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-rw-r--r--builtin/stripspace.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/builtin/stripspace.c b/builtin/stripspace.c
new file mode 100644
index 0000000000..4d3b93fedb
--- /dev/null
+++ b/builtin/stripspace.c
@@ -0,0 +1,90 @@
+#include "builtin.h"
+#include "cache.h"
+
+/*
+ * Returns the length of a line, without trailing spaces.
+ *
+ * If the line ends with newline, it will be removed too.
+ */
+static size_t cleanup(char *line, size_t len)
+{
+ while (len) {
+ unsigned char c = line[len - 1];
+ if (!isspace(c))
+ break;
+ len--;
+ }
+
+ return len;
+}
+
+/*
+ * Remove empty lines from the beginning and end
+ * and also trailing spaces from every line.
+ *
+ * Note that the buffer will not be NUL-terminated.
+ *
+ * Turn multiple consecutive empty lines between paragraphs
+ * into just one empty line.
+ *
+ * If the input has only empty lines and spaces,
+ * no output will be produced.
+ *
+ * If last line does not have a newline at the end, one is added.
+ *
+ * Enable skip_comments to skip every line starting with "#".
+ */
+void stripspace(struct strbuf *sb, int skip_comments)
+{
+ int empties = 0;
+ size_t i, j, len, newlen;
+ char *eol;
+
+ /* We may have to add a newline. */
+ strbuf_grow(sb, 1);
+
+ for (i = j = 0; i < sb->len; i += len, j += newlen) {
+ eol = memchr(sb->buf + i, '\n', sb->len - i);
+ len = eol ? eol - (sb->buf + i) + 1 : sb->len - i;
+
+ if (skip_comments && len && sb->buf[i] == '#') {
+ newlen = 0;
+ continue;
+ }
+ newlen = cleanup(sb->buf + i, len);
+
+ /* Not just an empty line? */
+ if (newlen) {
+ if (empties > 0 && j > 0)
+ sb->buf[j++] = '\n';
+ empties = 0;
+ memmove(sb->buf + j, sb->buf + i, newlen);
+ sb->buf[newlen + j++] = '\n';
+ } else {
+ empties++;
+ }
+ }
+
+ strbuf_setlen(sb, j);
+}
+
+int cmd_stripspace(int argc, const char **argv, const char *prefix)
+{
+ struct strbuf buf = STRBUF_INIT;
+ int strip_comments = 0;
+
+ if (argc == 2 && (!strcmp(argv[1], "-s") ||
+ !strcmp(argv[1], "--strip-comments")))
+ strip_comments = 1;
+ else if (argc > 1)
+ usage("git stripspace [-s | --strip-comments] < <stream>");
+
+ if (strbuf_read(&buf, 0, 1024) < 0)
+ die_errno("could not read the input");
+
+ stripspace(&buf, strip_comments);
+
+ write_or_die(1, buf.buf, buf.len);
+ strbuf_release(&buf);
+ return 0;
+}