From e1d613a20baeb81e9ac98feb91df494ec71c1e59 Mon Sep 17 00:00:00 2001
From: Werner Almesberger <werner@almesberger.net>
Date: Wed, 11 Jul 2012 12:22:23 -0300
Subject: [PATCH] gencat/pdf.c: add generation of alphabetic index with
 hyperlinks

---
 gencat/pdf.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 126 insertions(+), 7 deletions(-)

diff --git a/gencat/pdf.c b/gencat/pdf.c
index 0d0e941..5e5cc0d 100644
--- a/gencat/pdf.c
+++ b/gencat/pdf.c
@@ -12,8 +12,10 @@
 #define	_GNU_SOURCE
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <sys/types.h>
 
+#include "util.h"
 #include "gencat.h"
 #include "tree.h"
 #include "pdf.h"
@@ -28,8 +30,12 @@ static struct format {
 		const char *font;
 		int size;
 		int y;
-	} name, path, lib, comment;
+	} name, path, lib, comment, index;
 	int comment_line_skip;
+	int index_line_skip;
+	int index_column_skip;
+	int index_lines;
+	int index_columns;
 } landscape = {
 	.file_setup	= "%%Orientation: Landscape",
 	.overlay_setup	= "90 rotate",
@@ -39,7 +45,12 @@ static struct format {
 	.path		= { "Helvetica-Bold",	18,  30 },
 	.lib		= { "Courier",		12,  75 },
 	.comment	= { "Helvetica",	12, 600 },
+	.index		= { "Helvetica",	10,  32 },
 	.comment_line_skip = 14,
+	.index_line_skip = 12,
+	.index_column_skip = 140,
+	.index_lines	= 45,
+	.index_columns	= 6,
 }, portrait = {
 	.file_setup	= "%%Orientation: Portrait",
 	.overlay_setup	= "0 790 translate",
@@ -49,21 +60,32 @@ static struct format {
 	.path		= { "Helvetica-Bold",	18,  30 },
 	.lib		= { "Courier",		12,  75 },
 	.comment	= { "Helvetica",	12, 740 },
+	.index		= { "Helvetica",	10,   0 },
 	.comment_line_skip = 14,
+	.index_line_skip = 12,
+	.index_column_skip = 140,
+	.index_lines	= 63,
+	.index_columns	= 4,
 }, format;
 
 static int total, done = 0;
 
 
-static int children(const struct node *node)
+static char *sanitize_name(const char *s)
 {
-	int n = 0;
+	char *t, *tmp;
 
-	while (node) {
-		n++;
-		node = node->next;
+	tmp = alloc_size(strlen(s)+1);
+	for (t = tmp; *s; s++) {
+		if (*s <= ' ' || *s > '~')
+			continue;
+		/* PDF reference 3rd ed., 3.2.2 ASCII Encoding */
+		if (strchr("()<>[]{}/%", *s))
+			continue;
+		*t++ = *s;
 	}
-	return n;
+	*t = 0;
+	return tmp;
 }
 
 
@@ -80,6 +102,97 @@ static void ps_string(FILE *file, const char *s)
 }
 
 
+static void collect_names(const struct node *node, const char ***idx, int *n)
+{
+	const struct name *name;
+
+	while (node) {
+		if (node->child)
+			collect_names(node->child, idx, n);
+		else {
+			for (name = node->names; name; name = name->next) {
+				(*n)++;
+				*idx = realloc(*idx, *n*sizeof(char *));
+				if (!*idx)
+					abort();
+				(*idx)[*n-1] = name->s;
+			}
+		}
+		node = node->next;
+	}
+}
+
+
+static int comp(const void *a, const void *b)
+{
+	return strcmp(*(const char **) a, *(const char **) b);
+}
+
+
+static void make_index(FILE *file, const struct node *node)
+{
+	const char **idx = NULL, **p;
+	int n = 0;
+	int line = 0, col = 0;
+	char *s;
+
+	collect_names(node, &idx, &n);
+	qsort(idx, n, sizeof(char *), comp);
+
+	fprintf(file, "[ /Title (Index) /Count 0 /OUT pdfmark\n");
+
+	fprintf(file, "/%s findfont %d scalefont setfont\n",
+	    format.index.font, format.index.size);
+	fprintf(file, "gsave %s 0 setgray\n", format.overlay_setup);
+
+	for (p = idx; p != idx+n; p++) {
+		if (line == format.index_lines) {
+			line = 0;
+			col++;
+		}
+		if (col == format.index_columns) {
+			fprintf(file, "grestore showpage\n");
+			fprintf(file, "gsave %s 0 setgray\n",
+			    format.overlay_setup);
+			col = 0;
+		}
+		fprintf(file, "newpath %d -%d moveto currentpoint\n",
+		    format.left+col*format.index_column_skip,
+		    format.index.y+line*format.index_line_skip);
+
+		s = sanitize_name(*p);
+		fprintf(file, "[ /Rect [ ");
+		ps_string(file, *p);
+		fprintf(file, " false charpath flattenpath pathbbox ]\n");
+		fprintf(file, "  /Subtype /Link\n");
+		fprintf(file, "  /Border [ 0 0 0 ]\n");
+		fprintf(file, "  /Action << /Subtype /GoTo /Dest /%s >>\n", s);
+		fprintf(file, "  /ANN pdfmark\n");
+		free(s);
+
+		fprintf(file, "moveto ");
+		ps_string(file, *p);
+		fprintf(file, " show\n");
+		line++;
+	}
+	fprintf(file, "grestore showpage\n");
+
+	free(idx);
+}
+
+
+static int children(const struct node *node)
+{
+	int n = 0;
+
+	while (node) {
+		n++;
+		node = node->next;
+	}
+	return n;
+}
+
+
 static void print_path(FILE *file, const struct node *node)
 {
 	if (node->parent) {
@@ -94,6 +207,7 @@ static void print_path(FILE *file, const struct node *node)
 static void make_title(FILE *file, const struct node *node, int unit)
 {
 	const struct name *name;
+	char *s;
 
 	fprintf(file, "gsave %s 0 setgray\n", format.overlay_setup);
 
@@ -105,6 +219,10 @@ static void make_title(FILE *file, const struct node *node, int unit)
 			fprintf(file, "(, ) show 0.5 setgray\n");
 		ps_string(file, name->s);
 		fprintf(file, " show\n");
+		s = sanitize_name(name->s);
+		if (!unit)
+			fprintf(file, "[ /Dest /%s /DEST pdfmark\n", s);
+		free(s);
 	}
 	fprintf(file, "0 setgray\n");
 	if (node->units > 1)
@@ -260,6 +378,7 @@ void make_pdf(int pdf, int use_portrait)
 		exit(1);
 	}
 	fprintf(out, "%%!PS\n%s\n", format.file_setup);
+	make_index(out, tree);
 	total = count_tree(tree);
 	convert_tree(tree, out);
 	if (!quiet)