From: Denis Vlasenko Date: Sun, 7 Jan 2007 19:38:42 +0000 (-0000) Subject: gzip cleanup part #4 X-Git-Tag: 1_4_0~85 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=f824136f6b21558ac023bc53bcb69294e0676103;p=oweals%2Fbusybox.git gzip cleanup part #4 --- diff --git a/archival/gzip.c b/archival/gzip.c index dcbcae0b3..4f47a2782 100644 --- a/archival/gzip.c +++ b/archival/gzip.c @@ -61,12 +61,6 @@ aa: 85.1% -- replaced with aa.gz # 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 */ #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ #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 Trace(x) 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 Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;} +# define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x ;} #else # define Assert(cond,msg) # define Trace(x) @@ -313,7 +307,7 @@ static void clear_bufs(void) * pointer, then initialize the crc shift register contents instead. * 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) { uint32_t c; /* temporary variable */ @@ -1414,17 +1408,18 @@ static void set_file_type(void); #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) - /* Send a code of the given tree. c and tree must not have side effects */ - #else /* DEBUG */ # 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 #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 * must not have side effects. dist_code[256] and dist_code[257] are never * used. @@ -1432,6 +1427,7 @@ static void set_file_type(void); /* the arguments must not have side effects */ + /* =========================================================================== * Allocate the match buffer, initialize the various tables and save the * location of the internal file attribute (ascii/binary) and method @@ -1513,12 +1509,13 @@ static void ct_init(ush * attr, int *methodp) init_block(); } + /* =========================================================================== * Initialize a new block. */ static void init_block(void) { - int n; /* iterates over tree elements */ + int n; /* iterates over tree elements */ /* Initialize the trees. */ for (n = 0; n < L_CODES; n++) @@ -1535,28 +1532,22 @@ static void init_block(void) 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 * 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) \ -{\ - top = heap[SMALLEST]; \ - heap[SMALLEST] = heap[heap_len--]; \ - pqdownheap(tree, SMALLEST); \ +{ \ + top = heap[SMALLEST]; \ + heap[SMALLEST] = heap[heap_len--]; \ + 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, @@ -1564,6 +1555,14 @@ static void init_block(void) * when the heap property is re-established (each father smaller than its * 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) { int v = heap[k]; @@ -1588,6 +1587,7 @@ static void pqdownheap(ct_data * tree, int k) heap[k] = v; } + /* =========================================================================== * Compute the optimal bit lengths for a tree and update the total bit length * for the current block. @@ -1624,8 +1624,10 @@ static void gen_bitlen(tree_desc * desc) for (h = heap_max + 1; h < HEAP_SIZE; h++) { n = heap[h]; bits = tree[tree[n].Dad].Len + 1; - if (bits > max_length) - bits = max_length, overflow++; + if (bits > max_length) { + bits = max_length; + overflow++; + } tree[n].Len = (ush) bits; /* 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 */ int extra; /* number of extra bits to send */ - if (last_lit != 0) + if (last_lit != 0) { do { if ((lx & 7) == 0) flag = flag_buf[fx++]; @@ -2182,6 +2184,7 @@ static void compress_block(ct_data * ltree, ct_data * dtree) } /* literal or match pair ? */ flag >>= 1; } while (lx < last_lit); + } send_code(END_BLOCK, ltree); } @@ -2204,7 +2207,7 @@ static void set_file_type(void) ascii_freq += dyn_ltree[n++].Freq; while (n < LITERALS) 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) { 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 */ method = DEFLATED; - put_header_byte(GZIP_MAGIC[0]); /* magic header */ - put_header_byte(GZIP_MAGIC[1]); + put_header_byte(0x1f); /* magic header for gzip files, 1F 8B */ + put_header_byte(0x8b); + put_header_byte(DEFLATED); /* compression method */ put_header_byte(my_flags); /* general flags */