feat: add round scalar function

JeanArhancet · JeanArhancet · commit d696a67e3862 · 2024-07-21T10:29:30.000+02:00
diff --git a/COMPAT.md b/COMPAT.md
@@ -93,8 +93,8 @@ This document describes the SQLite compatibility status of Limbo:
 | random()                     | Yes     |         |
 | randomblob(N)                | No     |         |
 | replace(X,Y,Z)               | No     |         |
-| round(X)                     | No     |         |
-| round(X,Y)                   | No     |         |
+| round(X)                     | Yes     |         |
+| round(X,Y)                   | Yes     |         |
 | rtrim(X)                     | No     |         |
 | rtrim(X,Y)                   | No     |         |
 | sign(X)                      | No     |         |
diff --git a/core/expr.rs b/core/expr.rs
@@ -405,6 +405,43 @@ pub fn translate_expr(
                             }
                             Ok(target_register)
                         }
+                        SingleRowFunc::Round => {
+                            let args = if let Some(args) = args {
+                                if args.len() > 2 {
+                                    anyhow::bail!(
+                                        "Parse error: round function with more than 2 arguments"
+                                    );
+                                }
+                                args
+                            } else {
+                                anyhow::bail!("Parse error: round function with no arguments");
+                            };
+
+                            if args.len() == 1 {
+                                let regs = program.alloc_register();
+                                let _ = translate_expr(program, select, &args[0], regs)?;
+                                program.emit_insn(Insn::Function {
+                                    start_reg: regs,
+                                    dest: target_register,
+                                    func: SingleRowFunc::Round,
+                                });
+                            } else {
+                                for arg in args {
+                                    let reg = program.alloc_register();
+                                    let _ = translate_expr(program, select, arg, reg)?;
+                                    match arg {
+                                        ast::Expr::Literal(_) => program.mark_last_insn_constant(),
+                                        _ => {}
+                                    }
+                                }
+                                program.emit_insn(Insn::Function {
+                                    start_reg: target_register + 1,
+                                    dest: target_register,
+                                    func: SingleRowFunc::Round,
+                                });
+                            }
+                            Ok(target_register)
+                        }
                     }
                 }
                 None => {
diff --git a/core/function.rs b/core/function.rs
@@ -36,6 +36,7 @@ pub enum SingleRowFunc {
     Lower,
     Random,
     Trim,
+    Round,
 }
 
 impl ToString for SingleRowFunc {
@@ -48,6 +49,7 @@ impl ToString for SingleRowFunc {
             SingleRowFunc::Lower => "lower".to_string(),
             SingleRowFunc::Random => "random".to_string(),
             SingleRowFunc::Trim => "trim".to_string(),
+            SingleRowFunc::Round => "round".to_string(),
         }
     }
 }
@@ -77,6 +79,7 @@ impl FromStr for Func {
             "lower" => Ok(Func::SingleRow(SingleRowFunc::Lower)),
             "random" => Ok(Func::SingleRow(SingleRowFunc::Random)),
             "trim" => Ok(Func::SingleRow(SingleRowFunc::Trim)),
+            "round" => Ok(Func::SingleRow(SingleRowFunc::Round)),
             _ => Err(()),
         }
     }
diff --git a/core/vdbe.rs b/core/vdbe.rs
@@ -1303,6 +1303,14 @@ impl Program {
                         state.registers[*dest] = result;
                         state.pc += 1;
                     }
+                    SingleRowFunc::Round => {
+                        let start_reg = *start_reg;
+                        let reg_value = state.registers[start_reg].clone();
+                        let precision_value = state.registers.get(start_reg + 1).cloned();
+                        let result = exec_round(&reg_value, precision_value);
+                        state.registers[*dest] = result;
+                        state.pc += 1;
+                    }
                 },
             }
         }
@@ -1888,6 +1896,27 @@ fn exec_like(pattern: &str, text: &str) -> bool {
     re.is_match(text)
 }
 
+fn exec_round(reg: &OwnedValue, precision: Option<OwnedValue>) -> OwnedValue {
+    let precision = match precision {
+        Some(OwnedValue::Text(x)) => x.parse().unwrap_or(0.0),
+        Some(OwnedValue::Integer(x)) => x as f64,
+        Some(OwnedValue::Float(x)) => x,
+        None => 0.0,
+        _ => return OwnedValue::Null,
+    };
+
+    let reg = match reg {
+        OwnedValue::Text(x) => x.parse().unwrap_or(0.0),
+        OwnedValue::Integer(x) => *x as f64,
+        OwnedValue::Float(x) => *x,
+        _ => return reg.to_owned(),
+    };
+
+    let precision = if precision < 1.0 { 0.0 } else { precision };
+    let multiplier = 10f64.powi(precision as i32);
+    OwnedValue::Float(((reg * multiplier).round()) / multiplier)
+}
+
 // Implements TRIM pattern matching.
 fn exec_trim(reg: &OwnedValue, pattern: Option<OwnedValue>) -> OwnedValue {
     match (reg, pattern) {
@@ -1922,7 +1951,8 @@ fn exec_if(reg: &OwnedValue, null_reg: &OwnedValue, not: bool) -> bool {
 #[cfg(test)]
 mod tests {
     use super::{
-        exec_abs, exec_if, exec_like, exec_lower, exec_random, exec_trim, exec_upper, OwnedValue,
+        exec_abs, exec_if, exec_like, exec_lower, exec_random, exec_round, exec_trim, exec_upper,
+        OwnedValue,
     };
     use std::rc::Rc;
 
@@ -2001,6 +2031,33 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_exec_round() {
+        let input_val = OwnedValue::Float(123.456);
+        let expected_val = OwnedValue::Float(123.0);
+        assert_eq!(exec_round(&input_val, None), expected_val);
+
+        let input_val = OwnedValue::Float(123.456);
+        let precision_val = OwnedValue::Integer(2);
+        let expected_val = OwnedValue::Float(123.46);
+        assert_eq!(exec_round(&input_val, Some(precision_val)), expected_val);
+
+        let input_val = OwnedValue::Float(123.456);
+        let precision_val = OwnedValue::Text(Rc::new(String::from("1")));
+        let expected_val = OwnedValue::Float(123.5);
+        assert_eq!(exec_round(&input_val, Some(precision_val)), expected_val);
+
+        let input_val = OwnedValue::Text(Rc::new(String::from("123.456")));
+        let precision_val = OwnedValue::Integer(2);
+        let expected_val = OwnedValue::Float(123.46);
+        assert_eq!(exec_round(&input_val, Some(precision_val)), expected_val);
+
+        let input_val = OwnedValue::Integer(123);
+        let precision_val = OwnedValue::Integer(1);
+        let expected_val = OwnedValue::Float(123.0);
+        assert_eq!(exec_round(&input_val, Some(precision_val)), expected_val);
+    }
+
     #[test]
     fn test_exec_if() {
         let reg = OwnedValue::Integer(0);
diff --git a/sqlite3/tests/Makefile b/sqlite3/tests/Makefile
@@ -13,6 +13,7 @@ PROGRAM = sqlite3-tests
 CFLAGS = -g -Wall -std=c17 -MMD -MP
 
 LIBS ?= -lsqlite3
+LIBS += -lm
 
 OBJS += main.o
 OBJS += test-aux.o
diff --git a/testing/scalar-functions.test b/testing/scalar-functions.test
@@ -85,4 +85,40 @@ do_execsql_test trim-pattern-null {
 
 do_execsql_test trim-no-match-pattern {
   SELECT trim('Limbo', 'xyz');
-} {Limbo}
+} {Limbo}
+
+do_execsql_test round-float-no-precision {
+  SELECT round(123.456);
+} {123.0}
+
+do_execsql_test round-float-with-precision {
+  SELECT round(123.456, 2);
+} {123.46}
+
+do_execsql_test round-float-with-text-precision {
+  SELECT round(123.5, '1');
+} {123.5}
+
+do_execsql_test round-text-parsable {
+  SELECT round('123.456', 2);
+} {123.46}
+
+do_execsql_test round-text-non-parsable {
+  SELECT round('abc', 1);
+} {0.0}
+
+do_execsql_test round-integer-with-precision {
+  SELECT round(123, 1);
+} {123.0}
+
+do_execsql_test round-float-negative-precision {
+  SELECT round(123.456, -1);
+} {123.0}
+
+do_execsql_test round-float-zero-precision {
+  SELECT round(123.456, 0);
+} {123.0}
+
+do_execsql_test round-null-precision {
+  SELECT round(123.456, null);
+} {}

Original file line number	Diff line number	Diff line change
`@@ -36,6 +36,7 @@ pub enum SingleRowFunc {`
`36`	`36`	`Lower,`
`37`	`37`	`Random,`
`38`	`38`	`Trim,`
	`39`	`+ Round,`
`39`	`40`	`}`
`40`	`41`
`41`	`42`	`impl ToString for SingleRowFunc {`
`@@ -48,6 +49,7 @@ impl ToString for SingleRowFunc {`
`48`	`49`	`SingleRowFunc::Lower => "lower".to_string(),`
`49`	`50`	`SingleRowFunc::Random => "random".to_string(),`
`50`	`51`	`SingleRowFunc::Trim => "trim".to_string(),`
	`52`	`+ SingleRowFunc::Round => "round".to_string(),`
`51`	`53`	`}`
`52`	`54`	`}`
`53`	`55`	`}`
`@@ -77,6 +79,7 @@ impl FromStr for Func {`
`77`	`79`	`"lower" => Ok(Func::SingleRow(SingleRowFunc::Lower)),`
`78`	`80`	`"random" => Ok(Func::SingleRow(SingleRowFunc::Random)),`
`79`	`81`	`"trim" => Ok(Func::SingleRow(SingleRowFunc::Trim)),`
	`82`	`+ "round" => Ok(Func::SingleRow(SingleRowFunc::Round)),`
`80`	`83`	`_ => Err(()),`
`81`	`84`	`}`
`82`	`85`	`}`