/*
* Portable Free JBIG image compression library
*
* Markus Kuhn -- http://www.cl.cam.ac.uk/~mgk25/
*
* $Id: jbig.c,v 1.22 2004-06-11 15:17:06+01 mgk25 Exp $
*
* This module implements a portable standard C encoder and decoder
* using the JBIG lossless bi-level image compression algorithm as
* specified in International Standard ISO 11544:1993 or equivalently
* as specified in ITU-T Recommendation T.82. See the file jbig.doc
* for usage instructions and application examples.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* If you want to use this program under different license conditions,
* then contact the author for an arrangement.
*
* It is possible that certain products which can be built using this
* software module might form inventions protected by patent rights in
* some countries (e.g., by patents about arithmetic coding algorithms
* owned by IBM and AT&T in the USA). Provision of this software by the
* author does NOT include any licences for any patents. In those
* countries where a patent licence is required for certain applications
* of this software module, you will have to obtain such a licence
* yourself.
*/
#ifdef DEBUG
#include <stdio.h>
#else
#define NDEBUG
#endif
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "jbig.h"
/* optional export of arithmetic coder functions for test purposes */
#ifdef TEST_CODEC
#define ARITH
#define ARITH_INL
#else
#define ARITH static
#ifdef __GNUC__
#define ARITH_INL static __inline__
#else
#define ARITH_INL static
#endif
#endif
#define MX_MAX 127 /* maximal supported mx offset for
* adaptive template in the encoder */
#define TPB2CX 0x195 /* contexts for TP special pixels */
#define TPB3CX 0x0e5
#define TPDCX 0xc3f
/* marker codes */
#define MARKER_STUFF 0x00
#define MARKER_RESERVE 0x01
#define MARKER_SDNORM 0x02
#define MARKER_SDRST 0x03
#define MARKER_ABORT 0x04
#define MARKER_NEWLEN 0x05
#define MARKER_ATMOVE 0x06
#define MARKER_COMMENT 0x07
#define MARKER_ESC 0xff
/* loop array indices */
#define STRIPE 0
#define LAYER 1
#define PLANE 2
/* special jbg_buf pointers (instead of NULL) */
#define SDE_DONE ((struct jbg_buf *) -1)
#define SDE_TODO ((struct jbg_buf *) 0)
/* object code version id */
const char jbg_version[] =
" JBIG-KIT " JBG_VERSION " -- Markus Kuhn -- "
"$Id: jbig.c,v 1.22 2004-06-11 15:17:06+01 mgk25 Exp $ ";
/*
* the following array specifies for each combination of the 3
* ordering bits, which ii[] variable represents which dimension
* of s->sde.
*/
static const int iindex[8][3] = {
{ 2, 1, 0 }, /* no ordering bit set */
{ -1, -1, -1}, /* SMID -> illegal combination */
{ 2, 0, 1 }, /* ILEAVE */
{ 1, 0, 2 }, /* SMID + ILEAVE */
{ 0, 2, 1 }, /* SEQ */
{ 1, 2, 0 }, /* SEQ + SMID */
{ 0, 1, 2 }, /* SEQ + ILEAVE */
{ -1, -1, -1 } /* SEQ + SMID + ILEAVE -> illegal combination */
};
/*
* Array [language][message] with text string error messages that correspond
* to return values from public functions in this library.
*/
#define NEMSG 9 /* number of error codes */
#define NEMSG_LANG 3 /* number of supported languages */
static const char *errmsg[NEMSG_LANG][NEMSG] = {
/* English (JBG_EN) */
{
"Everything is ok", /* JBG_EOK */
"Reached specified maximum size", /* JBG_EOK_INTR */
"Unexpected end of data", /* JBG_EAGAIN */
"Not enough memory available", /* JBG_ENOMEM */
"ABORT marker found", /* JBG_EABORT */
"Unknown marker segment encountered", /* JBG_EMARKER */
"Incremental BIE does not fit to previous one", /* JBG_ENOCONT */
"Invalid data encountered", /* JBG_EINVAL */
"Unimplemented features used" /* JBG_EIMPL */
},
/* German (JBG_DE_8859_1) */
{
"Kein Problem aufgetreten", /* JBG_EOK */
"Angegebene maximale Bildgr\366\337e erreicht", /* JBG_EOK_INTR */
"Unerwartetes Ende der Daten", /* JBG_EAGAIN */
"Nicht gen\374gend Speicher vorhanden", /* JBG_ENOMEM */
"Es wurde eine Abbruch-Sequenz gefunden", /* JBG_EABORT */
"Eine unbekannte Markierungssequenz wurde gefunden", /* JBG_EMARKER */
"Neue Daten passen nicht zu vorangegangenen Daten", /* JBG_ENOCONT */
"Es wurden ung\374ltige Daten gefunden", /* JBG_EINVAL */
"Noch nicht implementierte Optionen wurden benutzt" /* JBG_EIMPL */
},
/* German (JBG_DE_UTF_8) */
{
"Kein Problem aufgetreten", /* JBG_EOK */
"Angegebene maximale Bildgr\303\266\303\237e erreicht", /* JBG_EOK_INTR */
"Unerwartetes Ende der Daten", /* JBG_EAGAIN */
"Nicht gen\303\274gend Speicher vorhanden", /* JBG_ENOMEM */
"Es wurde eine Abbruch-Sequenz gefunden", /* JBG_EABORT */
"Eine unbekannte Markierungssequenz wurde gefunden", /* JBG_EMARKER */
"Neue Daten passen nicht zu vorangegangenen Daten", /* JBG_ENOCONT */
"Es wurden ung\303\274ltige Daten gefunden", /* JBG_EINVAL */
"Noch nicht implementierte Optionen wurden benutzt" /* JBG_EIMPL */
}
};
/*
* The following three functions are the only places in this code, were
* C library memory management functions are called. The whole JBIG
* library has been designed in order to allow multi-threaded
* execution. No static or global variables are used, so all fuctions
* are fully reentrant. However if you want to use this multi-thread
* capability and your malloc, realloc and free are not reentrant,
* then simply add the necessary semaphores or mutex primitives below.
* In contrast to C's malloc() and realloc(), but like C's calloc(),
* these functions take two parameters nmemb and size that are multiplied
* before being passed on to the corresponding C function.
* This we can catch all overflows during a size_t multiplication a
* a single place.
*/
#ifndef SIZE_MAX
#define SIZE_MAX ((size_t) -1) /* largest value of size_t */
#endif
static void *checked_malloc(size_t nmemb, size_t size)
{
void *p;
/* Full manual exception handling is ugly here for performance
* reasons. If an adequate handling of lack of memory is required,
* then use C++ and throw a C++ exception instead of abort(). */
/* assert that nmemb * size <= SIZE_MAX */
if (size > SIZE_MAX / nmemb)
abort();
p = malloc(nmemb * size);
if (!p)
abort();
#if 0
fprintf(stderr, "%p = malloc(%lu * %lu)\n", p,
(unsigned long) nmemb, (unsigned long) size);
#endif
return p;
}
static void *checked_realloc(void *ptr, size_t nmemb, size_t size)
{
void *p;
/* Full manual exception handling is ugly here for performance
* reasons. If an adequate handling of lack of memory is required,
* then use C++ and throw a C++ exception here instead of abort(). */
/* assert that nmemb * size <= SIZE_MAX */
if (size > SIZE_MAX / nmemb)
abort();
p = realloc(ptr, nmemb * size);
if (!p)
abort();
#if 0
fprintf(stderr, "%p = realloc(%p, %lu * %lu)\n", p, ptr,
(unsigned long) nmemb, (unsigned long) size);
#endif
return p;
}
static void checked_free(void *ptr)
{
free(ptr);
#if 0
fprintf(stderr, "free(%p)\n", ptr);
#endif
}
/*
* The next functions implement the arithmedic encoder and decoder
* required for JBIG. The same algorithm is also used in the arithmetic
* variant of JPEG.
*/
#ifdef DEBUG
static long encoded_pixels = 0;
#endif
ARITH void arith_encode_init(struct jbg_arenc_state *s, int reuse_st)
{
int i;
if (!reuse_st)
for (i = 0; i < 4096; s->st[i++] = 0);
s->c = 0;
s->a = 0x10000L;
s->sc = 0;
s->ct = 11;
s->buffer = -1; /* empty */
return;
}
ARITH void arith_encode_flush(struct jbg_arenc_state *s)
{
unsigned long temp;
#ifdef DEBUG
fprintf(stderr, " encoded pixels = %ld, a = %05lx, c = %08lx\n",
encoded_pixels, s->a, s->c);
#endif
/* find the s->c in the coding interval with the largest
* number of trailing zero bits */
if ((temp = (s->a - 1 + s->c) & 0xffff0000L) < s->c)
s->c = temp + 0x8000;
else
s->c = temp;
/* send remaining bytes to output */
s->c <<= s->ct;
if (s->c & 0xf8000000L) {
/* one final overflow has to be handled */
if (s->buffer >= 0) {
s->byte_out(s->buffer + 1, s->file);
if (s->buffer + 1 == MARKER_ESC)
s->byte_out(MARKER_STUFF, s->file);
}
/* output 0x00 bytes only when more non-0x00 will follow */
if (s->c & 0x7fff800L)
for (; s->sc; --s->sc)
s->byte_out(0x00, s->file);
} else {
if (s->buffer >= 0)
s->byte_out(s->buffer, s->file);
/* T.82 figure 30 says buffer+1 for the above line! Typo? */
for (; s->sc; --s->sc) {
s->byte_out(0xff, s->file);
s->byte_out(MARKER_STUFF, s->file);
}
}
/* output final bytes only if they are not 0x00 */
if (s->c & 0x7fff800L) {
s->byte_out((s->c >> 19) & 0xff, s->file);
if (((s->c >> 19) & 0xff) == MARKER_ESC)
s->byte_out(MARKER_STUFF, s->file);
if (s->c & 0x7f800L) {
s->byte_out((s->c >> 11) & 0xff, s->file);
if (((s->c >> 11) & 0xff) == MARKER_ESC)
s->byte_out(MARKER_STUFF, s->file);
}
}
return;
}
ARITH_INL void arith_encode(struct jbg_arenc_state *s, int cx, int pix)
{
extern short jbg_lsz[];
extern unsigned char jbg_nmps[], jbg_nlps[];
register unsigned lsz, ss;
register unsigned char *st;
long temp;
#ifdef DEBUG
++encoded_pixels;
#endif
assert(cx >= 0 && cx < 4096);
st = s->st + cx;
ss = *st & 0x7f;
assert(ss < 113);
lsz = jbg_lsz[ss];
#if 0
fprintf(stderr, "pix = %d, cx = %d, mps = %d, st = %3d, lsz = 0x%04x, "
"a = 0x%05lx, c = 0x%08lx, ct = %2d, buf = 0x%02x\n",
pix, cx, !!(s->st[cx] & 0x80), ss, lsz, s->a, s->c, s->ct,
s->buffer);
#endif
if (((pix << 7) ^ s->st[cx]) & 0x80) {
/* encode the less probable symbol */
if ((s->a -= lsz) >= lsz) {
/* If the interval size (lsz) for the less probable symbol (LPS)
* is larger than the interval size for the MPS, then exchange
* the two symbols for coding efficiency, otherwise code the LPS
* as usual: */
s->c += s->a;
s->a = lsz;
}
/* Check whether MPS/LPS exchange is necessary
* and chose next probability estimator status */
*st &= 0x80;
*st ^= jbg_nlps[ss];
} else {
/* encode the more probable symbol */
if ((s->a -= lsz) & 0xffff8000L)
return; /* A >= 0x8000 -> ready, no renormalization required */
if (s->a < lsz) {
/* If the interval size (lsz) for the less probable symbol (LPS)
* is larger than the interval size for the MPS, then exchange
* the two symbols for coding efficiency: */
s->c += s->a;
s->a = lsz;
}
/* chose next probability estimator status */
*st &= 0x80;
*st |= jbg_nmps[ss];
}
/* renormalization of coding interval */
do {
s->a <<= 1;
s->c <<= 1;
--s->ct;
if (s->ct == 0) {
/* another byte is ready for output */
temp = s->c >> 19;
if (temp & 0xffffff00L) {
/* handle overflow over all buffered 0xff bytes */
if (s->buffer >= 0) {
++s->buffer;
s->byte_out(s->buffer, s->file);
if (s->buffer == MARKER_ESC)
s->byte_out(MARKER_STUFF, s->file);
}
for (; s->sc; --s->sc)
s->byte_out(0x00, s->file);
s->buffer = temp & 0xff; /* new output byte, might overflow later */
assert(s->buffer != 0xff);
/* can s->buffer really never become 0xff here? */
} else if (temp == 0xff) {
/* buffer 0xff byte (which might overflow later) */
++s->sc;
} else {
/* output all buffered 0xff bytes, they will not overflow any more */
if (s->buffer >= 0)
s->byte_out(s->buffer, s->file);
for (; s->sc; --s->sc) {
s->byte_out(0xff, s->file);
s->byte_out(MARKER_STUFF, s->file);
}
s->buffer = temp; /* buffer new output byte (can still overflow) */
}
s->c &= 0x7ffffL;
s->ct = 8;
}
} while (s->a < 0x8000);
return;
}
ARITH void arith_decode_init(struct jbg_ardec_state *s, int reuse_st)
{
int i;
if (!reuse_st)
for (i = 0; i < 4096; s->st[i++] = 0);
s->c = 0;
s->a = 1;
s->ct = 0;
s->result = JBG_OK;
s->startup = 1;
return;
}
ARITH_INL int arith_decode(struct jbg_ardec_state *s, int cx)
{
extern short jbg_lsz[];
extern unsigned char jbg_nmps[], jbg_nlps[];
register unsigned lsz, ss;
register unsigned char *st;
int pix;
/* renormalization */
while (s->a < 0x8000 || s->startup) {
if (s->ct < 1 && s->result != JBG_READY) {
/* first we have to move a new byte into s->c */
if (s->pscd_ptr >= s->pscd_end) {
s->result = JBG_MORE;
return -1;
}
if (*s->pscd_ptr == 0xff)
if (s->pscd_ptr + 1 >= s->pscd_end) {
s->result = JBG_MARKER;
return -1;
} else {
if (*(s->pscd_ptr + 1) == MARKER_STUFF) {
s->c |= 0xffL << (8 - s->ct);
s->ct += 8;
s->pscd_ptr += 2;
s->result = JBG_OK;
} else
s->result = JBG_READY;
}
else {
s->c |= (long)*(s->pscd_ptr++) << (8 - s->ct);
s->ct += 8;
s->result = JBG_OK;
}
}
s->c <<= 1;
s->a <<= 1;
--s->ct;
if (s->a == 0x10000L)
s->startup = 0;
}
st = s->st + cx;
ss = *st & 0x7f;
assert(ss < 113);
lsz = jbg_lsz[ss];
#if 0
fprintf(stderr, "cx = %d, mps = %d, st = %3d, lsz = 0x%04x, a = 0x%05lx, "
"c = 0x%08lx, ct = %2d\n",
cx, !!(s->st[cx] & 0x80), ss, lsz, s->a, s->c, s->ct);
#endif
if ((s->c >> 16) < (s->a -= lsz))
if (s->a & 0xffff8000L)
return *st >> 7;
else {
/* MPS_EXCHANGE */
if (s->a < lsz) {
pix = 1 - (*st >> 7);
/* Check whether MPS/LPS exchange is necessary
* and chose next probability estimator status */
*st &= 0x80;
*st ^= jbg_nlps[ss];
} else {
pix = *st >> 7;
*st &= 0x80;
*st |= jbg_nmps[ss];
}
}
else {
/* LPS_EXCHANGE */
if (s->a < lsz) {
s->c -= s->a << 16;
s->a = lsz;
pix = *st >> 7;
*st &= 0x80;
*st |= jbg_nmps[ss];
} else {
s->c -= s->a << 16;
s->a = lsz;
pix = 1 - (*st >> 7);
/* Check whether MPS/LPS exchange is necessary
* and chose next probability estimator status */
*st &= 0x80;
*st ^= jbg_nlps[ss];
}
}
return pix;
}
/*
* Memory management for buffers which are used for temporarily
* storing SDEs by the encoder.
*
* The following functions manage a set of struct jbg_buf storage
* containers were each can keep JBG_BUFSIZE bytes. The jbg_buf
* containers can be linked to form linear double-chained lists for
* which a number of operations are provided. Blocks which are
* tempoarily not used any more are returned to a freelist which each
* encoder keeps. Only the destructor of the encoder actually returns
* the block via checked_free() to the stdlib memory management.
*/
/*
* Allocate a new buffer block and initialize it. Try to get it from
* the free_list, and if it is empty, call checked_malloc().
*/
static struct jbg_buf *jbg_buf_init(struct jbg_buf **free_list)
{
struct jbg_buf *new_block;
/* Test whether a block from the free list is available */
if (*free_list) {
new_block = *free_list;
*free_list = new_block->next;
} else {
/* request a new memory block */
new_block = (struct jbg_buf *) checked_malloc(1, sizeof(struct jbg_buf));
}
new_block->len = 0;
new_block->next = NULL;
new_block->previous = NULL;
new_block->last = new_block;
new_block->free_list = free_list;
return new_block;
}
/*
* Return an entire free_list to the memory management of stdlib.
* This is only done by jbg_enc_free().
*/
static void jbg_buf_free(struct jbg_buf **free_list)
{
struct jbg_buf *tmp;
while (*free_list) {
tmp = (*free_list)->next;
checked_free(*free_list);
*free_list = tmp;
}
return;
}
/*
* Append a single byte to a single list that starts with the block
* *(struct jbg_buf *) head. The type of *head is void here in order to
* keep the interface of the arithmetic encoder gereric, which uses this
* function as a call-back function in order to deliver single bytes
* for a PSCD.
*/
static void jbg_buf_write(int b, void *head)
{
struct jbg_buf *now;
now = ((struct jbg_buf *) head)->last;
if (now->len < JBG_BUFSIZE - 1) {
now->d[now->len++] = b;
return;
}
now->next = jbg_buf_init(((struct jbg_buf *) head)->free_list);
now->next->previous = now;
now->next->d[now->next->len++] = b;
((struct jbg_buf *) head)->last = now->next;
return;
}
/*
* Remove any trailing zero bytes from the end of a linked jbg_buf list,
* however make sure that no zero byte is removed which directly
* follows a 0xff byte (i.e., keep MARKER_ESC MARKER_STUFF sequences
* intact). This function is used to remove any redundant final zero
* bytes from a PSCD.
*/
static void jbg_buf_remove_zeros(struct jbg_buf *head)
{
struct jbg_buf *last;
while (1) {
/* remove trailing 0x00 in last block of list until this block is empty */
last = head->last;
while (last->len && last->d[last->len - 1] == 0)
last->len--;
/* if block became really empty, remove it in case it is not the
* only remaining block and then loop to next block */
if (last->previous && !last->len) {
head->last->next = *head->free_list;
*head->free_list = head->last;
head->last = last->previous;
head->last->next = NULL;
} else
break;
}
/*
* If the final non-zero byte is 0xff (MARKER_ESC), then we just have
* removed a MARKER_STUFF and we will append it again now in order
* to preserve PSCD status of byte stream.
*/
if (head->last->len && head->last->d[head->last->len - 1] == MARKER_ESC)
jbg_buf_write(MARKER_STUFF, head);
return;
}
/*
* The jbg_buf list which starts with block *new_prefix is concatenated
* with the list which starts with block **start and *start will then point
* to the first block of the new list.
*/
static void jbg_buf_prefix(struct jbg_buf *new_prefix, struct jbg_buf **start)
{
new_prefix->last->next = *start;
new_prefix->last->next->previous = new_prefix->last;
new_prefix->last = new_prefix->last->next->last;
*start = new_prefix;
return;
}
/*
* Send the contents of a jbg_buf list that starts with block **head to
* the call back function data_out and return the blocks of the jbg_buf
* list to the freelist from which these jbg_buf blocks have been taken.
* After the call, *head == NULL.
*/
static void jbg_buf_output(struct jbg_buf **head,
void (*data_out)(unsigned char *start,
size_t len, void *file),
void *file)
{
struct jbg_buf *tmp;
while (*head) {
data_out((*head)->d, (*head)->len, file);
tmp = (*head)->next;
(*head)->next = *(*head)->free_list;
*(*head)->free_list = *head;
*head = tmp;
}
return;
}
/*
* Calculate y = ceil(x/2) applied n times, which is equivalent to
* y = ceil(x/(2^n)). This function is used to
* determine the number of pixels per row or column after n resolution
* reductions. E.g. X[d-1] = jbg_ceil_half(X[d], 1) and X[0] =
* jbg_ceil_half(X[d], d) as defined in clause 6.2.3 of T.82.
*/
unsigned long jbg_ceil_half(unsigned long x, int n)
{
unsigned long mask;
assert(n >= 0 && n < 32);
mask = (1UL << n) - 1; /* the lowest n bits are 1 here */
return (x >> n) + ((mask & x) != 0);
}
/*
* Set L0 (the number of lines in a stripe at lowest resolution)
* to a default value, such that there are about 35 stripes, as
* suggested in Annex C of ITU-T T.82, without exceeding the
* limit 128/2^D suggested in Annex A.
*/
static void jbg_set_default_l0(struct jbg_enc_state *s)
{
s->l0 = jbg_ceil_half(s->yd, s->d) / 35; /* 35 stripes/image */
while ((s->l0 << s->d) > 128) /* but <= 128 lines/stripe */
--s->l0;
if (s->l0 < 2) s->l0 = 2;
}
/*
* Calculate the number of stripes, as defined in clause 6.2.3 of T.82.
*/
static unsigned long jbg_stripes(unsigned long l0, unsigned long yd,
unsigned long d)
{
unsigned long y0 = jbg_ceil_half(yd, d);
return y0 / l0 + (y0 % l0 != 0);
}
/*
* Initialize the status struct for the encoder.
*/
void jbg_enc_init(struct jbg_enc_state *s, unsigned long x, unsigned long y,
int planes, unsigned char **p,
void (*data_out)(unsigned char *start, size_t len,
void *file),
void *file)
{
unsigned long l, lx;
int i;
extern char jbg_resred[], jbg_dptable[];
s->xd = x;
s->yd = y;
s->yd1 = y; /* This is the hight initially announced in BIH. To provoke
generation of NEWLEN for T.85 compatibility tests,
overwrite with new value s->yd1 > s->yd */
s->planes = planes;
s->data_out = data_out;
s->file = file;
s->d = 0;
s->dl = 0;
s->dh = s->d;
jbg_set_default_l0(s);
s->mx = 8;
s->my = 0;
s->order = JBG_ILEAVE | JBG_SMID;
s->options = JBG_TPBON | JBG_TPDON | JBG_DPON;
s->dppriv = jbg_dptable;
s->res_tab = jbg_resred;
s->highres = (int *) checked_malloc(planes, sizeof(int));
s->lhp[0] = p;
s->lhp[1] = (unsigned char **)
checked_malloc(planes, sizeof(unsigned char *));
for (i = 0; i < planes; i++) {
s->highres[i] = 0;
s->lhp[1][i] = (unsigned char *)
checked_malloc(jbg_ceil_half(y, 1), jbg_ceil_half(x, 1+3));
}
s->free_list = NULL;
s->s = (struct jbg_arenc_state *)
checked_malloc(s->planes, sizeof(struct jbg_arenc_state));
s->tx = (int *) checked_malloc(s->planes, sizeof(int));
lx = jbg_ceil_half(x, 1);
s->tp = (char *) checked_malloc(lx, sizeof(char));
for (l = 0; l < lx; s->tp[l++] = 2);
s->sde = NULL;
return;
}
/*
* This function selects the number of differential layers based on
* the maximum size requested for the lowest resolution layer. If
* possible, a number of differential layers is selected, which will
* keep the size of the lowest resolution layer below or equal to the
* given width x and height y. However not more than 6 differential
* resolution layers will be used. In addition, a reasonable value for
* l0 (height of one stripe in the lowest resolution layer) is
* selected, which obeys the recommended limitations for l0 in annex A
* and C of the JBIG standard. The selected number of resolution layers
* is returned.
*/
int jbg_enc_lrlmax(struct jbg_enc_state *s, unsigned long x,
unsigned long y)
{
for (s->d = 0; s->d < 6; s->d++)
if (jbg_ceil_half(s->xd, s->d) <= x && jbg_ceil_half(s->yd, s->d) <= y)
break;
s->dl = 0;
s->dh = s->d;
jbg_set_default_l0(s);
return s->d;
}
/*
* As an alternative to jbg_enc_lrlmax(), the following function allows
* to specify the number of layers directly. The stripe height and layer
* range is also adjusted automatically here.
*/
void jbg_enc_layers(struct jbg_enc_state *s, int d)
{
if (d < 0 || d > 31)
return;
s->d = d;
s->dl = 0;
s->dh = s->d;
jbg_set_default_l0(s);
return;
}
/*
* Specify the highest and lowest resolution layers which will be
* written to the output file. Call this function not before
* jbg_enc_layers() or jbg_enc_lrlmax(), because these two functions
* reset the lowest and highest resolution layer to default values.
* Negative values are ignored. The total number of layers is returned.
*/
int jbg_enc_lrange(struct jbg_enc_state *s, int dl, int dh)
{
if (dl >= 0 && dl <= s->d) s->dl = dl;
if (dh >= s->dl && dh <= s->d) s->dh = dh;
return s->d;
}
/*
* The following function allows to specify the bits describing the
* options of the format as well as the maximum AT movement window and
* the number of layer 0 lines per stripes.
*/
void jbg_enc_options(struct jbg_enc_state *s, int order, int options,
unsigned long l0, int mx, int my)
{
if (order >= 0 && order <= 0x0f) s->order = order;
if (options >= 0) s->options = options;
if (l0 > 0) s->l0 = l0;
if (mx >= 0 && my < 128) s->mx = mx;
if (my >= 0 && my < 256) s->my = my;
return;
}
/*
* This function actually does all the tricky work involved in producing
* a SDE, which is stored in the appropriate s->sde[][][] element
* for later output in the correct order.
*/
static void encode_sde(struct jbg_enc_state *s,
long stripe, int layer, int plane)
{
unsigned char *hp, *lp1, *lp2, *p0, *p1, *q1, *q2;
unsigned long hl, ll, hx, hy, lx, ly, hbpl, lbpl;
unsigned long line_h0 = 0, line_h1 = 0;
unsigned long line_h2, line_h3, line_l1, line_l2, line_l3;
struct jbg_arenc_state *se;
unsigned long i, j, y;
long o;
unsigned a, p, t;
int ltp, ltp_old, cx;
unsigned long c_all, c[MX_MAX + 1], cmin, cmax, clmin, clmax;
int tmax, at_determined;
int new_tx;
long new_tx_line = -1;
struct jbg_buf *new_jbg_buf;
#ifdef DEBUG
static long tp_lines, tp_exceptions, tp_pixels, dp_pixels;
static long encoded_pixels;
#endif
/* return immediately if this stripe has already been encoded */
if (s->sde[stripe][layer][plane] != SDE_TODO)
return;
#ifdef DEBUG
if (stripe == 0)
tp_lines = tp_exceptions = tp_pixels = dp_pixels = encoded_pixels = 0;
fprintf(stderr, "encode_sde: s/d/p = %2ld/%2d/%2d\n",
stripe, layer, plane);
#endif
/* number of lines per stripe in highres image */
hl = s->l0 << layer;
/* number of lines per stripe in lowres image */
ll = hl >> 1;
/* current line number in highres image */
y = stripe * hl;
/* number of pixels in highres image */
hx = jbg_ceil_half(s->xd, s->d - layer);
hy = jbg_ceil_half(s->yd, s->d - layer);
/* number of pixels in lowres image */
lx = jbg_ceil_half(hx, 1);
ly = jbg_ceil_half(hy, 1);
/* bytes per line in highres and lowres image */
hbpl = jbg_ceil_half(hx, 3);
lbpl = jbg_ceil_half(lx, 3);
/* pointer to first image byte of highres stripe */
hp = s->lhp[s->highres[plane]][plane] + stripe * hl * hbpl;
lp2 = s->lhp[1 - s->highres[plane]][plane] + stripe * ll * lbpl;
lp1 = lp2 + lbpl;
/* initialize arithmetic encoder */
se = s->s + plane;
arith_encode_init(se, stripe != 0);
s->sde[stripe][layer][plane] = jbg_buf_init(&s->free_list);
se->byte_out = jbg_buf_write;
se->file = s->sde[stripe][layer][plane];
/* initialize adaptive template movement algorithm */
c_all = 0;
for (t = 0; t <= s->mx; t++)
c[t] = 0;
if (stripe == 0)
s->tx[plane] = 0;
new_tx = -1;
at_determined = 0; /* we haven't yet decided the template move */
if (s->mx == 0)
at_determined = 1;
/* initialize typical prediction */
ltp = 0;
if (stripe == 0)
ltp_old = 0;
else {
ltp_old = 1;
p1 = hp - hbpl;
if (y > 1) {
q1 = p1 - hbpl;
while (p1 < hp && (ltp_old = (*p1++ == *q1++)) != 0);
} else
while (p1 < hp && (ltp_old = (*p1++ == 0)) != 0);
}
if (layer == 0) {
/*
* Encode lowest resolution layer
*/
for (i = 0; i < hl && y < hy; i++, y++) {
/* check whether it is worth to perform an ATMOVE */
if (!at_determined && c_all > 2048) {
cmin = clmin = 0xffffffffL;
cmax = clmax = 0;
tmax = 0;
for (t = (s->options & JBG_LRLTWO) ? 5 : 3; t <= s->mx; t++) {
if (c[t] > cmax) cmax = c[t];
if (c[t] < cmin) cmin = c[t];
if (c[t] > c[tmax]) tmax = t;
}
clmin = (c[0] < cmin) ? c[0] : cmin;
clmax = (c[0] > cmax) ? c[0] : cmax;
if (c_all - cmax < (c_all >> 3) &&
cmax - c[s->tx[plane]] > c_all - cmax &&
cmax - c[s->tx[plane]] > (c_all >> 4) &&
/* ^ T.82 said < here, fixed in Cor.1/25 */
cmax - (c_all - c[s->tx[plane]]) > c_all - cmax &&
cmax - (c_all - c[s->tx[plane]]) > (c_all >> 4) &&
cmax - cmin > (c_all >> 2) &&
(s->tx[plane] || clmax - clmin > (c_all >> 3))) {
/* we have decided to perform an ATMOVE */
new_tx = tmax;
if (!(s->options & JBG_DELAY_AT)) {
new_tx_line = i;
s->tx[plane] = new_tx;
}
#ifdef DEBUG
fprintf(stderr, "ATMOVE: line=%ld, tx=%d, c_all=%ld\n",
i, new_tx, c_all);
#endif
}
at_determined = 1;
}
assert(s->tx[plane] >= 0); /* i.e., tx can safely be cast to unsigned */
/* typical prediction */
if (s->options & JBG_TPBON) {
ltp = 1;
p1 = hp;
if (y > 0) {
q1 = hp - hbpl;
while (q1 < hp && (ltp = (*p1++ == *q1++)) != 0);
} else
while (p1 < hp + hbpl && (ltp = (*p1++ == 0)) != 0);
arith_encode(se, (s->options & JBG_LRLTWO) ? TPB2CX : TPB3CX,
ltp == ltp_old);
#ifdef DEBUG
tp_lines += ltp;
#endif
ltp_old = ltp;
if (ltp) {
/* skip next line */
hp += hbpl;
continue;
}
}
/*
* Layout of the variables line_h1, line_h2, line_h3, which contain
* as bits the neighbour pixels of the currently coded pixel X:
*
* 76543210765432107654321076543210 line_h3
* 76543210765432107654321076543210 line_h2
* 76543210765432107654321X76543210 line_h1
*/
line_h1 = line_h2 = line_h3 = 0;
if (y > 0) line_h2 = (long)*(hp - hbpl) << 8;
if (y > 1) line_h3 = (long)*(hp - hbpl - hbpl) << 8;
/* encode line */
for (j = 0; j < hx; hp++) {
line_h1 |= *hp;
if (j < hbpl * 8 - 8 && y > 0) {
line_h2 |= *(hp - hbpl + 1);
if (y > 1)
line_h3 |= *(hp - hbpl - hbpl + 1);
}
if (s->options & JBG_LRLTWO) {
/* two line template */
do {
line_h1 <<= 1; line_h2 <<= 1; line_h3 <<= 1;
if (s->tx[plane]) {
if ((unsigned) s->tx[plane] > j)
a = 0;
else {
o = (j - s->tx[plane]) - (j & ~7L);
a = (hp[o >> 3] >> (7 - (o & 7))) & 1;
a <<= 4;
}
assert(s->tx[plane] > 23 ||
a == ((line_h1 >> (4 + s->tx[plane])) & 0x010));
arith_encode(se, (((line_h2 >> 10) & 0x3e0) | a |
((line_h1 >> 9) & 0x00f)),
(line_h1 >> 8) & 1);
}
else
arith_encode(se, (((line_h2 >> 10) & 0x3f0) |
((line_h1 >> 9) & 0x00f)),
(line_h1 >> 8) & 1);
#ifdef DEBUG
encoded_pixels++;
#endif
/* statistics for adaptive template changes */
if (!at_determined && j >= s->mx && j < hx-2) {
p = (line_h1 & 0x100) != 0; /* current pixel value */
c[0] += ((line_h2 & 0x4000) != 0) == p; /* default position */
assert(!(((line_h2 >> 6) ^ line_h1) & 0x100) ==
(((line_h2 & 0x4000) != 0) == p));
for (t = 5; t <= s->mx && t <= j; t++) {
o = (j - t) - (j & ~7L);
a = (hp[o >> 3] >> (7 - (o & 7))) & 1;
assert(t > 23 ||
(a == p) == !(((line_h1 >> t) ^ line_h1) & 0x100));
c[t] += a == p;
}
for (; t <= s->mx; t++) {
c[t] += 0 == p;
}
++c_all;
}
} while (++j & 7 && j < hx);
} else {
/* three line template */
do {
line_h1 <<= 1; line_h2 <<= 1; line_h3 <<= 1;
if (s->tx[plane]) {
if ((unsigned) s->tx[plane] > j)
a = 0;
else {
o = (j - s->tx[plane]) - (j & ~7L);
a = (hp[o >> 3] >> (7 - (o & 7))) & 1;
a <<= 2;
}
assert(s->tx[plane] > 23 ||
a == ((line_h1 >> (6 + s->tx[plane])) & 0x004));
arith_encode(se, (((line_h3 >> 8) & 0x380) |
((line_h2 >> 12) & 0x078) | a |
((line_h1 >> 9) & 0x003)),
(line_h1 >> 8) & 1);
} else
arith_encode(se, (((line_h3 >> 8) & 0x380) |
((line_h2 >> 12) & 0x07c) |
((line_h1 >> 9) & 0x003)),
(line_h1 >> 8) & 1);
#ifdef DEBUG
encoded_pixels++;
#endif
/* statistics for adaptive template changes */
if (!at_determined && j >= s->mx && j < hx-2) {
p = (line_h1 & 0x100) != 0; /* current pixel value */
c[0] += ((line_h2 & 0x4000) != 0) == p; /* default position */
assert(!(((line_h2 >> 6) ^ line_h1) & 0x100) ==
(((line_h2 & 0x4000) != 0) == p));
for (t = 3; t <= s->mx && t <= j; t++) {
o = (j - t) - (j & ~7L);
a = (hp[o >> 3] >> (7 - (o & 7))) & 1;
assert(t > 23 ||
(a == p) == !(((line_h1 >> t) ^ line_h1) & 0x100));
c[t] += a == p;
}
for (; t <= s->mx; t++) {
c[t] += 0 == p;
}
++c_all;
}
} while (++j & 7 && j < hx);
} /* if (s->options & JBG_LRLTWO) */
} /* for (j = ...) */
} /* for (i = ...) */
} else {
/*
* Encode differential layer
*/
for (i = 0; i < hl && y < hy; i++, y++) {
/* check whether it is worth to perform an ATMOVE */
if (!at_determined && c_all > 2048) {
cmin = clmin = 0xffffffffL;
cmax = clmax = 0;
tmax = 0;
for (t = 3; t <= s->mx; t++) {
if (c[t] > cmax) cmax = c[t];
if (c[t] < cmin) cmin = c[t];
if (c[t] > c[tmax]) tmax = t;
}
clmin = (c[0] < cmin) ? c[0] : cmin;
clmax = (c[0] > cmax) ? c[0] : cmax;
if (c_all - cmax < (c_all >> 3) &&
cmax - c[s->tx[plane]] > c_all - cmax &&
cmax - c[s->tx[plane]] > (c_all >> 4) &&
/* ^ T.82 said < here, fixed in Cor.1/25 */
cmax - (c_all - c[s->tx[plane]]) > c_all - cmax &&
cmax - (c_all - c[s->tx[plane]]) > (c_all >> 4) &&
cmax - cmin > (c_all >> 2) &&
(s->tx[plane] || clmax - clmin > (c_all >> 3))) {
/* we have decided to perform an ATMOVE */
new_tx = tmax;
if (!(s->options & JBG_DELAY_AT)) {
new_tx_line = i;
s->tx[plane] = new_tx;
}
#ifdef DEBUG
fprintf(stderr, "ATMOVE: line=%ld, tx=%d, c_all=%ld\n",
i, new_tx, c_all);
#endif
}
at_determined = 1;
}
if ((i >> 1) >= ll - 1 || (y >> 1) >= ly - 1)
lp1 = lp2;
/* typical prediction */
if (s->options & JBG_TPDON && (i & 1) == 0) {
q1 = lp1; q2 = lp2;
p0 = p1 = hp;
if (i < hl - 1 && y < hy - 1)
p0 = hp + hbpl;
if (y > 1)
line_l3 = (long)*(q2 - lbpl) << 8;
else
line_l3 = 0;
line_l2 = (long)*q2 << 8;
line_l1 = (long)*q1 << 8;
ltp = 1;
for (j = 0; j < lx && ltp; q1++, q2++) {
if (j < lbpl * 8 - 8) {
if (y > 1)
line_l3 |= *(q2 - lbpl + 1);
line_l2 |= *(q2 + 1);
line_l1 |= *(q1 + 1);
}
do {
if ((j >> 2) < hbpl) {
line_h1 = *(p1++);
line_h0 = *(p0++);
}
do {
line_l3 <<= 1;
line_l2 <<= 1;
line_l1 <<= 1;
line_h1 <<= 2;
line_h0 <<= 2;
cx = (((line_l3 >> 15) & 0x007) |
((line_l2 >> 12) & 0x038) |
((line_l1 >> 9) & 0x1c0));
if (cx == 0x000)
if ((line_h1 & 0x300) == 0 && (line_h0 & 0x300) == 0)
s->tp[j] = 0;
else {
ltp = 0;
#ifdef DEBUG
tp_exceptions++;
#endif
}
else if (cx == 0x1ff)
if ((line_h1 & 0x300) == 0x300 && (line_h0 & 0x300) == 0x300)
s->tp[j] = 1;
else {
ltp = 0;
#ifdef DEBUG
tp_exceptions++;
#endif
}
else
s->tp[j] = 2;
} while (++j & 3 && j < lx);
} while (j & 7 && j < lx);
} /* for (j = ...) */
arith_encode(se, TPDCX, !ltp);
#ifdef DEBUG
tp_lines += ltp;
#endif
}
/*
* Layout of the variables line_h1, line_h2, line_h3, which contain
* as bits the high resolution neighbour pixels of the currently coded
* highres pixel X:
*
* 76543210 76543210 76543210 76543210 line_h3
* 76543210 76543210 76543210 76543210 line_h2
* 76543210 76543210 7654321X 76543210 line_h1
*
* Layout of the variables line_l1, line_l2, line_l3, which contain
* the low resolution pixels near the currently coded pixel as bits.
* The lowres pixel in which the currently coded highres pixel is
* located is marked as Y:
*
* 76543210 76543210 76543210 76543210 line_l3
* 76543210 7654321Y 76543210 76543210 line_l2
* 76543210 76543210 76543210 76543210 line_l1
*/
line_h1 = line_h2 = line_h3 = line_l1 = line_l2 = line_l3 = 0;
if (y > 0) line_h2 = (long)*(hp - hbpl) << 8;
if (y > 1) {
line_h3 = (long)*(hp - hbpl - hbpl) << 8;
line_l3 = (long)*(lp2 - lbpl) << 8;
}
line_l2 = (long)*lp2 << 8;
line_l1 = (long)*lp1 << 8;
/* encode line */
for (j = 0; j < hx; lp1++, lp2++) {
if ((j >> 1) < lbpl * 8 - 8) {
if (y > 1)
line_l3 |= *(lp2 - lbpl + 1);
line_l2 |= *(lp2 + 1);
line_l1 |= *(lp1 + 1);
}
do { /* ... while (j & 15 && j < hx) */
assert(hp - (s->lhp[s->highres[plane]][plane] +
(stripe * hl + i) * hbpl)
== (ptrdiff_t) j >> 3);
assert(lp2 - (s->lhp[1-s->highres[plane]][plane] +
(stripe * ll + (i>>1)) * lbpl)
== (ptrdiff_t) j >> 4);
line_h1 |= *hp;
if (j < hbpl * 8 - 8) {
if (y > 0) {
line_h2 |= *(hp - hbpl + 1);
if (y > 1)
line_h3 |= *(hp - hbpl - hbpl + 1);
}
}
do { /* ... while (j & 7 && j < hx) */
line_l1 <<= 1; line_l2 <<= 1; line_l3 <<= 1;
if (ltp && s->tp[j >> 1] < 2) {
/* pixel are typical and have not to be encoded */
line_h1 <<= 2; line_h2 <<= 2; line_h3 <<= 2;
#ifdef DEBUG
do {
++tp_pixels;
} while (++j & 1 && j < hx);
#else
j += 2;
#endif
} else
do { /* ... while (++j & 1 && j < hx) */
line_h1 <<= 1; line_h2 <<= 1; line_h3 <<= 1;
/* deterministic prediction */
if (s->options & JBG_DPON) {
if ((y & 1) == 0) {
if ((j & 1) == 0) {
/* phase 0 */
if (s->dppriv[((line_l3 >> 16) & 0x003) |
((line_l2 >> 14) & 0x00c) |
((line_h1 >> 5) & 0x010) |
((line_h2 >> 10) & 0x0e0)] < 2) {
#ifdef DEBUG
++dp_pixels;
#endif
continue;
}
} else {
/* phase 1 */
if (s->dppriv[(((line_l3 >> 16) & 0x003) |
((line_l2 >> 14) & 0x00c) |
((line_h1 >> 5) & 0x030) |
((line_h2 >> 10) & 0x1c0)) + 256] < 2) {
#ifdef DEBUG
++dp_pixels;
#endif
continue;
}
}
} else {
if ((j & 1) == 0) {
/* phase 2 */
if (s->dppriv[(((line_l3 >> 16) & 0x003) |
((line_l2 >> 14) & 0x00c) |
((line_h1 >> 5) & 0x010) |
((line_h2 >> 10) & 0x0e0) |
((line_h3 >> 7) & 0x700)) + 768] < 2) {
#ifdef DEBUG
++dp_pixels;
#endif
continue;
}
} else {
/* phase 3 */
if (s->dppriv[(((line_l3 >> 16) & 0x003) |
((line_l2 >> 14) & 0x00c) |
((line_h1 >> 5) & 0x030) |
((line_h2 >> 10) & 0x1c0) |
((line_h3 >> 7) & 0xe00)) + 2816] < 2) {
#ifdef DEBUG
++dp_pixels;
#endif
continue;
}
}
}
}
/* determine context */
if (s->tx[plane]) {
if ((unsigned) s->tx[plane] > j)
a = 0;
else {
o = (j - s->tx[plane]) - (j & ~7L);
a = (hp[o >> 3] >> (7 - (o & 7))) & 1;
a <<= 4;
}
assert(s->tx[plane] > 23 ||
a == ((line_h1 >> (4 + s->tx[plane])) & 0x010));
cx = (((line_h1 >> 9) & 0x003) | a |
((line_h2 >> 13) & 0x00c) |
((line_h3 >> 11) & 0x020));
} else
cx = (((line_h1 >> 9) & 0x003) |
((line_h2 >> 13) & 0x01c) |
((line_h3 >> 11) & 0x020));
if (j & 1)
cx |= (((line_l2 >> 9) & 0x0c0) |
((line_l1 >> 7) & 0x300)) | (1UL << 10);
else
cx |= (((line_l2 >> 10) & 0x0c0) |
((line_l1 >> 8) & 0x300));
cx |= (y & 1) << 11;
arith_encode(se, cx, (line_h1 >> 8) & 1);
#ifdef DEBUG
encoded_pixels++;
#endif
/* statistics for adaptive template changes */
if (!at_determined && j >= s->mx) {
c[0] += !(((line_h2 >> 6) ^ line_h1) & 0x100);
for (t = 3; t <= s->mx; t++)
c[t] += !(((line_h1 >> t) ^ line_h1) & 0x100);
++c_all;
}
} while (++j & 1 && j < hx);
} while (j & 7 && j < hx);
hp++;
} while (j & 15 && j < hx);
} /* for (j = ...) */
/* low resolution pixels are used twice */
if ((i & 1) == 0) {
lp1 -= lbpl;
lp2 -= lbpl;
}
} /* for (i = ...) */
}
arith_encode_flush(se);
jbg_buf_remove_zeros(s->sde[stripe][layer][plane]);
jbg_buf_write(MARKER_ESC, s->sde[stripe][layer][plane]);
jbg_buf_write(MARKER_SDNORM, s->sde[stripe][layer][plane]);
/* add ATMOVE */
if (new_tx != -1) {
if (s->options & JBG_DELAY_AT) {
/* ATMOVE will become active at the first line of the next stripe */
s->tx[plane] = new_tx;
jbg_buf_write(MARKER_ESC, s->sde[stripe][layer][plane]);
jbg_buf_write(MARKER_ATMOVE, s->sde[stripe][layer][plane]);
jbg_buf_write(0, s->sde[stripe][layer][plane]);
jbg_buf_write(0, s->sde[stripe][layer][plane]);
jbg_buf_write(0, s->sde[stripe][layer][plane]);
jbg_buf_write(0, s->sde[stripe][layer][plane]);
jbg_buf_write(s->tx[plane], s->sde[stripe][layer][plane]);
jbg_buf_write(0, s->sde[stripe][layer][plane]);
} else {
/* ATMOVE has already become active during this stripe
* => we have to prefix the SDE data with an ATMOVE marker */
new_jbg_buf = jbg_buf_init(&s->free_list);
jbg_buf_write(MARKER_ESC, new_jbg_buf);
jbg_buf_write(MARKER_ATMOVE, new_jbg_buf);
jbg_buf_write((new_tx_line >> 24) & 0xff, new_jbg_buf);
jbg_buf_write((new_tx_line >> 16) & 0xff, new_jbg_buf);
jbg_buf_write((new_tx_line >> 8) & 0xff, new_jbg_buf);
jbg_buf_write(new_tx_line & 0xff, new_jbg_buf);
jbg_buf_write(new_tx, new_jbg_buf);
jbg_buf_write(0, new_jbg_buf);
jbg_buf_prefix(new_jbg_buf, &s->sde[stripe][layer][plane]);
}
}
#if 0
if (stripe == s->stripes - 1)
fprintf(stderr, "tp_lines = %ld, tp_exceptions = %ld, tp_pixels = %ld, "
"dp_pixels = %ld, encoded_pixels = %ld\n",
tp_lines, tp_exceptions, tp_pixels, dp_pixels, encoded_pixels);
#endif
return;
}
/*
* Create the next lower resolution version of an image
*/
static void resolution_reduction(struct jbg_enc_state *s, int plane,
int higher_layer)
{
unsigned long hx, hy, lx, ly, hbpl, lbpl;
unsigned char *hp1, *hp2, *hp3, *lp;
unsigned long line_h1, line_h2, line_h3, line_l2;
unsigned long i, j;
int pix, k, l;
/* number of pixels in highres image */
hx = jbg_ceil_half(s->xd, s->d - higher_layer);
hy = jbg_ceil_half(s->yd, s->d - higher_layer);
/* number of pixels in lowres image */
lx = jbg_ceil_half(hx, 1);
ly = jbg_ceil_half(hy, 1);
/* bytes per line in highres and lowres image */
hbpl = jbg_ceil_half(hx, 3);
lbpl = jbg_ceil_half(lx, 3);
/* pointers to first image bytes */
hp2 = s->lhp[s->highres[plane]][plane];
hp1 = hp2 + hbpl;
hp3 = hp2 - hbpl;
lp = s->lhp[1 - s->highres[plane]][plane];
#ifdef DEBUG
fprintf(stderr, "resolution_reduction: plane = %d, higher_layer = %d\n",
plane, higher_layer);
#endif
/*
* Layout of the variables line_h1, line_h2, line_h3, which contain
* as bits the high resolution neighbour pixels of the currently coded
* lowres pixel /\:
* \/
*
* 76543210 76543210 76543210 76543210 line_h3
* 76543210 76543210 765432/\ 76543210 line_h2
* 76543210 76543210 765432\/ 76543210 line_h1
*
* Layout of the variable line_l2, which contains the low resolution
* pixels near the currently coded pixel as bits. The lowres pixel
* which is currently coded is marked as X:
*
* 76543210 76543210 76543210 76543210 line_l2
* X
*/
for (i = 0; i < ly; i++) {
if (2*i + 1 >= hy)
hp1 = hp2;
pix = 0;
line_h1 = line_h2 = line_h3 = line_l2 = 0;
for (j = 0; j < lbpl * 8; j += 8) {
*lp = 0;
line_l2 |= i ? *(lp-lbpl) : 0;
for (k = 0; k < 8 && j + k < lx; k += 4) {
if (((j + k) >> 2) < hbpl) {
line_h3 |= i ? *hp3 : 0;
++hp3;
line_h2 |= *(hp2++);
line_h1 |= *(hp1++);
}
for (l = 0; l < 4 && j + k + l < lx; l++) {
line_h3 <<= 2;
line_h2 <<= 2;
line_h1 <<= 2;
line_l2 <<= 1;
pix = s->res_tab[((line_h1 >> 8) & 0x007) |
((line_h2 >> 5) & 0x038) |
((line_h3 >> 2) & 0x1c0) |
(pix << 9) | ((line_l2 << 2) & 0xc00)];
*lp = (*lp << 1) | pix;
}
}
++lp;
}
*(lp - 1) <<= lbpl * 8 - lx;
hp1 += hbpl;
hp2 += hbpl;
hp3 += hbpl;
}
#ifdef DEBUG
{
FILE *f;
char fn[50];
sprintf(fn, "dbg_d=%02d.pbm", higher_layer - 1);
f = fopen(fn, "wb");
fprintf(f, "P4\n%lu %lu\n", lx, ly);
fwrite(s->lhp[1 - s->highres[plane]][plane], 1, lbpl * ly, f);
fclose(f);
}
#endif
return;
}
/*
* This function is called inside the three loops of jbg_enc_out() in
* order to write the next SDE. It has first to generate the required
* SDE and all SDEs which have to be encoded before this SDE can be
* created. The problem here is that if we want to output a lower
* resolution layer, we have to allpy the resolution reduction
* algorithm in order to get it. As we try to safe as much memory as
* possible, the resolution reduction will overwrite previous higher
* resolution bitmaps. Consequently, we have to encode and buffer SDEs
* which depend on higher resolution layers before we can start the
* resolution reduction. All this logic about which SDE has to be
* encoded before resolution reduction is allowed is handled here.
* This approach might be a little bit more complex than alternative
* ways to do it, but it allows us to do the encoding with the minimal
* possible amount of temporary memory.
*/
static void output_sde(struct jbg_enc_state *s,
unsigned long stripe, int layer, int plane)
{
int lfcl; /* lowest fully coded layer */
long i;
unsigned long u;
assert(s->sde[stripe][layer][plane] != SDE_DONE);
if (s->sde[stripe][layer][plane] != SDE_TODO) {
#ifdef DEBUG
fprintf(stderr, "writing SDE: s/d/p = %2lu/%2d/%2d\n",
stripe, layer, plane);
#endif
jbg_buf_output(&s->sde[stripe][layer][plane], s->data_out, s->file);
s->sde[stripe][layer][plane] = SDE_DONE;
return;
}
/* Determine the smallest resolution layer in this plane for which
* not yet all stripes have been encoded into SDEs. This layer will
* have to be completely coded, before we can apply the next
* resolution reduction step. */
lfcl = 0;
for (i = s->d; i >= 0; i--)
if (s->sde[s->stripes - 1][i][plane] == SDE_TODO) {
lfcl = i + 1;
break;
}
if (lfcl > s->d && s->d > 0 && stripe == 0) {
/* perform the first resolution reduction */
resolution_reduction(s, plane, s->d);
}
/* In case HITOLO is not used, we have to encode and store the higher
* resolution layers first, although we do not need them right now. */
while (lfcl - 1 > layer) {
for (u = 0; u < s->stripes; u++)
encode_sde(s, u, lfcl - 1, plane);
--lfcl;
s->highres[plane] ^= 1;
if (lfcl > 1)
resolution_reduction(s, plane, lfcl - 1);
}
encode_sde(s, stripe, layer, plane);
#ifdef DEBUG
fprintf(stderr, "writing SDE: s/d/p = %2lu/%2d/%2d\n", stripe, layer, plane);
#endif
jbg_buf_output(&s->sde[stripe][layer][plane], s->data_out, s->file);
s->sde[stripe][layer][plane] = SDE_DONE;
if (stripe == s->stripes - 1 && layer > 0 &&
s->sde[0][layer-1][plane] == SDE_TODO) {
s->highres[plane] ^= 1;
if (layer > 1)
resolution_reduction(s, plane, layer - 1);
}
return;
}
/*
* Convert the table which controls the deterministic prediction
* process from the internal format into the representation required
* for the 1728 byte long DPTABLE element of a BIH.
*
* The bit order of the DPTABLE format (see also ITU-T T.82 figure 13) is
*
* high res: 4 5 6 low res: 0 1
* 7 8 9 2 3
* 10 11 12
*
* were 4 table entries are packed into one byte, while we here use
* internally an unpacked 6912 byte long table indexed by the following
* bit order:
*
* high res: 7 6 5 high res: 8 7 6 low res: 1 0
* (phase 0) 4 . . (phase 1) 5 4 . 3 2
* . . . . . .
*
* high res: 10 9 8 high res: 11 10 9
* (phase 2) 7 6 5 (phase 3) 8 7 6
* 4 . . 5 4 .
*/
void jbg_int2dppriv(unsigned char *dptable, const char *internal)
{
int i, j, k;
int trans0[ 8] = { 1, 0, 3, 2, 7, 6, 5, 4 };
int trans1[ 9] = { 1, 0, 3, 2, 8, 7, 6, 5, 4 };
int trans2[11] = { 1, 0, 3, 2, 10, 9, 8, 7, 6, 5, 4 };
int trans3[12] = { 1, 0, 3, 2, 11, 10, 9, 8, 7, 6, 5, 4 };
for (i = 0; i < 1728; dptable[i++] = 0);
#define FILL_TABLE1(offset, len, trans) \
for (i = 0; i < len; i++) { \
k = 0; \
for (j = 0; j < 8; j++) \
k |= ((i >> j) & 1) << trans[j]; \
dptable[(i + offset) >> 2] |= \
(internal[k + offset] & 3) << ((3 - (i&3)) << 1); \
}
FILL_TABLE1( 0, 256, trans0);
FILL_TABLE1( 256, 512, trans1);
FILL_TABLE1( 768, 2048, trans2);
FILL_TABLE1(2816, 4096, trans3);
return;
}
/*
* Convert the table which controls the deterministic prediction
* process from the 1728 byte long DPTABLE format into the 6912 byte long
* internal format.
*/
void jbg_dppriv2int(char *internal, const unsigned char *dptable)
{
int i, j, k;
int trans0[ 8] = { 1, 0, 3, 2, 7, 6, 5, 4 };
int trans1[ 9] = { 1, 0, 3, 2, 8, 7, 6, 5, 4 };
int trans2[11] = { 1, 0, 3, 2, 10, 9, 8, 7, 6, 5, 4 };
int trans3[12] = { 1, 0, 3, 2, 11, 10, 9, 8, 7, 6, 5, 4 };
#define FILL_TABLE2(offset, len, trans) \
for (i = 0; i < len; i++) { \
k = 0; \
for (j = 0; j < 8; j++) \
k |= ((i >> j) & 1) << trans[j]; \
internal[k + offset] = \
(dptable[(i + offset) >> 2] >> ((3 - (i & 3)) << 1)) & 3; \
}
FILL_TABLE2( 0, 256, trans0);
FILL_TABLE2( 256, 512, trans1);
FILL_TABLE2( 768, 2048, trans2);
FILL_TABLE2(2816, 4096, trans3);
return;
}
/*
* Encode one full BIE and pass the generated data to the specified
* call-back function
*/
void jbg_enc_out(struct jbg_enc_state *s)
{
unsigned long bpl;
unsigned char buf[20];
unsigned long xd, yd, y;
long ii[3], is[3], ie[3]; /* generic variables for the 3 nested loops */
unsigned long stripe;
int layer, plane;
int order;
unsigned char dpbuf[1728];
extern char jbg_dptable[];
/* some sanity checks */
s->order &= JBG_HITOLO | JBG_SEQ | JBG_ILEAVE | JBG_SMID;
order = s->order & (JBG_SEQ | JBG_ILEAVE | JBG_SMID);
if (iindex[order][0] < 0)
s->order = order = JBG_SMID | JBG_ILEAVE;
if (s->options & JBG_DPON && s->dppriv != jbg_dptable)
s->options |= JBG_DPPRIV;
if (s->mx > MX_MAX)
s->mx = MX_MAX;
s->my = 0;
if (s->mx && s->mx < ((s->options & JBG_LRLTWO) ? 5U : 3U))
s->mx = 0;
if (s->d > 255 || s->d < 0 || s->dh > s->d || s->dh < 0 ||
s->dl < 0 || s->dl > s->dh || s->planes < 0 || s->planes > 255)
return;
/* prevent uint32 overflow: s->l0 * 2 ^ s->d < 2 ^ 32 */
if (s->d > 31 || (s->d != 0 && s->l0 >= (1UL << (32 - s->d))))
return;
if (s->yd1 < s->yd)
s->yd1 = s->yd;
if (s->yd1 > s->yd)
s->options |= JBG_VLENGTH;
/* ensure correct zero padding of bitmap at the final byte of each line */
if (s->xd & 7) {
bpl = jbg_ceil_half(s->xd, 3); /* bytes per line */
for (plane = 0; plane < s->planes; plane++)
for (y = 0; y < s->yd; y++)
s->lhp[0][plane][y * bpl + bpl - 1] &= ~((1 << (8 - (s->xd & 7))) - 1);
}
/* prepare BIH */
buf[0] = s->dl;
buf[1] = s->dh;
buf[2] = s->planes;
buf[3] = 0;
xd = jbg_ceil_half(s->xd, s->d - s->dh);
yd = jbg_ceil_half(s->yd1, s->d - s->dh);
buf[4] = xd >> 24;
buf[5] = (xd >> 16) & 0xff;
buf[6] = (xd >> 8) & 0xff;
buf[7] = xd & 0xff;
buf[8] = yd >> 24;
buf[9] = (yd >> 16) & 0xff;
buf[10] = (yd >> 8) & 0xff;
buf[11] = yd & 0xff;
buf[12] = s->l0 >> 24;
buf[13] = (s->l0 >> 16) & 0xff;
buf[14] = (s->l0 >> 8) & 0xff;
buf[15] = s->l0 & 0xff;
buf[16] = s->mx;
buf[17] = s->my;
buf[18] = s->order;
buf[19] = s->options & 0x7f;
#if 0
/* sanitize L0 (if it was set to 0xffffffff for T.85-style NEWLEN tests) */
if (s->l0 > (s->yd >> s->d))
s->l0 = s->yd >> s->d;
#endif
/* calculate number of stripes that will be required */
s->stripes = jbg_stripes(s->l0, s->yd, s->d);
/* allocate buffers for SDE pointers */
if (s->sde == NULL) {
s->sde = (struct jbg_buf ****)
checked_malloc(s->stripes, sizeof(struct jbg_buf ***));
for (stripe = 0; stripe < s->stripes; stripe++) {
s->sde[stripe] = (struct jbg_buf ***)
checked_malloc(s->d + 1, sizeof(struct jbg_buf **));
for (layer = 0; layer < s->d + 1; layer++) {
s->sde[stripe][layer] = (struct jbg_buf **)
checked_malloc(s->planes, sizeof(struct jbg_buf *));
for (plane = 0; plane < s->planes; plane++)
s->sde[stripe][layer][plane] = SDE_TODO;
}
}
}
/* output BIH */
s->data_out(buf, 20, s->file);
if ((s->options & (JBG_DPON | JBG_DPPRIV | JBG_DPLAST)) ==
(JBG_DPON | JBG_DPPRIV)) {
/* write private table */
jbg_int2dppriv(dpbuf, s->dppriv);
s->data_out(dpbuf, 1728, s->file);
}
#if 0
/*
* Encode everything first. This is a simple-minded alternative to
* all the tricky on-demand encoding logic in output_sde() for
* debugging purposes.
*/
for (layer = s->dh; layer >= s->dl; layer--) {
for (plane = 0; plane < s->planes; plane++) {
if (layer > 0)
resolution_reduction(s, plane, layer);
for (stripe = 0; stripe < s->stripes; stripe++)
encode_sde(s, stripe, layer, plane);
s->highres[plane] ^= 1;
}
}
#endif
/*
* Generic loops over all SDEs. Which loop represents layer, plane and
* stripe depends on the option flags.
*/
/* start and end value vor each loop */
is[iindex[order][STRIPE]] = 0;
ie[iindex[order][STRIPE]] = s->stripes - 1;
is[iindex[order][LAYER]] = s->dl;
ie[iindex[order][LAYER]] = s->dh;
is[iindex[order][PLANE]] = 0;
ie[iindex[order][PLANE]] = s->planes - 1;
for (ii[0] = is[0]; ii[0] <= ie[0]; ii[0]++)
for (ii[1] = is[1]; ii[1] <= ie[1]; ii[1]++)
for (ii[2] = is[2]; ii[2] <= ie[2]; ii[2]++) {
stripe = ii[iindex[order][STRIPE]];
if (s->order & JBG_HITOLO)
layer = s->dh - (ii[iindex[order][LAYER]] - s->dl);
else
layer = ii[iindex[order][LAYER]];
plane = ii[iindex[order][PLANE]];
output_sde(s, stripe, layer, plane);
/*
* When we generate a NEWLEN test case (s->yd1 > s->yd), output
* NEWLEN after last stripe if we have only a single
* resolution layer or plane (see ITU-T T.85 profile), otherwise
* output NEWLEN before last stripe.
*/
if (s->yd1 > s->yd &&
(stripe == s->stripes - 1 ||
(stripe == s->stripes - 2 &&
(s->dl != s->dh || s->planes > 1)))) {
s->yd1 = s->yd;
yd = jbg_ceil_half(s->yd, s->d - s->dh);
buf[0] = MARKER_ESC;
buf[1] = MARKER_NEWLEN;
buf[2] = yd >> 24;
buf[3] = (yd >> 16) & 0xff;
buf[4] = (yd >> 8) & 0xff;
buf[5] = yd & 0xff;
s->data_out(buf, 6, s->file);
#ifdef DEBUG
fprintf(stderr, "NEWLEN: yd=%lu\n", yd);
#endif
if (stripe == s->stripes - 1) {
buf[1] = MARKER_SDNORM;
s->data_out(buf, 2, s->file);
}
}
}
return;
}
void jbg_enc_free(struct jbg_enc_state *s)
{
unsigned long stripe;
int layer, plane;
#ifdef DEBUG
fprintf(stderr, "jbg_enc_free(%p)\n", (void *) s);
#endif
/* clear buffers for SDEs */
if (s->sde) {
for (stripe = 0; stripe < s->stripes; stripe++) {
for (layer = 0; layer < s->d + 1; layer++) {
for (plane = 0; plane < s->planes; plane++)
if (s->sde[stripe][layer][plane] != SDE_DONE &&
s->sde[stripe][layer][plane] != SDE_TODO)
jbg_buf_free(&s->sde[stripe][layer][plane]);
checked_free(s->sde[stripe][layer]);
}
checked_free(s->sde[stripe]);
}
checked_free(s->sde);
}
/* clear free_list */
jbg_buf_free(&s->free_list);
/* clear memory for arithmetic encoder states */
checked_free(s->s);
/* clear memory for differential-layer typical prediction buffer */
checked_free(s->tp);
/* clear memory for adaptive template pixel offsets */
checked_free(s->tx);
/* clear lowres image buffers */
if (s->lhp[1]) {
for (plane = 0; plane < s->planes; plane++)
checked_free(s->lhp[1][plane]);
checked_free(s->lhp[1]);
}
/* clear buffer for index of highres image in lhp */
checked_free(s->highres);
return;
}
/*
* Convert the error codes used by jbg_dec_in() into a string
* written in the selected language and character set.
*/
const char *jbg_strerror(int errnum, int language)
{
if (errnum < 0 || errnum >= NEMSG)
return "Unknown error code passed to jbg_strerror()";
if (language < 0 || language >= NEMSG_LANG)
return "Unknown language code passed to jbg_strerror()";
return errmsg[language][errnum];
}
/*
* The constructor for a decoder
*/
void jbg_dec_init(struct jbg_dec_state *s)
{
s->order = 0;
s->d = -1;
s->bie_len = 0;
s->buf_len = 0;
s->dppriv = NULL;
s->xmax = 4294967295UL;
s->ymax = 4294967295UL;
s->dmax = 256;
s->s = NULL;
return;
}
/*
* Specify a maximum image size for the decoder. If the JBIG file has
* the order bit ILEAVE, but not the bit SEQ set, then the decoder
* will abort to decode after the image has reached the maximal
* resolution layer which is still not wider than xmax or higher than
* ymax.
*/
void jbg_dec_maxsize(struct jbg_dec_state *s, unsigned long xmax,
unsigned long ymax)
{
if (xmax > 0) s->xmax = xmax;
if (ymax > 0) s->ymax = ymax;
return;
}
/*
* Decode the new len PSDC bytes to which data points and add them to
* the current stripe. Return the number of bytes which have actually
* been read (this will be less than len if a marker segment was
* part of the data or if the final byte was 0xff were this code
* can not determine, whether we have a marker segment.
*/
static size_t decode_pscd(struct jbg_dec_state *s, unsigned char *data,
size_t len)
{
unsigned long stripe;
unsigned int layer, plane;
unsigned long hl, ll, y, hx, hy, lx, ly, hbpl, lbpl;
unsigned char *hp, *lp1, *lp2, *p1, *q1;
register unsigned long line_h1, line_h2, line_h3;
register unsigned long line_l1, line_l2, line_l3;
struct jbg_ardec_state *se;
unsigned long x;
long o;
unsigned a;
int n;
int pix, cx = 0, slntp, tx;
/* SDE loop variables */
stripe = s->ii[iindex[s->order & 7][STRIPE]];
layer = s->ii[iindex[s->order & 7][LAYER]];
plane = s->ii[iindex[s->order & 7][PLANE]];
/* forward data to arithmetic decoder */
se = s->s[plane] + layer - s->dl;
se->pscd_ptr = data;
se->pscd_end = data + len;
/* number of lines per stripe in highres image */
hl = s->l0 << layer;
/* number of lines per stripe in lowres image */
ll = hl >> 1;
/* current line number in highres image */
y = stripe * hl + s->i;
/* number of pixels in highres image */
hx = jbg_ceil_half(s->xd, s->d - layer);
hy = jbg_ceil_half(s->yd, s->d - layer);
/* number of pixels in lowres image */
lx = jbg_ceil_half(hx, 1);
ly = jbg_ceil_half(hy, 1);
/* bytes per line in highres and lowres image */
hbpl = jbg_ceil_half(hx, 3);
lbpl = jbg_ceil_half(lx, 3);
/* pointer to highres and lowres image bytes */
hp = s->lhp[ layer & 1][plane] + (stripe * hl + s->i) * hbpl +
(s->x >> 3);
lp2 = s->lhp[(layer-1) & 1][plane] + (stripe * ll + (s->i >> 1)) * lbpl +
(s->x >> 4);
lp1 = lp2 + lbpl;
/* restore a few local variables */
line_h1 = s->line_h1;
line_h2 = s->line_h2;
line_h3 = s->line_h3;
line_l1 = s->line_l1;
line_l2 = s->line_l2;
line_l3 = s->line_l3;
x = s->x;
if (s->x == 0 && s->i == 0 &&
(stripe == 0 || s->reset[plane][layer - s->dl])) {
s->tx[plane][layer - s->dl] = s->ty[plane][layer - s->dl] = 0;
if (s->pseudo)
s->lntp[plane][layer - s->dl] = 1;
}
#ifdef DEBUG
if (s->x == 0 && s->i == 0 && s->pseudo)
fprintf(stderr, "decode_pscd(%p, %p, %ld): s/d/p = %2lu/%2u/%2u\n",
(void *) s, (void *) data, (long) len, stripe, layer, plane);
#endif
if (layer == 0) {
/*
* Decode lowest resolution layer
*/
for (; s->i < hl && y < hy; s->i++, y++) {
/* adaptive template changes */
if (x == 0)
for (n = 0; n < s->at_moves; n++)
if (s->at_line[n] == s->i) {
s->tx[plane][layer - s->dl] = s->at_tx[n];
s->ty[plane][layer - s->dl] = s->at_ty[n];
#ifdef DEBUG
fprintf(stderr, "ATMOVE: line=%lu, tx=%d, ty=%d.\n", s->i,
s->tx[plane][layer - s->dl], s->ty[plane][layer - s->dl]);
#endif
}
tx = s->tx[plane][layer - s->dl];
assert(tx >= 0); /* i.e., tx can safely be cast to unsigned */
/* typical prediction */
if (s->options & JBG_TPBON && s->pseudo) {
slntp = arith_decode(se, (s->options & JBG_LRLTWO) ? TPB2CX : TPB3CX);
if (se->result == JBG_MORE || se->result == JBG_MARKER)
goto leave;
s->lntp[plane][layer - s->dl] =
!(slntp ^ s->lntp[plane][layer - s->dl]);
if (s->lntp[plane][layer - s->dl]) {
/* this line is 'not typical' and has to be coded completely */
s->pseudo = 0;
} else {
/* this line is 'typical' (i.e. identical to the previous one) */
p1 = hp;
if (s->i == 0 && (stripe == 0 || s->reset[plane][layer - s->dl]))
while (p1 < hp + hbpl) *p1++ = 0;
else {
q1 = hp - hbpl;
while (q1 < hp) *p1++ = *q1++;
}
hp += hbpl;
continue;
}
}
/*
* Layout of the variables line_h1, line_h2, line_h3, which contain
* as bits the neighbour pixels of the currently decoded pixel X:
*
* 76543210 76543210 76543210 76543210 line_h3
* 76543210 76543210 76543210 76543210 line_h2
* 76543210 76543210 76543210 76543210 X line_h1
*/
if (x == 0) {
line_h1 = line_h2 = line_h3 = 0;
if (s->i > 0 || (y > 0 && !s->reset[plane][layer - s->dl]))
line_h2 = (long)*(hp - hbpl) << 8;
if (s->i > 1 || (y > 1 && !s->reset[plane][layer - s->dl]))
line_h3 = (long)*(hp - hbpl - hbpl) << 8;
}
/*
* Another tiny JBIG standard bug:
*
* While implementing the line_h3 handling here, I discovered
* another problem with the ITU-T T.82(1993 E) specification.
* This might be a somewhat pathological case, however. The
* standard is unclear about how a decoder should behave in the
* following situation:
*
* Assume we are in layer 0 and all stripes are single lines
* (L0=1 allowed by table 9). We are now decoding the first (and
* only) line of the third stripe. Assume, the first stripe was
* terminated by SDRST and the second stripe was terminated by
* SDNORM. While decoding the only line of the third stripe with
* the three-line template, we need access to pixels from the
* previous two stripes. We know that the previous stripe
* terminated with SDNROM, so we access the pixel from the
* second stripe. But do we have to replace the pixels from the
* first stripe by background pixels, because this stripe ended
* with SDRST? The standard, especially clause 6.2.5 does never
* mention this case, so the behaviour is undefined here. My
* current implementation remembers only the marker used to
* terminate the previous stripe. In the above example, the
* pixels of the first stripe are accessed despite the fact that
* this stripe ended with SDRST. An alternative (only slightly
* more complicated) implementation would be to remember the end
* marker (SDNORM or SDRST) of the previous two stripes in a
* plane/layer and to act accordingly when accessing the two
* previous lines. What am I supposed to do here?
*
* As the standard is unclear about the correct behaviour in the
* situation of the above example, I strongly suggest to avoid
* the following situation while encoding data with JBIG:
*
* LRLTWO = 0, L0=1 and both SDNORM and SDRST appear in layer 0.
*
* I guess that only a very few if any encoders will switch
* between SDNORM and SDRST, so let us hope that this ambiguity
* in the standard will never cause any interoperability
* problems.
*
* Markus Kuhn -- 1995-04-30
*/
/* decode line */
while (x < hx) {
if ((x & 7) == 0) {
if (x < hbpl * 8 - 8 &&
(s->i > 0 || (y > 0 && !s->reset[plane][layer - s->dl]))) {
line_h2 |= *(hp - hbpl + 1);
if (s->i > 1 || (y > 1 && !s->reset[plane][layer - s->dl]))
line_h3 |= *(hp - hbpl - hbpl + 1);
}
}
if (s->options & JBG_LRLTWO) {
/* two line template */
do {
if (tx) {
if ((unsigned) tx > x)
a = 0;
else if (tx < 8)
a = ((line_h1 >> (tx - 5)) & 0x010);
else {
o = (x - tx) - (x & ~7L);
a = (hp[o >> 3] >> (7 - (o & 7))) & 1;
a <<= 4;
}
assert(tx > 31 ||
a == ((line_h1 >> (tx - 5)) & 0x010));
pix = arith_decode(se, (((line_h2 >> 9) & 0x3e0) | a |
(line_h1 & 0x00f)));
} else
pix = arith_decode(se, (((line_h2 >> 9) & 0x3f0) |
(line_h1 & 0x00f)));
if (se->result == JBG_MORE || se->result == JBG_MARKER)
goto leave;
line_h1 = (line_h1 << 1) | pix;
line_h2 <<= 1;
} while ((++x & 7) && x < hx);
} else {
/* three line template */
do {
if (tx) {
if ((unsigned) tx > x)
a = 0;
else if (tx < 8)
a = ((line_h1 >> (tx - 3)) & 0x004);
else {
o = (x - tx) - (x & ~7L);
a = (hp[o >> 3] >> (7 - (o & 7))) & 1;
a <<= 2;
}
assert(tx > 31 ||
a == ((line_h1 >> (tx - 3)) & 0x004));
pix = arith_decode(se, (((line_h3 >> 7) & 0x380) |
((line_h2 >> 11) & 0x078) | a |
(line_h1 & 0x003)));
} else
pix = arith_decode(se, (((line_h3 >> 7) & 0x380) |
((line_h2 >> 11) & 0x07c) |
(line_h1 & 0x003)));
if (se->result == JBG_MORE || se->result == JBG_MARKER)
goto leave;
line_h1 = (line_h1 << 1) | pix;
line_h2 <<= 1;
line_h3 <<= 1;
} while ((++x & 7) && x < hx);
} /* if (s->options & JBG_LRLTWO) */
*hp++ = line_h1;
} /* while */
*(hp - 1) <<= hbpl * 8 - hx;
x = 0;
s->pseudo = 1;
} /* for (i = ...) */
} else {
/*
* Decode differential layer
*/
for (; s->i < hl && y < hy; s->i++, y++) {
/* adaptive template changes */
if (x == 0)
for (n = 0; n < s->at_moves; n++)
if (s->at_line[n] == s->i) {
s->tx[plane][layer - s->dl] = s->at_tx[n];
s->ty[plane][layer - s->dl] = s->at_ty[n];
#ifdef DEBUG
fprintf(stderr, "ATMOVE: line=%lu, tx=%d, ty=%d.\n", s->i,
s->tx[plane][layer - s->dl], s->ty[plane][layer - s->dl]);
#endif
}
tx = s->tx[plane][layer - s->dl];
/* handle lower border of low-resolution image */
if ((s->i >> 1) >= ll - 1 || (y >> 1) >= ly - 1)
lp1 = lp2;
/* typical prediction */
if (s->options & JBG_TPDON && s->pseudo) {
s->lntp[plane][layer - s->dl] = arith_decode(se, TPDCX);
if (se->result == JBG_MORE || se->result == JBG_MARKER)
goto leave;
s->pseudo = 0;
}
/*
* Layout of the variables line_h1, line_h2, line_h3, which contain
* as bits the high resolution neighbour pixels of the currently
* decoded highres pixel X:
*
* 76543210 76543210 76543210 76543210 line_h3
* 76543210 76543210 76543210 76543210 line_h2
* 76543210 76543210 76543210 76543210 X line_h1
*
* Layout of the variables line_l1, line_l2, line_l3, which contain
* the low resolution pixels near the currently decoded pixel as bits.
* The lowres pixel in which the currently coded highres pixel is
* located is marked as Y:
*
* 76543210 76543210 76543210 76543210 line_l3
* 76543210 76543210 Y6543210 76543210 line_l2
* 76543210 76543210 76543210 76543210 line_l1
*/
if (x == 0) {
line_h1 = line_h2 = line_h3 = line_l1 = line_l2 = line_l3 = 0;
if (s->i > 0 || (y > 0 && !s->reset[plane][layer - s->dl])) {
line_h2 = (long)*(hp - hbpl) << 8;
if (s->i > 1 || (y > 1 && !s->reset[plane][layer - s->dl]))
line_h3 = (long)*(hp - hbpl - hbpl) << 8;
}
if (s->i > 1 || (y > 1 && !s->reset[plane][layer-s->dl]))
line_l3 = (long)*(lp2 - lbpl) << 8;
line_l2 = (long)*lp2 << 8;
line_l1 = (long)*lp1 << 8;
}
/* decode line */
while (x < hx) {
if ((x & 15) == 0)
if ((x >> 1) < lbpl * 8 - 8) {
line_l1 |= *(lp1 + 1);
line_l2 |= *(lp2 + 1);
if (s->i > 1 ||
(y > 1 && !s->reset[plane][layer - s->dl]))
line_l3 |= *(lp2 - lbpl + 1);
}
do {
assert(hp - (s->lhp[ layer &1][plane] + (stripe * hl + s->i)
* hbpl) == (ptrdiff_t) x >> 3);
assert(lp2 - (s->lhp[(layer-1) &1][plane] + (stripe * ll + (s->i>>1))
* lbpl) == (ptrdiff_t) x >> 4);
if ((x & 7) == 0)
if (x < hbpl * 8 - 8) {
if (s->i > 0 || (y > 0 && !s->reset[plane][layer - s->dl])) {
line_h2 |= *(hp + 1 - hbpl);
if (s->i > 1 || (y > 1 && !s->reset[plane][layer - s->dl]))
line_h3 |= *(hp + 1 - hbpl - hbpl);
}
}
do {
if (!s->lntp[plane][layer - s->dl])
cx = (((line_l3 >> 14) & 0x007) |
((line_l2 >> 11) & 0x038) |
((line_l1 >> 8) & 0x1c0));
if (!s->lntp[plane][layer - s->dl] &&
(cx == 0x000 || cx == 0x1ff)) {
/* pixels are typical and have not to be decoded */
do {
line_h1 = (line_h1 << 1) | (cx & 1);
} while ((++x & 1) && x < hx);
line_h2 <<= 2; line_h3 <<= 2;
} else
do {
/* deterministic prediction */
if (s->options & JBG_DPON)
if ((y & 1) == 0)
if ((x & 1) == 0)
/* phase 0 */
pix = s->dppriv[((line_l3 >> 15) & 0x003) |
((line_l2 >> 13) & 0x00c) |
((line_h1 << 4) & 0x010) |
((line_h2 >> 9) & 0x0e0)];
else
/* phase 1 */
pix = s->dppriv[(((line_l3 >> 15) & 0x003) |
((line_l2 >> 13) & 0x00c) |
((line_h1 << 4) & 0x030) |
((line_h2 >> 9) & 0x1c0)) + 256];
else
if ((x & 1) == 0)
/* phase 2 */
pix = s->dppriv[(((line_l3 >> 15) & 0x003) |
((line_l2 >> 13) & 0x00c) |
((line_h1 << 4) & 0x010) |
((line_h2 >> 9) & 0x0e0) |
((line_h3 >> 6) & 0x700)) + 768];
else
/* phase 3 */
pix = s->dppriv[(((line_l3 >> 15) & 0x003) |
((line_l2 >> 13) & 0x00c) |
((line_h1 << 4) & 0x030) |
((line_h2 >> 9) & 0x1c0) |
((line_h3 >> 6) & 0xe00)) + 2816];
else
pix = 2;
if (pix & 2) {
if (tx)
cx = ((line_h1 & 0x003) |
(((line_h1 << 2) >> (tx - 3)) & 0x010) |
((line_h2 >> 12) & 0x00c) |
((line_h3 >> 10) & 0x020));
else
cx = ((line_h1 & 0x003) |
((line_h2 >> 12) & 0x01c) |
((line_h3 >> 10) & 0x020));
if (x & 1)
cx |= (((line_l2 >> 8) & 0x0c0) |
((line_l1 >> 6) & 0x300)) | (1UL << 10);
else
cx |= (((line_l2 >> 9) & 0x0c0) |
((line_l1 >> 7) & 0x300));
cx |= (y & 1) << 11;
pix = arith_decode(se, cx);
if (se->result == JBG_MORE || se->result == JBG_MARKER)
goto leave;
}
line_h1 = (line_h1 << 1) | pix;
line_h2 <<= 1;
line_h3 <<= 1;
} while ((++x & 1) && x < hx);
line_l1 <<= 1; line_l2 <<= 1; line_l3 <<= 1;
} while ((x & 7) && x < hx);
*hp++ = line_h1;
} while ((x & 15) && x < hx);
++lp1;
++lp2;
} /* while */
x = 0;
*(hp - 1) <<= hbpl * 8 - hx;
if ((s->i & 1) == 0) {
/* low resolution pixels are used twice */
lp1 -= lbpl;
lp2 -= lbpl;
} else
s->pseudo = 1;
} /* for (i = ...) */
}
leave:
/* save a few local variables */
s->line_h1 = line_h1;
s->line_h2 = line_h2;
s->line_h3 = line_h3;
s->line_l1 = line_l1;
s->line_l2 = line_l2;
s->line_l3 = line_l3;
s->x = x;
return se->pscd_ptr - data;
}
/*
* Provide a new BIE fragment to the decoder.
*
* If cnt is not NULL, then *cnt will contain after the call the
* number of actually read bytes. If the data was not complete, then
* the return value will be JBG_EAGAIN and *cnt == len. In case this
* function has returned with JBG_EOK, then it has reached the end of
* a BIE but it can be called again with data from the next BIE if
* there exists one in order to get to a higher resolution layer. In
* case the return value was JBG_EOK_INTR then this function can be
* called again with the rest of the BIE, because parsing the BIE has
* been interrupted by a jbg_dec_maxsize() specification. In both
* cases the remaining len - *cnt bytes of the previous block will
* have to passed to this function again (if len > *cnt). In case of
* any other return value than JBG_EOK, JBG_EOK_INTR or JBG_EAGAIN, a
* serious problem has occured and the only function you should call
* is jbg_dec_free() in order to remove the mess (and probably
* jbg_strerror() in order to find out what to tell the user).
*/
int jbg_dec_in(struct jbg_dec_state *s, unsigned char *data, size_t len,
size_t *cnt)
{
int i, j, required_length;
unsigned long x, y;
unsigned long is[3], ie[3];
extern char jbg_dptable[];
size_t dummy_cnt;
if (!cnt) cnt = &dummy_cnt;
*cnt = 0;
if (len < 1) return JBG_EAGAIN;
/* read in 20-byte BIH */
if (s->bie_len < 20) {
while (s->bie_len < 20 && *cnt < len)
s->buffer[s->bie_len++] = data[(*cnt)++];
if (s->bie_len < 20)
return JBG_EAGAIN;
if (s->buffer[1] < s->buffer[0])
return JBG_EINVAL;
/* test whether this looks like a valid JBIG header at all */
if (s->buffer[3] != 0 || (s->buffer[18] & 0xf0) != 0 ||
(s->buffer[19] & 0x80) != 0)
return JBG_EINVAL;
if (s->buffer[0] != s->d + 1)
return JBG_ENOCONT;
s->dl = s->buffer[0];
s->d = s->buffer[1];
if (s->dl == 0)
s->planes = s->buffer[2];
else
if (s->planes != s->buffer[2])
return JBG_ENOCONT;
x = (((long) s->buffer[ 4] << 24) | ((long) s->buffer[ 5] << 16) |
((long) s->buffer[ 6] << 8) | (long) s->buffer[ 7]);
y = (((long) s->buffer[ 8] << 24) | ((long) s->buffer[ 9] << 16) |
((long) s->buffer[10] << 8) | (long) s->buffer[11]);
if (s->dl != 0 && ((s->xd << (s->d - s->dl + 1)) != x &&
(s->yd << (s->d - s->dl + 1)) != y))
return JBG_ENOCONT;
s->xd = x;
s->yd = y;
s->l0 = (((long) s->buffer[12] << 24) | ((long) s->buffer[13] << 16) |
((long) s->buffer[14] << 8) | (long) s->buffer[15]);
/* ITU-T T.85 trick not directly supported by decoder; for full
* T.85 compatibility with respect to all NEWLEN marker scenarios,
* preprocess BIE with jbg_newlen() before passing it to the decoder. */
if (s->yd == 0xffffffff)
return JBG_EIMPL;
if (!s->planes || !s->xd || !s->yd || !s->l0)
return JBG_EINVAL;
/* prevent uint32 overflow: s->l0 * 2 ^ s->d < 2 ^ 32 */
if (s->d > 31 || (s->d != 0 && s->l0 >= (1UL << (32 - s->d))))
return JBG_EIMPL;
s->mx = s->buffer[16];
if (s->mx > 127)
return JBG_EINVAL;
s->my = s->buffer[17];
#if 0
if (s->my > 0)
return JBG_EIMPL;
#endif
s->order = s->buffer[18];
if (iindex[s->order & 7][0] < 0)
return JBG_EINVAL;
/* HITOLO and SEQ currently not yet implemented */
if (s->dl != s->d && (s->order & JBG_HITOLO || s->order & JBG_SEQ))
return JBG_EIMPL;
s->options = s->buffer[19];
/* calculate number of stripes that will be required */
s->stripes = jbg_stripes(s->l0, s->yd, s->d);
/* some initialization */
s->ii[iindex[s->order & 7][STRIPE]] = 0;
s->ii[iindex[s->order & 7][LAYER]] = s->dl;
s->ii[iindex[s->order & 7][PLANE]] = 0;
if (s->dl == 0) {
s->s = (struct jbg_ardec_state **)
checked_malloc(s->planes, sizeof(struct jbg_ardec_state *));
s->tx = (int **) checked_malloc(s->planes, sizeof(int *));
s->ty = (int **) checked_malloc(s->planes, sizeof(int *));
s->reset = (int **) checked_malloc(s->planes, sizeof(int *));
s->lntp = (int **) checked_malloc(s->planes, sizeof(int *));
s->lhp[0] = (unsigned char **)
checked_malloc(s->planes, sizeof(unsigned char *));
s->lhp[1] = (unsigned char **)
checked_malloc(s->planes, sizeof(unsigned char *));
for (i = 0; i < s->planes; i++) {
s->s[i] = (struct jbg_ardec_state *)
checked_malloc(s->d - s->dl + 1, sizeof(struct jbg_ardec_state));
s->tx[i] = (int *) checked_malloc(s->d - s->dl + 1, sizeof(int));
s->ty[i] = (int *) checked_malloc(s->d - s->dl + 1, sizeof(int));
s->reset[i] = (int *) checked_malloc(s->d - s->dl + 1, sizeof(int));
s->lntp[i] = (int *) checked_malloc(s->d - s->dl + 1, sizeof(int));
s->lhp[ s->d & 1][i] = (unsigned char *)
checked_malloc(s->yd, jbg_ceil_half(s->xd, 3));
s->lhp[(s->d-1) & 1][i] = (unsigned char *)
checked_malloc(jbg_ceil_half(s->yd, 1), jbg_ceil_half(s->xd, 1+3));
}
} else {
for (i = 0; i < s->planes; i++) {
s->s[i] = (struct jbg_ardec_state *)
checked_realloc(s->s[i], s->d - s->dl + 1,
sizeof(struct jbg_ardec_state));
s->tx[i] = (int *) checked_realloc(s->tx[i],
s->d - s->dl + 1, sizeof(int));
s->ty[i] = (int *) checked_realloc(s->ty[i],
s->d - s->dl + 1, sizeof(int));
s->reset[i] = (int *) checked_realloc(s->reset[i],
s->d - s->dl + 1, sizeof(int));
s->lntp[i] = (int *) checked_realloc(s->lntp[i],
s->d - s->dl + 1, sizeof(int));
s->lhp[ s->d & 1][i] = (unsigned char *)
checked_realloc(s->lhp[ s->d & 1][i],
s->yd, jbg_ceil_half(s->xd, 3));
s->lhp[(s->d-1) & 1][i] = (unsigned char *)
checked_realloc(s->lhp[(s->d-1) & 1][i],
jbg_ceil_half(s->yd, 1), jbg_ceil_half(s->xd, 1+3));
}
}
for (i = 0; i < s->planes; i++)
for (j = 0; j <= s->d - s->dl; j++)
arith_decode_init(s->s[i] + j, 0);
if (s->dl == 0 || (s->options & JBG_DPON && !(s->options & JBG_DPPRIV)))
s->dppriv = jbg_dptable;
s->comment_skip = 0;
s->buf_len = 0;
s->x = 0;
s->i = 0;
s->pseudo = 1;
s->at_moves = 0;
}
/* read in DPTABLE */
if (s->bie_len < 20 + 1728 &&
(s->options & (JBG_DPON | JBG_DPPRIV | JBG_DPLAST)) ==
(JBG_DPON | JBG_DPPRIV)) {
assert(s->bie_len >= 20);
while (s->bie_len < 20 + 1728 && *cnt < len)
s->buffer[s->bie_len++ - 20] = data[(*cnt)++];
if (s->bie_len < 20 + 1728)
return JBG_EAGAIN;
if (!s->dppriv || s->dppriv == jbg_dptable)
s->dppriv = (char *) checked_malloc(1728, sizeof(char));
jbg_dppriv2int(s->dppriv, s->buffer);
}
/*
* BID processing loop
*/
while (*cnt < len) {
/* process floating marker segments */
/* skip COMMENT contents */
if (s->comment_skip) {
if (s->comment_skip <= len - *cnt) {
*cnt += s->comment_skip;
s->comment_skip = 0;
} else {
s->comment_skip -= len - *cnt;
*cnt = len;
}
continue;
}
/* load complete marker segments into s->buffer for processing */
if (s->buf_len > 0) {
assert(s->buffer[0] == MARKER_ESC);
while (s->buf_len < 2 && *cnt < len)
s->buffer[s->buf_len++] = data[(*cnt)++];
if (s->buf_len < 2) continue;
switch (s->buffer[1]) {
case MARKER_COMMENT: required_length = 6; break;
case MARKER_ATMOVE: required_length = 8; break;
case MARKER_NEWLEN: required_length = 6; break;
case MARKER_ABORT:
case MARKER_SDNORM:
case MARKER_SDRST: required_length = 2; break;
case MARKER_STUFF:
/* forward stuffed 0xff to arithmetic decoder */
s->buf_len = 0;
decode_pscd(s, s->buffer, 2);
continue;
default:
return JBG_EMARKER;
}
while (s->buf_len < required_length && *cnt < len)
s->buffer[s->buf_len++] = data[(*cnt)++];
if (s->buf_len < required_length) continue;
/* now the buffer is filled with exactly one marker segment */
switch (s->buffer[1]) {
case MARKER_COMMENT:
s->comment_skip =
(((long) s->buffer[2] << 24) | ((long) s->buffer[3] << 16) |
((long) s->buffer[4] << 8) | (long) s->buffer[5]);
break;
case MARKER_ATMOVE:
if (s->at_moves < JBG_ATMOVES_MAX) {
s->at_line[s->at_moves] =
(((long) s->buffer[2] << 24) | ((long) s->buffer[3] << 16) |
((long) s->buffer[4] << 8) | (long) s->buffer[5]);
s->at_tx[s->at_moves] = (signed char) s->buffer[6];
s->at_ty[s->at_moves] = s->buffer[7];
if (s->at_tx[s->at_moves] < - (int) s->mx ||
s->at_tx[s->at_moves] > (int) s->mx ||
s->at_ty[s->at_moves] > (int) s->my ||
(s->at_ty[s->at_moves] == 0 && s->at_tx[s->at_moves] < 0))
return JBG_EINVAL;
if (s->at_ty[s->at_moves] != 0)
return JBG_EIMPL;
s->at_moves++;
} else
return JBG_EIMPL;
break;
case MARKER_NEWLEN:
y = (((long) s->buffer[2] << 24) | ((long) s->buffer[3] << 16) |
((long) s->buffer[4] << 8) | (long) s->buffer[5]);
if (y > s->yd || !(s->options & JBG_VLENGTH))
return JBG_EINVAL;
s->yd = y;
/* calculate again number of stripes that will be required */
s->stripes = jbg_stripes(s->l0, s->yd, s->d);
break;
case MARKER_ABORT:
return JBG_EABORT;
case MARKER_SDNORM:
case MARKER_SDRST:
/* decode final pixels based on trailing zero bytes */
decode_pscd(s, s->buffer, 2);
arith_decode_init(s->s[s->ii[iindex[s->order & 7][PLANE]]] +
s->ii[iindex[s->order & 7][LAYER]] - s->dl,
s->ii[iindex[s->order & 7][STRIPE]] != s->stripes - 1
&& s->buffer[1] != MARKER_SDRST);
s->reset[s->ii[iindex[s->order & 7][PLANE]]]
[s->ii[iindex[s->order & 7][LAYER]] - s->dl] =
(s->buffer[1] == MARKER_SDRST);
/* prepare for next SDE */
s->x = 0;
s->i = 0;
s->pseudo = 1;
s->at_moves = 0;
/* increment layer/stripe/plane loop variables */
/* start and end value for each loop: */
is[iindex[s->order & 7][STRIPE]] = 0;
ie[iindex[s->order & 7][STRIPE]] = s->stripes - 1;
is[iindex[s->order & 7][LAYER]] = s->dl;
ie[iindex[s->order & 7][LAYER]] = s->d;
is[iindex[s->order & 7][PLANE]] = 0;
ie[iindex[s->order & 7][PLANE]] = s->planes - 1;
i = 2; /* index to innermost loop */
do {
j = 0; /* carry flag */
if (++s->ii[i] > ie[i]) {
/* handling overflow of loop variable */
j = 1;
if (i > 0)
s->ii[i] = is[i];
}
} while (--i >= 0 && j);
s->buf_len = 0;
/* check whether this have been all SDEs */
if (j) {
#ifdef DEBUG
fprintf(stderr, "This was the final SDE in this BIE, "
"%d bytes left.\n", len - *cnt);
#endif
s->bie_len = 0;
return JBG_EOK;
}
/* check whether we have to abort because of xmax/ymax */
if (iindex[s->order & 7][LAYER] == 0 && i < 0) {
/* LAYER is the outermost loop and we have just gone to next layer */
if (jbg_ceil_half(s->xd, s->d - s->ii[0]) > s->xmax ||
jbg_ceil_half(s->yd, s->d - s->ii[0]) > s->ymax) {
s->xmax = 4294967295UL;
s->ymax = 4294967295UL;
return JBG_EOK_INTR;
}
if (s->ii[0] > (unsigned long) s->dmax) {
s->dmax = 256;
return JBG_EOK_INTR;
}
}
break;
}
s->buf_len = 0;
} else if (data[*cnt] == MARKER_ESC)
s->buffer[s->buf_len++] = data[(*cnt)++];
else {
/* we have found PSCD bytes */
*cnt += decode_pscd(s, data + *cnt, len - *cnt);
if (*cnt < len && data[*cnt] != 0xff) {
#ifdef DEBUG
fprintf(stderr, "PSCD was longer than expected, unread bytes "
"%02x %02x %02x %02x ...\n", data[*cnt], data[*cnt+1],
data[*cnt+2], data[*cnt+3]);
#endif
return JBG_EINVAL;
}
}
} /* of BID processing loop 'while (*cnt < len) ...' */
return JBG_EAGAIN;
}
/*
* After jbg_dec_in() returned JBG_EOK or JBG_EOK_INTR, you can call this
* function in order to find out the width of the image.
*/
long jbg_dec_getwidth(const struct jbg_dec_state *s)
{
if (s->d < 0)
return -1;
if (iindex[s->order & 7][LAYER] == 0) {
if (s->ii[0] < 1)
return -1;
else
return jbg_ceil_half(s->xd, s->d - (s->ii[0] - 1));
}
return s->xd;
}
/*
* After jbg_dec_in() returned JBG_EOK or JBG_EOK_INTR, you can call this
* function in order to find out the height of the image.
*/
long jbg_dec_getheight(const struct jbg_dec_state *s)
{
if (s->d < 0)
return -1;
if (iindex[s->order & 7][LAYER] == 0) {
if (s->ii[0] < 1)
return -1;
else
return jbg_ceil_half(s->yd, s->d - (s->ii[0] - 1));
}
return s->yd;
}
/*
* After jbg_dec_in() returned JBG_EOK or JBG_EOK_INTR, you can call this
* function in order to get a pointer to the image.
*/
unsigned char *jbg_dec_getimage(const struct jbg_dec_state *s, int plane)
{
if (s->d < 0)
return NULL;
if (iindex[s->order & 7][LAYER] == 0) {
if (s->ii[0] < 1)
return NULL;
else
return s->lhp[(s->ii[0] - 1) & 1][plane];
}
return s->lhp[s->d & 1][plane];
}
/*
* After jbg_dec_in() returned JBG_EOK or JBG_EOK_INTR, you can call
* this function in order to find out the size in bytes of one
* bitplane of the image.
*/
long jbg_dec_getsize(const struct jbg_dec_state *s)
{
if (s->d < 0)
return -1;
if (iindex[s->order & 7][LAYER] == 0) {
if (s->ii[0] < 1)
return -1;
else
return
jbg_ceil_half(s->xd, s->d - (s->ii[0] - 1) + 3) *
jbg_ceil_half(s->yd, s->d - (s->ii[0] - 1));
}
return jbg_ceil_half(s->xd, 3) * s->yd;
}
/*
* After jbg_dec_in() returned JBG_EOK or JBG_EOK_INTR, you can call
* this function in order to find out the size of the image that you
* can retrieve with jbg_merge_planes().
*/
long jbg_dec_getsize_merged(const struct jbg_dec_state *s)
{
if (s->d < 0)
return -1;
if (iindex[s->order & 7][LAYER] == 0) {
if (s->ii[0] < 1)
return -1;
else
return
jbg_ceil_half(s->xd, s->d - (s->ii[0] - 1)) *
jbg_ceil_half(s->yd, s->d - (s->ii[0] - 1)) *
((s->planes + 7) / 8);
}
return s->xd * s->yd * ((s->planes + 7) / 8);
}
/*
* The destructor function which releases any resources obtained by the
* other decoder functions.
*/
void jbg_dec_free(struct jbg_dec_state *s)
{
int i;
extern char jbg_dptable[];
if (s->d < 0 || s->s == NULL)
return;
s->d = -2;
for (i = 0; i < s->planes; i++) {
checked_free(s->s[i]);
checked_free(s->tx[i]);
checked_free(s->ty[i]);
checked_free(s->reset[i]);
checked_free(s->lntp[i]);
checked_free(s->lhp[0][i]);
checked_free(s->lhp[1][i]);
}
checked_free(s->s);
checked_free(s->tx);
checked_free(s->ty);
checked_free(s->reset);
checked_free(s->lntp);
checked_free(s->lhp[0]);
checked_free(s->lhp[1]);
if (s->dppriv && s->dppriv != jbg_dptable)
checked_free(s->dppriv);
s->s = NULL;
return;
}
/*
* Split bigendian integer pixel field into separate bit planes. In the
* src array, every pixel is represented by a ((has_planes + 7) / 8) byte
* long word, most significant byte first. While has_planes describes
* the number of used bits per pixel in the source image, encode_plane
* is the number of most significant bits among those that we
* actually transfer to dest.
*/
void jbg_split_planes(unsigned long x, unsigned long y, int has_planes,
int encode_planes,
const unsigned char *src, unsigned char **dest,
int use_graycode)
{
unsigned long bpl = jbg_ceil_half(x, 3); /* bytes per line in dest plane */
unsigned long line, i;
unsigned k = 8;
int p;
unsigned prev; /* previous *src byte shifted by 8 bit to the left */
register int bits, msb = has_planes - 1;
int bitno;
/* sanity checks */
if (encode_planes > has_planes)
encode_planes = has_planes;
use_graycode = use_graycode != 0 && encode_planes > 1;
for (p = 0; p < encode_planes; p++)
memset(dest[p], 0, bpl * y);
for (line = 0; line < y; line++) { /* lines loop */
for (i = 0; i * 8 < x; i++) { /* dest bytes loop */
for (k = 0; k < 8 && i * 8 + k < x; k++) { /* pixel loop */
prev = 0;
for (p = 0; p < encode_planes; p++) { /* bit planes loop */
/* calculate which bit in *src do we want */
bitno = (msb - p) & 7;
/* put this bit with its left neighbor right adjusted into bits */
bits = (prev | *src) >> bitno;
/* go to next *src byte, but keep old */
if (bitno == 0)
prev = *src++ << 8;
/* make space for inserting new bit */
dest[p][bpl * line + i] <<= 1;
/* insert bit, if requested apply Gray encoding */
dest[p][bpl * line + i] |= (bits ^ (use_graycode & (bits>>1))) & 1;
/*
* Theorem: Let b(n),...,b(1),b(0) be the digits of a
* binary word and let g(n),...,g(1),g(0) be the digits of the
* corresponding Gray code word, then g(i) = b(i) xor b(i+1).
*/
}
/* skip unused *src bytes */
for (;p < has_planes; p++)
if (((msb - p) & 7) == 0)
src++;
}
}
for (p = 0; p < encode_planes; p++) /* right padding loop */
dest[p][bpl * (line + 1) - 1] <<= 8 - k;
}
return;
}
/*
* Merge the separate bit planes decoded by the JBIG decoder into an
* integer pixel field. This is essentially the counterpart to
* jbg_split_planes().
*/
void jbg_dec_merge_planes(const struct jbg_dec_state *s, int use_graycode,
void (*data_out)(unsigned char *start, size_t len,
void *file), void *file)
{
#define BUFLEN 4096
int bpp;
unsigned long bpl, line, i;
unsigned k = 8;
int p;
unsigned char buf[BUFLEN];
unsigned char *bp = buf;
unsigned char **src;
unsigned long x, y;
unsigned v;
/* sanity check */
use_graycode = use_graycode != 0;
x = jbg_dec_getwidth(s);
y = jbg_dec_getheight(s);
if (x <= 0 || y <= 0)
return;
bpp = (s->planes + 7) / 8; /* bytes per pixel in dest image */
bpl = jbg_ceil_half(x, 3); /* bytes per line in src plane */
if (iindex[s->order & 7][LAYER] == 0)
if (s->ii[0] < 1)
return;
else
src = s->lhp[(s->ii[0] - 1) & 1];
else
src = s->lhp[s->d & 1];
for (line = 0; line < y; line++) { /* lines loop */
for (i = 0; i * 8 < x; i++) { /* src bytes loop */
for (k = 0; k < 8 && i * 8 + k < x; k++) { /* pixel loop */
v = 0;
for (p = 0; p < s->planes;) { /* dest bytes loop */
do {
v = (v << 1) |
(((src[p][bpl * line + i] >> (7 - k)) & 1) ^
(use_graycode & v));
} while ((s->planes - ++p) & 7);
*bp++ = v;
if (bp - buf == BUFLEN) {
data_out(buf, BUFLEN, file);
bp = buf;
}
}
}
}
}
if (bp - buf > 0)
data_out(buf, bp - buf, file);
return;
}
/*
* Given a pointer p to the first byte of either a marker segment or a
* PSCD, as well as the length len of the remaining data, return
* either the pointer to the first byte of the next marker segment or
* PSCD, or p+len if this was the last one, or NULL if some error was
* encountered.
*/
unsigned char *jbg_next_pscdms(unsigned char *p, size_t len)
{
unsigned char *pp;
unsigned long l;
if (len < 2)
return NULL;
if (p[0] != MARKER_ESC || p[1] == MARKER_STUFF) {
do {
while (p[0] == MARKER_ESC && p[1] == MARKER_STUFF) {
p += 2;
len -= 2;
if (len < 2) return NULL;
}
pp = (unsigned char *) memchr(p, MARKER_ESC, len - 1);
if (!pp) return NULL;
l = pp - p;
assert(l < len);
p += l;
len -= l;
} while (p[1] == MARKER_STUFF);
} else {
switch (p[1]) {
case MARKER_SDNORM:
case MARKER_SDRST:
case MARKER_ABORT:
return p + 2;
case MARKER_NEWLEN:
if (len < 6) return NULL;
return p + 6;
case MARKER_ATMOVE:
if (len < 8) return NULL;
return p + 8;
case MARKER_COMMENT:
if (len < 6) return NULL;
l = (((long) p[2] << 24) | ((long) p[3] << 16) |
((long) p[4] << 8) | (long) p[5]);
if (len - 6 < l) return NULL;
return p + 6 + l;
default:
return NULL;
}
}
return p;
}
/*
* Scan a complete BIE for a NEWLEN marker segment, then read the new
* YD value found in it and use it to overwrite the one in the BIE
* header. Use this procedure if a BIE initially declares an
* unreasonably high provisional YD value (e.g., 0xffffffff) or
* depends on the fact that section 6.2.6.2 of ITU-T T.82 says that a
* NEWLEN marker segment "could refer to a line in the immediately
* preceding stripe due to an unexpected termination of the image or
* the use of only such stripe". ITU-T.85 explicitely suggests the
* use of this for fax machines that start transmission before having
* encountered the end of the page. None of this is necessary for
* BIEs produced by JBIG-KIT, which normally does not use NEWLEN.
*/
int jbg_newlen(unsigned char *bie, size_t len)
{
unsigned char *p = bie + 20;
int i;
if (len < 20)
return JBG_EAGAIN;
if ((bie[19] & (JBG_DPON | JBG_DPPRIV | JBG_DPLAST))
== (JBG_DPON | JBG_DPPRIV))
p += 1728; /* skip DPTABLE */
if (p >= bie + len)
return JBG_EAGAIN;
while ((p = jbg_next_pscdms(p, len - (p - bie)))) {
if (p == bie + len)
return JBG_EOK;
else if (p[0] == MARKER_ESC)
switch (p[1]) {
case MARKER_NEWLEN:
/* overwrite YD in BIH with YD from NEWLEN */
for (i = 0; i < 4; i++) {
bie[8+i] = p[2+i];
}
return JBG_EOK;
case MARKER_ABORT:
return JBG_EABORT;
}
}
return JBG_EINVAL;
}
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