- sync to 1.6.0GD_1_6_0

1 files changed, 147 insertions, 0 deletions

diff --git a/src/gd_io_ss.c b/src/gd_io_ss.c
new file mode 100644
index 0000000..7392a87
--- /dev/null
+++ b/src/gd_io_ss.c
@@ -0,0 +1,147 @@
+/*
+* io_ss.c
+*
+* Implements the Source/Sink interface.
+*
+* As will all I/O modules, most functions are for local use only (called
+* via function pointers in the I/O context).
+*
+* The Source/Sink model is the primary 'user' interface for alternate data
+* sources; the IOCtx interface is intended (at least in version 1.5) to be
+* used internally until it settles down a bit.
+*
+* This module just layers the Source/Sink interface on top of the IOCtx; no
+* support is provided for tell/seek, so GD2 writing is not possible, and 
+* retrieving parts of GD2 files is also not possible.
+*
+* A new SS context does not need to be created with both a Source and a Sink.
+*
+* Written/Modified 1999, Philip Warner.
+*
+*/
+
+#include <math.h>
+#include <string.h>
+#include <stdlib.h>
+#include "gd.h"
+
+/* this is used for creating images in main memory*/
+
+typedef struct ssIOCtx {
+  gdIOCtx		ctx;
+  gdSourcePtr	src;
+  gdSinkPtr	snk;
+} ssIOCtx;
+
+typedef struct ssIOCtx 	*ssIOCtxPtr;
+
+gdIOCtx* gdNewSSCtx(gdSourcePtr src, gdSinkPtr snk);
+
+static int sourceGetbuf( gdIOCtx*, void *, int );
+static int sourceGetchar( gdIOCtx* ctx);
+static int sinkPutbuf( gdIOCtx* ctx, const void *buf, int size );
+static void sinkPutchar( gdIOCtx* ctx, int a );
+static void freeSsCtx(gdIOCtx *ctx);
+
+/* return data as a dynamic pointer */
+gdIOCtx* gdNewSSCtx (gdSourcePtr src, gdSinkPtr snk) {
+  ssIOCtxPtr 	ctx;
+
+  ctx = (ssIOCtxPtr) malloc(sizeof(ssIOCtx));
+  if (ctx == NULL) {
+    return NULL;
+  }
+
+  ctx->src = src;
+  ctx->snk = snk;
+
+  ctx->ctx.getC = sourceGetchar;
+  ctx->ctx.getBuf = sourceGetbuf;
+
+  ctx->ctx.putC = sinkPutchar;
+  ctx->ctx.putBuf = sinkPutbuf;
+
+  ctx->ctx.tell = NULL;
+  ctx->ctx.seek = NULL;
+
+  ctx->ctx.free = freeSsCtx;
+
+  return (gdIOCtx*)ctx;
+};
+
+static
+void freeSsCtx(gdIOCtx *ctx)
+{
+  free(ctx);
+}
+
+
+static int
+sourceGetbuf( gdIOCtx* ctx, void *buf, int size )
+{
+  ssIOCtx  *lctx;
+  int  res;
+
+  lctx = (ssIOCtx*) ctx;
+
+  res = ((lctx->src->source)(lctx->src->context, buf, size));
+
+/*
+** Translate the return values from the Source object: 
+** 0 is EOF, -1 is error
+*/
+
+  if (res == 0) {
+    return EOF;
+  } else if (res < 0) {
+    return 0;
+  } else {
+    return res;
+  };
+
+}
+
+static int sourceGetchar( gdIOCtx* ctx)
+{
+  int res;
+  unsigned char buf;
+
+  res = sourceGetbuf(ctx, &buf, 1);
+
+  if (res == 1) {
+    return buf;
+  } else {
+    return EOF;
+  };
+
+}
+
+static int
+sinkPutbuf( gdIOCtx* ctx, const void *buf, int size )
+{
+  ssIOCtxPtr	lctx;
+  int		res;
+
+  lctx = (ssIOCtx*) ctx;
+
+  res = (lctx->snk->sink)(lctx->snk->context, buf, size);
+
+  if (res <= 0) {
+    return 0;
+  } else {
+    return res;
+  };
+
+}
+
+static void
+sinkPutchar( gdIOCtx* ctx, int a )
+{
+  unsigned 	char b;
+
+  b = a;
+  sinkPutbuf(ctx, &b, 1);
+
+}
+
+