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#include <stdio.h>
#include "buf.h"
#include <string.h>
#include <stdlib.h>
typedef enum {
false,
true
} bool;
FILE* getfile(int argc, char** argv){
if (argc >= 2)
return fopen(argv[1], "r");
else
return stdin;
}
char* chrmult(char c, size_t ct){
char* str = malloc(sizeof(char)*(ct+1)); str[ct] = 0;
memset(str, c, ct);
return str;
}
// file read & buffer fill helpers
FILE* in;
buf* inbuf;
int addchr(void){
int c = fgetc(in);
if (c != EOF) inschrbuf(inbuf, c);
return c;
}
size_t fillbuf(size_t len){ // returns real len
int c;
size_t set;
for (set = buflen(inbuf); set < len && (c = addchr()) != EOF;set++);
return set;
}
size_t chrfill(char chr){
size_t len = buflen(inbuf);
char* str = peekstrbuf(inbuf, 0, len);
char* line = memchr(str,chr,len);
free(str);
if (line) return line-str+1;
for (int c = 0; c != chr && (c = addchr()) != EOF; len++);
return len;
}
#define min(a,b) a < b ? a : b
size_t chrnfill(char chr, size_t sz){//fills to first of chr or sz
size_t len = buflen(inbuf);
size_t lim = min(len,sz);
char* str = peekstrbuf(inbuf, 0, lim);
char* line = memchr(str, chr, lim);
free(str);
if (line) return line-str+1;
for (int c = 0; c != chr && (c = addchr()) != EOF&& len<sz; len++);
return len;
}
// typesetting config and commands to change.
int width = 80;
char* center(char* txt){
size_t len = strlen(txt);
int max = width/2 + len/2; // excluding terminator
int min = max-len+1; // first index of *txt
char* str = malloc(sizeof(char)*(max + 2));
memset(str, ' ', min);
memcpy(str+min, txt, len);
str[max] = '\n';
str[max+1] = 0;
return str;
}
char* setwidth(char* txt){
sscanf(txt, "%d", &width);
return NULL;
}
char* fillline(char* txt){
char* str = malloc(sizeof(char)*(width+2));
str[width] = '\n'; str[width+1] = 0;
memset(str, txt[0], width);
return str;
}
char* cmds[] = {"CT ", "FIL ", "W "}; // MUST be sorted alphabetically
char* (*call[])(char* txt) = {center, fillline, setwidth};
char* cmd(void){
char* dat = popstrbuf(inbuf, chrfill('\n'));
size_t low = 0; size_t high = sizeof(cmds)/sizeof(*cmds); //len
char* proc = NULL;
while (high >= low){
int mid = ((unsigned int)low + (unsigned int)high) >> 1;
char* mval = cmds[mid];
int cmp = strncmp(dat, mval, strlen(mval));
if (cmp < 0) // dat < mval
high = mid - 1;
else if (cmp > 0)
low = mid + 1;
else{
proc = call[mid](dat+strlen(mval));
break;
}
}
free(dat);
return proc;
}
// normal typesetting
bool cont_typst = false; // communicates with line() for broken lines.
size_t nextws(size_t start){//searches for \n or [^ \n]-1 in buffer
//starts at `start` (if not whitespace, returns start-1)
size_t len = buflen(inbuf);
char* str = peekstrbuf(inbuf, start, len-start);
size_t i;
for (i = 0; i<len-start; i++){
if (str[i] == '\n') return start+i;
else if (str[i] != ' ') return start+i-1;
}
free(str);
for (int c = 0; c != '\n' && ( c = addchr() ) != EOF && c == ' ';
len++); // if this is a newline, exit late (len is last, !(len-1)).
return len;
}
char* typeset(void){
size_t len = chrnfill('\n', width+1); //+1 for \n on 81-char lines
char* next = peekstrbuf(inbuf, 0, len);
size_t wsend = 0;
if (next[--len] == '\n'){
wsend = len;
} else if (next[len] == ' '){
wsend = nextws(len);
}
else for (wsend = len; next[wsend] != ' '; wsend--);
// wsend is last index with a piece of whitespace
for (len = min(wsend,len-1); next[len] == ' '; len--);
// check, within the string, behind the whitespace for a letter.
if (next[len] == '\n') len--; // "\n" shouldn't become "\n\n"
// len should be *index of* last letter
if (peekchrbuf(inbuf, wsend) == '\n') cont_typst = false;
else cont_typst = true;
free(next);
char* ln = popstrbuf(inbuf, wsend+1);
ln[len+1] = '\n'; ln[len+2] = 0;
return ln;
}
// a parser to choose when to typeset and when to run a command
char* line(void){
size_t sz;
if ( (sz = fillbuf(2)) == 0)
return "";
char* twobytes = peekstrbuf(inbuf, 0, 2); // .., .\n, or ^.?
if (sz == 1 || twobytes[1] == '\n' || cont_typst) return typeset();
if (twobytes[0] == '.') popchrbuf(inbuf);
if (twobytes[0] == '.' && twobytes[1] != '.'){
char* data = cmd();
if (data) return data;
return line();
} else {
return typeset();
}
}
// orchestration
int main(int argc, char** argv){
int c;
in = getfile(argc, argv);
inbuf = newbuf(256);
if (in == NULL){
perror(argv[1]);
return 1;
}
char* out;
while ( (out = line())[0] != '\0'){
printf("%s",out);
free(out);
}
fclose(in);
return 0;
}
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