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/*
* Copyright (C) 2021 Liquidaty and the zsv/lib contributors
* All rights reserved
*
* This file is part of zsv/lib, distributed under the license defined at
* https://opensource.org/licenses/MIT
*/
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
static inline char is_json_esc_char(unsigned char c) {
return (c == '"' || c == '\\' || c < 32);
}
static void str2hex(unsigned char *to, const unsigned char *p, size_t len) {
static const char *hex = "0123456789abcdef";
for (; len--; p++) {
*to++ = hex[p[0] >> 4];
*to++ = hex[p[0] & 0x0f];
}
}
static inline unsigned json_esc_char(unsigned char c, char replace[]) {
unsigned replacelen;
char hex = 0;
switch (c) {
case '"':
replace[1] = '"';
break;
case '\\':
replace[1] = '\\';
break;
case '\b':
replace[1] = 'b';
break;
case '\f':
replace[1] = 'f';
break;
case '\n':
replace[1] = 'n';
break;
case '\r':
replace[1] = 'r';
break;
case '\t':
replace[1] = 't';
break;
default:
hex = 1;
}
replace[0] = '\\';
if (hex) {
// unicode-hex: but 2/3 are not always zeroes...
replace[1] = 'u';
replace[2] = '0';
replace[3] = '0';
str2hex((unsigned char *)replace + 4, &c, 1);
replacelen = 6;
replace[6] = '\0';
} else {
replacelen = 2;
replace[2] = '\0';
}
return replacelen;
}
static unsigned json_escaped_str_len(const unsigned char *s, size_t len) {
unsigned count = 0;
for (size_t i = 0; i < len; i++, count++) {
switch (s[i]) {
case '"':
case '\\':
case '\b':
case '\f':
case '\n':
case '\r':
case '\t':
count++;
break;
default:
if (s[i] < 31)
count += 6;
break;
}
}
return count + 2; // + 2 for surrounding quotation marks
}
unsigned char *zsv_json_from_str_n(const unsigned char *s, size_t len) {
size_t new_len = json_escaped_str_len(s, len);
unsigned char *new_s = calloc(new_len + 2, sizeof(*new_s));
if (new_s) {
new_s[0] = new_s[new_len - 1] = (unsigned char)'"';
if (new_len == len + 2)
memcpy(new_s + 1, s, len);
else {
char replace[8];
for (size_t i = 0, j = 1; i < len && j < new_len - 1; i++) {
if (!is_json_esc_char(s[i]))
new_s[j++] = s[i];
else {
size_t rlen = json_esc_char(s[i], replace);
memcpy(new_s + j, replace, rlen);
j += rlen;
}
}
}
}
return new_s;
}
unsigned char *zsv_json_from_str(const unsigned char *s) {
if (!s)
return (unsigned char *)strdup("null");
return zsv_json_from_str_n(s, strlen((const char *)s));
}
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