X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Finternal%2Fshgetc.c;h=7455d2f00a04e477db9f4129fb4d5ba0809af1cb;hb=95a540e176b3ebd57d6033fd23cf9fec8a5ddbe8;hp=e878b00ad50ac709b33366f11619817c1e535636;hpb=c20804500deebaabc56f383d48dd1ac77dce8349;p=musl

diff --git a/src/internal/shgetc.c b/src/internal/shgetc.c
index e878b00a..7455d2f0 100644
--- a/src/internal/shgetc.c
+++ b/src/internal/shgetc.c
@@ -1,10 +1,16 @@
 #include "shgetc.h"
 
+/* The shcnt field stores the number of bytes read so far, offset by
+ * the value of buf-rpos at the last function call (__shlim or __shgetc),
+ * so that between calls the inline shcnt macro can add rpos-buf to get
+ * the actual count. */
+
 void __shlim(FILE *f, off_t lim)
 {
 	f->shlim = lim;
-	f->shcnt = f->rend - f->rpos;
-	if (lim && f->shcnt > lim)
+	f->shcnt = f->buf - f->rpos;
+	/* If lim is nonzero, rend must be a valid pointer. */
+	if (lim && f->rend - f->rpos > lim)
 		f->shend = f->rpos + lim;
 	else
 		f->shend = f->rend;
@@ -13,15 +19,19 @@ void __shlim(FILE *f, off_t lim)
 int __shgetc(FILE *f)
 {
 	int c;
-	if (f->shlim && f->shcnt >= f->shlim || (c=__uflow(f)) < 0) {
-		f->shend = 0;
+	off_t cnt = shcnt(f);
+	if (f->shlim && cnt >= f->shlim || (c=__uflow(f)) < 0) {
+		f->shcnt = f->buf - f->rpos + cnt;
+		f->shend = f->rpos;
+		f->shlim = -1;
 		return EOF;
 	}
-	if (f->shlim && f->rend - f->rpos > f->shlim - f->shcnt - 1)
-		f->shend = f->rpos + (f->shlim - f->shcnt - 1);
+	cnt++;
+	if (f->shlim && f->rend - f->rpos > f->shlim - cnt)
+		f->shend = f->rpos + (f->shlim - cnt);
 	else
 		f->shend = f->rend;
-	if (f->rend) f->shcnt += f->rend - f->rpos + 1;
-	if (f->rpos[-1] != c) f->rpos[-1] = c;
+	f->shcnt = f->buf - f->rpos + cnt;
+	if (f->rpos <= f->buf) f->rpos[-1] = c;
 	return c;
 }