Re: [libgpiod PATCH 3/7] tools: Add value support to line name lookup

[Zev Weiss <zweiss@equinix.com>]

On Wed, Feb 02, 2022 at 08:21:30PM PST, Joel Stanley wrote:
>Add support for pasring the values as well as the name in

Nit: typo ("pasring")

>line_names_to_offsets.
>
>Signed-off-by: Joel Stanley <joel@jms.id.au>
>---
> tools/tools-common.c | 51 ++++++++++++++++++++++++++++++++++++++++++--
> tools/tools-common.h |  4 +++-
> 2 files changed, 52 insertions(+), 3 deletions(-)
>
>diff --git a/tools/tools-common.c b/tools/tools-common.c
>index 958933ed6d51..586577566790 100644
>--- a/tools/tools-common.c
>+++ b/tools/tools-common.c
>@@ -204,15 +204,57 @@ struct gpiod_chip *chip_by_line_name(const char *name)
> 	return NULL;
> }
>
>+char *split_line(const char *line_pair)
>+{
>+	char *name_end;
>+	size_t name_len;
>+	char *line_name;
>+
>+	name_end = strchr(line_pair, '=');
>+	if (!name_end)
>+		die("invalid name/value '%s'", line_pair);
>+
>+	name_len = name_end - line_pair;
>+
>+	if (name_len > 32)
>+		die("line name exceeds maximum length");

For mult-line invocations it might be nice to give some feedback on
which line name we errored out on here; perhaps

  die("%s: line name exceeds maximum length", line_pair);

or move the check after the strncpy() below and use line_name if we want
a slightly tidier message without the trailing "=<value>"?

>+
>+	line_name = calloc(1, name_len + 1);
>+	strncpy(line_name, line_pair, name_len);
>+
>+	return line_name;
>+}
>+
> int line_names_to_offsets(struct gpiod_chip *chip, char **lines,
>-			  unsigned int *offsets, int num_lines)
>+			  unsigned int *offsets,
>+			  int *values,
>+			  int num_lines)
> {
> 	int i;
>
> 	for (i = 0; i < num_lines; i++) {
>-		const char *line_name = lines[i];
>+		char *line_name;
>+		int value;
> 		int offset;
>
>+		if (values) {
>+			const char *line_pair = lines[i];
>+			char *name_end;
>+			int rv;
>+
>+			line_name = split_line(line_pair);
>+			name_end = strchr(line_pair, '=');
>+
>+			rv = sscanf(name_end, "=%d", &value);
>+			if (rv != 1)
>+				die("invalid offset<->value mapping: %s", line_pair);
>+
>+			if (value != 0 && value != 1)
>+				die("value must be 0 or 1: %s", line_pair);
>+		} else {
>+			line_name = lines[i];
>+		}
>+
> 		offset = gpiod_chip_find_line(chip, line_name);
>
> 		if (offset < 0) {
>@@ -222,6 +264,11 @@ int line_names_to_offsets(struct gpiod_chip *chip, char **lines,
> 		}
>
> 		offsets[i] = offset;
>+
>+		if (values) {
>+			values[i] = value;
>+			free(line_name);
>+		}
> 	}
>
> 	return 0;
>diff --git a/tools/tools-common.h b/tools/tools-common.h
>index 7affea436a60..723999011733 100644
>--- a/tools/tools-common.h
>+++ b/tools/tools-common.h
>@@ -33,6 +33,8 @@ struct gpiod_chip *chip_open_by_name(const char *name);
> struct gpiod_chip *chip_open_lookup(const char *device);
> struct gpiod_chip *chip_by_line_name(const char *name);
> int line_names_to_offsets(struct gpiod_chip *chip, char **lines,
>-			  unsigned int *offsets, int num_lines);
>+			  unsigned int *offsets, int *values,
>+			  int num_lines);
>+char *split_line(const char *line_pair);
>
> #endif /* __GPIOD_TOOLS_COMMON_H__ */
>-- 
>2.34.1
>