1 files changed, 146 insertions, 0 deletions

diff --git a/src/man/preproc.c b/src/man/preproc.c
new file mode 100644
index 000000000..34a49d335
--- /dev/null
+++ b/src/man/preproc.c
@@ -0,0 +1,146 @@
+#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);
+}