeof(s->block));
- memzero(&s->index, sizeof(s->index));
+ memset(&s->block, 0, sizeof(s->block));
+ memset(&s->index, 0, sizeof(s->index));
s->temp.pos = 0;
s->temp.size = STREAM_HEADER_SIZE;
}
@@ -3364,9 +3330,12 @@ void xz_dec_reset(struct xz_dec *s)
void xz_dec_end(struct xz_dec *s)
{
if (s != NULL) {
- xz_dec_lzma2_end(s->lzma2);
+ if (DEC_IS_MULTI((s->lzma2)->dict.mode))
+ free((s->lzma2)->dict.buf);
+ free(s->lzma2);
+
#ifdef XZ_DEC_BCJ
- xz_dec_bcj_end(s->bcj);
+ free(s->bcj);
#endif
free(s);
}
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