From 7c2587b1f6bc86a74b80cb8e80a98a99eba8266e Mon Sep 17 00:00:00 2001
From: Alex Dowad <alexinbeijing@gmail.com>
Date: Sat, 23 Apr 2022 20:56:52 +0200
Subject: [PATCH] Implement fast text conversion interface for UUENCODE

---
 .../libmbfl/filters/mbfilter_uuencode.c       | 163 +++++++++++++++++-
 ext/mbstring/tests/uuencode_encoding.phpt     |  41 +++++
 2 files changed, 195 insertions(+), 9 deletions(-)
 create mode 100644 ext/mbstring/tests/uuencode_encoding.phpt

diff --git a/ext/mbstring/libmbfl/filters/mbfilter_uuencode.c b/ext/mbstring/libmbfl/filters/mbfilter_uuencode.c
index 9571131aad5..e2fef079c59 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_uuencode.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_uuencode.c
@@ -30,6 +30,9 @@
 #include "mbfilter.h"
 #include "mbfilter_uuencode.h"
 
+static size_t mb_uuencode_to_wchar(unsigned char **in, size_t *in_len, uint32_t *buf, size_t bufsize, unsigned int *state);
+static void mb_wchar_to_uuencode(uint32_t *in, size_t len, mb_convert_buf *buf, bool end);
+
 const mbfl_encoding mbfl_encoding_uuencode = {
 	mbfl_no_encoding_uuencode,
 	"UUENCODE",
@@ -39,8 +42,8 @@ const mbfl_encoding mbfl_encoding_uuencode = {
 	MBFL_ENCTYPE_SBCS,
 	NULL,
 	NULL,
-	NULL,
-	NULL
+	mb_uuencode_to_wchar,
+	mb_wchar_to_uuencode
 };
 
 const struct mbfl_convert_vtbl vtbl_uuencode_8bit = {
@@ -55,15 +58,21 @@ const struct mbfl_convert_vtbl vtbl_uuencode_8bit = {
 
 #define CK(statement)	do { if ((statement) < 0) return (-1); } while (0)
 
-/* uuencode => any */
-#define UUDEC(c)	(char)(((c)-' ')&077)
-static const char * uuenc_begin_text = "begin ";
-enum { uudec_state_ground=0, uudec_state_inbegin,
+#define UUDEC(c)	(char)(((c)-' ') & 077)
+static const char *uuenc_begin_text = "begin ";
+enum {
+	uudec_state_ground=0,
+	uudec_state_inbegin,
 	uudec_state_until_newline,
-	uudec_state_size, uudec_state_a, uudec_state_b, uudec_state_c, uudec_state_d,
-	uudec_state_skip_newline};
+	uudec_state_size,
+	uudec_state_a,
+	uudec_state_b,
+	uudec_state_c,
+	uudec_state_d,
+	uudec_state_skip_newline
+};
 
-int mbfl_filt_conv_uudec(int c, mbfl_convert_filter * filter)
+int mbfl_filt_conv_uudec(int c, mbfl_convert_filter *filter)
 {
 	int n;
 
@@ -135,6 +144,8 @@ int mbfl_filt_conv_uudec(int c, mbfl_convert_filter * filter)
 					CK((*filter->output_function)( (B << 4) | (C >> 2), filter->data));
 				if (n-- > 0)
 					CK((*filter->output_function)( (C << 6) | D, filter->data));
+				if (n < 0)
+					n = 0;
 				filter->cache = n << 24;
 
 				if (n == 0)
@@ -149,3 +160,137 @@ int mbfl_filt_conv_uudec(int c, mbfl_convert_filter * filter)
 	}
 	return 0;
 }
+
+/* Using mbstring to decode UUEncoded text is already deprecated
+ * However, to facilitate the move to the new, faster internal conversion interface,
+ * We will temporarily implement it for UUEncode */
+
+static size_t mb_uuencode_to_wchar(unsigned char **in, size_t *in_len, uint32_t *buf, size_t bufsize, unsigned int *state)
+{
+	unsigned char *p = *in, *e = p + *in_len;
+	uint32_t *out = buf, *limit = buf + bufsize;
+
+	unsigned int _state = *state & 0xFF;
+	unsigned int size = *state >> 8;
+
+	while (p < e && (limit - out) >= 3) {
+		unsigned char c = *p++;
+
+		switch (_state) {
+		case uudec_state_ground:
+			if (c == 'b') {
+				if ((e - p) >= 5 && memcmp(p, uuenc_begin_text+1, 5) == 0) {
+					p += 5;
+					while (p < e && *p++ != '\n'); /* Consume everything up to newline */
+					_state = uudec_state_size;
+				}
+				/* We didn't find "begin " */
+			}
+			break;
+
+		case uudec_state_size:
+			size = UUDEC(c);
+			_state = uudec_state_a;
+			break;
+
+		case uudec_state_a:
+			if ((e - p) < 4) {
+				p = e;
+				break;
+			}
+
+			unsigned int a = UUDEC(c);
+			unsigned int b = UUDEC(*p++);
+			unsigned int c = UUDEC(*p++);
+			unsigned int d = UUDEC(*p++);
+
+			if (size > 0) {
+				*out++ = ((a << 2) | (b >> 4)) & 0xFF;
+				size--;
+			}
+			if (size > 0) {
+				*out++ = ((b << 4) | (c >> 2)) & 0xFF;
+				size--;
+			}
+			if (size > 0) {
+				*out++ = ((c << 6) | d) & 0xFF;
+				size--;
+			}
+
+			_state = size ? uudec_state_a : uudec_state_skip_newline;
+			break;
+
+		case uudec_state_skip_newline:
+			_state = uudec_state_size;
+			break;
+		}
+	}
+
+	*state = (size << 8) | _state;
+	*in_len = e - p;
+	*in = p;
+	return out - buf;
+}
+
+static unsigned char uuencode_six_bits(unsigned int bits)
+{
+	if (bits == 0) {
+		return '`';
+	} else {
+		return bits + 32;
+	}
+}
+
+static void mb_wchar_to_uuencode(uint32_t *in, size_t len, mb_convert_buf *buf, bool end)
+{
+	unsigned char *out, *limit;
+	MB_CONVERT_BUF_LOAD(buf, out, limit);
+	/* Every 3 bytes of input gets encoded as 4 bytes of output
+	 * Additionally, we have a 'length' byte and a newline for each line of output
+	 * (Maximum 45 input bytes can be encoded on a single output line)
+	 * Make space for two more bytes in case we start close to where a line must end */
+	MB_CONVERT_BUF_ENSURE(buf, out, limit, ((len + 2) * 4 / 3) + (((len + 44) / 45) * 2) + (buf->state ? 0 : sizeof("begin 0644 filename\n")) + 2);
+
+	unsigned int bytes_encoded = buf->state >> 1;
+
+	if (!buf->state) {
+		for (char *s = "begin 0644 filename\n"; *s; s++) {
+			out = mb_convert_buf_add(out, *s);
+		}
+		out = mb_convert_buf_add(out, MIN(len, 45) + 32);
+		buf->state |= 1;
+	}
+
+	while (len--) {
+		uint32_t w = *in++;
+		uint32_t w2 = 0, w3 = 0;
+
+		if (len) {
+			w2 = *in++;
+			len--;
+		}
+		if (len) {
+			w3 = *in++;
+			len--;
+		}
+
+		out = mb_convert_buf_add4(out, uuencode_six_bits((w >> 2) & 0x3F), uuencode_six_bits(((w & 0x3) << 4) + ((w2 >> 4) & 0xF)), uuencode_six_bits(((w2 & 0xF) << 2) + ((w3 >> 6) & 0x3)), uuencode_six_bits(w3 & 0x3F));
+
+		bytes_encoded += 3;
+
+		if (bytes_encoded >= 45) {
+			out = mb_convert_buf_add(out, '\n');
+			if (len) {
+				out = mb_convert_buf_add(out, MIN(len, 45) + 32);
+			}
+			bytes_encoded = 0;
+		}
+	}
+
+	if (bytes_encoded) {
+		out = mb_convert_buf_add(out, '\n');
+	}
+
+	buf->state = (bytes_encoded << 1) | (buf->state & 1);
+	MB_CONVERT_BUF_STORE(buf, out, limit);
+}
diff --git a/ext/mbstring/tests/uuencode_encoding.phpt b/ext/mbstring/tests/uuencode_encoding.phpt
new file mode 100644
index 00000000000..70dedc60e90
--- /dev/null
+++ b/ext/mbstring/tests/uuencode_encoding.phpt
@@ -0,0 +1,41 @@
+--TEST--
+Temporary test of mbstring's UUEncode 'encoding'
+--EXTENSIONS--
+mbstring
+--FILE--
+<?php
+
+/* Using mbstring to convert strings from UUEncode has already been deprecated
+ * So this test should be removed when the UUEncode 'encoding' is */
+
+function testConversion($uuencode, $raw) {
+  $converted = mb_convert_encoding($uuencode, '8bit', 'UUENCODE');
+  if ($converted !== $raw)
+    die('Expected "' . $uuencode . '" to convert to ' . bin2hex($raw) . '; actually got ' . bin2hex($converted));
+  $converted = mb_convert_encoding($raw, 'UUENCODE', '8bit');
+  if ($converted !== $uuencode)
+    die('Expected ' . bin2hex($raw) . ' to convert to "' . $uuencode . '"; actually got "' . $converted . '"');
+}
+
+testConversion('', '');
+
+/* mbstring's uuencode requires the user to strip off the terminating "`\nend\n" */
+
+testConversion("begin 0644 filename\n#0V%T\n", 'Cat');
+testConversion("begin 0644 filename\n::'1T<#HO+W=W=RYW:6MI<&5D:6\$N;W)G#0H`\n", "http://www.wikipedia.org\r\n");
+testConversion("begin 0644 filename\n#`0(#\n", "\x01\x02\x03");
+testConversion("begin 0644 filename\n$`0(#\"@``\n", "\x01\x02\x03\n");
+
+echo "Done!\n";
+?>
+--EXPECTF--
+Deprecated: mb_convert_encoding(): Handling Uuencode via mbstring is deprecated; use convert_uuencode/convert_uudecode instead in %s
+
+Deprecated: mb_convert_encoding(): Handling Uuencode via mbstring is deprecated; use convert_uuencode/convert_uudecode instead in %s
+
+Deprecated: mb_convert_encoding(): Handling Uuencode via mbstring is deprecated; use convert_uuencode/convert_uudecode instead in %s
+
+Deprecated: mb_convert_encoding(): Handling Uuencode via mbstring is deprecated; use convert_uuencode/convert_uudecode instead in %s
+
+Deprecated: mb_convert_encoding(): Handling Uuencode via mbstring is deprecated; use convert_uuencode/convert_uudecode instead in %s
+Done!