From c7a67a1bf43bd8680bc9a52875e7100fb50b4a39 Mon Sep 17 00:00:00 2001
From: Pekka Enberg <penberg@iki.fi>
Date: Fri, 5 Jul 2024 18:13:06 +0300
Subject: [PATCH] Fix ResultRow operands

Fix ResultRow operands to follow SQLite bytecode format for consistency.
---
 core/translate.rs | 16 ++++++++--------
 core/vdbe.rs      | 32 +++++++++++---------------------
 2 files changed, 19 insertions(+), 29 deletions(-)

diff --git a/core/translate.rs b/core/translate.rs
index ded0f98ea..06b64d741 100644
--- a/core/translate.rs
+++ b/core/translate.rs
@@ -152,14 +152,14 @@ fn translate_select(select: Select) -> Result<Program> {
                 }
                 // only one result row
                 program.emit_insn(Insn::ResultRow {
-                    register_start,
-                    register_end,
+                    start_reg: register_start,
+                    count: register_end - register_start,
                 });
                 limit_reg.map(|_| program.emit_placeholder())
             } else {
                 program.emit_insn(Insn::ResultRow {
-                    register_start,
-                    register_end,
+                    start_reg: register_start,
+                    count: register_end - register_start,
                 });
                 let limit_decr_insn = limit_reg.map(|_| program.emit_placeholder());
                 program.emit_insn(Insn::NextAsync { cursor_id });
@@ -182,8 +182,8 @@ fn translate_select(select: Select) -> Result<Program> {
             assert!(!select.exist_aggregation);
             let (register_start, register_end) = translate_columns(&mut program, None, &select);
             program.emit_insn(Insn::ResultRow {
-                register_start,
-                register_end,
+                start_reg: register_start,
+                count: register_end - register_start,
             });
             limit_reg.map(|_| program.emit_placeholder())
         }
@@ -481,8 +481,8 @@ fn translate_pragma(
 
             let pragma_result_end = program.next_free_register();
             program.emit_insn(Insn::ResultRow {
-                register_start: pragma_result,
-                register_end: pragma_result_end,
+                start_reg: pragma_result,
+                count: pragma_result_end - pragma_result,
             });
         }
         Some(ast::PragmaBody::Equals(value)) => {
diff --git a/core/vdbe.rs b/core/vdbe.rs
index c59f89be1..76ac2aa78 100644
--- a/core/vdbe.rs
+++ b/core/vdbe.rs
@@ -50,8 +50,8 @@ pub enum Insn {
 
     // Emit a row of results.
     ResultRow {
-        register_start: usize,
-        register_end: usize,
+        start_reg: usize, // P1
+        count: usize,     // P2
     },
 
     // Advance the cursor to the next row.
@@ -289,11 +289,8 @@ impl Program {
                     }
                     state.pc += 1;
                 }
-                Insn::ResultRow {
-                    register_start,
-                    register_end,
-                } => {
-                    let record = make_record(&state.registers, register_end, register_start);
+                Insn::ResultRow { start_reg, count } => {
+                    let record = make_record(&state.registers, start_reg, count);
                     state.pc += 1;
                     return Ok(StepResult::Row(record));
                 }
@@ -431,13 +428,9 @@ impl Program {
     }
 }
 
-fn make_record<'a>(
-    registers: &'a [OwnedValue],
-    register_end: &usize,
-    register_start: &usize,
-) -> Record<'a> {
-    let mut values = Vec::with_capacity(*register_end - *register_start);
-    for i in *register_start..*register_end {
+fn make_record<'a>(registers: &'a [OwnedValue], start_reg: &usize, count: &usize) -> Record<'a> {
+    let mut values = Vec::with_capacity(*count);
+    for i in *start_reg..*start_reg + count {
         values.push(crate::types::to_value(&registers[i]));
     }
     Record::new(values)
@@ -522,17 +515,14 @@ fn insn_to_str(addr: BranchOffset, insn: &Insn) -> String {
                 0,
                 format!("r[{}]= cursor {} column {}", dest, cursor_id, column),
             ),
-            Insn::ResultRow {
-                register_start,
-                register_end,
-            } => (
+            Insn::ResultRow { start_reg, count } => (
                 "ResultRow",
-                *register_start as i32,
-                *register_end as i32,
+                *start_reg as i32,
+                *count as i32,
                 0,
                 OwnedValue::Text(Rc::new("".to_string())),
                 0,
-                format!("output=r[{}..{}]", register_start, register_end),
+                format!("output=r[{}..{}]", start_reg, start_reg + count),
             ),
             Insn::NextAsync { cursor_id } => (
                 "NextAsync",