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gzip cleanup part #4

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This commit is contained in:
Denis Vlasenko
2007-01-07 19:38:42 +00:00
parent ed0f6db35e
commit f824136f6b
1 changed files with 39 additions and 35 deletions
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74
archival/gzip.c
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@@ -61,12 +61,6 @@ aa: 85.1% -- replaced with aa.gz
# endif # endif
#endif #endif
#define PACK_MAGIC "\037\036" /* Magic header for packed files */
#define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */
#define OLD_GZIP_MAGIC "\037\236" /* Magic header for gzip 0.5 = freeze 1.x */
#define LZH_MAGIC "\037\240" /* Magic header for SCO LZH Compress files */
#define PKZIP_MAGIC "\120\113\003\004" /* Magic header for pkzip files */
/* gzip flag byte */ /* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
@@ -142,9 +136,9 @@ aa: 85.1% -- replaced with aa.gz
# define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);} # define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);}
# define Trace(x) fprintf x # define Trace(x) fprintf x
# define Tracev(x) {if (verbose) fprintf x ;} # define Tracev(x) {if (verbose) fprintf x ;}
# define Tracevv(x) {if (verbose>1) fprintf x ;} # define Tracevv(x) {if (verbose > 1) fprintf x ;}
# define Tracec(c,x) {if (verbose && (c)) fprintf x ;} # define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;} # define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x ;}
#else #else
# define Assert(cond,msg) # define Assert(cond,msg)
# define Trace(x) # define Trace(x)
@@ -313,7 +307,7 @@ static void clear_bufs(void)
* pointer, then initialize the crc shift register contents instead. * pointer, then initialize the crc shift register contents instead.
* Return the current crc in either case. * Return the current crc in either case.
*/ */
static uint32_t crc = ~0; /* shift register contents */ static uint32_t crc; /* shift register contents */
static uint32_t updcrc(uch * s, unsigned n) static uint32_t updcrc(uch * s, unsigned n)
{ {
uint32_t c; /* temporary variable */ uint32_t c; /* temporary variable */
@@ -1414,17 +1408,18 @@ static void set_file_type(void);
#ifndef DEBUG #ifndef DEBUG
/* Send a code of the given tree. c and tree must not have side effects */
# define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len) # define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
/* Send a code of the given tree. c and tree must not have side effects */
#else /* DEBUG */ #else /* DEBUG */
# define send_code(c, tree) \ # define send_code(c, tree) \
{ if (verbose>1) bb_error_msg("\ncd %3d ",(c)); \ { \
send_bits(tree[c].Code, tree[c].Len); } if (verbose > 1) bb_error_msg("\ncd %3d ",(c)); \
send_bits(tree[c].Code, tree[c].Len); \
}
#endif #endif
#define d_code(dist) \ #define d_code(dist) \
((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)]) ((dist) < 256 ? dist_code[dist] : dist_code[256 + ((dist)>>7)])
/* Mapping from a distance to a distance code. dist is the distance - 1 and /* Mapping from a distance to a distance code. dist is the distance - 1 and
* must not have side effects. dist_code[256] and dist_code[257] are never * must not have side effects. dist_code[256] and dist_code[257] are never
* used. * used.
@@ -1432,6 +1427,7 @@ static void set_file_type(void);
/* the arguments must not have side effects */ /* the arguments must not have side effects */
/* =========================================================================== /* ===========================================================================
* Allocate the match buffer, initialize the various tables and save the * Allocate the match buffer, initialize the various tables and save the
* location of the internal file attribute (ascii/binary) and method * location of the internal file attribute (ascii/binary) and method
@@ -1513,12 +1509,13 @@ static void ct_init(ush * attr, int *methodp)
init_block(); init_block();
} }
/* =========================================================================== /* ===========================================================================
* Initialize a new block. * Initialize a new block.
*/ */
static void init_block(void) static void init_block(void)
{ {
int n; /* iterates over tree elements */ int n; /* iterates over tree elements */
/* Initialize the trees. */ /* Initialize the trees. */
for (n = 0; n < L_CODES; n++) for (n = 0; n < L_CODES; n++)
@@ -1535,28 +1532,22 @@ static void init_block(void)
flag_bit = 1; flag_bit = 1;
} }
#define SMALLEST 1
/* Index within the heap array of least frequent node in the Huffman tree */
/* =========================================================================== /* ===========================================================================
* Remove the smallest element from the heap and recreate the heap with * Remove the smallest element from the heap and recreate the heap with
* one less element. Updates heap and heap_len. * one less element. Updates heap and heap_len.
*/ */
#define SMALLEST 1
/* Index within the heap array of least frequent node in the Huffman tree */
#define pqremove(tree, top) \ #define pqremove(tree, top) \
{\ { \
top = heap[SMALLEST]; \ top = heap[SMALLEST]; \
heap[SMALLEST] = heap[heap_len--]; \ heap[SMALLEST] = heap[heap_len--]; \
pqdownheap(tree, SMALLEST); \ pqdownheap(tree, SMALLEST); \
} }
/* ===========================================================================
* Compares to subtrees, using the tree depth as tie breaker when
* the subtrees have equal frequency. This minimizes the worst case length.
*/
#define smaller(tree, n, m) \
(tree[n].Freq < tree[m].Freq || \
(tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
/* =========================================================================== /* ===========================================================================
* Restore the heap property by moving down the tree starting at node k, * Restore the heap property by moving down the tree starting at node k,
@@ -1564,6 +1555,14 @@ static void init_block(void)
* when the heap property is re-established (each father smaller than its * when the heap property is re-established (each father smaller than its
* two sons). * two sons).
*/ */
/* Compares to subtrees, using the tree depth as tie breaker when
* the subtrees have equal frequency. This minimizes the worst case length.
*/
#define smaller(tree, n, m) \
(tree[n].Freq < tree[m].Freq \
|| (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
static void pqdownheap(ct_data * tree, int k) static void pqdownheap(ct_data * tree, int k)
{ {
int v = heap[k]; int v = heap[k];
@@ -1588,6 +1587,7 @@ static void pqdownheap(ct_data * tree, int k)
heap[k] = v; heap[k] = v;
} }
/* =========================================================================== /* ===========================================================================
* Compute the optimal bit lengths for a tree and update the total bit length * Compute the optimal bit lengths for a tree and update the total bit length
* for the current block. * for the current block.
@@ -1624,8 +1624,10 @@ static void gen_bitlen(tree_desc * desc)
for (h = heap_max + 1; h < HEAP_SIZE; h++) { for (h = heap_max + 1; h < HEAP_SIZE; h++) {
n = heap[h]; n = heap[h];
bits = tree[tree[n].Dad].Len + 1; bits = tree[tree[n].Dad].Len + 1;
if (bits > max_length) if (bits > max_length) {
bits = max_length, overflow++; bits = max_length;
overflow++;
}
tree[n].Len = (ush) bits; tree[n].Len = (ush) bits;
/* We overwrite tree[n].Dad which is no longer needed */ /* We overwrite tree[n].Dad which is no longer needed */
@@ -2151,7 +2153,7 @@ static void compress_block(ct_data * ltree, ct_data * dtree)
unsigned code; /* the code to send */ unsigned code; /* the code to send */
int extra; /* number of extra bits to send */ int extra; /* number of extra bits to send */
if (last_lit != 0) if (last_lit != 0) {
do { do {
if ((lx & 7) == 0) if ((lx & 7) == 0)
flag = flag_buf[fx++]; flag = flag_buf[fx++];
@@ -2182,6 +2184,7 @@ static void compress_block(ct_data * ltree, ct_data * dtree)
} /* literal or match pair ? */ } /* literal or match pair ? */
flag >>= 1; flag >>= 1;
} while (lx < last_lit); } while (lx < last_lit);
}
send_code(END_BLOCK, ltree); send_code(END_BLOCK, ltree);
} }
@@ -2204,7 +2207,7 @@ static void set_file_type(void)
ascii_freq += dyn_ltree[n++].Freq; ascii_freq += dyn_ltree[n++].Freq;
while (n < LITERALS) while (n < LITERALS)
bin_freq += dyn_ltree[n++].Freq; bin_freq += dyn_ltree[n++].Freq;
*file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII; *file_type = (bin_freq > (ascii_freq >> 2)) ? BINARY : ASCII;
if (*file_type == BINARY && translate_eol) { if (*file_type == BINARY && translate_eol) {
bb_error_msg("-l used on binary file"); bb_error_msg("-l used on binary file");
} }
@@ -2228,8 +2231,9 @@ static int zip(int in, int out)
/* Write the header to the gzip file. See algorithm.doc for the format */ /* Write the header to the gzip file. See algorithm.doc for the format */
method = DEFLATED; method = DEFLATED;
put_header_byte(GZIP_MAGIC[0]); /* magic header */ put_header_byte(0x1f); /* magic header for gzip files, 1F 8B */
put_header_byte(GZIP_MAGIC[1]); put_header_byte(0x8b);
put_header_byte(DEFLATED); /* compression method */ put_header_byte(DEFLATED); /* compression method */
put_header_byte(my_flags); /* general flags */ put_header_byte(my_flags); /* general flags */