From ca6027abcd276d2c46698e36d6703baccad3458c Mon Sep 17 00:00:00 2001
From: Kwarde <kevin@kwarde.com>
Date: Mon, 28 Jul 2025 17:29:03 +0200
Subject: [PATCH] strfind: assure re-check is done on mismatch after initial
 match + add tests

---
 src/string.asm | 11 +++++++++++
 src/tests.asm  | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/src/string.asm b/src/string.asm
index 50266b5..87df0a5 100644
--- a/src/string.asm
+++ b/src/string.asm
@@ -192,6 +192,17 @@ strfind:
 
 		.noMatch:
 		; not gonna figure out here if there was an existing match already. just XOR r10b,r10b and load original pointer to what[] to rsi
+		; EDIT: actually yes I am. strfind("gidgiddy", "giddy", 0); [gid]giddy<>[gid]dy is a match but then gid[g]iddy<>gid[d]y is not while it should check gid[g]iddy<>[g]iddy
+		test	r10b, r10b
+		jz	.continueLoop
+		mov	rsi, r11
+		mov	r9b, byte [rsi]
+		cmp	byte [rdi], r9b
+		jne	.itReallyWasNoMatchAfterAll
+		mov	r8, rcx
+		inc	rsi
+		jmp	.continueLoop
+		.itReallyWasNoMatchAfterAll:
 		xor	r10b, r10b
 		mov	rsi, r11
 
diff --git a/src/tests.asm b/src/tests.asm
index 7414275..5a0dd4b 100644
--- a/src/tests.asm
+++ b/src/tests.asm
@@ -83,6 +83,7 @@ extern	strcpy
 extern	strcat
 extern	strclr
 extern	strcmp
+extern	strfind
 ;convert.asm
 extern	atoi
 extern	itoa
@@ -132,6 +133,7 @@ section .rodata
 	TEST_strcat		equ	1
 	TEST_strclr		equ	1
 	TEST_strcmp		equ	1
+	TEST_strfind		equ	1
 	;convert.asm
 	TEST_atoi		equ	1
 	TEST_itoa		equ	1
@@ -315,6 +317,15 @@ section .rodata
 	addTest(strcmp5, "strcmp(strBuff1, str1)") ;14
 	addTest(strcmp6_1, "strclr(strBuff1, 64)")
 	addTest(strcmp6_2, "strcmp(str1, strBuff1)") ;0
+	;strfind()
+	addTestHeader(_strfind, "strfind")
+	strfind_str	db	"I am not a gidgiddy goat or a gigiddyd goat but a giddy goat!",EOS
+	strfind_what	db	"giddy",EOS
+	strfind_strs	db	"\tstrfind_str: %s\n\tstrfind_what: %s\n",EOS
+	addTest(strfind1, "strfind(strfind_str, strfind_what, 0)") ;15
+	addTest(strfind2, "strfind(strfind_str, strfind_what, 15)") ;33
+	addTest(strfind3, "strfind(strfind_str, strfind_what, 33)") ;51
+	addTest(strfind4, "strfind(strfind_str, strfind_what, 51)") ;0
 	;atoi()
 	addTestHeader(_atoi, "atoi")
 	addTest(atoi1, "atoi(''079168045'')") ;79168045
@@ -1144,6 +1155,48 @@ _start:
 	assert_eq(0)
 %endif
 
+;--- strfind()
+%if TEST_strfind
+	printTestHeader(_strfind)
+
+	lea	rdi, [rel strfind_strs]
+	lea	rsi, [rel strfind_str]
+	lea	rdx, [rel strfind_what]
+	call	printf
+
+	; TEST 1: strfind(strfind_str, strfind_what, 0) => 15
+	printTest(strfind1)
+	lea	rdi, [rel strfind_str]
+	lea	rsi, [rel strfind_what]
+	xor	rdx, rdx
+	call	strfind
+	assert_eq(15)
+
+	; TEST 2: strfind(strfind_str, strfind_what, 15) => 33
+	printTest(strfind2)
+	lea	rdi, [rel strfind_str]
+	lea	rsi, [rel strfind_what]
+	mov	rdx, 15
+	call	strfind
+	assert_eq(33)
+
+	; TEST 3: strfind(strfind_str, strfind_what, 33) => 51
+	printTest(strfind3)
+	lea	rdi, [rel strfind_str]
+	lea	rsi, [rel strfind_what]
+	mov	rdx, 33
+	call	strfind
+	assert_eq(51)
+
+	; TEST 4: strfind(strfind_str, strfind_what, 51)
+	printTest(strfind4)
+	lea	rdi, [rel strfind_str]
+	lea	rsi, [rel strfind_what]
+	mov	rdx, 51
+	call	strfind
+	assert_eq(0)
+%endif
+
 ;--- atoi()
 %if TEST_atoi
 	printTestHeader(_atoi)