echo: add --skip-until and related test (#151)

app/echo.c

@@ -50,6 +50,8 @@ struct zsv_echo_data {
     } sqlite3;
   } o;
 
+  unsigned char *skip_until_prefix;
+  size_t skip_until_prefix_len;
   unsigned char trim_white:1;
   unsigned char _:7;
 };
@@ -111,6 +113,17 @@ static void zsv_echo_row(void *hook) {
   data->row_ix++;
 }
 
+static void zsv_echo_row_skip_until(void *hook) {
+  struct zsv_echo_data *data = hook;
+  struct zsv_cell cell = zsv_get_cell(data->parser, 0);
+  if(cell.len && cell.str && cell.len >= data->skip_until_prefix_len
+     && (!data->skip_until_prefix_len || !zsv_strincmp(cell.str, data->skip_until_prefix_len,
+                                                       data->skip_until_prefix, data->skip_until_prefix_len))) {
+    zsv_set_row_handler(data->parser, zsv_echo_row);
+    zsv_echo_row(hook);
+  }
+}
+
 const char *zsv_echo_usage_msg[] = {
   APPNAME ": write tabular input to stdout with optional cell overwrites",
   "",
@@ -119,6 +132,7 @@ const char *zsv_echo_usage_msg[] = {
   "Options:",
   "  -b                  : output with BOM",
   "  --trim              : trim whitespace",
+  "  --skip-until <value>: ignore all leading rows until the first row whose first column starts with the given value ",
   "  --overwrite <source>: overwrite cells using given source. Source may be:",
   "                        - sqlite3://<filename>[?sql=<query>]",
   "                          ex: sqlite3://overwrites.db?sql=select row, column, value from overwrites order by row, column",
@@ -136,6 +150,7 @@ static int zsv_echo_usage() {
 static void zsv_echo_cleanup(struct zsv_echo_data *data) {
   zsv_writer_delete(data->csv_writer);
   free(data->o.sqlite3.filename);
+  free(data->skip_until_prefix);
   if(data->o.sqlite3.stmt)
     sqlite3_finalize(data->o.sqlite3.stmt);
   if(data->in && data->in != stdin)
@@ -216,7 +231,19 @@ int ZSV_MAIN_FUNC(ZSV_COMMAND)(int argc, const char *argv[], struct zsv_opts *op
       writer_opts.with_bom = 1;
     else if(!strcmp(arg, "--trim"))
       data.trim_white = 1;
-    else if(!strcmp(arg, "--overwrite")) {
+    else if(!strcmp(arg, "--skip-until")) {
+      if(++arg_i >= argc) {
+        fprintf(stderr, "Option %s requires a value\n", arg);
+        err = 1;
+      } else if(!argv[arg_i][0]) {
+        fprintf(stderr, "--skip-until requires a non-empty value\n");
+        err = 1;
+      } else {
+        free(data.skip_until_prefix);
+        data.skip_until_prefix = (unsigned char *)strdup(argv[arg_i]);
+        data.skip_until_prefix_len = data.skip_until_prefix ? strlen((char *)data.skip_until_prefix) : 0;
+      }
+    } else if(!strcmp(arg, "--overwrite")) {
       if(arg_i+1 >= argc) {
         fprintf(stderr, "Option %s requires a value\n", arg);
         err = 1;
@@ -261,7 +288,10 @@ int ZSV_MAIN_FUNC(ZSV_COMMAND)(int argc, const char *argv[], struct zsv_opts *op
     return 1;
   }
 
-  opts->row_handler = zsv_echo_row;
+  if(data.skip_until_prefix)
+    opts->row_handler = zsv_echo_row_skip_until;
+  else
+    opts->row_handler = zsv_echo_row;
   opts->stream = data.in;
   opts->ctx = &data;
   data.csv_writer = zsv_writer_new(&writer_opts);

app/select.c

@@ -557,8 +557,7 @@ const char *zsv_select_usage_msg[] = {
   "  -H,--head <n>               : (head) only process the first n rows of data from all rows (including header) in the input",
   "  --no-header                 : do not output a header row",
   "  --prepend-header <value>    : prepend each column header with the given text value",
-  "  -s,--search <value>         : only output rows with at least one cell containing"
-  "                                value",
+  "  -s,--search <value>         : only output rows with at least one cell containing value",
   // to do: " -s,--search /<pattern>/modifiers: search on regex pattern; modifiers include 'g' (global) and 'i' (case-insensitive)",
   "  --sample-every <num of rows>: output a sample consisting of the first row, then every nth row",
   "  --sample-pct <percentage>   : output a randomly-selected sample (32 bits of randomness) of n percent of the input rows",

app/test/Makefile

@@ -100,7 +100,7 @@ test: ${TESTS}
 test-prop:
 	EXE=${BUILD_DIR}/bin/zsv_prop${EXE} make -C prop test
 
-test-echo : test-echo1 test-echo-overwrite test-echo-eol test-echo-overwrite-csv test-echo-chars test-echo-trim
+test-echo : test-echo1 test-echo-overwrite test-echo-eol test-echo-overwrite-csv test-echo-chars test-echo-trim test-echo-skip-until
 
 test-echo1: ${BUILD_DIR}/bin/zsv_echo${EXE}
 	@${TEST_INIT}
@@ -116,7 +116,12 @@ test-echo-eol-%: ${BUILD_DIR}/bin/zsv_echo${EXE}
 
 test-echo-trim: ${BUILD_DIR}/bin/zsv_echo${EXE}
 	@${TEST_INIT}
-	@${PREFIX} $< ${TEST_DATA_DIR}/test/echo-trim.csv ${REDIRECT} ${TMP_DIR}/$@.out
+	@${PREFIX} $< --trim ${TEST_DATA_DIR}/test/echo-trim.csv ${REDIRECT} ${TMP_DIR}/$@.out
+	@${CMP} ${TMP_DIR}/$@.out expected/$@.out && ${TEST_PASS} || ${TEST_FAIL}
+
+test-echo-skip-until: ${BUILD_DIR}/bin/zsv_echo${EXE}
+	@${TEST_INIT}
+	@${PREFIX} $< --skip-until ASF ${TEST_DATA_DIR}/test/echo-skip-until.csv ${REDIRECT} ${TMP_DIR}/$@.out
 	@${CMP} ${TMP_DIR}/$@.out expected/$@.out && ${TEST_PASS} || ${TEST_FAIL}
 
 test-echo-chars: ${BUILD_DIR}/bin/zsv_echo${EXE}

app/test/expected/test-echo-skip-until.out

@@ -0,0 +1,4 @@
+asfdd,8,9
+10,11,12
+asfd,13,14
+15,16,17

app/test/expected/test-echo-trim.out

@@ -1,2 +1,2 @@
- hi, there
- how ,are,  you,?  
+hi,there
+how,are,you,?

data/test/echo-skip-until.csv

@@ -0,0 +1,6 @@
+1,2,3
+4,5,6
+asfdd,8,9
+10,11,12
+asfd,13,14
+15,16,17