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uri: speedup encode and decode functions
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Patch replaces encoding and decoding functions written in Lua with
functions implemented in C.

Performance of Lua implementation (before the patch):

```
uri.escape   152.37  runs/sec
uri.unescape 263.44  runs/sec
```

Performance of C implementation (after the patch):

```
uri.escape   4983.03  runs/sec
uri.unescape 4197.19  runs/sec
```

Follows up tarantool#3682

NO_CHANGELOG=see previous commit
NO_DOC=see previous commit

Co-authored-by: Alexander Turenko <alexander.turenko@tarantool.org>
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@ligurio @Totktonada
ligurio and Totktonada committed Dec 25, 2022
1 parent a017495 commit dfc6d1a
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Showing 5 changed files with 295 additions and 24 deletions.
2 changes: 2 additions & 0 deletions extra/exports
View file
Expand Up @@ -549,6 +549,8 @@ tt_uuid_to_string
uri_destroy
uri_format
uri_set_destroy
uri_escape
uri_unescape
uuid_nil
uuid_unpack
_say
Expand Down
65 changes: 65 additions & 0 deletions src/lib/uri/uri.c
View file
Expand Up @@ -3,6 +3,7 @@
*
* Copyright 2010-2021, Tarantool AUTHORS, please see AUTHORS file.
*/
#include <ctype.h>
#include "uri.h"
#include "uri_parser.h"
#include "trivia/util.h"
Expand Down Expand Up @@ -371,3 +372,67 @@ uri_set_create(struct uri_set *uri_set, const char *str)
uri_set->uri_count = 0;
return -1;
}

/**
* String percent-encoding.
*/
size_t
uri_escape(const char *src, size_t src_size, char *dst,
const unsigned char unreserved[256], bool encode_plus)
{
int pos = 0;
const char *hex = "0123456789ABCDEF";
while (src_size--) {
unsigned char ch = (unsigned char)*src;
if ((ch == ' ') && encode_plus) {
dst[pos++] = '+';
} else if (!unreserved[(int)ch]) {
dst[pos++] = '%';
dst[pos++] = hex[ch >> 4];
dst[pos++] = hex[ch & 15];
} else {
dst[pos++] = *src;
}
src++;
}
return (size_t)pos;
};

/**
* Converts a hex character to its integer value.
*/
static char
hex2ch(unsigned char ch)
{
return isdigit(ch) ? ch - '0' : tolower(ch) - 'a' + 10;
}

/**
* String percent-decoding.
*/
size_t
uri_unescape(const char *src, size_t src_size, char *dst, bool decode_plus)
{
char *dst_buf = dst;
const char *src_end = src + src_size;
for (const char *p = src; p < src_end; ++p) {
if (*p == '%') {
bool is_hex_1 = p + 1 < src_end &&
isxdigit((unsigned char)p[1]);
bool is_hex_2 = p + 2 < src_end &&
isxdigit((unsigned char)p[2]);
if (is_hex_1 && is_hex_2) {
*dst_buf++ = hex2ch(p[1]) << 4 |
hex2ch(p[2]);
p += 2;
} else {
*dst_buf++ = '%';
}
} else if (decode_plus && *p == '+') {
*dst_buf++ = ' ';
} else {
*dst_buf++ = *p;
}
}
return (size_t)(dst_buf - dst);
}
13 changes: 13 additions & 0 deletions src/lib/uri/uri.h
View file
Expand Up @@ -141,6 +141,19 @@ uri_param(const struct uri *uri, const char *name, int idx);
int
uri_param_count(const struct uri *uri, const char *name);

/**
* String percent-encoding.
*/
size_t
uri_escape(const char *src, size_t src_size, char *dst,
const unsigned char unreserved[256], bool plus);

/**
* String percent-decoding.
*/
size_t
uri_unescape(const char *src, size_t src_size, char *dst, bool decode_plus);

#if defined(__cplusplus)
} /* extern "C" */
#endif /* defined(__cplusplus) */
40 changes: 17 additions & 23 deletions src/lua/uri.lua
View file
Expand Up @@ -47,6 +47,13 @@ uri_set_destroy(struct uri_set *uri_set);
int
uri_format(char *str, size_t len, struct uri *uri, bool write_password);
size_t
uri_escape(const char *src, size_t src_size, char *dst,
const unsigned char unreserved[256], bool plus);
size_t
uri_unescape(const char *src, size_t src_size, char *dst, bool decode_plus);
]]

pcall(ffi.cdef, uri_cdef) -- Required for running unit tests.
Expand Down Expand Up @@ -234,10 +241,6 @@ local function format(uri, write_password)
return str
end

local char_to_hex = function(c)
return string.format("%%%02X", string.byte(c))
end

-- Encodes a string into its escaped hexadecimal representation.
local function escape(buf, opts)
if type(buf) ~= "string" then
Expand All @@ -258,19 +261,12 @@ local function escape(buf, opts)
error("opts.plus must be a boolean")
end

return (buf:gsub("(.)", function(ch)
if options.plus == true and ch == " " then
return "+"
elseif options.unreserved[string.byte(ch)] == 1 then
return ch
else
return char_to_hex(ch)
end
end))
end

local hex_to_char = function(x)
return string.char(tonumber(x, 16))
-- The worst case is when all characters are encoded.
local dst = ffi.new("char[?]", #buf * 3)
local dst_size = builtin.uri_escape(buf, #buf, dst,
options.unreserved,
options.plus)
return ffi.string(dst, dst_size)
end

-- Decodes an escaped hexadecimal string into its binary representation.
Expand All @@ -290,12 +286,10 @@ local function unescape(buf, opts)
error("opts.plus must be a boolean")
end

local str = buf
if options.plus == true then
str = str:gsub("+", " ")
end
str = str:gsub("%%(%x%x)", hex_to_char)
return str
-- The worst case is when all characters were not decoded.
local dst = ffi.new("char[?]", #buf)
local dst_size = builtin.uri_unescape(buf, #buf, dst, options.plus)
return ffi.string(dst, dst_size)
end

local function encode_kv(key, values, res)
Expand Down
199 changes: 198 additions & 1 deletion test/unit/uri.c
View file
Expand Up @@ -164,6 +164,13 @@ struct uri_set_expected {
struct uri_expected uris[URI_MAX];
};

struct str_escape {
const char *str;
const char *escaped;
const char *unreserved;
bool plus;
};

static int
uri_param_expected_check(const struct uri_param_expected *param,
const struct uri *uri)
Expand Down Expand Up @@ -583,16 +590,206 @@ test_invalid_string_uri_set(void)
footer();
}

#define RFC3986_unreserved "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-._~"

const struct str_escape escape_testcase[] = {
[0] = {
.str = "-._~",
.escaped = "-._~",
.unreserved = RFC3986_unreserved,
.plus = false,
},
[1] = {
.str = "0123456789",
.escaped = "0123456789",
.unreserved = RFC3986_unreserved,
.plus = false,
},
[2] = {
.str = "abcdefghijklm",
.escaped = "abcdefghijklm",
.unreserved = RFC3986_unreserved,
.plus = false,
},
[3] = {
.str = "nopqrstuvwxyz",
.escaped = "nopqrstuvwxyz",
.unreserved = RFC3986_unreserved,
.plus = false,
},
[4] = {
.str = "ABCDEFGHIJKLM",
.escaped = "ABCDEFGHIJKLM",
.unreserved = RFC3986_unreserved,
.plus = false,
},
[5] = {
.str = "NOPQRSTUVWXYZ",
.escaped = "NOPQRSTUVWXYZ",
.unreserved = RFC3986_unreserved,
.plus = false,
},
[6] = {
.str = "!$&'()*+,;=",
.escaped = "%21%24%26%27%28%29%2A%2B%2C%3B%3D",
.unreserved = RFC3986_unreserved,
.plus = false,
},
};

/**
* Builds an array with unreserved characters.
* uri.unreserved() implemented as a Lua function,
* unreserved_tbl() replaces Lua implementation for testing purposes.
*/
static void
unreserved_tbl(const char *str, unsigned char unreserved[256])
{
for (int i = 0; i < 256; i++)
unreserved[i] = 0;

for (; *str; str++) {
unsigned char ch = (unsigned char)*str;
unreserved[ch] = 1;
}
}

static void
test_escape(void)
{
header();
plan(lengthof(escape_testcase) * 3);
unsigned char unreserved[256];
for (unsigned i = 0; i < lengthof(escape_testcase); i++) {
const char *unescaped = escape_testcase[i].str;
const char *escaped = escape_testcase[i].escaped;
bool plus = escape_testcase[i].plus;
char *dst = xcalloc(strlen(unescaped) * 3 + 1, sizeof("char"));
unreserved_tbl(escape_testcase[i].unreserved, unreserved);
size_t dst_size = uri_escape(unescaped, strlen(unescaped),
dst, unreserved, plus);
is(dst_size, strlen(escaped),
"escaped string ('%s') length != %ld", dst, strlen(escaped));
is(strlen(dst), strlen(escaped),
"escaped string ('%s') length != %ld", dst, strlen(escaped));
is(memcmp(escaped, dst, dst_size), 0,
"escape: '%s' == '%s'", escaped, dst);
free(dst);
}
check_plan();
footer();
}

static void
test_unescape(void)
{
header();
plan(lengthof(escape_testcase) * 3);
for (unsigned i = 0; i < lengthof(escape_testcase); i++) {
const char *unescaped = escape_testcase[i].str;
const char *escaped = escape_testcase[i].escaped;
bool decode_plus = escape_testcase[i].plus;
char *dst = xcalloc(strlen(unescaped) + 1, sizeof("char"));
size_t dst_size = uri_unescape(escaped, strlen(escaped),
dst, decode_plus);
is(dst_size, strlen(unescaped),
"unescaped string ('%s') length != %ld", dst,
strlen(unescaped));
is(strlen(dst), strlen(unescaped),
"unescaped string ('%s') length != %ld", dst,
strlen(unescaped));
is(memcmp(dst, unescaped, dst_size), 0,
"unescape: '%s' == '%s'", unescaped, dst);
free(dst);
}
check_plan();
footer();
}

const struct str_escape unescape_testcase[] = {
/* Special case: %<non-hex><non-hex> */
[0] = {
.str = "%##",
.escaped = "%##",
.unreserved = "%%#",
.plus = false,
},
/* Special case: %<hex><non-hex> */
[1] = {
.str = "%A$",
.escaped = "%A$",
.unreserved = "%%A$",
.plus = false,
},
/* Special case: %<non-hex><hex> */
[2] = {
.str = "%$A",
.escaped = "%$A",
.unreserved = "%%$A",
.plus = false,
},
/* Special case: %<EOS> (<EOS> -- the end of a string) */
[3] = {
.str = "%",
.escaped = "%",
.unreserved = "%%",
.plus = false,
},
/* Special case: %<hex><EOS> (<EOS> -- the end of a string) */
[4] = {
.str = "%A",
.escaped = "%A",
.unreserved = "%%A",
.plus = false,
},
/* Special case: %<non-hex><EOS> (<EOS> -- the end of a string) */
[5] = {
.str = "%&",
.escaped = "%&",
.unreserved = "%%&",
.plus = false,
},
};

static void
test_unescape_special_cases(void)
{
header();
plan(lengthof(unescape_testcase) * 3);
for (unsigned i = 0; i < lengthof(unescape_testcase); i++) {
const char *unescaped = unescape_testcase[i].str;
const char *escaped = unescape_testcase[i].escaped;
bool decode_plus = escape_testcase[i].plus;
char *dst = xcalloc(strlen(unescaped) + 1, sizeof("char"));
size_t dst_size = uri_unescape(escaped, strlen(escaped),
dst, decode_plus);
is(dst_size, strlen(unescaped),
"unescaped string ('%s') length != %ld", dst,
strlen(unescaped));
is(strlen(dst), strlen(unescaped),
"unescaped string ('%s') length != %ld", dst,
strlen(unescaped));
is(memcmp(dst, unescaped, dst_size), 0,
"unescape: '%s' == '%s'", unescaped, dst);
free(dst);
}
check_plan();
footer();
}

int
main(void)
{
plan(7);
plan(10);
test_copy_sample();
test_copy_empty();
test_move_sample();
test_move_empty();
test_string_uri_with_query_params_parse();
test_string_uri_set_with_query_params_parse();
test_invalid_string_uri_set();
test_escape();
test_unescape();
test_unescape_special_cases();
return check_plan();
}

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