Refactor parse_loc

[thirdparty/git.git] / line-range.c

diff --git a/line-range.c b/line-range.c
new file mode 100644 (file)
index 0000000..5a226ab
--- /dev/null
+++ b/line-range.c
@@ -0,0 +1,92 @@
+#include "git-compat-util.h"
+#include "line-range.h"
+
+/*
+ * Parse one item in the -L option
+ */
+static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
+                            void *data, long lines, long begin, long *ret)
+{
+       char *term;
+       const char *line;
+       long num;
+       int reg_error;
+       regex_t regexp;
+       regmatch_t match[1];
+
+       /* Allow "-L <something>,+20" to mean starting at <something>
+        * for 20 lines, or "-L <something>,-5" for 5 lines ending at
+        * <something>.
+        */
+       if (1 < begin && (spec[0] == '+' || spec[0] == '-')) {
+               num = strtol(spec + 1, &term, 10);
+               if (term != spec + 1) {
+                       if (spec[0] == '-')
+                               num = 0 - num;
+                       if (0 < num)
+                               *ret = begin + num - 2;
+                       else if (!num)
+                               *ret = begin;
+                       else
+                               *ret = begin + num;
+                       return term;
+               }
+               return spec;
+       }
+       num = strtol(spec, &term, 10);
+       if (term != spec) {
+               *ret = num;
+               return term;
+       }
+       if (spec[0] != '/')
+               return spec;
+
+       /* it could be a regexp of form /.../ */
+       for (term = (char *) spec + 1; *term && *term != '/'; term++) {
+               if (*term == '\\')
+                       term++;
+       }
+       if (*term != '/')
+               return spec;
+
+       /* try [spec+1 .. term-1] as regexp */
+       *term = 0;
+       begin--; /* input is in human terms */
+       line = nth_line(data, begin);
+
+       if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
+           !(reg_error = regexec(&regexp, line, 1, match, 0))) {
+               const char *cp = line + match[0].rm_so;
+               const char *nline;
+
+               while (begin++ < lines) {
+                       nline = nth_line(data, begin);
+                       if (line <= cp && cp < nline)
+                               break;
+                       line = nline;
+               }
+               *ret = begin;
+               regfree(&regexp);
+               *term++ = '/';
+               return term;
+       }
+       else {
+               char errbuf[1024];
+               regerror(reg_error, &regexp, errbuf, 1024);
+               die("-L parameter '%s': %s", spec + 1, errbuf);
+       }
+}
+
+int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
+                   void *cb_data, long lines, long *begin, long *end)
+{
+       arg = parse_loc(arg, nth_line_cb, cb_data, lines, 1, begin);
+
+       if (*arg == ',')
+               arg = parse_loc(arg + 1, nth_line_cb, cb_data, lines, *begin + 1, end);
+
+       if (*arg)
+               return -1;
+
+       return 0;
+}