Workshop o mikrokontrolérech na SKSP 2024.
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/*
* UCW Library -- Universal Sorter
*
* (c) 2001--2007 Martin Mares <mj@ucw.cz>
* (c) 2004 Robert Spalek <robert@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
*/
/*
* This is not a normal header file, but a generator of sorting
* routines. Each time you include it with parameters set in the
* corresponding preprocessor macros, it generates a file sorter
* with the parameters given.
*
* The sorter operates on fastbufs containing sequences of items. Each item
* consists of a key, optionally followed by data. The keys are represented
* by fixed-size structures of type SORT_KEY internally, if this format differs
* from the on-disk format, explicit reading and writing routines can be provided.
* The data are always copied verbatim, unless the sorter is in the merging
* mode in which it calls callbacks for merging of items with equal keys.
*
* All callbacks must be thread-safe.
*
* Basic parameters and callbacks:
*
* SORT_PREFIX(x) add a name prefix (used on all global names defined by the sorter)
*
* SORT_KEY data type capable of holding a single key in memory (the on-disk
* representation can be different). Alternatively, you can use:
* SORT_KEY_REGULAR data type holding a single key both in memory and on disk;
* in this case, bread() and bwrite() is used to read/write keys
* and it's also assumed that the keys are not very long.
* int PREFIX_compare(SORT_KEY *a, SORT_KEY *b)
* compares two keys, returns result like strcmp(). Mandatory.
* int PREFIX_read_key(struct fastbuf *f, SORT_KEY *k)
* reads a key from a fastbuf, returns nonzero=ok, 0=EOF.
* Mandatory unless SORT_KEY_REGULAR is defined.
* void PREFIX_write_key(struct fastbuf *f, SORT_KEY *k)
* writes a key to a fastbuf. Mandatory unless SORT_KEY_REGULAR.
*
* SORT_KEY_SIZE(key) returns the real size of a key (a SORT_KEY type in memory
* can be truncated to this number of bytes without any harm;
* used to save memory when the keys have variable sizes).
* Default: always store the whole SORT_KEY.
* SORT_DATA_SIZE(key) gets a key and returns the amount of data following it.
* Default: records consist of keys only.
*
* Integer sorting:
*
* SORT_INT(key) we are sorting by an integer value returned by this macro.
* In this mode, PREFIX_compare is supplied automatically and the sorting
* function gets an extra parameter specifying the range of the integers.
* The better the range fits, the faster we sort.
* Sets up SORT_HASH_xxx automatically.
* SORT_INT64(key) the same for 64-bit integers.
*
* Hashing (optional, but it can speed sorting up):
*
* SORT_HASH_BITS signals that a monotone hashing function returning a given number of
* bits is available. A monotone hash is a function f from keys to integers
* such that f(x) < f(y) implies x < y, which is approximately uniformly
* distributed. It should be declared as:
* uint PREFIX_hash(SORT_KEY *a)
*
* Unification:
*
* SORT_UNIFY merge items with identical keys. It requires the following functions:
* void PREFIX_write_merged(struct fastbuf *f, SORT_KEY **keys, void **data, uint n, void *buf)
* takes n records in memory with keys which compare equal and writes
* a single record to the given fastbuf. `buf' points to a buffer which
* is guaranteed to hold the sum of workspace requirements (see below)
* over all given records. The function is allowed to modify all its inputs.
* void PREFIX_copy_merged(SORT_KEY **keys, struct fastbuf **data, uint n, struct fastbuf *dest)
* takes n records with keys in memory and data in fastbufs and writes
* a single record. Used only if SORT_DATA_SIZE or SORT_UNIFY_WORKSPACE
* is defined.
* SORT_UNIFY_WORKSPACE(key)
* gets a key and returns the amount of workspace required when merging
* the given record. Defaults to 0.
*
* Input (choose one of these):
*
* SORT_INPUT_FILE file of a given name
* SORT_INPUT_FB seekable fastbuf stream
* SORT_INPUT_PIPE non-seekable fastbuf stream
* SORT_INPUT_PRESORT custom presorter. Calls function
* int PREFIX_presort(struct fastbuf *dest, void *buf, size_t bufsize)
* to get successive batches of pre-sorted data.
* The function is passed a page-aligned presorting buffer.
* It returns 1 on success or 0 on EOF.
* SORT_DELETE_INPUT A C expression, if true, then the input files are deleted
* as soon as possible.
*
* Output (chose one of these):
*
* SORT_OUTPUT_FILE file of a given name
* SORT_OUTPUT_FB temporary fastbuf stream
* SORT_OUTPUT_THIS_FB a given fastbuf stream which can already contain some data
*
* Other switches:
*
* SORT_UNIQUE all items have distinct keys (checked in debug mode)
*
* The function generated:
*
* <outfb> PREFIX_sort(<in>, <out> [,<range>]), where:
* <in> = input file name/fastbuf or NULL
* <out> = output file name/fastbuf or NULL
* <range> = maximum integer value for the SORT_INT mode
*
* After including this file, all parameter macros are automatically
* undef'd.
*/
#include <ucw/sorter/common.h>
#include <ucw/fastbuf.h>
#include <ucw/time.h>
#include <fcntl.h>
#define P(x) SORT_PREFIX(x)
#ifdef SORT_KEY_REGULAR
typedef SORT_KEY_REGULAR P(key);
static inline int P(read_key) (struct fastbuf *f, P(key) *k)
{
return breadb(f, k, sizeof(P(key)));
}
static inline void P(write_key) (struct fastbuf *f, P(key) *k)
{
bwrite(f, k, sizeof(P(key)));
}
#elif defined(SORT_KEY)
typedef SORT_KEY P(key);
#else
#error Missing definition of sorting key.
#endif
#ifdef SORT_INT64
typedef u64 P(hash_t);
#define SORT_INT SORT_INT64
#define SORT_LONG_HASH
#else
typedef uint P(hash_t);
#endif
#ifdef SORT_INT
static inline int P(compare) (P(key) *x, P(key) *y)
{
if (SORT_INT(*x) < SORT_INT(*y))
return -1;
if (SORT_INT(*x) > SORT_INT(*y))
return 1;
return 0;
}
#ifndef SORT_HASH_BITS
static inline P(hash_t) P(hash) (P(key) *x)
{
return SORT_INT((*x));
}
#endif
#endif
#ifdef SORT_UNIFY
#define LESS <
#else
#define LESS <=
#endif
#define SWAP(x,y,z) do { z=x; x=y; y=z; } while(0)
#if defined(SORT_UNIQUE) && defined(DEBUG_ASSERTS)
#define SORT_ASSERT_UNIQUE
#endif
#ifdef SORT_KEY_SIZE
#define SORT_VAR_KEY
#else
#define SORT_KEY_SIZE(key) sizeof(key)
#endif
#ifdef SORT_DATA_SIZE
#define SORT_VAR_DATA
#else
#define SORT_DATA_SIZE(key) 0
#endif
static inline void P(copy_data)(P(key) *key, struct fastbuf *in, struct fastbuf *out)
{
P(write_key)(out, key);
#ifdef SORT_VAR_DATA
bbcopy(in, out, SORT_DATA_SIZE(*key));
#else
(void) in;
#endif
}
#if defined(SORT_UNIFY) && !defined(SORT_VAR_DATA) && !defined(SORT_UNIFY_WORKSPACE)
static inline void P(copy_merged)(P(key) **keys, struct fastbuf **data UNUSED, uint n, struct fastbuf *dest)
{
P(write_merged)(dest, keys, NULL, n, NULL);
}
#endif
#if defined(SORT_HASH_BITS) || defined(SORT_INT)
#define SORT_INTERNAL_RADIX
#include <ucw/sorter/s-radix.h>
#endif
#if defined(SORT_VAR_KEY) || defined(SORT_VAR_DATA) || defined(SORT_UNIFY_WORKSPACE)
#include <ucw/sorter/s-internal.h>
#else
#include <ucw/sorter/s-fixint.h>
#endif
#include <ucw/sorter/s-twoway.h>
#include <ucw/sorter/s-multiway.h>
static struct fastbuf *P(sort)(
#ifdef SORT_INPUT_FILE
byte *in,
#else
struct fastbuf *in,
#endif
#ifdef SORT_OUTPUT_FILE
byte *out
#else
struct fastbuf *out
#endif
#ifdef SORT_INT
, u64 int_range
#endif
)
{
struct sort_context ctx;
bzero(&ctx, sizeof(ctx));
#ifdef SORT_INPUT_FILE
ctx.in_fb = bopen_file(in, O_RDONLY, &sorter_fb_params);
ctx.in_size = bfilesize(ctx.in_fb);
#elif defined(SORT_INPUT_FB)
ctx.in_fb = in;
ctx.in_size = bfilesize(in);
#elif defined(SORT_INPUT_PIPE)
ctx.in_fb = in;
ctx.in_size = ~(u64)0;
#elif defined(SORT_INPUT_PRESORT)
ASSERT(!in);
ctx.custom_presort = P(presort);
ctx.in_size = ~(u64)0;
#else
#error No input given.
#endif
#ifdef SORT_DELETE_INPUT
if (SORT_DELETE_INPUT)
bconfig(ctx.in_fb, BCONFIG_IS_TEMP_FILE, 1);
#endif
#ifdef SORT_OUTPUT_FB
ASSERT(!out);
#elif defined(SORT_OUTPUT_THIS_FB)
ctx.out_fb = out;
#elif defined(SORT_OUTPUT_FILE)
/* Just assume fastbuf output and rename the fastbuf later */
#else
#error No output given.
#endif
#ifdef SORT_HASH_BITS
ctx.hash_bits = SORT_HASH_BITS;
ctx.radix_split = P(radix_split);
#elif defined(SORT_INT)
ctx.hash_bits = 0;
while (ctx.hash_bits < 64 && (int_range >> ctx.hash_bits))
ctx.hash_bits++;
ctx.radix_split = P(radix_split);
#endif
ctx.internal_sort = P(internal);
ctx.internal_estimate = P(internal_estimate);
ctx.twoway_merge = P(twoway_merge);
ctx.multiway_merge = P(multiway_merge);
sorter_run(&ctx);
#ifdef SORT_OUTPUT_FILE
bfix_tmp_file(ctx.out_fb, out);
ctx.out_fb = NULL;
#endif
return ctx.out_fb;
}
#undef SORT_ASSERT_UNIQUE
#undef SORT_DATA_SIZE
#undef SORT_DELETE_INPUT
#undef SORT_HASH_BITS
#undef SORT_INPUT_FB
#undef SORT_INPUT_FILE
#undef SORT_INPUT_PIPE
#undef SORT_INPUT_PRESORT
#undef SORT_INT
#undef SORT_INT64
#undef SORT_INTERNAL_RADIX
#undef SORT_KEY
#undef SORT_KEY_REGULAR
#undef SORT_KEY_SIZE
#undef SORT_LONG_HASH
#undef SORT_OUTPUT_FB
#undef SORT_OUTPUT_FILE
#undef SORT_OUTPUT_THIS_FB
#undef SORT_PREFIX
#undef SORT_UNIFY
#undef SORT_UNIFY_WORKSPACE
#undef SORT_UNIQUE
#undef SORT_VAR_DATA
#undef SORT_VAR_KEY
#undef SWAP
#undef LESS
#undef P