From: Timo Sirainen <tss@iki.fi>
Date: Fri, 10 Aug 2012 03:45:25 +0000 (+0300)
Subject: Added istream-base64-decoder.
X-Git-Tag: 2.2.alpha1~383
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3700eab7818bcf8a68424c418485ae4e8770865d;p=thirdparty%2Fdovecot%2Fcore.git

Added istream-base64-decoder.
---

diff --git a/src/lib/Makefile.am b/src/lib/Makefile.am
index 36fbfbb195..f4348592e1 100644
--- a/src/lib/Makefile.am
+++ b/src/lib/Makefile.am
@@ -54,6 +54,7 @@ liblib_la_SOURCES = \
 	iostream-rawlog.c \
 	iso8601-date.c \
 	istream.c \
+	istream-base64-decoder.c \
 	istream-base64-encoder.c \
 	istream-chain.c \
 	istream-concat.c \
@@ -178,7 +179,7 @@ headers = \
 	iostream-rawlog-private.h \
 	iso8601-date.h \
 	istream.h \
-	istream-base64-encoder.h \
+	istream-base64.h \
 	istream-chain.h \
 	istream-concat.h \
 	istream-crlf.h \
@@ -263,6 +264,7 @@ test_lib_SOURCES = \
 	test-hash-format.c \
 	test-hex-binary.c \
 	test-iso8601-date.c \
+	test-istream-base64-decoder.c \
 	test-istream-base64-encoder.c \
 	test-istream-concat.c \
 	test-istream-crlf.c \
diff --git a/src/lib/istream-base64-decoder.c b/src/lib/istream-base64-decoder.c
new file mode 100644
index 0000000000..1138490717
--- /dev/null
+++ b/src/lib/istream-base64-decoder.c
@@ -0,0 +1,131 @@
+/* Copyright (c) 2012 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "buffer.h"
+#include "base64.h"
+#include "istream-private.h"
+#include "istream-base64.h"
+
+struct base64_decoder_istream {
+	struct istream_private istream;
+};
+
+static int i_stream_read_parent(struct istream_private *stream)
+{
+	size_t size;
+	ssize_t ret;
+
+	size = i_stream_get_data_size(stream->parent);
+	if (size >= 4)
+		return 1;
+
+	/* we have less than one base64 block.
+	   see if there is more data available. */
+	ret = i_stream_read(stream->parent);
+	if (ret <= 0) {
+		stream->istream.stream_errno = stream->parent->stream_errno;
+		stream->istream.eof = stream->parent->eof;
+		return ret;
+	}
+	size = i_stream_get_data_size(stream->parent);
+	i_assert(size != 0);
+	return 1;
+}
+
+static int
+i_stream_base64_try_decode_block(struct base64_decoder_istream *bstream)
+{
+	struct istream_private *stream = &bstream->istream;
+	const unsigned char *data;
+	size_t size, avail, buffer_avail, pos;
+	buffer_t buf;
+
+	data = i_stream_get_data(stream->parent, &size);
+	if (size == 0)
+		return 0;
+
+	i_stream_try_alloc(stream, (size+3)/4*3, &avail);
+	buffer_avail = stream->buffer_size - stream->pos;
+
+	if ((size + 3) / 4 * 3 > buffer_avail) {
+		/* can't fit everything to destination buffer.
+		   write as much as we can. */
+		size = (buffer_avail / 3) * 4;
+		if (size == 0)
+			return -2;
+	}
+
+	buffer_create_data(&buf, stream->w_buffer + stream->pos, buffer_avail);
+	if (base64_decode(data, size, &pos, &buf) < 0) {
+		stream->istream.stream_errno = EINVAL;
+		return -1;
+	}
+
+	stream->pos += buf.used;
+	i_stream_skip(stream->parent, pos);
+	return pos > 0 ? 1 : 0;
+}
+
+static ssize_t i_stream_base64_decoder_read(struct istream_private *stream)
+{
+	struct base64_decoder_istream *bstream =
+		(struct base64_decoder_istream *)stream;
+	size_t pre_count, post_count;
+	int ret;
+
+	do {
+		ret = i_stream_read_parent(stream);
+		if (ret <= 0) {
+			if (ret < 0 && stream->istream.stream_errno == 0 &&
+			    i_stream_get_data_size(stream->parent) > 0) {
+				/* base64 input with a partial block */
+				stream->istream.stream_errno = EINVAL;
+			}
+			return ret;
+		}
+
+		/* encode as many blocks as fits into destination buffer */
+		pre_count = stream->pos - stream->skip;
+		while ((ret = i_stream_base64_try_decode_block(bstream)) > 0) ;
+		post_count = stream->pos - stream->skip;
+	} while (ret == 0);
+
+	if (ret < 0)
+		return ret;
+
+	i_assert(post_count > pre_count);
+	return post_count - pre_count;
+}
+
+static void
+i_stream_base64_decoder_seek(struct istream_private *stream,
+			     uoff_t v_offset, bool mark)
+{
+	if (v_offset < stream->istream.v_offset) {
+		/* seeking backwards - go back to beginning and seek
+		   forward from there. */
+		stream->parent_expected_offset = stream->parent_start_offset;
+		stream->skip = stream->pos = 0;
+		stream->istream.v_offset = 0;
+		i_stream_seek(stream->parent, 0);
+	}
+	i_stream_default_seek_nonseekable(stream, v_offset, mark);
+}
+
+struct istream *
+i_stream_create_base64_decoder(struct istream *input)
+{
+	struct base64_decoder_istream *bstream;
+
+	bstream = i_new(struct base64_decoder_istream, 1);
+	bstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
+
+	bstream->istream.read = i_stream_base64_decoder_read;
+	bstream->istream.seek = i_stream_base64_decoder_seek;
+
+	bstream->istream.istream.readable_fd = FALSE;
+	bstream->istream.istream.blocking = input->blocking;
+	bstream->istream.istream.seekable = input->seekable;
+	return i_stream_create(&bstream->istream, input,
+			       i_stream_get_fd(input));
+}
diff --git a/src/lib/istream-base64-encoder.c b/src/lib/istream-base64-encoder.c
index d4cf26cd8f..5bcb804a62 100644
--- a/src/lib/istream-base64-encoder.c
+++ b/src/lib/istream-base64-encoder.c
@@ -4,7 +4,7 @@
 #include "buffer.h"
 #include "base64.h"
 #include "istream-private.h"
-#include "istream-base64-encoder.h"
+#include "istream-base64.h"
 
 struct base64_encoder_istream {
 	struct istream_private istream;
diff --git a/src/lib/istream-base64-encoder.h b/src/lib/istream-base64.h
similarity index 71%
rename from src/lib/istream-base64-encoder.h
rename to src/lib/istream-base64.h
index 841ba86d2e..8639cf78bc 100644
--- a/src/lib/istream-base64-encoder.h
+++ b/src/lib/istream-base64.h
@@ -4,5 +4,7 @@
 struct istream *
 i_stream_create_base64_encoder(struct istream *input,
 			       unsigned int chars_per_line, bool crlf);
+struct istream *
+i_stream_create_base64_decoder(struct istream *input);
 
 #endif
diff --git a/src/lib/test-istream-base64-decoder.c b/src/lib/test-istream-base64-decoder.c
new file mode 100644
index 0000000000..06e7a032a4
--- /dev/null
+++ b/src/lib/test-istream-base64-decoder.c
@@ -0,0 +1,69 @@
+/* Copyright (c) 2010-2012 Dovecot authors, see the included COPYING file */
+
+#include "test-lib.h"
+#include "str.h"
+#include "istream-private.h"
+#include "istream-base64.h"
+
+struct {
+	const char *input;
+	const char *output;
+} tests[] = {
+	{ "aGVsbG8gd29ybGQ=", "hello world" },
+	{ "\naGVs\nbG8g\nd29y\nbGQ=\n", "hello world" },
+	{ "  aGVs    \r\n bG8g  \r\n   d29y  \t \r\n    bGQ= \r\n\r\n", "hello world" },
+};
+
+static void
+decode_test(const char *base64_input, const char *output, bool broken_input)
+{
+	unsigned int base64_input_len = strlen(base64_input);
+	struct istream *input_data, *input;
+	const unsigned char *data;
+	size_t i, size;
+	int ret = 0;
+
+	input_data = test_istream_create_data(base64_input, base64_input_len);
+	test_istream_set_allow_eof(input_data, FALSE);
+	input = i_stream_create_base64_decoder(input_data);
+
+	for (i = 1; i <= base64_input_len; i++) {
+		test_istream_set_size(input_data, i);
+		while ((ret = i_stream_read(input)) > 0) ;
+		if (ret == -1 && broken_input)
+			break;
+		test_assert(ret == 0);
+	}
+	if (ret == 0) {
+		test_istream_set_allow_eof(input_data, TRUE);
+		while ((ret = i_stream_read(input)) > 0) ;
+	}
+	test_assert(ret == -1);
+	test_assert((input->stream_errno == 0 && !broken_input) ||
+		    (input->stream_errno == EINVAL && broken_input));
+
+	data = i_stream_get_data(input, &size);
+	test_assert(size == strlen(output) && memcmp(data, output, size) == 0);
+	i_stream_unref(&input);
+	i_stream_unref(&input_data);
+}
+
+void test_istream_base64_decoder(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < N_ELEMENTS(tests); i++) {
+		test_begin(t_strdup_printf("istream base64 decoder %u", i+1));
+		decode_test(tests[i].input, tests[i].output, FALSE);
+		test_end();
+	}
+	test_begin("istream base64 decoder error");
+	decode_test("foo", "", TRUE);
+	decode_test("Zm9vC", "foo", TRUE);
+	decode_test("Zm9v!", "foo", TRUE);
+	decode_test("Zm9!v", "", TRUE);
+	decode_test("Zm9 v", "", TRUE);
+	decode_test("Zm 9v", "", TRUE);
+	decode_test("Z m9v", "", TRUE);
+	test_end();
+}
diff --git a/src/lib/test-istream-base64-encoder.c b/src/lib/test-istream-base64-encoder.c
index c0b8c99c62..fc40dcc0f6 100644
--- a/src/lib/test-istream-base64-encoder.c
+++ b/src/lib/test-istream-base64-encoder.c
@@ -3,7 +3,7 @@
 #include "test-lib.h"
 #include "str.h"
 #include "istream-private.h"
-#include "istream-base64-encoder.h"
+#include "istream-base64.h"
 
 static const char *hello = "hello world";
 
diff --git a/src/lib/test-lib.c b/src/lib/test-lib.c
index 984b1d704b..dc2795c2b3 100644
--- a/src/lib/test-lib.c
+++ b/src/lib/test-lib.c
@@ -14,6 +14,7 @@ int main(void)
 		test_hash_format,
 		test_hex_binary,
 		test_iso8601_date,
+		test_istream_base64_decoder,
 		test_istream_base64_encoder,
 		test_istream_concat,
 		test_istream_crlf,
diff --git a/src/lib/test-lib.h b/src/lib/test-lib.h
index 9b9bfe3d59..9519cced6f 100644
--- a/src/lib/test-lib.h
+++ b/src/lib/test-lib.h
@@ -13,6 +13,7 @@ void test_crc32(void);
 void test_hash_format(void);
 void test_hex_binary(void);
 void test_iso8601_date(void);
+void test_istream_base64_decoder(void);
 void test_istream_base64_encoder(void);
 void test_istream_concat(void);
 void test_istream_crlf(void);