builtin-stripspace.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "strbuf.h"
   4
   5 /*
   6  * Returns the length of a line, without trailing spaces.
   7  *
   8  * If the line ends with newline, it will be removed too.
   9  */
  10 static size_t cleanup(char *line, size_t len)
  11 {
  12         if (len) {
  13                 if (line[len - 1] == '\n')
  14                         len--;
  15
  16                 while (len) {
  17                         unsigned char c = line[len - 1];
  18                         if (!isspace(c))
  19                                 break;
  20                         len--;
  21                 }
  22         }
  23         return len;
  24 }
  25
  26 /*
  27  * Remove empty lines from the beginning and end
  28  * and also trailing spaces from every line.
  29  *
  30  * Note that the buffer will not be NUL-terminated.
  31  *
  32  * Turn multiple consecutive empty lines between paragraphs
  33  * into just one empty line.
  34  *
  35  * If the input has only empty lines and spaces,
  36  * no output will be produced.
  37  *
  38  * If last line has a newline at the end, it will be removed.
  39  *
  40  * Enable skip_comments to skip every line starting with "#".
  41  */
  42 size_t stripspace(char *buffer, size_t length, int skip_comments)
  43 {
  44         int empties = -1;
  45         size_t i, j, len, newlen;
  46         char *eol;
  47
  48         for (i = j = 0; i < length; i += len, j += newlen) {
  49                 eol = memchr(buffer + i, '\n', length - i);
  50                 len = eol ? eol - (buffer + i) + 1 : length - i;
  51
  52                 if (skip_comments && len && buffer[i] == '#') {
  53                         newlen = 0;
  54                         continue;
  55                 }
  56                 newlen = cleanup(buffer + i, len);
  57
  58                 /* Not just an empty line? */
  59                 if (newlen) {
  60                         if (empties != -1)
  61                                 buffer[j++] = '\n';
  62                         if (empties > 0)
  63                                 buffer[j++] = '\n';
  64                         empties = 0;
  65                         memmove(buffer + j, buffer + i, newlen);
  66                         continue;
  67                 }
  68                 if (empties < 0)
  69                         continue;
  70                 empties++;
  71         }
  72
  73         return j;
  74 }
  75
  76 int cmd_stripspace(int argc, const char **argv, const char *prefix)
  77 {
  78         struct strbuf buf;
  79         int strip_comments = 0;
  80
  81         if (argc > 1 && (!strcmp(argv[1], "-s") ||
  82                                 !strcmp(argv[1], "--strip-comments")))
  83                 strip_comments = 1;
  84
  85         strbuf_init(&buf, 0);
  86         if (strbuf_read(&buf, 0, 1024) < 0)
  87                 die("could not read the input");
  88
  89         strbuf_setlen(&buf, stripspace(buf.buf, buf.len, strip_comments));
  90         if (buf.len)
  91                 strbuf_addch(&buf, '\n');
  92
  93         write_or_die(1, buf.buf, buf.len);
  94         strbuf_release(&buf);
  95         return 0;
  96 }