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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#define MAXBUF 4096
#define MAXMACROS 64
static char *macro[MAXMACROS] = {NULL};
static void add_macro(char *m) {
assert(m);
int i;
for (i = 0; i < MAXMACROS && macro[i]; i++);
if (i == MAXMACROS) {
fprintf(stderr, "Error: maximum number of marcros (%d) exceeded\n", MAXMACROS);
exit(1);
}
macro[i] = m;
}
static char *find_macro(char *m) {
assert(m);
int i = 0;
while (i < MAXMACROS && macro[i]) {
if (strcmp(macro[i], m) == 0)
return m;
i++;
}
return NULL;
}
static void usage(void) {
printf("Simple preprocessor for man pages. It supports:\n");
printf("\t#if 0 ... #endif\n");
printf("\t#ifdef macro ... #endif\n");
printf("Usage: preproc [--help] [-Dmacro] manpage.txt\n");
return;
}
int main(int argc, char **argv) {
if (argc == 1) {
fprintf(stderr, "Error: no files/arguments provided\n");
usage();
exit(1);
}
int i;
for (i = 1; i < argc; i++) {
if (strncmp(argv[i], "-D", 2) == 0)
add_macro(argv[i] + 2);
else if (strcmp(argv[i], "--help") == 0) {
usage();
return 0;
}
else if (*argv[i] == '-') {
fprintf(stderr, "Error: invalid argument %s\n", argv[i]);
exit(1);
}
else
break;
}
char *ptr = strstr(argv[i], ".txt");
if (!ptr || strlen(ptr) != 4) {
fprintf(stderr, "Error: input file needs to have a .txt extension\n"),
exit(1);
}
FILE *fp = fopen(argv[i], "r");
if (!fp) {
fprintf(stderr, "Error: cannot open %s\n", argv[i]);
exit(1);
}
char *outfile = strdup(argv[i]);
if (!outfile)
goto errout;
ptr = strstr(outfile, ".txt");
assert(ptr);
strcpy(ptr, ".man");
FILE *fpout = fopen(outfile, "w");
if (!fpout)
goto errout;
char buf[MAXBUF];
int disabled = 0;
int enabled = 0;
int line = 0;;
while (fgets(buf, MAXBUF, fp)) {
line++;
if (disabled && strncmp(buf, "#if", 3) == 0) {
fprintf(stderr, "Error %d: already in a #if block on line %d\n", __LINE__, line);
exit(1);
}
if ((!disabled && !enabled) && strncmp(buf, "#endif", 6) == 0) {
fprintf(stderr, "Error %d: unmatched #endif on line %d\n", __LINE__, line);
exit(1);
}
char *ptr = strchr(buf, '\n');
if (ptr)
*ptr = '\0';
if (strncmp(buf, "#if 0", 5) == 0) {
disabled = 1;
continue;
}
if (strncmp(buf, "#ifdef", 6) == 0) {
char *ptr = buf + 6;
if (*ptr != ' ' && *ptr != '\t') {
fprintf(stderr, "Error %d: invalid macro on line %d\n", __LINE__, line);
exit(1);
}
while (*ptr == ' ' || *ptr == '\t')
ptr++;
if (!find_macro(ptr))
disabled = 1;
else
enabled = 1;
continue;
}
if (strncmp(buf, "#endif", 6) == 0) {
disabled = 0;
enabled = 1;
continue;
}
if (!disabled) {
// printf("%s\n", buf);
fprintf(fpout, "%s\n", buf);
}
}
fclose(fp);
return 0;
errout:
fclose(fp);
fprintf(stderr, "Error: cannot open output file\n");
exit(1);
}
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