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/******************************************************************************
libpammap.c
*******************************************************************************
These are functions that deal with tuple hashes and tuple tables.
Both tuple hashes and tuple tables let you associate an arbitrary
integer with a tuple value. A tuple hash lets you look up the one
integer value (if any) associated with a given tuple value, having
the low memory and execution time characteristics of a hash table.
A tuple table lets you scan all the values, being a table of elements
that consist of an ordered pair of a tuple value and integer.
******************************************************************************/
#include <assert.h>
#include "pm_c_util.h"
#include "mallocvar.h"
#include "pam.h"
#include "pammap.h"
#define HASH_SIZE 20023
unsigned int
pnm_hashtuple(struct pam * const pamP,
tuple const tuple) {
/*----------------------------------------------------------------------------
Return the hash value of the tuple 'tuple' -- i.e. an index into a hash
table.
-----------------------------------------------------------------------------*/
unsigned int i;
unsigned int hash;
const unsigned int hash_factor[] = {33023, 30013, 27011};
hash = 0; /* initial value */
for (i = 0; i < MIN(pamP->depth, 3); ++i) {
hash += tuple[i] * hash_factor[i]; /* May overflow */
}
hash %= HASH_SIZE;
return hash;
}
tuplehash
pnm_createtuplehash(void) {
/*----------------------------------------------------------------------------
Create an empty tuple hash -- i.e. a hash table of zero length hash chains.
-----------------------------------------------------------------------------*/
tuplehash retval;
unsigned int i;
MALLOCARRAY(retval, HASH_SIZE);
if (retval == NULL)
pm_error("Out of memory allocating tuple hash of size %u",
HASH_SIZE);
for (i = 0; i < HASH_SIZE; ++i)
retval[i] = NULL;
return retval;
}
void
pnm_destroytuplehash(tuplehash const tuplehash) {
int i;
/* Free the chains */
for (i = 0; i < HASH_SIZE; ++i) {
struct tupleint_list_item * p;
struct tupleint_list_item * next;
/* Walk this chain, freeing each element */
for (p = tuplehash[i]; p; p = next) {
next = p->next;
free(p);
}
}
/* Free the table of chains */
free(tuplehash);
}
static struct tupleint_list_item *
allocTupleIntListItem(struct pam * const pamP) {
/* This is complicated by the fact that the last element of a
tupleint_list_item is of variable length, because the last element
of _it_ is of variable length
*/
struct tupleint_list_item * retval;
unsigned int const size =
sizeof(*retval) - sizeof(retval->tupleint.tuple)
+ pamP->depth * sizeof(sample);
retval = (struct tupleint_list_item *) malloc(size);
return retval;
}
void
pnm_addtotuplehash(struct pam * const pamP,
tuplehash const tuplehash,
tuple const tupletoadd,
int const value,
int * const fitsP) {
/*----------------------------------------------------------------------------
Add a tuple value to the hash -- assume it isn't already there.
Allocate new space for the tuple value and the hash chain element.
If we can't allocate space for the new hash chain element, don't
change anything and return *fitsP = FALSE;
-----------------------------------------------------------------------------*/
struct tupleint_list_item * const listItemP = allocTupleIntListItem(pamP);
if (listItemP == NULL)
*fitsP = FALSE;
else {
unsigned int const hashvalue = pnm_hashtuple(pamP, tupletoadd);
*fitsP = TRUE;
pnm_assigntuple(pamP, listItemP->tupleint.tuple, tupletoadd);
listItemP->tupleint.value = value;
listItemP->next = tuplehash[hashvalue];
tuplehash[hashvalue] = listItemP;
}
}
void
pnm_lookuptuple(struct pam * const pamP,
const tuplehash tuplehash,
const tuple searchval,
int * const foundP,
int * const retvalP) {
unsigned int const hashvalue = pnm_hashtuple(pamP, searchval);
struct tupleint_list_item * p;
struct tupleint_list_item * found;
found = NULL; /* None found yet */
for (p = tuplehash[hashvalue]; p && !found; p = p->next)
if (pnm_tupleequal(pamP, p->tupleint.tuple, searchval)) {
found = p;
}
if (found) {
*foundP = TRUE;
*retvalP = found->tupleint.value;
} else
*foundP = FALSE;
}
static void
addColorOccurrenceToHash(tuple const color,
tuplehash const tuplefreqhash,
struct pam * const pamP,
unsigned int const maxsize,
unsigned int * const sizeP,
bool * const fullP) {
unsigned int const hashvalue = pnm_hashtuple(pamP, color);
struct tupleint_list_item *p;
for (p = tuplefreqhash[hashvalue];
p && !pnm_tupleequal(pamP, p->tupleint.tuple, color);
p = p->next);
if (p) {
/* It's in the hash; just tally one more occurence */
++p->tupleint.value;
*fullP = FALSE;
} else {
/* It's not in the hash yet, so add it (if allowed) */
++(*sizeP);
if (maxsize > 0 && *sizeP > maxsize)
*fullP = TRUE;
else {
*fullP = FALSE;
p = allocTupleIntListItem(pamP);
if (p == NULL)
pm_error("out of memory computing hash table");
pnm_assigntuple(pamP, p->tupleint.tuple, color);
p->tupleint.value = 1;
p->next = tuplefreqhash[hashvalue];
tuplefreqhash[hashvalue] = p;
}
}
}
void
pnm_addtuplefreqoccurrence(struct pam * const pamP,
tuple const value,
tuplehash const tuplefreqhash,
int * const firstOccurrenceP) {
unsigned int const hashvalue = pnm_hashtuple(pamP, value);
struct tupleint_list_item * p;
for (p = tuplefreqhash[hashvalue];
p && !pnm_tupleequal(pamP, p->tupleint.tuple, value);
p = p->next);
if (p) {
/* It's in the hash; just tally one more occurence */
++p->tupleint.value;
*firstOccurrenceP = FALSE;
} else {
struct tupleint_list_item * p;
/* It's not in the hash yet, so add it */
*firstOccurrenceP = TRUE;
p = allocTupleIntListItem(pamP);
if (p == NULL)
pm_error("out of memory computing hash table");
pnm_assigntuple(pamP, p->tupleint.tuple, value);
p->tupleint.value = 1;
p->next = tuplefreqhash[hashvalue];
tuplefreqhash[hashvalue] = p;
}
}
static void
computehashrecoverable(struct pam * const pamP,
tuple ** const tupleArray,
unsigned int const maxsize,
sample const newMaxval,
unsigned int * const sizeP,
tuplehash * const tuplefreqhashP,
tuple ** const rowbufferP,
tuple * const colorP) {
/*----------------------------------------------------------------------------
This is computetuplefreqhash(), only it leaves a trail so that if it
happens to longjmp out because of a failed memory allocation, the
setjmp'er can cleanup whatever it had done so far.
-----------------------------------------------------------------------------*/
unsigned int row;
struct pam freqPam;
bool full;
freqPam = *pamP;
freqPam.maxval = newMaxval;
*tuplefreqhashP = pnm_createtuplehash();
*sizeP = 0; /* initial value */
*rowbufferP = pnm_allocpamrow(pamP);
*colorP = pnm_allocpamtuple(&freqPam);
full = FALSE; /* initial value */
/* Go through the entire raster, building a hash table of
tuple values.
*/
for (row = 0; row < pamP->height && !full; ++row) {
unsigned int col;
const tuple * tuplerow; /* The row of tuples we are processing */
if (tupleArray)
tuplerow = tupleArray[row];
else {
pnm_readpamrow(pamP, *rowbufferP);
tuplerow = *rowbufferP;
}
for (col = 0; col < pamP->width && !full; ++col) {
pnm_scaletuple(pamP, *colorP, tuplerow[col], freqPam.maxval);
addColorOccurrenceToHash(
*colorP, *tuplefreqhashP, &freqPam, maxsize, sizeP, &full);
}
}
pnm_freepamtuple(*colorP); *colorP = NULL;
pnm_freepamrow(*rowbufferP); *rowbufferP = NULL;
if (full) {
pnm_destroytuplehash(*tuplefreqhashP);
*tuplefreqhashP = NULL;
}
}
static tuplehash
computetuplefreqhash(struct pam * const pamP,
tuple ** const tupleArray,
unsigned int const maxsize,
sample const newMaxval,
unsigned int * const sizeP) {
/*----------------------------------------------------------------------------
Compute a tuple frequency hash from a PAM. This is a hash that gives
you the number of times a given tuple value occurs in the PAM. You can
supply the input PAM in one of two ways:
1) a two-dimensional array of tuples tupleArray[][]; In this case,
'tupleArray' is non-NULL.
2) an open PAM file, positioned to the raster. In this case,
'tupleArray' is NULL. *pamP contains the file descriptor.
We return with the file still open and its position undefined.
In either case, *pamP contains parameters of the tuple array.
Return the number of unique tuple values found as *sizeP.
However, if the number of unique tuple values is greater than 'maxsize',
return a null return value and *sizeP undefined.
The tuple values that index the hash are scaled to a new maxval of
'newMaxval'. E.g. if the input has maxval 100 and 'newMaxval' is
50, and a particular tuple has sample value 50, it would be counted
as sample value 25 in the hash.
-----------------------------------------------------------------------------*/
tuplehash tuplefreqhash;
tuple * rowbuffer; /* malloc'ed */
/* Buffer for a row read from the input file; undefined (but still
allocated) if input is not from a file.
*/
tuple color;
/* The color currently being added, scaled to the new maxval */
jmp_buf jmpbuf;
jmp_buf * origJmpbufP;
/* Initialize to "none" for purposes of error recovery */
tuplefreqhash = NULL;
rowbuffer = NULL;
color = NULL;
if (setjmp(jmpbuf) != 0) {
if (color)
pnm_freepamtuple(color);
if (rowbuffer)
pnm_freepamrow(rowbuffer);
if (tuplefreqhash)
pnm_destroytuplehash(tuplefreqhash);
pm_setjmpbuf(origJmpbufP);
pm_longjmp();
} else {
pm_setjmpbufsave(&jmpbuf, &origJmpbufP);
computehashrecoverable(pamP, tupleArray, maxsize, newMaxval, sizeP,
&tuplefreqhash, &rowbuffer, &color);
pm_setjmpbuf(origJmpbufP);
}
return tuplefreqhash;
}
tuplehash
pnm_computetuplefreqhash(struct pam * const pamP,
tuple ** const tupleArray,
unsigned int const maxsize,
unsigned int * const sizeP) {
/*----------------------------------------------------------------------------
Compute the tuple frequency hash for the tuple array tupleArray[][].
-----------------------------------------------------------------------------*/
return computetuplefreqhash(pamP, tupleArray, maxsize, pamP->maxval,
sizeP);
}
tupletable
pnm_alloctupletable(const struct pam * const pamP,
unsigned int const size) {
tupletable retval;
if (UINT_MAX / sizeof(struct tupleint) < size)
pm_error("size %u is too big for arithmetic", size);
else {
unsigned int const mainTableSize = size * sizeof(struct tupleint *);
unsigned int const tupleIntSize =
sizeof(struct tupleint) - sizeof(sample)
+ pamP->depth * sizeof(sample);
/* To save the enormous amount of time it could take to allocate
each individual tuple, we do a trick here and allocate everything
as a single malloc block and suballocate internally.
*/
if ((UINT_MAX - mainTableSize) / tupleIntSize < size)
pm_error("size %u is too big for arithmetic", size);
else {
void * pool;
unsigned int i;
pool = malloc(mainTableSize + size * tupleIntSize);
retval = (tupletable) pool;
for (i = 0; i < size; ++i)
retval[i] = (struct tupleint *)
((char*)pool + mainTableSize + i * tupleIntSize);
}
}
return retval;
}
void
pnm_freetupletable(struct pam * const pamP,
tupletable const tupletable) {
/* Note that the address 'tupletable' is, to the operating system,
the address of a larger block of memory that contains not only
tupletable, but all the samples to which it points (e.g.
tupletable[0].tuple[0])
*/
free(tupletable);
}
void
pnm_freetupletable2(struct pam * const pamP,
tupletable2 const tupletable) {
pnm_freetupletable(pamP, tupletable.table);
}
static tupletable
tuplehashtotable(const struct pam * const pamP,
tuplehash const tuplehash,
unsigned int const allocsize) {
/*----------------------------------------------------------------------------
Create a tuple table containing the info from a tuple hash. Allocate
space in the table for 'allocsize' elements even if there aren't that
many tuple values in the input hash. That's so the caller has room
for expansion.
Caller must ensure that 'allocsize' is at least as many tuple values
as there are in the input hash.
We allocate new space for all the table contents; there are no pointers
in the table to tuples or anything else in existing space.
-----------------------------------------------------------------------------*/
tupletable tupletable;
tupletable = pnm_alloctupletable(pamP, allocsize);
if (tupletable != NULL) {
unsigned int i, j;
/* Loop through the hash table. */
j = 0;
for (i = 0; i < HASH_SIZE; ++i) {
/* Walk this hash chain */
struct tupleint_list_item * p;
for (p = tuplehash[i]; p; p = p->next) {
assert(j < allocsize);
tupletable[j]->value = p->tupleint.value;
pnm_assigntuple(pamP, tupletable[j]->tuple, p->tupleint.tuple);
++j;
}
}
}
return tupletable;
}
tupletable
pnm_tuplehashtotable(const struct pam * const pamP,
tuplehash const tuplehash,
unsigned int const allocsize) {
tupletable tupletable;
tupletable = tuplehashtotable(pamP, tuplehash, allocsize);
if (tupletable == NULL)
pm_error("out of memory generating tuple table");
return tupletable;
}
tuplehash
pnm_computetupletablehash(struct pam * const pamP,
tupletable const tupletable,
unsigned int const tupletableSize) {
/*----------------------------------------------------------------------------
Create a tuple hash containing indices into the tuple table
'tupletable'. The hash index for the hash is the value of a tuple;
the hash value is the tuple table index for the element in the
tuple table that contains that tuple value.
Assume there are no duplicate tuple values in the tuple table.
We allocate space for the main hash table and all the elements of the
hash chains.
-----------------------------------------------------------------------------*/
tuplehash tupletablehash;
unsigned int i;
bool fits;
tupletablehash = pnm_createtuplehash();
fits = TRUE; /* initial assumption */
for (i = 0; i < tupletableSize && fits; ++i) {
pnm_addtotuplehash(pamP, tupletablehash,
tupletable[i]->tuple, i, &fits);
}
if (!fits) {
pnm_destroytuplehash(tupletablehash);
pm_error("Out of memory computing tuple hash from tuple table");
}
return tupletablehash;
}
tupletable
pnm_computetuplefreqtable2(struct pam * const pamP,
tuple ** const tupleArray,
unsigned int const maxsize,
sample const newMaxval,
unsigned int * const countP) {
/*----------------------------------------------------------------------------
Compute a tuple frequency table from a PAM image. This is an
array that tells how many times each tuple value occurs in the
image.
Except for the format of the output, this function is the same as
computetuplefreqhash().
If there are more than 'maxsize' unique tuple values in tupleArray[][],
give up.
Return the array in newly malloc'ed storage. Allocate space for
'maxsize' entries even if there aren't that many distinct tuple
values in tupleArray[]. That's so the caller has room for
expansion.
If 'maxsize' is zero, allocate exactly as much space as there are
distinct tuple values in tupleArray[], and don't give up no matter
how many tuple values we find (except, of course, we abort if we
can't get enough memory).
Return the number of unique tuple values in tupleArray[][] as
*countP.
Scale the tuple values to a new maxval of 'newMaxval' before
processing them. E.g. if the input has maxval 100 and 'newMaxval'
is 50, and a particular tuple has sample value 50, it would be
listed as sample value 25 in the output table. This makes the
output table smaller and the processing time less.
-----------------------------------------------------------------------------*/
tuplehash tuplefreqhash;
tupletable tuplefreqtable;
unsigned int uniqueCount;
tuplefreqhash = computetuplefreqhash(pamP, tupleArray, maxsize,
newMaxval, &uniqueCount);
if (tuplefreqhash == NULL)
tuplefreqtable = NULL;
else {
unsigned int tableSize = (maxsize == 0 ? uniqueCount : maxsize);
assert(tableSize >= uniqueCount);
tuplefreqtable = tuplehashtotable(pamP, tuplefreqhash, tableSize);
pnm_destroytuplehash(tuplefreqhash);
if (tuplefreqtable == NULL)
pm_error("Out of memory generating tuple table");
}
*countP = uniqueCount;
return tuplefreqtable;
}
tupletable
pnm_computetuplefreqtable(struct pam * const pamP,
tuple ** const tupleArray,
unsigned int const maxsize,
unsigned int * const sizeP) {
return pnm_computetuplefreqtable2(pamP, tupleArray, maxsize, pamP->maxval,
sizeP);
}
char*
pam_colorname(struct pam * const pamP,
tuple const color,
enum colornameFormat const format) {
unsigned int r, g, b;
FILE* f;
static char colorname[200];
r = pnm_scalesample(color[PAM_RED_PLANE], pamP->maxval, 255);
g = pnm_scalesample(color[PAM_GRN_PLANE], pamP->maxval, 255);
b = pnm_scalesample(color[PAM_BLU_PLANE], pamP->maxval, 255);
f = pm_openColornameFile(NULL, format == PAM_COLORNAME_ENGLISH);
if (f != NULL) {
unsigned int best_diff;
bool done;
best_diff = 32767;
done = FALSE;
while (!done) {
struct colorfile_entry const ce = pm_colorget(f);
if (ce.colorname) {
unsigned int const this_diff =
abs((int)r - (int)ce.r) +
abs((int)g - (int)ce.g) +
abs((int)b - (int)ce.b);
if (this_diff < best_diff) {
best_diff = this_diff;
strcpy(colorname, ce.colorname);
}
} else
done = TRUE;
}
fclose(f);
if (best_diff != 32767 &&
(best_diff == 0 || format == PAM_COLORNAME_ENGLISH))
return colorname;
}
/* Color lookup failed, but caller is willing to take an X11-style
hex specifier, so return that.
*/
sprintf(colorname, "#%02x%02x%02x", r, g, b);
return colorname;
}
|