hare

commit ebb371e6409074aa037052c83c93ccc110232f28
parent 2a10eb194237b03e83ab9bdda579c20e814156cb
Author: Drew DeVault <sir@cmpwn.com>
Date:   Fri, 12 Feb 2021 14:11:14 -0500

all: improve slice allocation usage

Diffstat:
M
fmt/fmt.ha
 | 
2
+-
M
rt/ensure.ha
 | 
12
+++++++++---
M
rt/malloc.ha
 | 
9
+++++----
M
strings/tokenize.ha
 | 
2
+-

4 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/fmt/fmt.ha b/fmt/fmt.ha
@@ -207,7 +207,7 @@ fn format(
 };
 
 fn scan_uint(iter: *strings::iterator) uint = {
-	let num = alloc([]u8, [], 1); // TODO: alloc slice w/o cap
+	let num = alloc([]u8, []);
 	defer free(num);
 	for (true) {
 		let r = match (strings::next(iter)) {
diff --git a/rt/ensure.ha b/rt/ensure.ha
@@ -5,10 +5,16 @@ export type slice = struct {
 };
 
 export fn ensure(s: *slice, membsz: size, length: size) void = {
-	// TODO: make sure length * membsz < SIZE_MAX
-	for (s.capacity < length) {
-		s.capacity *= 2;
+	let cap = s.capacity;
+	for (cap < length) {
+		assert(cap >= s.capacity, "slice out of memory (overflow)");
+		if (cap == 0) {
+			cap = length;
+		} else {
+			cap *= 2;
+		};
 	};
+	s.capacity = cap;
 	let data = realloc(s.data, s.capacity * membsz);
 	assert(data != null);
 	s.data = data;
diff --git a/rt/malloc.ha b/rt/malloc.ha
@@ -47,8 +47,8 @@ fn size2bin(s: size) size = {
 // Allocates n bytes of memory and returns a pointer to them, or null if there
 // is insufficient memory.
 export fn malloc(n: size) nullable *void = {
-	assert(n > 0);
-	return if (n > bin2size(len(bins) - 1)) malloc_large(n)
+	return if (n == 0) null
+		else if (n > bin2size(len(bins) - 1)) malloc_large(n)
 		else malloc_small(n);
 };
 
@@ -135,8 +135,9 @@ fn free_small(p: *void, s: size) void = {
 // in-place. Returns null if there is insufficient memory to support the
 // request.
 export fn realloc(_p: nullable *void, n: size) nullable *void = {
-	assert(n > 0);
-	if (_p == null) {
+	if (n == 0) {
+		return null;
+	} else if (_p == null) {
 		return malloc(n);
 	};
 
diff --git a/strings/tokenize.ha b/strings/tokenize.ha
@@ -54,7 +54,7 @@ export fn remaining_tokens(s: *tokenizer) str = {
 // borrowed from 'in', and needn't be freed - but should be [strings::dup_all]'d
 // if they should outlive 'in'.
 export fn splitN(in: str, delim: str, n: size) []str = {
-	let toks = alloc([]str, [], 8); // TODO: Drop explicit capacity
+	let toks = alloc([]str, []);
 	let tok = tokenize(in, delim);
 	for (let i = 0z; i < n - 1z; i += 1) {
 		match (next_token(&tok)) {