From 9310b54d439d4a1a8d4d337987aa63884df0af76 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Wed, 20 May 2026 11:38:19 +0300
Subject: feat: add syscall aggregate sampling infrastructure (task 17)

---
 internal/flags/sampling.go | 88 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 internal/flags/sampling.go

(limited to 'internal/flags/sampling.go')

diff --git a/internal/flags/sampling.go b/internal/flags/sampling.go
new file mode 100644
index 0000000..19b4f9d
--- /dev/null
+++ b/internal/flags/sampling.go
@@ -0,0 +1,88 @@
+package flags
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"ior/internal/types"
+)
+
+func cloneFamilySamplingRates(in map[types.SyscallFamily]uint32) map[types.SyscallFamily]uint32 {
+	out := make(map[types.SyscallFamily]uint32, len(in))
+	for family, rate := range in {
+		out[family] = rate
+	}
+	return out
+}
+
+func cloneSyscallSamplingRates(in map[string]uint32) map[string]uint32 {
+	out := make(map[string]uint32, len(in))
+	for syscall, rate := range in {
+		out[syscall] = rate
+	}
+	return out
+}
+
+func parseFamilySamplingRates(raw string) (map[types.SyscallFamily]uint32, error) {
+	entries, err := parseSamplingEntries(raw)
+	if err != nil {
+		return nil, err
+	}
+	out := make(map[types.SyscallFamily]uint32, len(entries))
+	for key, rate := range entries {
+		family, ok := types.ParseSyscallFamily(key)
+		if !ok {
+			return nil, fmt.Errorf("invalid syscall family in sampling map: %q", key)
+		}
+		out[family] = rate
+	}
+	return out, nil
+}
+
+func parseSyscallSamplingRates(raw string) (map[string]uint32, error) {
+	entries, err := parseSamplingEntries(raw)
+	if err != nil {
+		return nil, err
+	}
+	out := make(map[string]uint32, len(entries))
+	for syscall, rate := range entries {
+		syscall = strings.ToLower(strings.TrimSpace(syscall))
+		if syscall == "" {
+			return nil, fmt.Errorf("invalid syscall sampling key %q", syscall)
+		}
+		if _, ok := types.EnterTraceIDByName(syscall); !ok {
+			return nil, fmt.Errorf("invalid syscall in sampling map: %q", syscall)
+		}
+		out[syscall] = rate
+	}
+	return out, nil
+}
+
+func parseSamplingEntries(raw string) (map[string]uint32, error) {
+	out := make(map[string]uint32)
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return out, nil
+	}
+	for _, part := range strings.Split(raw, ",") {
+		part = strings.TrimSpace(part)
+		if part == "" {
+			continue
+		}
+		key, valueRaw, ok := strings.Cut(part, "=")
+		if !ok {
+			return nil, fmt.Errorf("invalid sampling entry %q: expected name=rate", part)
+		}
+		key = strings.TrimSpace(key)
+		if key == "" {
+			return nil, fmt.Errorf("invalid sampling entry %q: empty name", part)
+		}
+		rate, err := strconv.ParseUint(strings.TrimSpace(valueRaw), 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("invalid sampling rate for %q: %w", key, err)
+		}
+		out[key] = uint32(rate)
+	}
+	return out, nil
+}
-- 
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