line-range.c

   1 #include "git-compat-util.h"
   2 #include "line-range.h"
   3
   4 /*
   5  * Parse one item in the -L option
   6  */
   7 static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
   8                              void *data, long lines, long begin, long *ret)
   9 {
  10         char *term;
  11         const char *line;
  12         long num;
  13         int reg_error;
  14         regex_t regexp;
  15         regmatch_t match[1];
  16
  17         /* Allow "-L <something>,+20" to mean starting at <something>
  18          * for 20 lines, or "-L <something>,-5" for 5 lines ending at
  19          * <something>.
  20          */
  21         if (1 < begin && (spec[0] == '+' || spec[0] == '-')) {
  22                 num = strtol(spec + 1, &term, 10);
  23                 if (term != spec + 1) {
  24                         if (!ret)
  25                                 return term;
  26                         if (spec[0] == '-')
  27                                 num = 0 - num;
  28                         if (0 < num)
  29                                 *ret = begin + num - 2;
  30                         else if (!num)
  31                                 *ret = begin;
  32                         else
  33                                 *ret = begin + num;
  34                         return term;
  35                 }
  36                 return spec;
  37         }
  38         num = strtol(spec, &term, 10);
  39         if (term != spec) {
  40                 if (ret)
  41                         *ret = num;
  42                 return term;
  43         }
  44         if (spec[0] != '/')
  45                 return spec;
  46
  47         /* it could be a regexp of form /.../ */
  48         for (term = (char *) spec + 1; *term && *term != '/'; term++) {
  49                 if (*term == '\\')
  50                         term++;
  51         }
  52         if (*term != '/')
  53                 return spec;
  54
  55         /* in the scan-only case we are not interested in the regex */
  56         if (!ret)
  57                 return term+1;
  58
  59         /* try [spec+1 .. term-1] as regexp */
  60         *term = 0;
  61         begin--; /* input is in human terms */
  62         line = nth_line(data, begin);
  63
  64         if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
  65             !(reg_error = regexec(&regexp, line, 1, match, 0))) {
  66                 const char *cp = line + match[0].rm_so;
  67                 const char *nline;
  68
  69                 while (begin++ < lines) {
  70                         nline = nth_line(data, begin);
  71                         if (line <= cp && cp < nline)
  72                                 break;
  73                         line = nline;
  74                 }
  75                 *ret = begin;
  76                 regfree(&regexp);
  77                 *term++ = '/';
  78                 return term;
  79         }
  80         else {
  81                 char errbuf[1024];
  82                 regerror(reg_error, &regexp, errbuf, 1024);
  83                 die("-L parameter '%s': %s", spec + 1, errbuf);
  84         }
  85 }
  86
  87 int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
  88                     void *cb_data, long lines, long *begin, long *end)
  89 {
  90         arg = parse_loc(arg, nth_line_cb, cb_data, lines, 1, begin);
  91
  92         if (*arg == ',')
  93                 arg = parse_loc(arg + 1, nth_line_cb, cb_data, lines, *begin + 1, end);
  94
  95         if (*arg)
  96                 return -1;
  97
  98         return 0;
  99 }
 100
 101 const char *skip_range_arg(const char *arg)
 102 {
 103         arg = parse_loc(arg, NULL, NULL, 0, -1, NULL);
 104
 105         if (*arg == ',')
 106                 arg = parse_loc(arg+1, NULL, NULL, 0, 0, NULL);
 107
 108         return arg;
 109 }