ref: 5613e3f978e406268fe5c42b7da322c0e4bfa7a9
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 1.4 2002/06/24 19:09:47 giles Exp $
*/
#include <stddef.h>
#include <stdint.h>
#include <string.h> /* memset() */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "jbig2.h"
#include "jbig2_priv.h"
#include "jbig2_arith.h"
#include "jbig2_arith_int.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
**/
int jbig2_decode_text_region(Jbig2Ctx *ctx, Jbig2Segment *segment,
const Jbig2TextRegionParams *params,
const Jbig2SymbolDict **dicts, const int n_dicts,
Jbig2Image *image,
const byte *data, 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 = TRUE;
Jbig2Image *IB;
Jbig2ArithState *as;
Jbig2ArithIntCtx *IADT = NULL;
Jbig2ArithIntCtx *IAFS = NULL;
Jbig2ArithIntCtx *IADS = NULL;
Jbig2ArithIntCtx *IAIT = NULL;
Jbig2ArithIntCtx *IAID = NULL;
int code;
if (!params->SBHUFF) {
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);
IAID = jbig2_arith_int_ctx_new(ctx);
}
/* 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;
/* (3c) */
if (first_symbol) {
/* 6.4.7 */
if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_int_decode(IAFS, as, &DFS);
}
FIRSTS += DFS;
CURS = FIRSTS;
} else {
/* 6.4.8 */
if (params->SBHUFF) {
/* todo */
} else {
code = jbig2_arith_int_decode(IADS, as, &IDS);
}
CURS += IDS + params->SBDSOFFSET;
}
/* 6.4.9 */
code = jbig2_arith_int_decode(IAIT, as, &CURT);
T = STRIPT + CURT;
/* (3b.iv) / 6.4.10 */
code = jbig2_arith_int_decode(IAID, as, &ID);
/* (3b.v) */
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; y = T; break;
case JBIG2_CORNER_BOTTOMLEFT: x = S; y = T - IB->height; break;
case JBIG2_CORNER_BOTTOMRIGHT: x = S - IB->width; y = T - IB->height; break;
}
} else { /* TRANSPOSED */
switch (params->REFCORNER) {
case JBIG2_CORNER_TOPLEFT: x = S; y = T; break;
case JBIG2_CORNER_TOPRIGHT: x = S - IB->width; y = T; break;
case JBIG2_CORNER_BOTTOMLEFT: x = S; y = T - IB->height; break;
case JBIG2_CORNER_BOTTOMRIGHT: x = S - IB->width; y = T - IB->height; break;
}
}
/* (3b.vi) */
if ((!params->TRANSPOSED) && (params->REFCORNER > 1)) {
CURS += IB->width - 1;
} else if ((params->TRANSPOSED) && (params->REFCORNER < 2)) {
CURS += IB->height - 1;
}
/* (3b.vii) */
S = CURS;
/* (3b.viii) */
// todo: choose glyph bitmap
/* (3b.ix) */
jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number,
"composing glyph id %d at (%d, %d)", ID, x, y);
jbig2_image_compose(ctx, image, IB, x, y, params->SBCOMBOP);
/* (3b.x) */
if ((!params->TRANSPOSED) && (params->REFCORNER < 2)) {
CURS += IB->width -1 ;
} else if ((params->TRANSPOSED) && (params->REFCORNER > 1)) {
CURS += IB->height - 1;
}
/* (3b.xi) */
NINSTANCES++;
}
return 0;
}
/**
* jbig2_read_text_info: read a text region segment header
**/
int
jbig2_read_text_info(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;
uint32_t num_instances;
uint16_t segment_flags;
uint16_t huffman_flags;
int8_t sbrat[4];
int index;
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 */
segment_flags = jbig2_get_int16(segment_data + offset);
offset += 2;
if (segment_flags & 0x01) /* Huffman coding */
{
/* 7.4.3.1.2 */
huffman_flags = jbig2_get_int16(segment_data + offset);
offset += 2;
}
else /* arithmetic coding */
{
/* 7.4.3.1.3 */
if ((segment_flags & 0x02) && !(segment_flags & 0x80)) /* SBREFINE & !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 */
num_instances = jbig2_get_int32(segment_data + offset);
offset += 4;
/* 7.4.3.1.7 */
if (segment_flags & 0x01) {
jbig2_error(ctx, JBIG2_SEVERITY_WARNING, segment->number,
"symbol id huffman table decoding NYI");
}
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, num_instances);
}
/* compose the list of symbol dictionaries */
n_dicts = 0;
for (index = 0; index < segment->referred_to_segment_count; index++) {
if (ctx->segments[segment->referred_to_segments[index]]->flags & 63 == 0)
n_dicts++;
}
dicts = jbig2_alloc(ctx->allocator, sizeof(Jbig2SymbolDict *) * n_dicts);
for (index = 0; index < segment->referred_to_segment_count; index++) {
int dindex = 0;
if (ctx->segments[segment->referred_to_segments[index]]->flags & 63 == 0)
dicts[dindex++] = (Jbig2SymbolDict *)ctx->segments[segment->referred_to_segments[index]]->result;
}
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 */
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");
}