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[njs] Separating string length counting and encoding conversion.

Alexander Borisov
September 07, 2020 10:58AM
details: https://hg.nginx.org/njs/rev/9a25433b4c76
branches:
changeset: 1519:9a25433b4c76
user: Alexander Borisov <alexander.borisov@nginx.com>
date: Mon Sep 07 17:54:47 2020 +0300
description:
Separating string length counting and encoding conversion.

diffstat:

src/njs_string.c | 378 +++++++++++++++++++++++++++++++---------------
src/njs_string.h | 13 +
src/test/njs_unit_test.c | 6 +
3 files changed, 273 insertions(+), 124 deletions(-)

diffs (537 lines):

diff -r 0e927892f0bf -r 9a25433b4c76 src/njs_string.c
--- a/src/njs_string.c Mon Sep 07 12:44:07 2020 +0000
+++ b/src/njs_string.c Mon Sep 07 17:54:47 2020 +0300
@@ -12,10 +12,52 @@
#define NJS_TRIM_END 2


+static u_char njs_basis64[] = {
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 62, 77, 77, 77, 63,
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 77, 77, 77, 77, 77, 77,
+ 77, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
+ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 77, 77, 77, 77, 77,
+ 77, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 77, 77, 77, 77, 77,
+
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77
+};
+
+
+static u_char njs_basis64url[] = {
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 62, 77, 77,
+ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 77, 77, 77, 77, 77, 77,
+ 77, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
+ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 77, 77, 77, 77, 63,
+ 77, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 77, 77, 77, 77, 77,
+
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
+ 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77
+};
+
+
static void njs_encode_base64_core(njs_str_t *dst, const njs_str_t *src,
const u_char *basis, njs_uint_t padding);
-static njs_int_t njs_decode_base64_core(njs_vm_t *vm,
- njs_value_t *value, const njs_str_t *src, const u_char *basis);
+static njs_int_t njs_string_decode_base64_core(njs_vm_t *vm,
+ njs_value_t *value, const njs_str_t *src, njs_bool_t url);
static njs_int_t njs_string_slice_prop(njs_vm_t *vm, njs_string_prop_t *string,
njs_slice_prop_t *slice, njs_value_t *args, njs_uint_t nargs);
static njs_int_t njs_string_slice_args(njs_vm_t *vm, njs_slice_prop_t *slice,
@@ -34,8 +76,8 @@ static njs_int_t njs_string_split_part_a
njs_utf8_t utf8, const u_char *start, size_t size);


-#define njs_base64_encoded_length(len) (((len + 2) / 3) * 4)
-#define njs_base64_decoded_length(len) (((len + 3) / 4) * 3)
+#define njs_base64_encoded_length(len) (((len + 2) / 3) * 4)
+#define njs_base64_decoded_length(len, pad) (((len / 4) * 3) - pad)


njs_int_t
@@ -206,9 +248,26 @@ njs_string_truncate(njs_value_t *value,
njs_int_t
njs_string_hex(njs_vm_t *vm, njs_value_t *value, const njs_str_t *src)
{
+ size_t length;
+ njs_str_t dst;
+
+ length = njs_encode_hex_length(src, &dst.length);
+
+ dst.start = njs_string_alloc(vm, value, dst.length, length);
+ if (njs_fast_path(dst.start != NULL)) {
+ njs_encode_hex(&dst, src);
+ return NJS_OK;
+ }
+
+ return NJS_ERROR;
+}
+
+
+void
+njs_encode_hex(njs_str_t *dst, const njs_str_t *src)
+{
u_char *p, c;
- size_t len;
- njs_uint_t i;
+ size_t i, len;
const u_char *start;

static const u_char hex[16] = "0123456789abcdef";
@@ -216,23 +275,32 @@ njs_string_hex(njs_vm_t *vm, njs_value_t
len = src->length;
start = src->start;

- p = njs_string_alloc(vm, value, len * 2, len * 2);
-
- if (njs_fast_path(p != NULL)) {
- for (i = 0; i < len; i++) {
- c = start[i];
- *p++ = hex[c >> 4];
- *p++ = hex[c & 0x0f];
- }
-
- return NJS_OK;
+ p = dst->start;
+
+ for (i = 0; i < len; i++) {
+ c = start[i];
+ *p++ = hex[c >> 4];
+ *p++ = hex[c & 0x0f];
}
-
- return NJS_ERROR;
}


-static void
+size_t
+njs_encode_hex_length(const njs_str_t *src, size_t *out_size)
+{
+ size_t size;
+
+ size = src->length * 2;
+
+ if (out_size != NULL) {
+ *out_size = size;
+ }
+
+ return size;
+}
+
+
+void
njs_encode_base64(njs_str_t *dst, const njs_str_t *src)
{
static u_char basis64[] =
@@ -242,6 +310,21 @@ njs_encode_base64(njs_str_t *dst, const
}


+size_t
+njs_encode_base64_length(const njs_str_t *src, size_t *out_size)
+{
+ size_t size;
+
+ size = (src->length == 0) ? 0 : njs_base64_encoded_length(src->length);
+
+ if (out_size != NULL) {
+ *out_size = size;
+ }
+
+ return size;
+}
+
+
static void
njs_encode_base64url(njs_str_t *dst, const njs_str_t *src)
{
@@ -308,16 +391,17 @@ njs_encode_base64_core(njs_str_t *dst, c
njs_int_t
njs_string_base64(njs_vm_t *vm, njs_value_t *value, const njs_str_t *src)
{
+ size_t length;
njs_str_t dst;

- if (njs_slow_path(src->length == 0)) {
+ length = njs_encode_base64_length(src, &dst.length);
+
+ if (njs_slow_path(dst.length == 0)) {
vm->retval = njs_string_empty;
return NJS_OK;
}

- dst.length = njs_base64_encoded_length(src->length);
-
- dst.start = njs_string_alloc(vm, value, dst.length, dst.length);
+ dst.start = njs_string_alloc(vm, value, dst.length, length);
if (njs_slow_path(dst.start == NULL)) {
return NJS_ERROR;
}
@@ -1666,30 +1750,31 @@ njs_string_bytes_from_string(njs_vm_t *v
}


-njs_int_t
-njs_string_decode_hex(njs_vm_t *vm, njs_value_t *value, const njs_str_t *src)
+size_t
+njs_decode_hex_length(const njs_str_t *src, size_t *out_size)
{
- u_char *p, *dst;
+ if (out_size != NULL) {
+ *out_size = src->length / 2;
+ }
+
+ return 0;
+}
+
+
+void
+njs_decode_hex(njs_str_t *dst, const njs_str_t *src)
+{
+ u_char *p;
size_t len;
njs_int_t c;
njs_uint_t i, n;
const u_char *start;

- len = src->length;
+ n = 0;
+ p = dst->start;
+
start = src->start;
-
- if (njs_slow_path(len == 0)) {
- vm->retval = njs_string_empty;
- return NJS_OK;
- }
-
- dst = njs_string_alloc(vm, value, len / 2, 0);
- if (njs_slow_path(dst == NULL)) {
- return NJS_ERROR;
- }
-
- n = 0;
- p = dst;
+ len = src->length;

for (i = 0; i < len; i++) {
c = njs_char_to_hex(start[i]);
@@ -1705,81 +1790,47 @@ njs_string_decode_hex(njs_vm_t *vm, njs_
}
}

- if (njs_slow_path((size_t) (p - dst) != (len / 2))) {
- njs_string_truncate(value, p - dst, 0);
- }
-
- return NJS_OK;
-}
-
-
-njs_int_t
-njs_string_decode_base64(njs_vm_t *vm, njs_value_t *value, const njs_str_t *src)
-{
- static u_char basis64[] = {
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 62, 77, 77, 77, 63,
- 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 77, 77, 77, 77, 77, 77,
- 77, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
- 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 77, 77, 77, 77, 77,
- 77, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
- 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 77, 77, 77, 77, 77,
-
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77
- };
-
- return njs_decode_base64_core(vm, value, src, basis64);
+ dst->length -= (dst->start + dst->length) - p;
}


njs_int_t
-njs_string_decode_base64url(njs_vm_t *vm, njs_value_t *value,
- const njs_str_t *src)
+njs_string_decode_hex(njs_vm_t *vm, njs_value_t *value, const njs_str_t *src)
{
- static u_char basis64[] = {
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 62, 77, 77,
- 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 77, 77, 77, 77, 77, 77,
- 77, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
- 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 77, 77, 77, 77, 63,
- 77, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
- 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 77, 77, 77, 77, 77,
-
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77,
- 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77, 77
- };
-
- return njs_decode_base64_core(vm, value, src, basis64);
-}
-
-
-static njs_int_t
-njs_decode_base64_core(njs_vm_t *vm, njs_value_t *value, const njs_str_t *src,
- const u_char *basis)
-{
- size_t len, dst_len;
- u_char *d, *s, *dst;
-
- if (njs_slow_path(src->length == 0)) {
+ size_t size, length;
+ njs_str_t dst;
+
+ length = njs_decode_hex_length(src, &size);
+
+ if (njs_slow_path(size == 0)) {
vm->retval = njs_string_empty;
return NJS_OK;
}

+ dst.start = njs_string_alloc(vm, value, size, length);
+ if (njs_slow_path(dst.start == NULL)) {
+ return NJS_ERROR;
+ }
+
+ dst.length = size;
+
+ njs_decode_hex(&dst, src);
+
+ if (njs_slow_path(dst.length != size)) {
+ njs_string_truncate(value, dst.length, 0);
+ }
+
+ return NJS_OK;
+}
+
+
+static size_t
+njs_decode_base64_length_core(const njs_str_t *src, const u_char *basis,
+ size_t *out_size)
+{
+ uint pad;
+ size_t len;
+
for (len = 0; len < src->length; len++) {
if (src->start[len] == '=') {
break;
@@ -1790,46 +1841,125 @@ njs_decode_base64_core(njs_vm_t *vm, njs
}
}

- if (len % 4 == 1) {
- /* Rounding down to integer multiple of 4. */
- len -= 1;
+ pad = 0;
+
+ if (len % 4 != 0) {
+ pad = 4 - (len % 4);
+ len += pad;
+ }
+
+ len = njs_base64_decoded_length(len, pad);
+
+ if (out_size != NULL) {
+ *out_size = len;
}

- dst_len = njs_base64_decoded_length(len);
-
- dst = njs_string_alloc(vm, value, dst_len, 0);
- if (njs_slow_path(dst == NULL)) {
- return NJS_ERROR;
- }
+ return 0;
+}
+
+
+size_t
+njs_decode_base64_length(const njs_str_t *src, size_t *out_size)
+{
+ return njs_decode_base64_length_core(src, njs_basis64, out_size);
+}
+
+
+size_t
+njs_decode_base64url_length(const njs_str_t *src, size_t *out_size)
+{
+ return njs_decode_base64_length_core(src, njs_basis64url, out_size);
+}
+
+
+static void
+njs_decode_base64_core(njs_str_t *dst, const njs_str_t *src,
+ const u_char *basis)
+{
+ size_t len;
+ u_char *d, *s;

s = src->start;
- d = dst;
-
- while (len > 3) {
+ d = dst->start;
+
+ len = dst->length;
+
+ while (len >= 3) {
*d++ = (u_char) (basis[s[0]] << 2 | basis[s[1]] >> 4);
*d++ = (u_char) (basis[s[1]] << 4 | basis[s[2]] >> 2);
*d++ = (u_char) (basis[s[2]] << 6 | basis[s[3]]);

s += 4;
- len -= 4;
+ len -= 3;
}

- if (len > 1) {
+ if (len >= 1) {
*d++ = (u_char) (basis[s[0]] << 2 | basis[s[1]] >> 4);
}

- if (len > 2) {
+ if (len >= 2) {
*d++ = (u_char) (basis[s[1]] << 4 | basis[s[2]] >> 2);
}
-
- if (njs_slow_path((size_t) (d - dst) != dst_len)) {
- njs_string_truncate(value, d - dst, 0);
+}
+
+
+void
+njs_decode_base64(njs_str_t *dst, const njs_str_t *src)
+{
+ njs_decode_base64_core(dst, src, njs_basis64);
+}
+
+
+void
+njs_decode_base64url(njs_str_t *dst, const njs_str_t *src)
+{
+ njs_decode_base64_core(dst, src, njs_basis64url);
+}
+
+
+static njs_int_t
+njs_string_decode_base64_core(njs_vm_t *vm, njs_value_t *value,
+ const njs_str_t *src, njs_bool_t url)
+{
+ size_t length;
+ const u_char *basis;
+ njs_str_t dst;
+
+ basis = (url) ? njs_basis64url : njs_basis64;
+
+ length = njs_decode_base64_length_core(src, basis, &dst.length);
+
+ if (njs_slow_path(dst.length == 0)) {
+ vm->retval = njs_string_empty;
+ return NJS_OK;
}

+ dst.start = njs_string_alloc(vm, value, dst.length, length);
+ if (njs_slow_path(dst.start == NULL)) {
+ return NJS_ERROR;
+ }
+
+ njs_decode_base64_core(&dst, src, basis);
+
return NJS_OK;
}


+njs_int_t
+njs_string_decode_base64(njs_vm_t *vm, njs_value_t *value, const njs_str_t *src)
+{
+ return njs_string_decode_base64_core(vm, value, src, 0);
+}
+
+
+njs_int_t
+njs_string_decode_base64url(njs_vm_t *vm, njs_value_t *value,
+ const njs_str_t *src)
+{
+ return njs_string_decode_base64_core(vm, value, src, 1);
+}
+
+
static njs_int_t
njs_string_from_char_code(njs_vm_t *vm, njs_value_t *args, njs_uint_t nargs,
njs_index_t is_point)
diff -r 0e927892f0bf -r 9a25433b4c76 src/njs_string.h
--- a/src/njs_string.h Mon Sep 07 12:44:07 2020 +0000
+++ b/src/njs_string.h Mon Sep 07 17:54:47 2020 +0300
@@ -185,6 +185,19 @@ u_char *njs_string_alloc(njs_vm_t *vm, n
uint64_t length);
njs_int_t njs_string_new(njs_vm_t *vm, njs_value_t *value, const u_char *start,
uint32_t size, uint32_t length);
+
+void njs_encode_hex(njs_str_t *dst, const njs_str_t *src);
+size_t njs_encode_hex_length(const njs_str_t *src, size_t *out_size);
+void njs_encode_base64(njs_str_t *dst, const njs_str_t *src);
+size_t njs_encode_base64_length(const njs_str_t *src, size_t *out_size);
+
+void njs_decode_hex(njs_str_t *dst, const njs_str_t *src);
+size_t njs_decode_hex_length(const njs_str_t *src, size_t *out_size);
+void njs_decode_base64(njs_str_t *dst, const njs_str_t *src);
+size_t njs_decode_base64_length(const njs_str_t *src, size_t *out_size);
+void njs_decode_base64url(njs_str_t *dst, const njs_str_t *src);
+size_t njs_decode_base64url_length(const njs_str_t *src, size_t *out_size);
+
njs_int_t njs_string_hex(njs_vm_t *vm, njs_value_t *value,
const njs_str_t *src);
njs_int_t njs_string_base64(njs_vm_t *vm, njs_value_t *value,
diff -r 0e927892f0bf -r 9a25433b4c76 src/test/njs_unit_test.c
--- a/src/test/njs_unit_test.c Mon Sep 07 12:44:07 2020 +0000
+++ b/src/test/njs_unit_test.c Mon Sep 07 17:54:47 2020 +0300
@@ -8824,9 +8824,15 @@ static njs_unit_test_t njs_test[] =
{ njs_str("String.bytesFrom('QQ==', 'base64')"),
njs_str("A") },

+ { njs_str("String.bytesFrom('QQ=', 'base64')"),
+ njs_str("A") },
+
{ njs_str("String.bytesFrom('QQ', 'base64')"),
njs_str("A") },

+ { njs_str("String.bytesFrom('Q', 'base64')"),
+ njs_str("") },
+
{ njs_str("String.bytesFrom('QUI=', 'base64')"),
njs_str("AB") },

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[njs] Separating string length counting and encoding conversion.

Alexander Borisov 77 September 07, 2020 10:58AM



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