From: Nick Bowler <nbowler@draconx.ca>
Date: Mon, 8 Jun 2009 16:53:53 +0000 (-0400)
Subject: Implement file reading API on exports.
X-Git-Url: https://git.draconx.ca/gitweb/upkg.git/commitdiff_plain/fdfd7c7a49a780dedf2d8f0225d710b521ae87e3

Implement file reading API on exports.
---

diff --git a/src/libupkg.c b/src/libupkg.c
index 66546fd..e2bcf29 100644
--- a/src/libupkg.c
+++ b/src/libupkg.c
@@ -47,6 +47,8 @@ struct upkg_import {
 struct upkg_private {
 	FILE *f;
 
+	struct upkg_file *last_file;
+
 	struct upkg_name   *names;
 	struct upkg_export *exports;
 	struct upkg_import *imports;
@@ -385,3 +387,49 @@ const char *upkg_get_name(struct upkg *pkg, unsigned long idx)
 		return 0;
 	return pkg->priv->names[idx].name;
 }
+
+struct upkg_file *upkg_export_open(struct upkg *pkg, unsigned long idx)
+{
+	struct upkg_file *f;
+
+	if (idx >= pkg->export_count)
+		return NULL;
+
+	f = malloc(sizeof *f);
+	if (f == NULL)
+		return NULL;
+
+	*f = (struct upkg_file) {
+		.pkg  = pkg,
+		.base = pkg->priv->exports[idx].offset,
+		.len  = pkg->priv->exports[idx].size,
+	};
+
+	return f;
+}
+
+void upkg_export_close(struct upkg_file *f)
+{
+	if (f->pkg->priv->last_file == f)
+		f->pkg->priv->last_file = NULL;
+	free(f);
+}
+
+size_t upkg_export_read(struct upkg_file *f, void *buf, size_t n)
+{
+	size_t want = MIN(n, f->len - f->offset);
+	size_t rc;
+
+	if (want == 0) {
+		return 0;
+	}
+
+	if (f != f->pkg->priv->last_file) {
+		if (fseek(f->pkg->priv->f, f->base + f->offset, SEEK_SET))
+			return 0;
+	}
+
+	rc = fread(buf, 1, want, f->pkg->priv->f);
+	f->offset += rc;
+	return rc;
+}
diff --git a/src/upkg.h b/src/upkg.h
index 50793c5..ef6363e 100644
--- a/src/upkg.h
+++ b/src/upkg.h
@@ -20,6 +20,8 @@
 #ifndef UPKG_H_
 #define UPKG_H_
 
+#include <stddef.h>
+
 #define UPKG_FLAG_ALLOW_DOWNLOAD  0x0001
 #define UPKG_FLAG_CLIENT_OPTIONAL 0x0002
 #define UPKG_FLAG_SERVER_ONLY     0x0004
@@ -49,8 +51,18 @@ struct upkg {
 	struct upkg_private *priv;
 };
 
+struct upkg_file {
+	struct upkg *pkg;
+	unsigned long base, offset, len;
+};
+
 struct upkg *upkg_fopen(const char *path);
 int upkg_close(struct upkg *pkg);
+
 const char *upkg_get_name(struct upkg *pkg, unsigned long idx);
 
+struct upkg_file *upkg_export_open(struct upkg *pkg, unsigned long idx);
+size_t upkg_export_read(struct upkg_file *f, void *buf, size_t n);
+void upkg_export_close(struct upkg_file *f);
+
 #endif