ref: 7ea3cbeb28b39fe56c7d791361f969b255fb59bd
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 1.12 2002/07/08 13:40:15 giles Exp $ */ #ifdef HAVE_CONFIG_H #include "config.h" #include "config_types.h" #endif #ifdef HAVE_STDINT_H #include <stdint.h> #endif #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 **/ 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; 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; } /** * 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 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 */ 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 = 0; for (index = 0; index < segment->referred_to_segment_count; index++) { int sindex = segment->referred_to_segments[index]; if ((ctx->segments[sindex]->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 sindex = segment->referred_to_segments[index]; int dindex = 0; if ((ctx->segments[sindex]->flags & 63) == 0) dicts[dindex++] = (Jbig2SymbolDict *)ctx->segments[sindex]->result; } jbig2_error(ctx, JBIG2_SEVERITY_DEBUG, segment->number, "refers to %d symbol dictionaries", n_dicts); 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"); }