1 files changed, 341 insertions, 353 deletions
diff --git a/archival/gzip.c b/archival/gzip.c
index c882a4a2a..034bda005 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -201,7 +201,8 @@ typedef unsigned IPos;
        array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type)); \
 }
-#define FREE(array) { \
+#define FREE(array) \
+{ \
        free(array); \
        array = NULL; \
 }
@@ -272,21 +273,6 @@ enum {
 };
-/* ===========================================================================
- */
-static void fill_window(void);
-static int longest_match(IPos cur_match);
-#ifdef DEBUG
-static void check_match(IPos start, IPos match, int length);
-#endif
-/* from trees.c */
-static int ct_tally(int dist, int lc);
-static ulg flush_block(char *buf, ulg stored_len, int eof);
 /* global buffers */
 /* To save memory for 16 bit systems, some arrays are overlaid between
@@ -586,6 +572,65 @@ static void copy_block(char *buf, unsigned len, int header)
 /* ===========================================================================
+ * Fill the window when the lookahead becomes insufficient.
+ * Updates strstart and lookahead, and sets eofile if end of input file.
+ * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
+ * OUT assertions: at least one byte has been read, or eofile is set;
+ *    file reads are performed for at least two bytes (required for the
+ *    translate_eol option).
+ */
+static void fill_window(void)
+{
+        unsigned n, m;
+        unsigned more = WINDOW_SIZE - lookahead - strstart;
+        /* Amount of free space at the end of the window. */
+        /* If the window is almost full and there is insufficient lookahead,
+         * move the upper half to the lower one to make room in the upper half.
+         */
+        if (more == (unsigned) -1) {
+                /* Very unlikely, but possible on 16 bit machine if strstart == 0
+                 * and lookahead == 1 (input done one byte at time)
+                 */
+                more--;
+        } else if (strstart >= WSIZE + MAX_DIST) {
+                /* By the IN assertion, the window is not empty so we can't confuse
+                 * more == 0 with more == 64K on a 16 bit machine.
+                 */
+                Assert(WINDOW_SIZE == 2 * WSIZE, "no sliding with BIG_MEM");
+                memcpy(window, window + WSIZE, WSIZE);
+                match_start -= WSIZE;
+                strstart -= WSIZE;      /* we now have strstart >= MAX_DIST: */
+                block_start -= WSIZE;
+                for (n = 0; n < HASH_SIZE; n++) {
+                        m = head[n];
+                        head[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
+                }
+                for (n = 0; n < WSIZE; n++) {
+                        m = prev[n];
+                        prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
+                        /* If n is not on any hash chain, prev[n] is garbage but
+                         * its value will never be used.
+                         */
+                }
+                more += WSIZE;
+        }
+        /* At this point, more >= 2 */
+        if (!eofile) {
+                n = file_read(window + strstart + lookahead, more);
+                if (n == 0 || n == (unsigned) -1) {
+                        eofile = 1;
+                } else {
+                        lookahead += n;
+                }
+        }
+}
+/* ===========================================================================
 * Update a hash value with the given input byte
 * IN  assertion: all calls to to UPDATE_HASH are made with consecutive
 *    input characters, so that a running hash key can be computed from the
@@ -746,202 +791,6 @@ static void check_match(IPos start, IPos match, int length)
 #endif
-/* ===========================================================================
- * Fill the window when the lookahead becomes insufficient.
- * Updates strstart and lookahead, and sets eofile if end of input file.
- * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
- * OUT assertions: at least one byte has been read, or eofile is set;
- *    file reads are performed for at least two bytes (required for the
- *    translate_eol option).
- */
-static void fill_window(void)
-{
-        unsigned n, m;
-        unsigned more = WINDOW_SIZE - lookahead - strstart;
-        /* Amount of free space at the end of the window. */
-        /* If the window is almost full and there is insufficient lookahead,
-         * move the upper half to the lower one to make room in the upper half.
-         */
-        if (more == (unsigned) -1) {
-                /* Very unlikely, but possible on 16 bit machine if strstart == 0
-                 * and lookahead == 1 (input done one byte at time)
-                 */
-                more--;
-        } else if (strstart >= WSIZE + MAX_DIST) {
-                /* By the IN assertion, the window is not empty so we can't confuse
-                 * more == 0 with more == 64K on a 16 bit machine.
-                 */
-                Assert(WINDOW_SIZE == 2 * WSIZE, "no sliding with BIG_MEM");
-                memcpy(window, window + WSIZE, WSIZE);
-                match_start -= WSIZE;
-                strstart -= WSIZE;      /* we now have strstart >= MAX_DIST: */
-                block_start -= WSIZE;
-                for (n = 0; n < HASH_SIZE; n++) {
-                        m = head[n];
-                        head[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
-                }
-                for (n = 0; n < WSIZE; n++) {
-                        m = prev[n];
-                        prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
-                        /* If n is not on any hash chain, prev[n] is garbage but
-                         * its value will never be used.
-                         */
-                }
-                more += WSIZE;
-        }
-        /* At this point, more >= 2 */
-        if (!eofile) {
-                n = file_read(window + strstart + lookahead, more);
-                if (n == 0 || n == (unsigned) -1) {
-                        eofile = 1;
-                } else {
-                        lookahead += n;
-                }
-        }
-}
-/* ===========================================================================
- * Same as above, but achieves better compression. We use a lazy
- * evaluation for matches: a match is finally adopted only if there is
- * no better match at the next window position.
- *
- * Processes a new input file and return its compressed length. Sets
- * the compressed length, crc, deflate flags and internal file
- * attributes.
- */
-/* Flush the current block, with given end-of-file flag.
- * IN assertion: strstart is set to the end of the current match. */
-#define FLUSH_BLOCK(eof) \
-        flush_block( \
-                block_start >= 0L \
-                        ? (char*)&window[(unsigned)block_start] \
-                        : (char*)NULL, \
-                (long)strstart - block_start, \
-                (eof) \
-        )
-/* Insert string s in the dictionary and set match_head to the previous head
- * of the hash chain (the most recent string with same hash key). Return
- * the previous length of the hash chain.
- * IN  assertion: all calls to to INSERT_STRING are made with consecutive
- *    input characters and the first MIN_MATCH bytes of s are valid
- *    (except for the last MIN_MATCH-1 bytes of the input file). */
-#define INSERT_STRING(s, match_head) \
-{ \
-        UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]); \
-        prev[(s) & WMASK] = match_head = head[ins_h]; \
-        head[ins_h] = (s); \
-}
-static ulg deflate(void)
-{
-        IPos hash_head;         /* head of hash chain */
-        IPos prev_match;        /* previous match */
-        int flush;                      /* set if current block must be flushed */
-        int match_available = 0;        /* set if previous match exists */
-        unsigned match_length = MIN_MATCH - 1;  /* length of best match */
-        /* Process the input block. */
-        while (lookahead != 0) {
-                /* Insert the string window[strstart .. strstart+2] in the
-                 * dictionary, and set hash_head to the head of the hash chain:
-                 */
-                INSERT_STRING(strstart, hash_head);
-                /* Find the longest match, discarding those <= prev_length.
-                 */
-                prev_length = match_length, prev_match = match_start;
-                match_length = MIN_MATCH - 1;
-                if (hash_head != 0 && prev_length < max_lazy_match
-                 && strstart - hash_head <= MAX_DIST
-                ) {
-                        /* To simplify the code, we prevent matches with the string
-                         * of window index 0 (in particular we have to avoid a match
-                         * of the string with itself at the start of the input file).
-                         */
-                        match_length = longest_match(hash_head);
-                        /* longest_match() sets match_start */
-                        if (match_length > lookahead)
-                                match_length = lookahead;
-                        /* Ignore a length 3 match if it is too distant: */
-                        if (match_length == MIN_MATCH && strstart - match_start > TOO_FAR) {
-                                /* If prev_match is also MIN_MATCH, match_start is garbage
-                                 * but we will ignore the current match anyway.
-                                 */
-                                match_length--;
-                        }
-                }
-                /* If there was a match at the previous step and the current
-                 * match is not better, output the previous match:
-                 */
-                if (prev_length >= MIN_MATCH && match_length <= prev_length) {
-                        check_match(strstart - 1, prev_match, prev_length);
-                        flush = ct_tally(strstart - 1 - prev_match, prev_length - MIN_MATCH);
-                        /* Insert in hash table all strings up to the end of the match.
-                         * strstart-1 and strstart are already inserted.
-                         */
-                        lookahead -= prev_length - 1;
-                        prev_length -= 2;
-                        do {
-                                strstart++;
-                                INSERT_STRING(strstart, hash_head);
-                                /* strstart never exceeds WSIZE-MAX_MATCH, so there are
-                                 * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
-                                 * these bytes are garbage, but it does not matter since the
-                                 * next lookahead bytes will always be emitted as literals.
-                                 */
-                        } while (--prev_length != 0);
-                        match_available = 0;
-                        match_length = MIN_MATCH - 1;
-                        strstart++;
-                        if (flush) {
-                                FLUSH_BLOCK(0);
-                                block_start = strstart;
-                        }
-                } else if (match_available) {
-                        /* If there was no match at the previous position, output a
-                         * single literal. If there was a match but the current match
-                         * is longer, truncate the previous match to a single literal.
-                         */
-                        Tracevv((stderr, "%c", window[strstart - 1]));
-                        if (ct_tally(0, window[strstart - 1])) {
-                                FLUSH_BLOCK(0);
-                                block_start = strstart;
-                        }
-                        strstart++;
-                        lookahead--;
-                } else {
-                        /* There is no previous match to compare with, wait for
-                         * the next step to decide.
-                         */
-                        match_available = 1;
-                        strstart++;
-                        lookahead--;
-                }
-                Assert(strstart <= isize && lookahead <= isize, "a bit too far");
-                /* Make sure that we always have enough lookahead, except
-                 * at the end of the input file. We need MAX_MATCH bytes
-                 * for the next match, plus MIN_MATCH bytes to insert the
-                 * string following the next match.
-                 */
-                while (lookahead < MIN_LOOKAHEAD && !eofile)
-                        fill_window();
-        }
-        if (match_available)
-                ct_tally(0, window[strstart - 1]);
-        return FLUSH_BLOCK(1);  /* eof */
-}
 /* trees.c -- output deflated data using Huffman coding
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * This is free software; you can redistribute it and/or modify it under the
@@ -991,10 +840,6 @@ static ulg deflate(void)
 *          file. Returns the total compressed length for the file so far.
 */
-/* ===========================================================================
- * Constants
- */
 #define MAX_BITS 15
 /* All codes must not exceed MAX_BITS bits */
@@ -1087,9 +932,7 @@ static const extra_bits_t extra_blbits[BL_CODES] = {
 /* repeat a zero length 11-138 times  (7 bits of repeat count) */
 /* ===========================================================================
- * Local data
+*/
- */
 /* Data structure describing a single value and its code string. */
 typedef struct ct_data {
        union {
@@ -1231,8 +1074,6 @@ static int *file_method;	/* pointer to DEFLATE or STORE */
 /* ===========================================================================
 */
-static void init_block(void);
-static void gen_bitlen(tree_desc * desc);
 static void gen_codes(ct_data * tree, int max_code);
 static void build_tree(tree_desc * desc);
 static void scan_tree(ct_data * tree, int max_code);
@@ -1240,7 +1081,6 @@ static void send_tree(ct_data * tree, int max_code);
 static int build_bl_tree(void);
 static void send_all_trees(int lcodes, int dcodes, int blcodes);
 static void compress_block(ct_data * ltree, ct_data * dtree);
-static void set_file_type(void);
 #ifndef DEBUG
@@ -1259,9 +1099,31 @@ static void set_file_type(void);
 /* 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.
+ * The arguments must not have side effects.
+ */
+/* ===========================================================================
+ * Initialize a new block.
 */
+static void init_block(void)
+{
+        int n; /* iterates over tree elements */
-/* the arguments must not have side effects */
+        /* Initialize the trees. */
+        for (n = 0; n < L_CODES; n++)
+                dyn_ltree[n].Freq = 0;
+        for (n = 0; n < D_CODES; n++)
+                dyn_dtree[n].Freq = 0;
+        for (n = 0; n < BL_CODES; n++)
+                bl_tree[n].Freq = 0;
+        dyn_ltree[END_BLOCK].Freq = 1;
+        opt_len = static_len = 0L;
+        last_lit = last_dist = last_flags = 0;
+        flags = 0;
+        flag_bit = 1;
+}
 /* ===========================================================================
@@ -1289,7 +1151,7 @@ static void ct_init(ush * attr, int *methodp)
        for (code = 0; code < LENGTH_CODES - 1; code++) {
                base_length[code] = length;
                for (n = 0; n < (1 << extra_lbits[code]); n++) {
-                        length_code[length++] = (uch) code;
+                        length_code[length++] = code;
                }
        }
        Assert(length == 256, "ct_init: length != 256");
@@ -1297,7 +1159,7 @@ static void ct_init(ush * attr, int *methodp)
         * in two different ways: code 284 + 5 bits or code 285, so we
         * overwrite length_code[255] to use the best encoding:
         */
-        length_code[length - 1] = (uch) code;
+        length_code[length - 1] = code;
        /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
        dist = 0;
@@ -1356,29 +1218,6 @@ static void ct_init(ush * attr, int *methodp)
 /* ===========================================================================
- * Initialize a new block.
- */
-static void init_block(void)
-{
-        int n; /* iterates over tree elements */
-        /* Initialize the trees. */
-        for (n = 0; n < L_CODES; n++)
-                dyn_ltree[n].Freq = 0;
-        for (n = 0; n < D_CODES; n++)
-                dyn_dtree[n].Freq = 0;
-        for (n = 0; n < BL_CODES; n++)
-                bl_tree[n].Freq = 0;
-        dyn_ltree[END_BLOCK].Freq = 1;
-        opt_len = static_len = 0L;
-        last_lit = last_dist = last_flags = 0;
-        flags = 0;
-        flag_bit = 1;
-}
-/* ===========================================================================
 * Restore the heap property by moving down the tree starting at node k,
 * exchanging a node with the smallest of its two sons if necessary, stopping
 * when the heap property is re-established (each father smaller than its
@@ -1470,7 +1309,7 @@ static void gen_bitlen(tree_desc * desc)
                opt_len += (ulg) f *(bits + xbits);
                if (stree)
-                        static_len += (ulg) f *(stree[n].Len + xbits);
+                        static_len += (ulg) f * (stree[n].Len + xbits);
        }
        if (overflow == 0)
                return;
@@ -1513,6 +1352,7 @@ static void gen_bitlen(tree_desc * desc)
        }
 }
 /* ===========================================================================
 * Generate the codes for a given tree and bit counts (which need not be
 * optimal).
@@ -1556,6 +1396,7 @@ static void gen_codes(ct_data * tree, int max_code)
        }
 }
 /* ===========================================================================
 * Construct one Huffman tree and assigns the code bit strings and lengths.
 * Update the total bit length for the current block.
@@ -1662,6 +1503,7 @@ static void build_tree(tree_desc * desc)
        gen_codes((ct_data *) tree, max_code);
 }
 /* ===========================================================================
 * Scan a literal or distance tree to determine the frequencies of the codes
 * in the bit length tree. Updates opt_len to take into account the repeat
@@ -1715,6 +1557,7 @@ static void scan_tree(ct_data * tree, int max_code)
        }
 }
 /* ===========================================================================
 * Send a literal or distance tree in compressed form, using the codes in
 * bl_tree.
@@ -1772,6 +1615,7 @@ static void send_tree(ct_data * tree, int max_code)
        }
 }
 /* ===========================================================================
 * Construct the Huffman tree for the bit lengths and return the index in
 * bl_order of the last bit length code to send.
@@ -1805,6 +1649,7 @@ static int build_bl_tree(void)
        return max_blindex;
 }
 /* ===========================================================================
 * Send the header for a block using dynamic Huffman trees: the counts, the
 * lengths of the bit length codes, the literal tree and the distance tree.
@@ -1834,100 +1679,32 @@ static void send_all_trees(int lcodes, int dcodes, int blcodes)
        Tracev((stderr, "\ndist tree: sent %ld", bits_sent));
 }
 /* ===========================================================================
- * Determine the best encoding for the current block: dynamic trees, static
+ * Set the file type to ASCII or BINARY, using a crude approximation:
- * trees or store, and output the encoded block to the zip file. This function
+ * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
- * returns the total compressed length for the file so far.
+ * IN assertion: the fields freq of dyn_ltree are set and the total of all
+ * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
 */
-static ulg flush_block(char *buf, ulg stored_len, int eof)
+static void set_file_type(void)
 {
-        ulg opt_lenb, static_lenb;      /* opt_len and static_len in bytes */
+        int n = 0;
-        int max_blindex;        /* index of last bit length code of non zero freq */
+        unsigned ascii_freq = 0;
+        unsigned bin_freq = 0;
-        flag_buf[last_flags] = flags;   /* Save the flags for the last 8 items */
-        /* Check if the file is ascii or binary */
-        if (*file_type == (ush) UNKNOWN)
-                set_file_type();
-        /* Construct the literal and distance trees */
-        build_tree((tree_desc *) (&l_desc));
-        Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));
-        build_tree((tree_desc *) (&d_desc));
-        Tracev((stderr, "\ndist data: dyn %ld, stat %ld", opt_len, static_len));
-        /* At this point, opt_len and static_len are the total bit lengths of
-         * the compressed block data, excluding the tree representations.
-         */
-        /* Build the bit length tree for the above two trees, and get the index
-         * in bl_order of the last bit length code to send.
-         */
-        max_blindex = build_bl_tree();
-        /* Determine the best encoding. Compute first the block length in bytes */
-        opt_lenb = (opt_len + 3 + 7) >> 3;
-        static_lenb = (static_len + 3 + 7) >> 3;
-        Trace((stderr,
-                   "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
-                   opt_lenb, opt_len, static_lenb, static_len, stored_len,
-                   last_lit, last_dist));
-        if (static_lenb <= opt_lenb)
-                opt_lenb = static_lenb;
-        /* If compression failed and this is the first and last block,
-         * and if the zip file can be seeked (to rewrite the local header),
-         * the whole file is transformed into a stored file:
-         */
-        if (stored_len <= opt_lenb && eof && compressed_len == 0L && seekable()) {
-                /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
-                if (buf == NULL)
-                        bb_error_msg("block vanished");
-                copy_block(buf, (unsigned) stored_len, 0);      /* without header */
-                compressed_len = stored_len << 3;
-                *file_method = STORED;
-        } else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) {
-                /* 4: two words for the lengths */
-                /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
-                 * Otherwise we can't have processed more than WSIZE input bytes since
-                 * the last block flush, because compression would have been
-                 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
-                 * transform a block into a stored block.
-                 */
-                send_bits((STORED_BLOCK << 1) + eof, 3);        /* send block type */
-                compressed_len = (compressed_len + 3 + 7) & ~7L;
-                compressed_len += (stored_len + 4) << 3;
-                copy_block(buf, (unsigned) stored_len, 1);      /* with header */
-        } else if (static_lenb == opt_lenb) {
-                send_bits((STATIC_TREES << 1) + eof, 3);
-                compress_block((ct_data *) static_ltree, (ct_data *) static_dtree);
-                compressed_len += 3 + static_len;
-        } else {
-                send_bits((DYN_TREES << 1) + eof, 3);
-                send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1,
-                                           max_blindex + 1);
-                compress_block((ct_data *) dyn_ltree, (ct_data *) dyn_dtree);
-                compressed_len += 3 + opt_len;
-        }
-        Assert(compressed_len == bits_sent, "bad compressed size");
-        init_block();
-        if (eof) {
+        while (n < 7)
-                bi_windup();
+                bin_freq += dyn_ltree[n++].Freq;
-                compressed_len += 7;    /* align on byte boundary */
+        while (n < 128)
+                ascii_freq += dyn_ltree[n++].Freq;
+        while (n < LITERALS)
+                bin_freq += dyn_ltree[n++].Freq;
+        *file_type = (bin_freq > (ascii_freq >> 2)) ? BINARY : ASCII;
+        if (*file_type == BINARY && translate_eol) {
+                bb_error_msg("-l used on binary file");
        }
-        Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3,
-                        compressed_len - 7 * eof));
-        return compressed_len >> 3;
 }
 /* ===========================================================================
 * Save the match info and tally the frequency counts. Return true if
 * the current block must be flushed.
@@ -2034,30 +1811,241 @@ static void compress_block(ct_data * ltree, ct_data * dtree)
        SEND_CODE(END_BLOCK, ltree);
 }
 /* ===========================================================================
- * Set the file type to ASCII or BINARY, using a crude approximation:
+ * Determine the best encoding for the current block: dynamic trees, static
- * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
+ * trees or store, and output the encoded block to the zip file. This function
- * IN assertion: the fields freq of dyn_ltree are set and the total of all
+ * returns the total compressed length for the file so far.
- * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
 */
-static void set_file_type(void)
+static ulg flush_block(char *buf, ulg stored_len, int eof)
 {
-        int n = 0;
+        ulg opt_lenb, static_lenb;      /* opt_len and static_len in bytes */
-        unsigned ascii_freq = 0;
+        int max_blindex;        /* index of last bit length code of non zero freq */
-        unsigned bin_freq = 0;
-        while (n < 7)
+        flag_buf[last_flags] = flags;   /* Save the flags for the last 8 items */
-                bin_freq += dyn_ltree[n++].Freq;
-        while (n < 128)
+        /* Check if the file is ascii or binary */
-                ascii_freq += dyn_ltree[n++].Freq;
+        if (*file_type == (ush) UNKNOWN)
-        while (n < LITERALS)
+                set_file_type();
-                bin_freq += dyn_ltree[n++].Freq;
-        *file_type = (bin_freq > (ascii_freq >> 2)) ? BINARY : ASCII;
+        /* Construct the literal and distance trees */
-        if (*file_type == BINARY && translate_eol) {
+        build_tree((tree_desc *) (&l_desc));
-                bb_error_msg("-l used on binary file");
+        Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));
+        build_tree((tree_desc *) (&d_desc));
+        Tracev((stderr, "\ndist data: dyn %ld, stat %ld", opt_len, static_len));
+        /* At this point, opt_len and static_len are the total bit lengths of
+         * the compressed block data, excluding the tree representations.
+         */
+        /* Build the bit length tree for the above two trees, and get the index
+         * in bl_order of the last bit length code to send.
+         */
+        max_blindex = build_bl_tree();
+        /* Determine the best encoding. Compute first the block length in bytes */
+        opt_lenb = (opt_len + 3 + 7) >> 3;
+        static_lenb = (static_len + 3 + 7) >> 3;
+        Trace((stderr,
+                   "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
+                   opt_lenb, opt_len, static_lenb, static_len, stored_len,
+                   last_lit, last_dist));
+        if (static_lenb <= opt_lenb)
+                opt_lenb = static_lenb;
+        /* If compression failed and this is the first and last block,
+         * and if the zip file can be seeked (to rewrite the local header),
+         * the whole file is transformed into a stored file:
+         */
+        if (stored_len <= opt_lenb && eof && compressed_len == 0L && seekable()) {
+                /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
+                if (buf == NULL)
+                        bb_error_msg("block vanished");
+                copy_block(buf, (unsigned) stored_len, 0);      /* without header */
+                compressed_len = stored_len << 3;
+                *file_method = STORED;
+        } else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) {
+                /* 4: two words for the lengths */
+                /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
+                 * Otherwise we can't have processed more than WSIZE input bytes since
+                 * the last block flush, because compression would have been
+                 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
+                 * transform a block into a stored block.
+                 */
+                send_bits((STORED_BLOCK << 1) + eof, 3);        /* send block type */
+                compressed_len = (compressed_len + 3 + 7) & ~7L;
+                compressed_len += (stored_len + 4) << 3;
+                copy_block(buf, (unsigned) stored_len, 1);      /* with header */
+        } else if (static_lenb == opt_lenb) {
+                send_bits((STATIC_TREES << 1) + eof, 3);
+                compress_block((ct_data *) static_ltree, (ct_data *) static_dtree);
+                compressed_len += 3 + static_len;
+        } else {
+                send_bits((DYN_TREES << 1) + eof, 3);
+                send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1,
+                                           max_blindex + 1);
+                compress_block((ct_data *) dyn_ltree, (ct_data *) dyn_dtree);
+                compressed_len += 3 + opt_len;
+        }
+        Assert(compressed_len == bits_sent, "bad compressed size");
+        init_block();
+        if (eof) {
+                bi_windup();
+                compressed_len += 7;    /* align on byte boundary */
+        }
+        Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3,
+                        compressed_len - 7 * eof));
+        return compressed_len >> 3;
+}
+/* ===========================================================================
+ * Same as above, but achieves better compression. We use a lazy
+ * evaluation for matches: a match is finally adopted only if there is
+ * no better match at the next window position.
+ *
+ * Processes a new input file and return its compressed length. Sets
+ * the compressed length, crc, deflate flags and internal file
+ * attributes.
+ */
+/* Flush the current block, with given end-of-file flag.
+ * IN assertion: strstart is set to the end of the current match. */
+#define FLUSH_BLOCK(eof) \
+        flush_block( \
+                block_start >= 0L \
+                        ? (char*)&window[(unsigned)block_start] \
+                        : (char*)NULL, \
+                (long)strstart - block_start, \
+                (eof) \
+        )
+/* Insert string s in the dictionary and set match_head to the previous head
+ * of the hash chain (the most recent string with same hash key). Return
+ * the previous length of the hash chain.
+ * IN  assertion: all calls to to INSERT_STRING are made with consecutive
+ *    input characters and the first MIN_MATCH bytes of s are valid
+ *    (except for the last MIN_MATCH-1 bytes of the input file). */
+#define INSERT_STRING(s, match_head) \
+{ \
+        UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]); \
+        prev[(s) & WMASK] = match_head = head[ins_h]; \
+        head[ins_h] = (s); \
+}
+static ulg deflate(void)
+{
+        IPos hash_head;         /* head of hash chain */
+        IPos prev_match;        /* previous match */
+        int flush;                      /* set if current block must be flushed */
+        int match_available = 0;        /* set if previous match exists */
+        unsigned match_length = MIN_MATCH - 1;  /* length of best match */
+        /* Process the input block. */
+        while (lookahead != 0) {
+                /* Insert the string window[strstart .. strstart+2] in the
+                 * dictionary, and set hash_head to the head of the hash chain:
+                 */
+                INSERT_STRING(strstart, hash_head);
+                /* Find the longest match, discarding those <= prev_length.
+                 */
+                prev_length = match_length, prev_match = match_start;
+                match_length = MIN_MATCH - 1;
+                if (hash_head != 0 && prev_length < max_lazy_match
+                 && strstart - hash_head <= MAX_DIST
+                ) {
+                        /* To simplify the code, we prevent matches with the string
+                         * of window index 0 (in particular we have to avoid a match
+                         * of the string with itself at the start of the input file).
+                         */
+                        match_length = longest_match(hash_head);
+                        /* longest_match() sets match_start */
+                        if (match_length > lookahead)
+                                match_length = lookahead;
+                        /* Ignore a length 3 match if it is too distant: */
+                        if (match_length == MIN_MATCH && strstart - match_start > TOO_FAR) {
+                                /* If prev_match is also MIN_MATCH, match_start is garbage
+                                 * but we will ignore the current match anyway.
+                                 */
+                                match_length--;
+                        }
+                }
+                /* If there was a match at the previous step and the current
+                 * match is not better, output the previous match:
+                 */
+                if (prev_length >= MIN_MATCH && match_length <= prev_length) {
+                        check_match(strstart - 1, prev_match, prev_length);
+                        flush = ct_tally(strstart - 1 - prev_match, prev_length - MIN_MATCH);
+                        /* Insert in hash table all strings up to the end of the match.
+                         * strstart-1 and strstart are already inserted.
+                         */
+                        lookahead -= prev_length - 1;
+                        prev_length -= 2;
+                        do {
+                                strstart++;
+                                INSERT_STRING(strstart, hash_head);
+                                /* strstart never exceeds WSIZE-MAX_MATCH, so there are
+                                 * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
+                                 * these bytes are garbage, but it does not matter since the
+                                 * next lookahead bytes will always be emitted as literals.
+                                 */
+                        } while (--prev_length != 0);
+                        match_available = 0;
+                        match_length = MIN_MATCH - 1;
+                        strstart++;
+                        if (flush) {
+                                FLUSH_BLOCK(0);
+                                block_start = strstart;
+                        }
+                } else if (match_available) {
+                        /* If there was no match at the previous position, output a
+                         * single literal. If there was a match but the current match
+                         * is longer, truncate the previous match to a single literal.
+                         */
+                        Tracevv((stderr, "%c", window[strstart - 1]));
+                        if (ct_tally(0, window[strstart - 1])) {
+                                FLUSH_BLOCK(0);
+                                block_start = strstart;
+                        }
+                        strstart++;
+                        lookahead--;
+                } else {
+                        /* There is no previous match to compare with, wait for
+                         * the next step to decide.
+                         */
+                        match_available = 1;
+                        strstart++;
+                        lookahead--;
+                }
+                Assert(strstart <= isize && lookahead <= isize, "a bit too far");
+                /* Make sure that we always have enough lookahead, except
+                 * at the end of the input file. We need MAX_MATCH bytes
+                 * for the next match, plus MIN_MATCH bytes to insert the
+                 * string following the next match.
+                 */
+                while (lookahead < MIN_LOOKAHEAD && !eofile)
+                        fill_window();
        }
+        if (match_available)
+                ct_tally(0, window[strstart - 1]);
+        return FLUSH_BLOCK(1);  /* eof */
 }
 /* ===========================================================================
 * Deflate in to out.
 * IN assertions: the input and output buffers are cleared.