Revamp pdf lexing code

A huge amount (20%+ on some files) of our runtime is spent in
fz_atof. A survey of results on the net suggests we will get
much better speed by writing our own atof.

Part of the job of doing this involves parsing the string to
identify the component parts of the number - ludicrously, we
are already doing this as part of the lexing process, so it
would make sense to do the atoi/atof as part of this process.

In order to do this, we need somewhere to store the lexed
results; rather than add a float * and an int * to every single
pdf_lex call, we generalise the calls to pass a pdf_lexbuf *
pointer instead of separate buffer/max/string length pointers.
This should help us overall.

1 files changed, 17 insertions, 16 deletions

diff --git a/pdf/pdf_function.c b/pdf/pdf_function.c
index 4478827c..17373f42 100644
--- a/pdf/pdf_function.c
+++ b/pdf/pdf_function.c
@@ -683,18 +683,18 @@ resize_code(fz_context *ctx, pdf_function *func, int newsize)
 static void
 parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 {
-	char buf[64];
-	int len;
+	pdf_lexbuf buf;
 	int tok;
 	int opptr, elseptr, ifptr;
 	int a, b, mid, cmp;
 	fz_context *ctx = stream->ctx;
 
-	memset(buf, 0, sizeof(buf));
+        buf.size = PDF_LEXBUF_SMALL;
+	memset(buf.scratch, 0, sizeof(buf.scratch));
 
 	while (1)
 	{
-		tok = pdf_lex(stream, buf, sizeof buf, &len);
+		tok = pdf_lex(stream, &buf);
 		/* RJW: "calculator function lexical error" */
 
 		switch(tok)
@@ -705,7 +705,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 		case PDF_TOK_INT:
 			resize_code(ctx, func, *codeptr);
 			func->u.p.code[*codeptr].type = PS_INT;
-			func->u.p.code[*codeptr].u.i = atoi(buf);
+			func->u.p.code[*codeptr].u.i = buf.i;
 			++*codeptr;
 			break;
 
@@ -726,7 +726,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 		case PDF_TOK_REAL:
 			resize_code(ctx, func, *codeptr);
 			func->u.p.code[*codeptr].type = PS_REAL;
-			func->u.p.code[*codeptr].u.f = fz_atof(buf);
+			func->u.p.code[*codeptr].u.f = buf.f;
 			++*codeptr;
 			break;
 
@@ -740,7 +740,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 			parse_code(func, stream, codeptr);
 			/* RJW: "error in 'if' branch" */
 
-			tok = pdf_lex(stream, buf, sizeof buf, &len);
+			tok = pdf_lex(stream, &buf);
 			/* RJW: "calculator function syntax error" */
 
 			if (tok == PDF_TOK_OPEN_BRACE)
@@ -749,7 +749,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 				parse_code(func, stream, codeptr);
 				/* RJW: "error in 'else' branch" */
 
-				tok = pdf_lex(stream, buf, sizeof buf, &len);
+				tok = pdf_lex(stream, &buf);
 				/* RJW: "calculator function syntax error" */
 			}
 			else
@@ -760,7 +760,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 			if (tok != PDF_TOK_KEYWORD)
 				fz_throw(ctx, "missing keyword in 'if-else' context");
 
-			if (!strcmp(buf, "if"))
+			if (!strcmp(buf.scratch, "if"))
 			{
 				if (elseptr >= 0)
 					fz_throw(ctx, "too many branches for 'if'");
@@ -771,7 +771,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 				func->u.p.code[opptr+3].type = PS_BLOCK;
 				func->u.p.code[opptr+3].u.block = *codeptr;
 			}
-			else if (!strcmp(buf, "ifelse"))
+			else if (!strcmp(buf.scratch, "ifelse"))
 			{
 				if (elseptr < 0)
 					fz_throw(ctx, "not enough branches for 'ifelse'");
@@ -786,7 +786,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 			}
 			else
 			{
-				fz_throw(ctx, "unknown keyword in 'if-else' context: '%s'", buf);
+				fz_throw(ctx, "unknown keyword in 'if-else' context: '%s'", buf.scratch);
 			}
 			break;
 
@@ -804,7 +804,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 			while (b - a > 1)
 			{
 				mid = (a + b) / 2;
-				cmp = strcmp(buf, ps_op_names[mid]);
+				cmp = strcmp(buf.scratch, ps_op_names[mid]);
 				if (cmp > 0)
 					a = mid;
 				else if (cmp < 0)
@@ -813,7 +813,7 @@ parse_code(pdf_function *func, fz_stream *stream, int *codeptr)
 					a = b = mid;
 			}
 			if (cmp != 0)
-				fz_throw(ctx, "unknown operator: '%s'", buf);
+				fz_throw(ctx, "unknown operator: '%s'", buf.scratch);
 
 			resize_code(ctx, func, *codeptr);
 			func->u.p.code[*codeptr].type = PS_OPERATOR;
@@ -832,12 +832,13 @@ load_postscript_func(pdf_function *func, pdf_document *xref, fz_obj *dict, int n
 {
 	fz_stream *stream = NULL;
 	int codeptr;
-	char buf[64];
+	pdf_lexbuf buf;
 	int tok;
-	int len;
 	fz_context *ctx = xref->ctx;
 	int locked = 0;
 
+	buf.size = PDF_LEXBUF_SMALL;
+
 	fz_var(stream);
 	fz_var(locked);
 
@@ -846,7 +847,7 @@ load_postscript_func(pdf_function *func, pdf_document *xref, fz_obj *dict, int n
 		stream = pdf_open_stream(xref, num, gen);
 		/* RJW: "cannot open calculator function stream" */
 
-		tok = pdf_lex(stream, buf, sizeof buf, &len);
+		tok = pdf_lex(stream, &buf);
 		if (tok != PDF_TOK_OPEN_BRACE)
 		{
 			fz_throw(ctx, "stream is not a calculator function");