|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 1/8] gzip: clean up comments and fix code alignment
This commit cleans up the comments and fixes the code alignment using Xen
coding style. This is done to make the code more legible before refactoring.
Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
xen/common/gzip/gunzip.c | 14 +-
xen/common/gzip/inflate.c | 787 +++++++++++++++++++-------------------
2 files changed, 406 insertions(+), 395 deletions(-)
diff --git a/xen/common/gzip/gunzip.c b/xen/common/gzip/gunzip.c
index 53cee9ee178a..d07c451cd875 100644
--- a/xen/common/gzip/gunzip.c
+++ b/xen/common/gzip/gunzip.c
@@ -54,11 +54,10 @@ static __init void error(const char *x)
static __init int fill_inbuf(void)
{
- error("ran out of input data");
- return 0;
+ error("ran out of input data");
+ return 0;
}
-
#include "inflate.c"
static __init void flush_window(void)
@@ -122,3 +121,12 @@ __init int perform_gunzip(char *output, char *image,
unsigned long image_len)
return rc;
}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/common/gzip/inflate.c b/xen/common/gzip/inflate.c
index a03903f73116..220d2ff4d9d9 100644
--- a/xen/common/gzip/inflate.c
+++ b/xen/common/gzip/inflate.c
@@ -1,11 +1,13 @@
#define DEBG(x)
#define DEBG1(x)
-/* inflate.c -- Not copyrighted 1992 by Mark Adler
- version c10p1, 10 January 1993 */
+/*
+ * inflate.c -- Not copyrighted 1992 by Mark Adler
+ * version c10p1, 10 January 1993
+ */
-/*
+/*
* Adapted for booting Linux by Hannu Savolainen 1993
- * based on gzip-1.0.3
+ * based on gzip-1.0.3
*
* Nicolas Pitre <nico@xxxxxxx>, 1999/04/14 :
* Little mods for all variable to reside either into rodata or bss segments
@@ -15,92 +17,91 @@
*/
/*
- Inflate deflated (PKZIP's method 8 compressed) data. The compression
- method searches for as much of the current string of bytes (up to a
- length of 258) in the previous 32 K bytes. If it doesn't find any
- matches (of at least length 3), it codes the next byte. Otherwise, it
- codes the length of the matched string and its distance backwards from
- the current position. There is a single Huffman code that codes both
- single bytes (called "literals") and match lengths. A second Huffman
- code codes the distance information, which follows a length code. Each
- length or distance code actually represents a base value and a number
- of "extra" (sometimes zero) bits to get to add to the base value. At
- the end of each deflated block is a special end-of-block (EOB) literal/
- length code. The decoding process is basically: get a literal/length
- code; if EOB then done; if a literal, emit the decoded byte; if a
- length then get the distance and emit the referred-to bytes from the
- sliding window of previously emitted data.
-
- There are (currently) three kinds of inflate blocks: stored, fixed, and
- dynamic. The compressor deals with some chunk of data at a time, and
- decides which method to use on a chunk-by-chunk basis. A chunk might
- typically be 32 K or 64 K. If the chunk is incompressible, then the
- "stored" method is used. In this case, the bytes are simply stored as
- is, eight bits per byte, with none of the above coding. The bytes are
- preceded by a count, since there is no longer an EOB code.
-
- If the data is compressible, then either the fixed or dynamic methods
- are used. In the dynamic method, the compressed data is preceded by
- an encoding of the literal/length and distance Huffman codes that are
- to be used to decode this block. The representation is itself Huffman
- coded, and so is preceded by a description of that code. These code
- descriptions take up a little space, and so for small blocks, there is
- a predefined set of codes, called the fixed codes. The fixed method is
- used if the block codes up smaller that way (usually for quite small
- chunks), otherwise the dynamic method is used. In the latter case, the
- codes are customized to the probabilities in the current block, and so
- can code it much better than the pre-determined fixed codes.
-
- The Huffman codes themselves are decoded using a multi-level table
- lookup, in order to maximize the speed of decoding plus the speed of
- building the decoding tables. See the comments below that precede the
- lbits and dbits tuning parameters.
+ * Inflate deflated (PKZIP's method 8 compressed) data. The compression
+ * method searches for as much of the current string of bytes (up to a
+ * length of 258) in the previous 32 K bytes. If it doesn't find any
+ * matches (of at least length 3), it codes the next byte. Otherwise, it
+ * codes the length of the matched string and its distance backwards from
+ * the current position. There is a single Huffman code that codes both
+ * single bytes (called "literals") and match lengths. A second Huffman
+ * code codes the distance information, which follows a length code. Each
+ * length or distance code actually represents a base value and a number
+ * of "extra" (sometimes zero) bits to get to add to the base value. At
+ * the end of each deflated block is a special end-of-block (EOB) literal/
+ * length code. The decoding process is basically: get a literal/length
+ * code; if EOB then done; if a literal, emit the decoded byte; if a
+ * length then get the distance and emit the referred-to bytes from the
+ * sliding window of previously emitted data.
+ *
+ * There are (currently) three kinds of inflate blocks: stored, fixed, and
+ * dynamic. The compressor deals with some chunk of data at a time, and
+ * decides which method to use on a chunk-by-chunk basis. A chunk might
+ * typically be 32 K or 64 K. If the chunk is incompressible, then the
+ * "stored" method is used. In this case, the bytes are simply stored as
+ * is, eight bits per byte, with none of the above coding. The bytes are
+ * preceded by a count, since there is no longer an EOB code.
+ *
+ * If the data is compressible, then either the fixed or dynamic methods
+ * are used. In the dynamic method, the compressed data is preceded by
+ * an encoding of the literal/length and distance Huffman codes that are
+ * to be used to decode this block. The representation is itself Huffman
+ * coded, and so is preceded by a description of that code. These code
+ * descriptions take up a little space, and so for small blocks, there is
+ * a predefined set of codes, called the fixed codes. The fixed method is
+ * used if the block codes up smaller that way (usually for quite small
+ * chunks), otherwise the dynamic method is used. In the latter case, the
+ * codes are customized to the probabilities in the current block, and so
+ * can code it much better than the pre-determined fixed codes.
+ *
+ * The Huffman codes themselves are decoded using a multi-level table
+ * lookup, in order to maximize the speed of decoding plus the speed of
+ * building the decoding tables. See the comments below that precede the
+ * lbits and dbits tuning parameters.
*/
-
/*
- Notes beyond the 1.93a appnote.txt:
-
- 1. Distance pointers never point before the beginning of the output
- stream.
- 2. Distance pointers can point back across blocks, up to 32k away.
- 3. There is an implied maximum of 7 bits for the bit length table and
- 15 bits for the actual data.
- 4. If only one code exists, then it is encoded using one bit. (Zero
- would be more efficient, but perhaps a little confusing.) If two
- codes exist, they are coded using one bit each (0 and 1).
- 5. There is no way of sending zero distance codes--a dummy must be
- sent if there are none. (History: a pre 2.0 version of PKZIP would
- store blocks with no distance codes, but this was discovered to be
- too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
- zero distance codes, which is sent as one code of zero bits in
- length.
- 6. There are up to 286 literal/length codes. Code 256 represents the
- end-of-block. Note however that the static length tree defines
- 288 codes just to fill out the Huffman codes. Codes 286 and 287
- cannot be used though, since there is no length base or extra bits
- defined for them. Similarly, there are up to 30 distance codes.
- However, static trees define 32 codes (all 5 bits) to fill out the
- Huffman codes, but the last two had better not show up in the data.
- 7. Unzip can check dynamic Huffman blocks for complete code sets.
- The exception is that a single code would not be complete (see #4).
- 8. The five bits following the block type is really the number of
- literal codes sent minus 257.
- 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
- (1+6+6). Therefore, to output three times the length, you output
- three codes (1+1+1), whereas to output four times the same length,
- you only need two codes (1+3). Hmm.
- 10. In the tree reconstruction algorithm, Code = Code + Increment
- only if BitLength(i) is not zero. (Pretty obvious.)
- 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
- 12. Note: length code 284 can represent 227-258, but length code 285
- really is 258. The last length deserves its own, short code
- since it gets used a lot in very redundant files. The length
- 258 is special since 258 - 3 (the min match length) is 255.
- 13. The literal/length and distance code bit lengths are read as a
- single stream of lengths. It is possible (and advantageous) for
- a repeat code (16, 17, or 18) to go across the boundary between
- the two sets of lengths.
+ * Notes beyond the 1.93a appnote.txt:
+ *
+ * 1. Distance pointers never point before the beginning of the output
+ * stream.
+ * 2. Distance pointers can point back across blocks, up to 32k away.
+ * 3. There is an implied maximum of 7 bits for the bit length table and
+ * 15 bits for the actual data.
+ * 4. If only one code exists, then it is encoded using one bit. (Zero
+ * would be more efficient, but perhaps a little confusing.) If two
+ * codes exist, they are coded using one bit each (0 and 1).
+ * 5. There is no way of sending zero distance codes--a dummy must be
+ * sent if there are none. (History: a pre 2.0 version of PKZIP would
+ * store blocks with no distance codes, but this was discovered to be
+ * too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
+ * zero distance codes, which is sent as one code of zero bits in
+ * length.
+ * 6. There are up to 286 literal/length codes. Code 256 represents the
+ * end-of-block. Note however that the static length tree defines
+ * 288 codes just to fill out the Huffman codes. Codes 286 and 287
+ * cannot be used though, since there is no length base or extra bits
+ * defined for them. Similarly, there are up to 30 distance codes.
+ * However, static trees define 32 codes (all 5 bits) to fill out the
+ * Huffman codes, but the last two had better not show up in the data.
+ * 7. Unzip can check dynamic Huffman blocks for complete code sets.
+ * The exception is that a single code would not be complete (see #4).
+ * 8. The five bits following the block type is really the number of
+ * literal codes sent minus 257.
+ * 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
+ * (1+6+6). Therefore, to output three times the length, you output
+ * three codes (1+1+1), whereas to output four times the same length,
+ * you only need two codes (1+3). Hmm.
+ * 10. In the tree reconstruction algorithm, Code = Code + Increment
+ * only if BitLength(i) is not zero. (Pretty obvious.)
+ * 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
+ * 12. Note: length code 284 can represent 227-258, but length code 285
+ * really is 258. The last length deserves its own, short code
+ * since it gets used a lot in very redundant files. The length
+ * 258 is special since 258 - 3 (the min match length) is 255.
+ * 13. The literal/length and distance code bit lengths are read as a
+ * single stream of lengths. It is possible (and advantageous) for
+ * a repeat code (16, 17, or 18) to go across the boundary between
+ * the two sets of lengths.
*/
#ifdef RCSID
@@ -120,13 +121,15 @@ static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10
13:27:04 jloup Exp #";
#define slide window
-/* Huffman code lookup table entry--this entry is four bytes for machines
- that have 16-bit pointers (e.g. PC's in the small or medium model).
- Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
- means that v is a literal, 16 < e < 32 means that v is a pointer to
- the next table, which codes e - 16 bits, and lastly e == 99 indicates
- an unused code. If a code with e == 99 is looked up, this implies an
- error in the data. */
+/*
+ * Huffman code lookup table entry--this entry is four bytes for machines
+ * that have 16-bit pointers (e.g. PC's in the small or medium model).
+ * Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
+ * means that v is a literal, 16 < e < 32 means that v is a pointer to
+ * the next table, which codes e - 16 bits, and lastly e == 99 indicates
+ * an unused code. If a code with e == 99 is looked up, this implies an
+ * error in the data.
+ */
struct huft {
uch e; /* number of extra bits or operation */
uch b; /* number of bits in this code or subcode */
@@ -136,7 +139,6 @@ struct huft {
} v;
};
-
/* Function prototypes */
static int huft_build(unsigned *, unsigned, unsigned,
const ush *, const ush *, struct huft **, int *);
@@ -148,15 +150,17 @@ static int inflate_dynamic(void);
static int inflate_block(int *);
static int inflate(void);
-
-/* The inflate algorithm uses a sliding 32 K byte window on the uncompressed
- stream to find repeated byte strings. This is implemented here as a
- circular buffer. The index is updated simply by incrementing and then
- ANDing with 0x7fff (32K-1). */
-/* It is left to other modules to supply the 32 K area. It is assumed
- to be usable as if it were declared "uch slide[32768];" or as just
- "uch *slide;" and then malloc'ed in the latter case. The definition
- must be in unzip.h, included above. */
+/*
+ * The inflate algorithm uses a sliding 32 K byte window on the uncompressed
+ * stream to find repeated byte strings. This is implemented here as a
+ * circular buffer. The index is updated simply by incrementing and then
+ * ANDing with 0x7fff (32K-1).
+ *
+ * It is left to other modules to supply the 32 K area. It is assumed
+ * to be usable as if it were declared "uch slide[32768];" or as just
+ * "uch *slide;" and then malloc'ed in the latter case. The definition
+ * must be in unzip.h, included above.
+ */
/* unsigned wp; current position in slide */
#define wp outcnt
#define flush_output(w) (wp=(w),flush_window())
@@ -180,36 +184,35 @@ static const ush cpdext[] = { /* Extra bits for
distance codes */
7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
12, 12, 13, 13};
-
-
-/* Macros for inflate() bit peeking and grabbing.
- The usage is:
-
- NEEDBITS(j)
- x = b & mask_bits[j];
- DUMPBITS(j)
-
- where NEEDBITS makes sure that b has at least j bits in it, and
- DUMPBITS removes the bits from b. The macros use the variable k
- for the number of bits in b. Normally, b and k are register
- variables for speed, and are initialized at the beginning of a
- routine that uses these macros from a global bit buffer and count.
-
- If we assume that EOB will be the longest code, then we will never
- ask for bits with NEEDBITS that are beyond the end of the stream.
- So, NEEDBITS should not read any more bytes than are needed to
- meet the request. Then no bytes need to be "returned" to the buffer
- at the end of the last block.
-
- However, this assumption is not true for fixed blocks--the EOB code
- is 7 bits, but the other literal/length codes can be 8 or 9 bits.
- (The EOB code is shorter than other codes because fixed blocks are
- generally short. So, while a block always has an EOB, many other
- literal/length codes have a significantly lower probability of
- showing up at all.) However, by making the first table have a
- lookup of seven bits, the EOB code will be found in that first
- lookup, and so will not require that too many bits be pulled from
- the stream.
+/*
+ * Macros for inflate() bit peeking and grabbing.
+ * The usage is:
+ *
+ * NEEDBITS(j)
+ * x = b & mask_bits[j];
+ * DUMPBITS(j)
+ *
+ * where NEEDBITS makes sure that b has at least j bits in it, and
+ * DUMPBITS removes the bits from b. The macros use the variable k
+ * for the number of bits in b. Normally, b and k are register
+ * variables for speed, and are initialized at the beginning of a
+ * routine that uses these macros from a global bit buffer and count.
+ *
+ * If we assume that EOB will be the longest code, then we will never
+ * ask for bits with NEEDBITS that are beyond the end of the stream.
+ * So, NEEDBITS should not read any more bytes than are needed to
+ * meet the request. Then no bytes need to be "returned" to the buffer
+ * at the end of the last block.
+ *
+ * However, this assumption is not true for fixed blocks--the EOB code
+ * is 7 bits, but the other literal/length codes can be 8 or 9 bits.
+ * (The EOB code is shorter than other codes because fixed blocks are
+ * generally short. So, while a block always has an EOB, many other
+ * literal/length codes have a significantly lower probability of
+ * showing up at all.) However, by making the first table have a
+ * lookup of seven bits, the EOB code will be found in that first
+ * lookup, and so will not require that too many bits be pulled from
+ * the stream.
*/
static ulg __initdata bb; /* bit buffer */
@@ -226,60 +229,62 @@ static const ush mask_bits[] = {
#define DUMPBITS(n) {b>>=(n);k-=(n);}
/*
- Huffman code decoding is performed using a multi-level table lookup.
- The fastest way to decode is to simply build a lookup table whose
- size is determined by the longest code. However, the time it takes
- to build this table can also be a factor if the data being decoded
- is not very long. The most common codes are necessarily the
- shortest codes, so those codes dominate the decoding time, and hence
- the speed. The idea is you can have a shorter table that decodes the
- shorter, more probable codes, and then point to subsidiary tables for
- the longer codes. The time it costs to decode the longer codes is
- then traded against the time it takes to make longer tables.
-
- This results of this trade are in the variables lbits and dbits
- below. lbits is the number of bits the first level table for literal/
- length codes can decode in one step, and dbits is the same thing for
- the distance codes. Subsequent tables are also less than or equal to
- those sizes. These values may be adjusted either when all of the
- codes are shorter than that, in which case the longest code length in
- bits is used, or when the shortest code is *longer* than the requested
- table size, in which case the length of the shortest code in bits is
- used.
-
- There are two different values for the two tables, since they code a
- different number of possibilities each. The literal/length table
- codes 286 possible values, or in a flat code, a little over eight
- bits. The distance table codes 30 possible values, or a little less
- than five bits, flat. The optimum values for speed end up being
- about one bit more than those, so lbits is 8+1 and dbits is 5+1.
- The optimum values may differ though from machine to machine, and
- possibly even between compilers. Your mileage may vary.
+ * Huffman code decoding is performed using a multi-level table lookup.
+ * The fastest way to decode is to simply build a lookup table whose
+ * size is determined by the longest code. However, the time it takes
+ * to build this table can also be a factor if the data being decoded
+ * is not very long. The most common codes are necessarily the
+ * shortest codes, so those codes dominate the decoding time, and hence
+ * the speed. The idea is you can have a shorter table that decodes the
+ * shorter, more probable codes, and then point to subsidiary tables for
+ * the longer codes. The time it costs to decode the longer codes is
+ * then traded against the time it takes to make longer tables.
+ *
+ * This results of this trade are in the variables lbits and dbits
+ * below. lbits is the number of bits the first level table for literal/
+ * length codes can decode in one step, and dbits is the same thing for
+ * the distance codes. Subsequent tables are also less than or equal to
+ * those sizes. These values may be adjusted either when all of the
+ * codes are shorter than that, in which case the longest code length in
+ * bits is used, or when the shortest code is *longer* than the requested
+ * table size, in which case the length of the shortest code in bits is
+ * used.
+ *
+ * There are two different values for the two tables, since they code a
+ * different number of possibilities each. The literal/length table
+ * codes 286 possible values, or in a flat code, a little over eight
+ * bits. The distance table codes 30 possible values, or a little less
+ * than five bits, flat. The optimum values for speed end up being
+ * about one bit more than those, so lbits is 8+1 and dbits is 5+1.
+ * The optimum values may differ though from machine to machine, and
+ * possibly even between compilers. Your mileage may vary.
*/
-
static const int lbits = 9; /* bits in base literal/length lookup
table */
static const int dbits = 6; /* bits in base distance lookup table */
-
/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
#define BMAX 16 /* maximum bit length of any code (16 for explode) */
#define N_MAX 288 /* maximum number of codes in any set */
+/*
+ * Given a list of code lengths and a maximum table size, make a set of
+ * tables to decode that set of codes. Return zero on success, one if
+ * the given code set is incomplete (the tables are still built in this
+ * case), two if the input is invalid (all zero length codes or an
+ * oversubscribed set of lengths), and three if not enough memory.
+ *
+ * @param b Code lengths in bits (all assumed <= BMAX)
+ * @param n Number of codes (assumed <= N_MAX)
+ * @param s Number of simple-valued codes (0..s-1)
+ * @param d List of base values for non-simple codes
+ * @param e List of extra bits for non-simple codes
+ * @param t Result: starting table
+ * @param m Maximum lookup bits, returns actual
+ */
static int __init huft_build(
- unsigned *b, /* code lengths in bits (all assumed <= BMAX) */
- unsigned n, /* number of codes (assumed <= N_MAX) */
- unsigned s, /* number of simple-valued codes (0..s-1) */
- const ush *d, /* list of base values for non-simple codes */
- const ush *e, /* list of extra bits for non-simple codes */
- struct huft **t, /* result: starting table */
- int *m /* maximum lookup bits, returns actual */
- )
-/* Given a list of code lengths and a maximum table size, make a set of
- tables to decode that set of codes. Return zero on success, one if
- the given code set is incomplete (the tables are still built in this
- case), two if the input is invalid (all zero length codes or an
- oversubscribed set of lengths), and three if not enough memory. */
+ unsigned *b, unsigned n, unsigned s, const ush *d, const ush *e,
+ struct huft **t, int *m)
{
unsigned a; /* counter for codes of length k */
unsigned f; /* i repeats in table every f entries */
@@ -321,7 +326,7 @@ static int __init huft_build(
memzero(stk->c, sizeof(stk->c));
p = b; i = n;
do {
- Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x
%d\n"),
+ Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x
%d\n"),
n-i, *p));
c[*p]++; /* assume all entries <= BMAX */
p++; /* Can't combine with above line (Solaris
bug) */
@@ -508,18 +513,17 @@ static int __init huft_build(
return ret;
}
-
-
-static int __init huft_free(
- struct huft *t /* table to free */
- )
-/* Free the malloc'ed tables built by huft_build(), which makes a linked
- list of the tables it made, with the links in a dummy first entry of
- each table. */
+/*
+ * Free the malloc'ed tables built by huft_build(), which makes a linked
+ * list of the tables it made, with the links in a dummy first entry of
+ * each table.
+ *
+ * @param t Table to free
+ */
+static int __init huft_free(struct huft *t)
{
register struct huft *p, *q;
-
/* Go through linked list, freeing from the malloced (t[-1]) address. */
p = t;
while (p != (struct huft *)NULL)
@@ -527,19 +531,21 @@ static int __init huft_free(
q = (--p)->v.t;
free((char*)p);
p = q;
- }
+ }
return 0;
}
-
+/*
+ * inflate (decompress) the codes in a deflated (compressed) block.
+ * Return an error code or zero if it all goes ok.
+ *
+ * @param huft tl Literal/length decoder tables
+ * @param huft td Distance decoder tables
+ * @param bl Number of bits decoded by tl[]
+ * @param bd Number of bits decoded by td[]
+ */
static int __init inflate_codes(
- struct huft *tl, /* literal/length decoder tables */
- struct huft *td, /* distance decoder tables */
- int bl, /* number of bits decoded by tl[] */
- int bd /* number of bits decoded by td[] */
- )
-/* inflate (decompress) the codes in a deflated (compressed) block.
- Return an error code or zero if it all goes ok. */
+ struct huft *tl, struct huft *td, int bl, int bd)
{
register unsigned e; /* table entry flag/number of extra bits */
unsigned n, d; /* length and index for copy */
@@ -560,77 +566,76 @@ static int __init inflate_codes(
md = mask_bits[bd];
for (;;) /* do until end of block */
{
- NEEDBITS((unsigned)bl)
- if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
+ NEEDBITS((unsigned)bl);
+ if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
+ do {
+ if (e == 99)
+ return 1;
+ DUMPBITS(t->b);
+ e -= 16;
+ NEEDBITS(e);
+ } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) >
16);
+ DUMPBITS(t->b);
+ if (e == 16) /* then it's a literal */
+ {
+ slide[w++] = (uch)t->v.n;
+ Tracevv((stderr, "%c", slide[w-1]));
+ if (w == WSIZE)
+ {
+ flush_output(w);
+ w = 0;
+ }
+ }
+ else /* it's an EOB or a length */
+ {
+ /* exit if end of block */
+ if (e == 15)
+ break;
+
+ /* get length of block to copy */
+ NEEDBITS(e);
+ n = t->v.n + ((unsigned)b & mask_bits[e]);
+ DUMPBITS(e);
+
+ /* decode distance of block to copy */
+ NEEDBITS((unsigned)bd);
+ if ((e = (t = td + ((unsigned)b & md))->e) > 16)
do {
if (e == 99)
return 1;
- DUMPBITS(t->b)
- e -= 16;
- NEEDBITS(e)
- } while ((e = (t = t->v.t + ((unsigned)b &
mask_bits[e]))->e) > 16);
- DUMPBITS(t->b)
- if (e == 16) /* then it's a literal */
- {
- slide[w++] = (uch)t->v.n;
- Tracevv((stderr, "%c", slide[w-1]));
+ DUMPBITS(t->b);
+ e -= 16;
+ NEEDBITS(e);
+ } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e)
> 16);
+ DUMPBITS(t->b);
+ NEEDBITS(e);
+ d = w - t->v.n - ((unsigned)b & mask_bits[e]);
+ DUMPBITS(e);
+ Tracevv((stderr,"\\[%d,%d]", w-d, n));
+
+ /* do the copy */
+ do {
+ n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n :
e);
+ if (w - d >= e) /* (this test assumes unsigned
comparison) */
+ {
+ memcpy(slide + w, slide + d, e);
+ w += e;
+ d += e;
+ }
+ else /* do it slow to avoid memcpy()
overlap */
+ do {
+ slide[w++] = slide[d++];
+ Tracevv((stderr, "%c", slide[w-1]));
+ } while (--e);
if (w == WSIZE)
{
flush_output(w);
w = 0;
}
- }
- else /* it's an EOB or a length */
- {
- /* exit if end of block */
- if (e == 15)
- break;
-
- /* get length of block to copy */
- NEEDBITS(e)
- n = t->v.n + ((unsigned)b & mask_bits[e]);
- DUMPBITS(e);
-
- /* decode distance of block to copy */
- NEEDBITS((unsigned)bd)
- if ((e = (t = td + ((unsigned)b & md))->e) > 16)
- do {
- if (e == 99)
- return 1;
- DUMPBITS(t->b)
- e -= 16;
- NEEDBITS(e)
- } while ((e = (t = t->v.t + ((unsigned)b &
mask_bits[e]))->e) > 16);
- DUMPBITS(t->b)
- NEEDBITS(e)
- d = w - t->v.n - ((unsigned)b & mask_bits[e]);
- DUMPBITS(e)
- Tracevv((stderr,"\\[%d,%d]", w-d, n));
-
- /* do the copy */
- do {
- n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ?
n : e);
- if (w - d >= e) /* (this test assumes unsigned
comparison) */
- {
- memcpy(slide + w, slide + d, e);
- w += e;
- d += e;
- }
- else /* do it slow to avoid memcpy()
overlap */
- do {
- slide[w++] = slide[d++];
- Tracevv((stderr, "%c", slide[w-1]));
- } while (--e);
- if (w == WSIZE)
- {
- flush_output(w);
- w = 0;
- }
- } while (n);
- }
+ } while (n);
+ }
}
-
/* restore the globals from the locals */
wp = w; /* restore global window pointer */
bb = b; /* restore global bit buffer */
@@ -643,10 +648,8 @@ static int __init inflate_codes(
return 4; /* Input underrun */
}
-
-
-static int __init inflate_stored(void)
/* "decompress" an inflated type 0 (stored) block. */
+static int __init inflate_stored(void)
{
unsigned n; /* number of bytes in block */
unsigned w; /* current window position */
@@ -667,28 +670,26 @@ static int __init inflate_stored(void)
/* get the length and its complement */
- NEEDBITS(16)
- n = ((unsigned)b & 0xffff);
- DUMPBITS(16)
- NEEDBITS(16)
- if (n != (unsigned)((~b) & 0xffff))
- return 1; /* error in compressed data */
- DUMPBITS(16)
-
-
- /* read and output the compressed data */
- while (n--)
+ NEEDBITS(16);
+ n = ((unsigned)b & 0xffff);
+ DUMPBITS(16);
+ NEEDBITS(16);
+ if (n != (unsigned)((~b) & 0xffff))
+ return 1; /* error in compressed data */
+ DUMPBITS(16);
+
+ /* read and output the compressed data */
+ while (n--)
+ {
+ NEEDBITS(8);
+ slide[w++] = (uch)b;
+ if (w == WSIZE)
{
- NEEDBITS(8)
- slide[w++] = (uch)b;
- if (w == WSIZE)
- {
- flush_output(w);
- w = 0;
- }
- DUMPBITS(8)
- }
-
+ flush_output(w);
+ w = 0;
+ }
+ DUMPBITS(8);
+ }
/* restore the globals from the locals */
wp = w; /* restore global window pointer */
@@ -706,10 +707,13 @@ static int __init inflate_stored(void)
/*
* We use `noinline' here to prevent gcc-3.5 from using too much stack space
*/
+
+/*
+ * decompress an inflated type 1 (fixed Huffman codes) block. We should
+ * either replace this with a custom decoder, or at least precompute the
+ * Huffman tables.
+ */
static int noinline __init inflate_fixed(void)
-/* decompress an inflated type 1 (fixed Huffman codes) block. We should
- either replace this with a custom decoder, or at least precompute the
- Huffman tables. */
{
int i; /* temporary variable */
struct huft *tl; /* literal/length code table */
@@ -752,7 +756,6 @@ static int noinline __init inflate_fixed(void)
return i;
}
-
/* decompress until an end-of-block code */
if (inflate_codes(tl, td, bl, bd)) {
free(l);
@@ -766,12 +769,12 @@ static int noinline __init inflate_fixed(void)
return 0;
}
-
/*
* We use `noinline' here to prevent gcc-3.5 from using too much stack space
*/
-static int noinline __init inflate_dynamic(void)
+
/* decompress an inflated type 2 (dynamic Huffman codes) block. */
+static int noinline __init inflate_dynamic(void)
{
int i; /* temporary variables */
unsigned j;
@@ -801,32 +804,31 @@ static int noinline __init inflate_dynamic(void)
b = bb;
k = bk;
-
/* read in table lengths */
- NEEDBITS(5)
- nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length
codes */
- DUMPBITS(5)
- NEEDBITS(5)
- nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */
- DUMPBITS(5)
- NEEDBITS(4)
- nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */
- DUMPBITS(4)
- if (nl > 286 || nd > 30)
- {
- ret = 1; /* bad lengths */
- goto out;
- }
+ NEEDBITS(5);
+ nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */
+ DUMPBITS(5);
+ NEEDBITS(5);
+ nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */
+ DUMPBITS(5);
+ NEEDBITS(4);
+ nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */
+ DUMPBITS(4);
+ if (nl > 286 || nd > 30)
+ {
+ ret = 1; /* bad lengths */
+ goto out;
+ }
DEBG("dyn1 ");
/* read in bit-length-code lengths */
for (j = 0; j < nb; j++)
{
- NEEDBITS(3)
- ll[border[j]] = (unsigned)b & 7;
- DUMPBITS(3)
- }
+ NEEDBITS(3);
+ ll[border[j]] = (unsigned)b & 7;
+ DUMPBITS(3);
+ }
for (; j < 19; j++)
ll[border[j]] = 0;
@@ -850,46 +852,46 @@ static int noinline __init inflate_dynamic(void)
i = l = 0;
while ((unsigned)i < n)
{
- NEEDBITS((unsigned)bl)
- j = (td = tl + ((unsigned)b & m))->b;
- DUMPBITS(j)
- j = td->v.n;
+ NEEDBITS((unsigned)bl);
+ j = (td = tl + ((unsigned)b & m))->b;
+ DUMPBITS(j);
+ j = td->v.n;
if (j < 16) /* length of code in bits (0..15) */
ll[i++] = l = j; /* save last length in l */
else if (j == 16) /* repeat last length 3 to 6 times */
{
- NEEDBITS(2)
- j = 3 + ((unsigned)b & 3);
- DUMPBITS(2)
- if ((unsigned)i + j > n) {
- ret = 1;
- goto out;
- }
+ NEEDBITS(2);
+ j = 3 + ((unsigned)b & 3);
+ DUMPBITS(2);
+ if ((unsigned)i + j > n) {
+ ret = 1;
+ goto out;
+ }
while (j--)
ll[i++] = l;
}
else if (j == 17) /* 3 to 10 zero length codes */
{
- NEEDBITS(3)
- j = 3 + ((unsigned)b & 7);
- DUMPBITS(3)
- if ((unsigned)i + j > n) {
- ret = 1;
- goto out;
- }
+ NEEDBITS(3);
+ j = 3 + ((unsigned)b & 7);
+ DUMPBITS(3);
+ if ((unsigned)i + j > n) {
+ ret = 1;
+ goto out;
+ }
while (j--)
ll[i++] = 0;
l = 0;
}
else /* j == 18: 11 to 138 zero length codes */
{
- NEEDBITS(7)
- j = 11 + ((unsigned)b & 0x7f);
- DUMPBITS(7)
- if ((unsigned)i + j > n) {
- ret = 1;
- goto out;
- }
+ NEEDBITS(7);
+ j = 11 + ((unsigned)b & 0x7f);
+ DUMPBITS(7);
+ if ((unsigned)i + j > n) {
+ ret = 1;
+ goto out;
+ }
while (j--)
ll[i++] = 0;
l = 0;
@@ -928,67 +930,64 @@ static int noinline __init inflate_dynamic(void)
DEBG("dyn5d ");
if (i == 1) {
error("incomplete distance tree");
- huft_free(td);
+ huft_free(td);
+ }
+ huft_free(tl);
+ ret = i; /* incomplete code set */
+ goto out;
}
- huft_free(tl);
- ret = i; /* incomplete code set */
- goto out;
-}
-DEBG("dyn6 ");
+ DEBG("dyn6 ");
- /* decompress until an end-of-block code */
-if (inflate_codes(tl, td, bl, bd)) {
- ret = 1;
- goto out;
-}
+ /* decompress until an end-of-block code */
+ if (inflate_codes(tl, td, bl, bd)) {
+ ret = 1;
+ goto out;
+ }
-DEBG("dyn7 ");
+ DEBG("dyn7 ");
- /* free the decoding tables, return */
-huft_free(tl);
-huft_free(td);
+ /* free the decoding tables, return */
+ huft_free(tl);
+ huft_free(td);
-DEBG(">");
-ret = 0;
-out:
-free(ll);
-return ret;
+ DEBG(">");
+ ret = 0;
+ out:
+ free(ll);
+ return ret;
-underrun:
-ret = 4; /* Input underrun */
-goto out;
+ underrun:
+ ret = 4; /* Input underrun */
+ goto out;
}
-
-
-static int __init inflate_block(
-int *e /* last block flag */
-)
-/* decompress an inflated block */
+/*
+ * decompress an inflated block
+ *
+ * @param e Last block flag
+ */
+static int __init inflate_block(int *e)
{
-unsigned t; /* block type */
-register ulg b; /* bit buffer */
-register unsigned k; /* number of bits in bit buffer */
-
-DEBG("<blk");
+ unsigned t; /* block type */
+ register ulg b; /* bit buffer */
+ register unsigned k; /* number of bits in bit buffer */
-/* make local bit buffer */
-b = bb;
-k = bk;
+ DEBG("<blk");
+ /* make local bit buffer */
+ b = bb;
+ k = bk;
-/* read in last block bit */
-NEEDBITS(1)
+ /* read in last block bit */
+ NEEDBITS(1);
*e = (int)b & 1;
- DUMPBITS(1)
-
+ DUMPBITS(1);
/* read in block type */
- NEEDBITS(2)
+ NEEDBITS(2);
t = (unsigned)b & 3;
- DUMPBITS(2)
-
+ DUMPBITS(2);
/* restore the global bit buffer */
bb = b;
@@ -996,25 +995,23 @@ NEEDBITS(1)
/* inflate that block type */
if (t == 2)
- return inflate_dynamic();
+ return inflate_dynamic();
if (t == 0)
- return inflate_stored();
+ return inflate_stored();
if (t == 1)
- return inflate_fixed();
+ return inflate_fixed();
DEBG(">");
/* bad block type */
return 2;
- underrun:
+ underrun:
return 4; /* Input underrun */
}
-
-
-static int __init inflate(void)
/* decompress an inflated entry */
+static int __init inflate(void)
{
int e; /* last block flag */
int r; /* result code */
@@ -1024,7 +1021,6 @@ static int __init inflate(void)
bk = 0;
bb = 0;
-
/* decompress until the last block */
do {
r = inflate_block(&e);
@@ -1043,7 +1039,6 @@ static int __init inflate(void)
/* flush out slide */
flush_output(wp);
-
/* return success */
return 0;
}
@@ -1059,12 +1054,11 @@ static ulg __initdata crc; /* initialized in makecrc()
so it'll reside in bss *
#define CRC_VALUE (crc ^ 0xffffffffUL)
/*
- * Code to compute the CRC-32 table. Borrowed from
+ * Code to compute the CRC-32 table. Borrowed from
* gzip-1.0.3/makecrc.c.
*/
-static void __init
-makecrc(void)
+static void __init makecrc(void)
{
/* Not copyrighted 1990 Mark Adler */
@@ -1167,7 +1161,7 @@ static int __init gunzip(void)
if ((flags & ORIG_NAME) != 0) {
/* Discard the old name */
while (NEXTBYTE() != 0) /* null */ ;
- }
+ }
/* Discard file comment if any */
if ((flags & COMMENT) != 0) {
@@ -1196,7 +1190,7 @@ static int __init gunzip(void)
}
return -1;
}
-
+
/* Get the crc and original length */
/* crc32 (see algorithm.doc)
* uncompressed input size modulo 2^32
@@ -1205,12 +1199,12 @@ static int __init gunzip(void)
orig_crc |= (ulg) NEXTBYTE() << 8;
orig_crc |= (ulg) NEXTBYTE() << 16;
orig_crc |= (ulg) NEXTBYTE() << 24;
-
+
orig_len = (ulg) NEXTBYTE();
orig_len |= (ulg) NEXTBYTE() << 8;
orig_len |= (ulg) NEXTBYTE() << 16;
orig_len |= (ulg) NEXTBYTE() << 24;
-
+
/* Validate decompression */
if (orig_crc != CRC_VALUE) {
error("crc error");
@@ -1226,3 +1220,12 @@ static int __init gunzip(void)
error("out of input data");
return -1;
}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.30.2
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |