--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lib-imap/imap-base-subject.c	Tue Dec 17 06:33:38 2002 +0200
@@ -0,0 +1,260 @@
+/* Copyright (C) 2002 Timo Sirainen */
+
+#include "lib.h"
+#include "buffer.h"
+#include "charset-utf8.h"
+#include "message-header-decode.h"
+#include "imap-base-subject.h"
+
+static int header_decode(const unsigned char *data, size_t size,
+			 const char *charset, void *context)
+{
+	Buffer *buf = context;
+	const char *utf8_str;
+	unsigned char *buf_data;
+	size_t i, used_size;
+
+	if (charset == NULL) {
+		/* It's ASCII. */
+		buffer_append(buf, data, size);
+	} else {
+		t_push();
+		utf8_str = charset_to_utf8_string(charset, NULL, data, size, &size);
+		if (utf8_str == NULL)
+			size = 0;
+		else
+			buffer_append(buf, utf8_str, size);
+		t_pop();
+	}
+
+	if (size > 0) {
+		/* @UNSAFE: uppercase it. Current draft specifies that we
+		   should touch only ASCII. */
+		buf_data = buffer_get_modifyable_data(buf, &used_size);
+		for (i = used_size - size; i < used_size; i++) {
+			if (buf_data[i] >= 'a' && buf_data[i] <= 'z')
+				buf_data[i] = buf_data[i] - 'a' + 'A';
+		}
+	}
+
+	return TRUE;
+}
+
+static void pack_whitespace(Buffer *buf)
+{
+	char *data, *dest;
+	int last_lwsp;
+
+	data = buffer_get_modifyable_data(buf, NULL);
+
+	/* check if we need to do anything */
+	while (*data != '\0') {
+		if (*data == '\t' ||
+		    (*data == ' ' && (data[1] == ' ' || data[1] == '\t')))
+			break;
+		data++;
+	}
+
+	if (*data == '\0')
+		return;
+
+	/* @UNSAFE: convert/pack the whitespace */
+	dest = data; last_lwsp = FALSE;
+	while (*data != '\0') {
+		if (*data == '\t' || *data == ' ') {
+			if (!last_lwsp) {
+				*dest++ = ' ';
+				last_lwsp = TRUE;
+			}
+		} else {
+			*dest++ = *data;
+			last_lwsp = FALSE;
+		}
+		data++;
+	}
+	*dest = '\0';
+
+	data = buffer_get_modifyable_data(buf, NULL);
+	buffer_set_used_size(buf, (size_t) (dest - data)+1);
+}
+
+static void remove_subj_trailers(Buffer *buf)
+{
+	const char *data;
+	size_t orig_size, size;
+
+	/* subj-trailer    = "(fwd)" / WSP */
+	data = buffer_get_data(buf, &orig_size);
+
+	if (orig_size < 2) /* size includes trailing \0 */
+		return;
+
+	for (size = orig_size-2; size > 0; ) {
+		if (data[size] == ' ')
+			size--;
+		else if (size >= 5 && memcmp(data + size - 5, "(fwd)", 5) == 0)
+			size -= 5;
+		else
+			break;
+	}
+
+	if (size != orig_size-2) {
+		buffer_set_used_size(buf, size);
+		buffer_append_c(buf, '\0');
+	}
+}
+
+static int remove_blob(const char **datap)
+{
+	const char *data = *datap;
+
+	if (*data != '[')
+		return FALSE;
+
+	while (*data != '\0' && *data != '[' && *data != ']')
+		data++;
+
+	if (*data != ']')
+		return FALSE;
+
+	data++;
+	if (*data == ' ')
+		data++;
+
+	*datap = data;
+	return TRUE;
+}
+
+static int remove_subj_leader(Buffer *buf)
+{
+	const char *data, *orig_data;
+	int ret = FALSE;
+
+	/* subj-leader     = (*subj-blob subj-refwd) / WSP
+
+	   subj-blob       = "[" *BLOBCHAR "]" *WSP
+	   subj-refwd      = ("re" / ("fw" ["d"])) *WSP [subj-blob] ":"
+
+	   BLOBCHAR        = %x01-5a / %x5c / %x5e-7f
+	                   ; any CHAR except '[' and ']' */
+	orig_data = data = buffer_get_data(buf, NULL);
+
+	if (*data == ' ') {
+		/* independent from checks below - always removed */
+		data++;
+		buffer_set_start_pos(buf, buffer_get_start_pos(buf)+1);
+		ret = TRUE;
+	}
+
+	while (*data == '[') {
+		if (!remove_blob(&data))
+			return ret;
+	}
+
+	if (strncasecmp(data, "re", 2) == 0)
+		data += 2;
+	else if (strncasecmp(data, "fwd", 3) == 0)
+		data += 3;
+	else if (strncasecmp(data, "fw", 2) == 0)
+		data += 2;
+	else
+		return ret;
+
+	if (*data == ' ')
+		data++;
+
+	if (*data == '[' && !remove_blob(&data))
+		return ret;
+
+	if (*data != ':')
+		return ret;
+
+	data++;
+	buffer_set_start_pos(buf, buffer_get_start_pos(buf) +
+			     (size_t) (data - orig_data));
+	return TRUE;
+}
+
+static int remove_blob_when_nonempty(Buffer *buf)
+{
+	const char *data, *orig_data;
+
+	orig_data = data = buffer_get_data(buf, NULL);
+	if (*data == '[' && remove_blob(&data) && *data != '\0') {
+		buffer_set_start_pos(buf, buffer_get_start_pos(buf) +
+				     (size_t) (data - orig_data));
+		return TRUE;
+	}
+
+	return FALSE;
+}
+
+static int remove_subj_fwd_hdr(Buffer *buf)
+{
+	const char *data;
+	size_t size;
+
+	/* subj-fwd        = subj-fwd-hdr subject subj-fwd-trl
+	   subj-fwd-hdr    = "[fwd:"
+	   subj-fwd-trl    = "]" */
+	data = buffer_get_data(buf, &size);
+
+	if (strncasecmp(data, "[fwd:", 5) != 0)
+		return FALSE;
+
+	if (data[size-2] != ']')
+		return FALSE;
+
+	buffer_set_used_size(buf, size-2);
+	buffer_append_c(buf, '\0');
+
+	buffer_set_start_pos(buf, buffer_get_start_pos(buf) + 5);
+	return TRUE;
+}
+
+const char *imap_get_base_subject_cased(Pool pool, const char *subject)
+{
+	Buffer *buf;
+	size_t subject_len;
+	int found;
+
+	subject_len = strlen(subject);
+	buf = buffer_create_dynamic(pool, subject_len, (size_t)-1);
+
+	/* (1) Convert any RFC 2047 encoded-words in the subject to
+	   UTF-8.  Convert all tabs and continuations to space.
+	   Convert all multiple spaces to a single space. */
+	message_header_decode(subject, subject_len, header_decode, buf);
+	buffer_append_c(buf, '\0');
+
+	pack_whitespace(buf);
+
+	do {
+		/* (2) Remove all trailing text of the subject that matches
+		   the subj-trailer ABNF, repeat until no more matches are
+		   possible. */
+		remove_subj_trailers(buf);
+
+		do {
+			/* (3) Remove all prefix text of the subject that
+			   matches the subj-leader ABNF. */
+			found = remove_subj_leader(buf);
+
+			/* (4) If there is prefix text of the subject that
+			   matches the subj-blob ABNF, and removing that prefix
+			   leaves a non-empty subj-base, then remove the prefix
+			   text. */
+			found = remove_blob_when_nonempty(buf) || found;
+
+			/* (5) Repeat (3) and (4) until no matches remain. */
+		} while (found);
+
+		/* (6) If the resulting text begins with the subj-fwd-hdr ABNF
+		   and ends with the subj-fwd-trl ABNF, remove the
+		   subj-fwd-hdr and subj-fwd-trl and repeat from step (2). */
+	} while (remove_subj_fwd_hdr(buf));
+
+	/* (7) The resulting text is the "base subject" used in the
+	   SORT. */
+	return buffer_get_data(buf, NULL);
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lib-imap/imap-base-subject.h	Tue Dec 17 06:33:38 2002 +0200
@@ -0,0 +1,9 @@
+#ifndef __IMAP_BASE_SUBJECT_H
+#define __IMAP_BASE_SUBJECT_H
+
+/* Returns the base subject of the given string, according to
+   draft-ietf-imapext-sort-10. String is returned so that it's suitable for
+   strcmp() comparing with another base subject. */
+const char *imap_get_base_subject_cased(Pool pool, const char *subject);
+
+#endif