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#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "parse.h"
static int parse_string(const char * str, char * data, size_t * offset) {
char escape = false;
int i = 0;
size_t len = strlen(str);
switch (str[i]) {
case '\'':
escape = false;
break;
case '\"':
escape = true;
break;
default:
return -i;
}
char closing = str[i];
for (i = 1; i < len && str[i] != '\0'; i++, *offset += 1) {
char c = str[i];
if (c == closing) return i + 1; // +1 for closing quote
if (escape && c == '\\') {
char x = str[i + 1];
if (x == '0') c = '\0';
else if (x == 't') c = '\t';
else if (x == 'n') c = '\n';
else if (x == 'r') c = '\r';
else if (x == '\\') c = '\\';
else if (x == '\"') c = '\"';
else if (x == '\'') c = '\'';
else break;
i++;
}
if (data != NULL) data[*offset] = c;
}
return -i;
}
static int parse_hexstr(const char * str, char * data, size_t * offset) {
size_t len = strcspn(str, IFS);
int i = 0;
// check if token contains at least one colon
const char * colon = strchr(str, ':');
if (colon == NULL) return -i;
if (colon >= str + len) return -i;
// check if token only contains allowed characters [0-9a-fA-F:]
size_t len_ok = strspn(str + i, SET_HEX_STR) + i;
if (len != len_ok) return -len_ok;
size_t c = 0;
while (c < len) { // count bytes in bytestring
if (strspn(str + c, SET_HEX) != 2) return -i - c;
if (data != NULL) data[*offset] = strtol(str + c, NULL, 16) & 0xff;
c += 2;
*offset += 1;
if (str[c] == ':') {
c += 1;
continue;
}
break;
}
i += len;
return i;
}
static int parse_number(const char * str, char * data, size_t * offset) {
size_t len = strcspn(str, IFS);
int i = 0;
int base = 10;
bool bytestring = false;
if (len > 2 && strncmp(str, "0x", 2) == 0) { // hexadecimal prefix
base = 16;
i += 2;
} /* else if (len > 1 && strncmp(str, "0", 1) == 0) { // octal prefix
base = 8;
i += 1;
}*/
const char * set;
// if (base == 8) set = SET_OCT;
if (base == 10) set = SET_DEC;
if (base == 16) set = SET_HEX;
size_t len_ok = strspn(str + i, set) + i;
if (len != len_ok) return -len_ok;
size_t size = 1; // default integer size in bytes
if (base == 16) {
size_t prefixless = len - i;
switch (prefixless) {
case 2: // 8-bit (2 hex characters)
case 4: // 16-bit
case 8: // 32-bit
case 16: // 64-bit
break;
default:
return -i;
}
size = prefixless / 2;
}
if (data != NULL) {
unsigned long number = strtol(str + i, NULL, base);
long long mask = (1 << 8 * size) - 1;
number &= mask;
// NOTE: the hton? functions are used to convert host endianness to network
// endianness (big), and are required
switch (size) {
case 1:
data[*offset] = number & 0xff;
break;
case 2:
number = htons(number);
// TODO: check if the endianness is OK, or reverse these *offset indices*
data[*offset + 1] = (number) & 0xff;
data[*offset + 0] = (number >>= 8) & 0xff;
break;
case 4:
number = htonl(number);
data[*offset + 3] = (number) & 0xff;
data[*offset + 2] = (number >>= 8) & 0xff;
data[*offset + 1] = (number >>= 8) & 0xff;
data[*offset + 0] = (number >>= 8) & 0xff;
break;
}
}
*offset += size;
return len;
}
static int _strtodata_main(const char * str, char * data, size_t * offset) {
size_t len = strlen(str);
int i, run;
for (i = 0; i < len; i += run) {
i += strspn(&str[i], IFS); // skip whitespace
if (str[i] == '\0') break; // end of string
if ((run = parse_string(str + i, data, offset)) > 0) continue;
if ((run = parse_hexstr(str + i, data, offset)) > 0) continue;
if ((run = parse_number(str + i, data, offset)) > 0) continue;
// no format detected
return -i + run;
}
return i;
}
int strtodata(const char * str, char ** data, size_t * size) {
*size = 0;
// 1st pass: check data format
int ret = _strtodata_main(str, NULL, size);
if (ret <= 0) return ret; // on error
// 2nd pass: convert string literals into binary data
*data = (char *) malloc(*size);
size_t written = 0;
return _strtodata_main(str, *data, &written);
}
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