mupdf-rtt/pdf/pdf_unicode.c

#include "fitz-internal.h"
#include "mupdf-internal.h"

/* Load or synthesize ToUnicode map for fonts */

void
pdf_load_to_unicode(pdf_document *xref, pdf_font_desc *font,
	char **strings, char *collection, pdf_obj *cmapstm)
{
	pdf_cmap *cmap;
	int cid;
	int ucsbuf[8];
	int ucslen;
	int i;
	fz_context *ctx = xref->ctx;

	if (pdf_is_stream(xref, pdf_to_num(cmapstm), pdf_to_gen(cmapstm)))
	{
		cmap = pdf_load_embedded_cmap(xref, cmapstm);

		font->to_unicode = pdf_new_cmap(ctx);

		for (i = 0; i < (strings ? 256 : 65536); i++)
		{
			cid = pdf_lookup_cmap(font->encoding, i);
			if (cid >= 0)
			{
				ucslen = pdf_lookup_cmap_full(cmap, i, ucsbuf);
				if (ucslen == 1)
					pdf_map_range_to_range(ctx, font->to_unicode, cid, cid, ucsbuf[0]);
				if (ucslen > 1)
					pdf_map_one_to_many(ctx, font->to_unicode, cid, ucsbuf, ucslen);
			}
		}

		pdf_sort_cmap(ctx, font->to_unicode);

		pdf_drop_cmap(ctx, cmap);
		font->size += pdf_cmap_size(ctx, font->to_unicode);
	}

	else if (collection)
	{
		if (!strcmp(collection, "Adobe-CNS1"))
			font->to_unicode = pdf_load_system_cmap(ctx, "Adobe-CNS1-UCS2");
		else if (!strcmp(collection, "Adobe-GB1"))
			font->to_unicode = pdf_load_system_cmap(ctx, "Adobe-GB1-UCS2");
		else if (!strcmp(collection, "Adobe-Japan1"))
			font->to_unicode = pdf_load_system_cmap(ctx, "Adobe-Japan1-UCS2");
		else if (!strcmp(collection, "Adobe-Korea1"))
			font->to_unicode = pdf_load_system_cmap(ctx, "Adobe-Korea1-UCS2");

		return;
	}

	if (strings)
	{
		/* TODO one-to-many mappings */

		font->cid_to_ucs_len = 256;
		font->cid_to_ucs = fz_malloc_array(ctx, 256, sizeof(unsigned short));
		font->size += 256 * sizeof(unsigned short);

		for (i = 0; i < 256; i++)
		{
			if (strings[i])
				font->cid_to_ucs[i] = pdf_lookup_agl(strings[i]);
			else
				font->cid_to_ucs[i] = '?';
		}
	}

	if (!font->to_unicode && !font->cid_to_ucs)
	{
		/* TODO: synthesize a ToUnicode if it's a freetype font with
		 * cmap and/or post tables or if it has glyph names. */
	}
}