From 62adee58659edffc15c3c5ff3a95a763ced316ca Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Fri, 29 Aug 2003 18:25:17 +0000
Subject: [PATCH] Initial revision

---
 shredtree.c | 174 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 174 insertions(+)
 create mode 100644 shredtree.c

diff --git a/shredtree.c b/shredtree.c
new file mode 100644
index 0000000..e598481
--- /dev/null
+++ b/shredtree.c
@@ -0,0 +1,174 @@
+/* shedtree.c -- generate MD5 hash list in SHIF-A format from a file tree */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <ftw.h>
+#include <errno.h>
+#include <alloca.h>
+#include "md5.h"
+
+static c_only = 0;
+static rws = 0;
+static shredsize = 5;
+
+static int eligible(const char *file)
+/* is the specified file eligible to be compared? */ 
+{
+#define endswith(suff)	!strcmp(suff, file + strlen(file) - strlen(suff))
+    if (c_only)
+	return endswith(".c") || endswith(".h") || endswith(".txt");
+    else
+	return(1);
+#undef endswith
+}
+
+static int normalize(char *buf)
+/* normalize a buffer in place, return 0 if it should be skipped */
+{
+    if (rws)		/* strip whitespace, ignore blank lines */
+    {
+	char *tp, *sp;
+
+	for (tp = sp = buf; *sp; sp++)
+	    if (*sp != ' ' && *sp != '\t' && *sp != '\n')
+		*tp++ = *sp;
+	*tp = '\0';
+    }
+
+    return(buf[0]);
+}
+
+typedef struct
+{
+    char	*line;
+    int  	number;
+}
+shred;
+
+void shredfile(const char *file)
+/* emit hash section for specified file */
+{
+    FILE *fp;
+    char buf[BUFSIZ];
+    int i, linecount, accepted;
+    unsigned char hash[32];
+    shred *display;
+
+    if ((fp = fopen(file, "r")) == NULL)
+    {
+	fprintf(stderr, "shredtree: couldn't open %s, error %d\n",
+		file, errno);
+	exit(1);
+    }
+
+    display = (shred *)calloc(sizeof(shred), shredsize);
+
+    puts(file);
+
+    accepted = linecount = 0;
+    while(fgets(buf, sizeof(buf), fp) != NULL)
+    {
+	linecount++;
+	if (!normalize(buf))
+	    continue;
+	accepted++;
+
+	/* create new shred */
+	display[shredsize-1].line = strdup(buf);
+	display[shredsize-1].number = linecount;
+
+	/* flush completed chunk */
+	if (accepted >= shredsize)
+	{
+	    struct md5_ctx	ctx;
+
+#ifdef SHOWCHUNK
+	    printf("Chunk starts at: %d\n", display[0].number);
+	    for (i = 0; i < shredsize; i++)
+		puts(display[i].line);
+#endif /* SHOWCHUNK */
+
+	    /* flush completed chunk */
+	    md5_init_ctx(&ctx);
+	    for (i = 0; i < shredsize; i++)
+		md5_process_bytes(buf, strlen(buf), &ctx);
+	    md5_finish_ctx(&ctx, (void *)hash);
+	    fprintf(stdout, 
+		    "%d\t%d\t%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n", 
+		    display[0].number, linecount, 
+		    hash[0],
+		    hash[1],
+		    hash[2],
+		    hash[3],
+		    hash[4],
+		    hash[5],
+		    hash[6],
+		    hash[7],
+		    hash[8],
+		    hash[9],
+		    hash[10],
+		    hash[11],
+		    hash[12],
+		    hash[13],
+		    hash[14],
+		    hash[15]);
+	}
+
+	/* shreds in progress are shifted down */
+	free(display[0].line);
+	for (i=1; i < shredsize; i++)
+	    display[i-1] = display[i];
+    }
+
+    puts("");
+
+    free(display);
+    fclose(fp);
+}
+
+int treewalker(const char *file, const struct stat *sb, int flag)
+/* walk the tree, emitting hash sections for eligible files */
+{
+    if (flag == FTW_F && eligible(file))
+        shredfile(file);
+    return(0);
+}
+
+main(int argc, char *argv[])
+{
+    extern char	*optarg;	/* set by getopt */
+    extern int	optind;		/* set by getopt */
+
+    int status;
+    char *dir = ".";
+    while ((status = getopt(argc, argv, "cs:w")) != EOF)
+    {
+	switch (status)
+	{
+	case 'c':
+	    c_only = 1;
+	    break;
+
+	case 's':
+	    shredsize = atoi(optarg);
+	    break;
+
+	case 'w':
+	    rws = 1;
+	    break;
+
+	default:
+	    fputs("usage: [-s shredsize] [-w] path", stderr);
+	}
+    }
+
+    puts("#SHIF-A 1.0");
+    puts("Generator: shredtree 1.0");
+    puts("Hash: MD5");
+    printf("Shred-Size: %d\n", shredsize);
+    printf("Normalization: %s\n", rws ? "remove_whitespace" : "none");
+    puts("%%");
+
+    ftw(argv[optind], treewalker, 16);
+}
-- 
2.43.0