Clarify snprintf length when printing to fz_buffer and fz_output.

The +1's for zero terminating bytes are not needed: printf to a fz_buffer
or fz_output does not write a zero terminator. The extra code to add
space for a zero terminator when calling snprintf internally are
merely confusing.

2 files changed, 6 insertions, 6 deletions

diff --git a/source/fitz/buffer.c b/source/fitz/buffer.c
index 26d0afea..86947df0 100644
--- a/source/fitz/buffer.c
+++ b/source/fitz/buffer.c
@@ -236,9 +236,9 @@ fz_buffer_vprintf(fz_context *ctx, fz_buffer *buffer, const char *fmt, va_list o
 	len = fz_vsnprintf((char *)buffer->data + buffer->len, slack, fmt, args);
 	va_copy_end(args);
 
-	/* len = number of chars written, not including the terminating
-	 * NULL, so len+1 > slack means "truncated". */
-	if (len+1 > slack)
+	/* len is the number of characters in the formatted string (not including
+	 * the terminating zero), so if (len > slack) the string was truncated. */
+	if (len > slack)
 	{
 		/* Grow the buffer and retry */
 		fz_ensure_buffer(ctx, buffer, buffer->len + len);
diff --git a/source/fitz/output.c b/source/fitz/output.c
index 1f713709..b3efb121 100644
--- a/source/fitz/output.c
+++ b/source/fitz/output.c
@@ -162,11 +162,11 @@ fz_vprintf(fz_context *ctx, fz_output *out, const char *fmt, va_list old_args)
 	va_copy_end(args);
 
 	/* If that failed, allocate a big enough buffer */
-	if (len >= sizeof buffer)
+	if (len > sizeof buffer)
 	{
-		p = fz_malloc(ctx, len + 1);
+		p = fz_malloc(ctx, len);
 		va_copy(args, old_args);
-		fz_vsnprintf(p, len + 1, fmt, args);
+		fz_vsnprintf(p, len, fmt, args);
 		va_copy_end(args);
 	}