fmt: improved version using less memory
functional identical, but uses different data structure. instead of reading all words into memory, we read and tokenize on demand keeping a simple linked list of words to conume by further calls of getword(). once the list is empty we read the next line, tokenize it and fill the list up again. so we only need as mutch memory to hold all the words of the longest line.
This commit is contained in:
cinap_lenrek
parent
22c7584780
commit
4fdc7dbe9c
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@ -12,14 +12,19 @@ int indent = 0; /* current value of indent, before extra indent */
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int length = 70; /* how many columns per output line */
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int join = 1; /* can lines be joined? */
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int maxtab = 8;
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Biobuf bin;
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Biobuf bout;
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typedef struct Word Word;
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struct Word{
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int bol;
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struct Word
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{
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Word *next;
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int indent;
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char text[1];
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int length;
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char bol;
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char text[];
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};
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void fmt(void);
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@ -84,17 +89,14 @@ main(int argc, char **argv)
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}
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int
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indentof(char **linep)
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indentof(char *s)
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{
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int i, ind;
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char *line;
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int ind;
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ind = 0;
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line = *linep;
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for(i=0; line[i]; i++)
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switch(line[i]){
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for(; *s != '\0'; s++)
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switch(*s){
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default:
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*linep = line;
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return ind;
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case ' ':
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ind++;
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@ -104,53 +106,65 @@ indentof(char **linep)
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ind -= ind%maxtab;
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break;
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}
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/* plain white space doesn't change the indent */
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*linep = "";
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return indent;
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}
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Word**
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addword(Word **words, int *nwordp, char *s, int l, int indent, int bol)
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Word*
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newword(char *s, int n, int ind, int bol)
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{
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Word *w;
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w = malloc(sizeof(Word)+l+1);
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memmove(w->text, s, l);
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w->text[l] = '\0';
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w->indent = indent;
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w = malloc(sizeof(Word) + n+1);
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w->next = nil;
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w->indent = ind;
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w->bol = bol;
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words = realloc(words, (*nwordp+1)*sizeof(Word*));
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words[(*nwordp)++] = w;
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return words;
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memmove(w->text, s, n);
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w->text[n] = 0;
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w->length = utflen(w->text);
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return w;
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}
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Word**
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parseline(char *line, Word **words, int *nwordp)
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Word*
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getword(void)
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{
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int ind, l, bol;
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ind = indentof(&line);
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indent = ind;
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bol = 1;
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static Word *head, *tail;
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char *line, *s;
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Word *w;
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w = head;
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if(w != nil){
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head = w->next;
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return w;
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}
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line = Brdstr(&bin, '\n', 1);
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if(line == nil)
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return nil;
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tail = nil;
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indent = indentof(line);
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for(;;){
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/* find next word */
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while(*line==' ' || *line=='\t')
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while(*line == ' ' || *line == '\t')
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line++;
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if(*line == '\0'){
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if(bol)
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return addword(words, nwordp, "", 0, -1, bol);
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if(head == nil)
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return newword("", 0, -1, 1);
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break;
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}
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/* how long is this word? */
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for(l=0; line[l]; l++)
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if(line[l]==' ' || line[l]=='\t')
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for(s=line++; *line != '\0'; line++)
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if(*line==' ' || *line=='\t')
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break;
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words = addword(words, nwordp, line, l, indent, bol);
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bol = 0;
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line += l;
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w = newword(s, line-s, indent, head==nil);
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if(head == nil)
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head = w;
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else
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tail->next = w;
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tail = w;
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}
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return words;
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w = head;
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head = w->next;
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return w;
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}
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void
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@ -181,61 +195,46 @@ nspaceafter(char *s)
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return 2;
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return 1;
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}
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void
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printwords(Word **w, int nw)
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{
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int i, j, n, col, nsp;
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/* one output line per loop */
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for(i=0; i<nw; ){
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/* if it's a blank line, print it */
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if(w[i]->indent == -1){
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Bputc(&bout, '\n');
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if(++i == nw) /* out of words */
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break;
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}
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/* emit leading indent */
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col = extraindent+w[i]->indent;
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printindent(col);
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/* emit words until overflow; always emit at least one word */
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for(n=0;; n++){
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Bprint(&bout, "%s", w[i]->text);
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col += utflen(w[i]->text);
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if(++i == nw)
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break; /* out of words */
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if(w[i]->indent != w[i-1]->indent)
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break; /* indent change */
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nsp = nspaceafter(w[i-1]->text);
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if(col+nsp+utflen(w[i]->text) > extraindent+length)
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break; /* fold line */
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if(!join && w[i]->bol)
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break;
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for(j=0; j<nsp; j++)
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Bputc(&bout, ' '); /* emit space; another word will follow */
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col += nsp;
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}
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/* emit newline */
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Bputc(&bout, '\n');
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}
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}
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void
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fmt(void)
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{
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char *s;
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int i, nw;
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Word **w;
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Word *w, *o;
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int col, nsp;
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nw = 0;
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w = nil;
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while((s = Brdstr(&bin, '\n', 1)) != nil){
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w = parseline(s, w, &nw);
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free(s);
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w = getword();
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while(w != nil){
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if(w->indent == -1){
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Bputc(&bout, '\n');
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free(w);
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w = getword();
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if(w == nil)
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break;
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}
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col = w->indent;
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printindent(extraindent+col);
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/* emit words until overflow; always emit at least one word */
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for(;;){
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Bprint(&bout, "%s", w->text);
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col += w->length;
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o = w;
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w = getword();
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if(w == nil)
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break;
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if(w->indent != o->indent)
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break; /* indent change */
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nsp = nspaceafter(o->text);
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if(col+nsp+w->length > length)
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break; /* fold line */
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if(!join && w->bol)
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break;
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while(--nsp >= 0){
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Bputc(&bout, ' '); /* emit space; another word will follow */
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col++;
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}
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free(o);
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}
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free(o);
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Bputc(&bout, '\n');
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}
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printwords(w, nw);
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for(i=0; i<nw; i++)
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free(w[i]);
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free(w);
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}
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