ref: 9e4350a4eedb67290d35526d526878ab99d8a1a2
dir: /jbig2_text.c/
/*
jbig2dec
Copyright (C) 2002 artofcode LLC.
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.
$Id: jbig2_text.c,v 1.22 2003/03/05 14:29:35 giles Exp $
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "os_types.h"
#include <stddef.h>
#include <string.h> /* memset() */
#include "jbig2.h"
#include "jbig2_priv.h"
#include "jbig2_arith.h"
#include "jbig2_arith_int.h"
#include "jbig2_arith_iaid.h"
#include "jbig2_generic.h"
#include "jbig2_symbol_dict.h"
typedef enum {
JBIG2_CORNER_BOTTOMLEFT = 0,
JBIG2_CORNER_TOPLEFT = 1,
JBIG2_CORNER_BOTTOMRIGHT = 2,
JBIG2_CORNER_TOPRIGHT = 3
} Jbig2RefCorner;
typedef struct {
bool SBHUFF;
bool SBREFINE;
bool SBDEFPIXEL;
Jbig2ComposeOp SBCOMBOP;
bool TRANSPOSED;
Jbig2RefCorner REFCORNER;
int SBDSOFFSET;
/* SBW */
/* SBH */
uint32_t SBNUMINSTANCES;
int SBSTRIPS;
/* SBNUMSYMS */
int *SBSYMCODES;
/* SBSYMCODELEN */
/* SBSYMS */
int SBHUFFFS;
int SBHUFFDS;
int SBHUFFDT;
int SBHUFFRDW;
int SBHUFFRDH;
int SBHUFFRDX;
int SBHUFFRDY;
bool SBHUFFRSIZE;
bool SBRTEMPLATE;
int8_t sbrat[4];
} Jbig2TextRegionParams;
/**
* jbig2_decode_text_region: decode a text region segment
*
* @ctx: jbig2 decoder context
* @segment: jbig2 segment (header) structure
* @params: parameters from the text region header
* @dicts: an array of referenced symbol dictionaries
* @n_dicts: the number of referenced symbol dictionaries
* @image: image structure in which to store the decoded region bitmap
* @data: pointer to text region data to be decoded
* @size: length of text region data
*
* Implements the text region decoding proceedure
* described in section 6.4 of the JBIG2 spec.
*
* returns: 0 on success
**/
static int
jbig2_decode_text_region(Jbig2Ctx *ctx, Jbig2Segment *segment,
const Jbig2TextRegionParams *params,
const Jbig2SymbolDict * const *dicts, const int n_dicts,
Jbig2Image *image,
const byte *data, const size_t size)
{
/* relevent bits of 6.4.4 */
uint32_t NINSTANCES;
uint32_t ID;
int32_t STRIPT;
int32_t FIRSTS;
int32_t DT;
int32_t DFS;
int32_t IDS;
int32_t CURS;
int32_t CURT;
int S,T;
int x,y;
bool first_symbol;
uint32_t index, max_id;
Jbig2Image *IB;
Jbig2ArithState *as;
Jbig2ArithIntCtx *IADT = NULL;
Jbig2ArithIntCtx *IAFS = NULL;
Jbig2ArithIntCtx *IADS = NULL;
Jbig2ArithIntCtx *IAIT = NULL;
Jbig2ArithIaidCtx *IAID = NULL;
int code;
max_id = 0;
for (index = 0; index < n_dicts; index ++) {
max_id += dicts[index]->n_symbols;
}
jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
"symbol list contains %d glyphs in %d dictionaries", max_id, n_dicts);
if (params->SBREFINE) {
return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
"text regions with refinement bitmaps NYI");
}
if (!params->SBHUFF) {
int SBSYMCODELEN;
Jbig2WordStream *ws = jbig2_word_stream_buf_new(ctx, data, size);
as = jbig2_arith_new(ctx, ws);
IADT = jbig2_arith_int_ctx_new(ctx);
IAFS = jbig2_arith_int_ctx_new(ctx);
IADS = jbig2_arith_int_ctx_new(ctx);
IAIT = jbig2_arith_int_ctx_new(ctx);
/* Table 31 */
for (SBSYMCODELEN = 0; (1 << SBSYMCODELEN) < max_id; SBSYMCODELEN++);
IAID = jbig2_arith_iaid_ctx_new(ctx, SBSYMCODELEN);
}
/* 6.4.5 (1) */
memset(image->data, image->stride*image->height, params->SBDEFPIXEL ? 0xFF: 0x00);
/* 6.4.6 */
if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_int_decode(IADT, as, &STRIPT);
}
/* 6.4.5 (2) */
STRIPT *= -(params->SBSTRIPS);
FIRSTS = 0;
NINSTANCES = 0;
/* 6.4.5 (3) */
while (NINSTANCES < params->SBNUMINSTANCES) {
/* (3b) */
if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_int_decode(IADT, as, &DT);
}
DT *= params->SBSTRIPS;
STRIPT += DT;
first_symbol = TRUE;
/* 6.4.5 (3c) - decode symbols in strip */
for (;;) {
/* (3c.i) */
if (first_symbol) {
/* 6.4.7 */
if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_int_decode(IAFS, as, &DFS);
}
FIRSTS += DFS;
CURS = FIRSTS;
first_symbol = FALSE;
} else {
/* (3c.ii / 6.4.8) */
if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_int_decode(IADS, as, &IDS);
}
if (code) {
break;
}
CURS += IDS + params->SBDSOFFSET;
}
/* (3c.iii / 6.4.9) */
if (params->SBSTRIPS == 1) {
CURT = 0;
} else if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_int_decode(IAIT, as, &CURT);
}
T = STRIPT + CURT;
/* (3b.iv / 6.4.10) decode the symbol id */
if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_iaid_decode(IAID, as, &ID);
}
if (ID < 0 || ID >= max_id) {
return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
"symbol id out of range! (%d/%d)", ID, max_id);
}
/* (3c.v) look up the symbol bitmap IB */
{
int id = ID;
index = 0;
while (id >= dicts[index]->n_symbols)
id -= dicts[index++]->n_symbols;
IB = dicts[index]->glyphs[id];
}
/* (3c.vi) */
if ((!params->TRANSPOSED) && (params->REFCORNER > 1)) {
CURS += IB->width - 1;
} else if ((params->TRANSPOSED) && !(params->REFCORNER & 1)) {
CURS += IB->height - 1;
}
/* (3c.vii) */
S = CURS;
/* (3c.viii) */
if (!params->TRANSPOSED) {
switch (params->REFCORNER) { /* FIXME: double check offsets */
case JBIG2_CORNER_TOPLEFT: x = S; y = T; break;
case JBIG2_CORNER_TOPRIGHT: x = S - IB->width + 1; y = T; break;
case JBIG2_CORNER_BOTTOMLEFT: x = S; y = T - IB->height + 1; break;
case JBIG2_CORNER_BOTTOMRIGHT: x = S - IB->width + 1; y = T - IB->height + 1; break;
}
} else { /* TRANSPOSED */
switch (params->REFCORNER) {
case JBIG2_CORNER_TOPLEFT: y = T; x = T; break;
case JBIG2_CORNER_TOPRIGHT: y = S - IB->width + 1; x = T; break;
case JBIG2_CORNER_BOTTOMLEFT: y = S; x = T - IB->height + 1; break;
case JBIG2_CORNER_BOTTOMRIGHT: y = S - IB->width + 1; x = T - IB->height + 1; break;
}
}
/* (3c.ix) */
#ifdef DEBUG
jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
"composing glyph id %d: %dx%d @ (%d,%d) symbol %d/%d",
ID, IB->width, IB->height, x, y, NINSTANCES + 1,
params->SBNUMINSTANCES);
#endif
jbig2_image_compose(ctx, image, IB, x, y, params->SBCOMBOP);
/* (3c.x) */
if ((!params->TRANSPOSED) && (params->REFCORNER < 2)) {
CURS += IB->width -1 ;
} else if ((params->TRANSPOSED) && (params->REFCORNER & 1)) {
CURS += IB->height - 1;
}
/* (3c.xi) */
NINSTANCES++;
}
/* end strip */
}
/* 6.4.5 (4) */
return 0;
}
/* count the number of dictionary segments referred to by the given segment */
static int
count_referred_dicts(Jbig2Ctx *ctx, Jbig2Segment *segment)
{
int index;
Jbig2Segment *rsegment;
int n_dicts = 0;
for (index = 0; index < segment->referred_to_segment_count; index++) {
rsegment = jbig2_find_segment(ctx, segment->referred_to_segments[index]);
if (rsegment && ((rsegment->flags & 63) == 0))
n_dicts++;
}
return (n_dicts);
}
/* return an array of pointers to symbol dictionaries referred to by the given segment */
static Jbig2SymbolDict **
list_referred_dicts(Jbig2Ctx *ctx, Jbig2Segment *segment)
{
int index;
Jbig2Segment *rsegment;
Jbig2SymbolDict **dicts;
int n_dicts = count_referred_dicts(ctx, segment);
int dindex = 0;
dicts = jbig2_alloc(ctx->allocator, sizeof(Jbig2SymbolDict *) * n_dicts);
for (index = 0; index < segment->referred_to_segment_count; index++) {
rsegment = jbig2_find_segment(ctx, segment->referred_to_segments[index]);
if (rsegment && ((rsegment->flags & 63) == 0))
dicts[dindex++] = (Jbig2SymbolDict *)rsegment->result;
}
return (dicts);
}
/**
* jbig2_read_text_info: read a text region segment header
**/
int
jbig2_parse_text_region(Jbig2Ctx *ctx, Jbig2Segment *segment, const byte *segment_data)
{
int offset = 0;
Jbig2RegionSegmentInfo region_info;
Jbig2TextRegionParams params;
Jbig2Image *image, *page_image;
Jbig2SymbolDict **dicts;
int n_dicts;
uint16_t flags;
uint16_t huffman_flags;
int8_t sbrat[4];
int code;
/* 7.4.1 */
if (segment->data_length < 17)
goto too_short;
jbig2_get_region_segment_info(®ion_info, segment_data);
offset += 17;
/* 7.4.3.1.1 */
flags = jbig2_get_int16(segment_data + offset);
offset += 2;
params.SBHUFF = flags & 0x0001;
params.SBREFINE = flags & 0x0002;
params.SBSTRIPS = 1 << ((flags & 0x000c) >> 2);
params.REFCORNER = (flags & 0x0030) >> 4;
params.TRANSPOSED = flags & 0x0040;
params.SBCOMBOP = (flags & 0x00e0) >> 7;
params.SBDEFPIXEL = flags & 0x0100;
params.SBDSOFFSET = (flags & 0x7C00) >> 10;
params.SBRTEMPLATE = flags & 0x8000;
if (params.SBHUFF) /* Huffman coding */
{
/* 7.4.3.1.2 */
huffman_flags = jbig2_get_int16(segment_data + offset);
offset += 2;
if (huffman_flags & 0x8000)
jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
"reserved bit 15 of text region huffman flags is not zero");
}
else /* arithmetic coding */
{
/* 7.4.3.1.3 */
if ((params.SBREFINE) && !(params.SBRTEMPLATE))
{
sbrat[0] = segment_data[offset];
sbrat[0] = segment_data[offset + 1];
sbrat[0] = segment_data[offset + 2];
sbrat[0] = segment_data[offset + 3];
offset += 4;
}
/* 7.4.3.1.4 */
params.SBNUMINSTANCES = jbig2_get_int32(segment_data + offset);
offset += 4;
if (params.SBHUFF) {
/* 7.4.3.1.5 */
/* todo: symbol ID huffman decoding table decoding */
jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
"symbol id huffman table decoding NYI");
/* 7.4.3.1.6 */
params.SBHUFFFS = (huffman_flags & 0x0003);
params.SBHUFFDS = (huffman_flags & 0x000c) >> 2;
params.SBHUFFDT = (huffman_flags & 0x0030) >> 4;
params.SBHUFFRDW = (huffman_flags & 0x00c0) >> 6;
params.SBHUFFRDH = (huffman_flags & 0x0300) >> 8;
params.SBHUFFRDX = (huffman_flags & 0x0c00) >> 10;
params.SBHUFFRDY = (huffman_flags & 0x3000) >> 12;
/* todo: conformance */
params.SBHUFFRSIZE = huffman_flags & 0x8000;
/* 7.4.3.1.7 */
/* todo: symbol ID huffman table decoding */
}
jbig2_error(ctx, JBIG2_SEVERITY_INFO, segment->number,
"text region: %d x %d @ (%d,%d) %d symbols",
region_info.width, region_info.height,
region_info.x, region_info.y, params.SBNUMINSTANCES);
}
/* compose the list of symbol dictionaries */
n_dicts = count_referred_dicts(ctx, segment);
if (n_dicts != 0) {
dicts = list_referred_dicts(ctx, segment);
} else {
return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
"text region refers to no symbol dictionaries!");
}
page_image = ctx->pages[ctx->current_page].image;
image = jbig2_image_new(ctx, region_info.width, region_info.height);
code = jbig2_decode_text_region(ctx, segment, ¶ms,
dicts, n_dicts, image,
segment_data + offset, segment->data_length - offset);
/* todo: check errors */
if ((segment->flags & 63) == 4) {
/* we have an intermediate region here. save it for later */
segment->result = image;
} else {
/* otherwise composite onto the page */
jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
"composing %dx%d decoded text region onto page at (%d, %d)",
region_info.width, region_info.height, region_info.x, region_info.y);
jbig2_image_compose(ctx, page_image, image, region_info.x, region_info.y, JBIG2_COMPOSE_OR);
if (image != page_image)
jbig2_image_free(ctx, image);
}
/* success */
return 0;
too_short:
return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, segment->number,
"Segment too short");
}