Fix base encoding beeing skipped when parsing string.
This commit is contained in:
tim.schubert@tu-bs.de
parent
7e2f5a7673
commit
80dc59be01
1 changed files with 57 additions and 84 deletions
139
netcalc.c
139
netcalc.c
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@ -76,41 +76,6 @@ int prepsocket(struct addrinfo *ainfo)
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return SOCKFD;
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}
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int readnum(char *buf, size_t buflen, unsigned int *res)
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{
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size_t bytes_read = 0;
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char *p = buf;
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while (bytes_read < buflen && *p!='+' && *p!='+'&& *p!='-'&& *p!='*'&& *p!='/' && *p!='\n') {
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bytes_read++;
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p++;
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}
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int bytes_to_copy = bytes_read;
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int base = 10;
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if (bytes_read > 2 && buf[0] == '0' && buf[1] == 'x') {
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base = 16;
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} else if (bytes_read > 1 && buf[bytes_read-1] == 'b') {
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base = 2;
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bytes_to_copy--;
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}
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char num[35];
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strncpy(num, buf, bytes_to_copy);
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num[bytes_to_copy] = '\0';
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unsigned long parsed = strtoul(num, NULL, base);
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if (parsed == ULONG_MAX) {
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perror("strtoul");
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return -1;
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}
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*res = (unsigned int) parsed;
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return bytes_read;
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}
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int calc(unsigned int num1, unsigned int num2, char op, unsigned int *result)
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{
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switch (op) {
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@ -141,27 +106,54 @@ int calc(unsigned int num1, unsigned int num2, char op, unsigned int *result)
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return 0;
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}
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int base(char *numstr, unsigned int *num)
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{
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short base = 10;
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size_t len = strlen(numstr);
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if (len > 1 && numstr[len-1] == 'b') {
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base = 2;
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} else if (len > 2 && numstr[0] == '0' && numstr[1] == 'x') {
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base = 16;
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}
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unsigned long test = strtoul(numstr, NULL, base);
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if (test <= UINT_MAX) {
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*num = (unsigned int) test;
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return base;
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} else {
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return 0;
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}
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}
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int parse(char *buf, size_t buflen, unsigned int *first, unsigned int *second, char *op)
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{
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//read first number
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char *num1str = NULL;
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char *num2str = NULL;
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char *opstr = NULL;
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size_t read = readnum(buf, buflen, first);
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if (read == -1) {
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return -1;
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ssize_t num_items = sscanf(buf, "%m[x,0-9,A-F,b]%m[+,-,*,/]%m[x,0-9,A-F,b]", &num1str, &opstr, &num2str);
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int status = 0;
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if (num_items < 3) {
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if (num_items == 1 && base(num1str, first) > 0) {
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status = -2;
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} else {
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status = -1;
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}
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} else if (base(num2str, second) == 0 || base(num1str, first) == 0) {
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status = -1;
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}
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// read operator
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if (read < buflen && buf[read] != '\n' && buf[read] != '\0') {
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*op = buf[read];
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read++;
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if (opstr) {
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*op = opstr[0];
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}
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// read second number
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if (readnum(buf+read, buflen-read, second) == -1) {
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return -1;
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}
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free(num1str);
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free(num2str);
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free(opstr);
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return 0;
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return status;
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}
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void report_error(char *buf, unsigned long buflen, char *msg)
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@ -199,7 +191,7 @@ int server()
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char op;
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unsigned int result;
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if (parse(buf, sizeof buf, &first, &second, &op) == -1) {
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if (parse(buf, sizeof buf, &first, &second, &op) < 0) {
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report_error(buf, BUFLEN, "parse: failed to parse");
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} else if (calc(first, second, op, &result) == -1) {
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report_error(buf, BUFLEN, "calc: failed to calculate");
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@ -229,54 +221,35 @@ int connectclient(struct addrinfo *ainfo)
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return 0;
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}
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int base(char *num)
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{
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size_t len = strlen(num);
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char *num_cpy;
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if (sscanf(num, "%m[0-9]", &num_cpy) == 1 && strtoul(num_cpy, NULL, 10) < UINT_MAX) { // dec
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return 10;
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} else if (sscanf(num, "%m[0-1]b", &num_cpy) == 1 && strtoul(num_cpy, NULL, 2) < UINT_MAX) { // bin
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return 2;
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} else if (sscanf(num, "%m[0-1]b", &num_cpy) == 1 && strtoul(num_cpy, NULL, 2) < UINT_MAX) { // hex
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return 16;
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} else {
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return 0;
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}
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}
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int client()
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{
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char buf[BUFLEN];
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size_t nullsize = 0;
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char *line = NULL;
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while (getline(&line, &nullsize, stdin) != -1) {
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char *num1 = NULL;
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char *num2 = NULL;
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char *op = NULL;
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unsigned int num1;
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unsigned int num2;
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char op;
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ssize_t num_items = sscanf(line, "%m[0-9,A-F,x,b]%m[+,-,*,/]%m[x,0-9,A-F,b]", &num1, &op, &num2);
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printf("debug: %lu items read from %s", num_items, line);
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int status = parse(line, sizeof buf, &num1, &num2, &op);
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memset(buf, 0, BUFLEN);
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if (num_items == 3 && (base(num1) == 0 || base(num2) == 0)) {
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fprintf(stderr, "base: illegal input");
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} else if (num_items == 1 && num1 != NULL && base(num1) > 0) {
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op = "+";
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num2 = "0";
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} else if (num_items < 3) {
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fprintf(stderr, "too few arguments");
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} else { // send input
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printf("debug: sending %s", line);
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if (status == -1) {
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report_error(buf, BUFLEN, "parse: failed to parse");
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continue;
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} else if (status == -2) {
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op = '+';
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num2 = 0;
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}
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if (send(SOCKFD, line, strlen(line), 0) == -1) {
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sprintf(buf, "%u%c%u", num1, op, num2);
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if (send(SOCKFD, buf, strlen(buf), 0) == -1) {
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perror("recv");
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continue;
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}
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free(num1);
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free(num2);
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free(op);
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free(line);
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line = NULL; // so getline allocates a buffer for us
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