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-rw-r--r--builtin-stripspace.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/builtin-stripspace.c b/builtin-stripspace.c
new file mode 100644
index 0000000..2ce1264
--- /dev/null
+++ b/builtin-stripspace.c
@@ -0,0 +1,61 @@
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include "builtin.h"
+
+/*
+ * Remove empty lines from the beginning and end.
+ *
+ * Turn multiple consecutive empty lines into just one
+ * empty line. Return true if it is an incomplete line.
+ */
+static int cleanup(char *line)
+{
+ int len = strlen(line);
+
+ if (len && line[len-1] == '\n') {
+ if (len == 1)
+ return 0;
+ do {
+ unsigned char c = line[len-2];
+ if (!isspace(c))
+ break;
+ line[len-2] = '\n';
+ len--;
+ line[len] = 0;
+ } while (len > 1);
+ return 0;
+ }
+ return 1;
+}
+
+void stripspace(FILE *in, FILE *out)
+{
+ int empties = -1;
+ int incomplete = 0;
+ char line[1024];
+
+ while (fgets(line, sizeof(line), in)) {
+ incomplete = cleanup(line);
+
+ /* Not just an empty line? */
+ if (line[0] != '\n') {
+ if (empties > 0)
+ fputc('\n', out);
+ empties = 0;
+ fputs(line, out);
+ continue;
+ }
+ if (empties < 0)
+ continue;
+ empties++;
+ }
+ if (incomplete)
+ fputc('\n', out);
+}
+
+int cmd_stripspace(int argc, const char **argv, char **envp)
+{
+ stripspace(stdin, stdout);
+ return 0;
+}