101 lines
2.3 KiB
C
101 lines
2.3 KiB
C
#include <r_util.h>
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struct buf_ref_user {
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RBuffer *parent;
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ut64 offset;
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ut64 size;
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};
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struct buf_ref_priv {
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RBuffer *parent;
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ut64 cur;
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ut64 base;
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ut64 size;
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};
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static inline struct buf_ref_priv *get_priv_ref(RBuffer *b) {
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struct buf_ref_priv *priv = (struct buf_ref_priv *)b->priv;
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r_warn_if_fail (priv);
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return priv;
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}
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static bool buf_ref_init(RBuffer *b, const void *user) {
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const struct buf_ref_user *u = (const struct buf_ref_user *)user;
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struct buf_ref_priv *priv = R_NEW0 (struct buf_ref_priv);
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if (!priv) {
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return false;
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}
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// NOTE: we only support readonly ref-buffers for now. Supporting
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// read-write would mean to choose how we want to handle writing to the
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// referencer. Copy-on-write? Write to the buffer underneath?
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ut64 parent_sz = r_buf_size (u->parent);
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b->readonly = true;
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priv->parent = r_buf_ref (u->parent);
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priv->base = R_MIN (u->offset, parent_sz);
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priv->size = R_MIN (parent_sz - priv->base, u->size);
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b->priv = priv;
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return true;
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}
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static bool buf_ref_fini(RBuffer *b) {
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struct buf_ref_priv *priv = get_priv_ref (b);
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r_buf_free (priv->parent);
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R_FREE (b->priv);
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return true;
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}
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static bool buf_ref_resize(RBuffer *b, ut64 newsize) {
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struct buf_ref_priv *priv = get_priv_ref (b);
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ut64 parent_sz = r_buf_size (priv->parent);
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priv->size = R_MIN (parent_sz - priv->base, newsize);
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return true;
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}
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static st64 buf_ref_read(RBuffer *b, ut8 *buf, ut64 len) {
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struct buf_ref_priv *priv = get_priv_ref (b);
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if (priv->size < priv->cur) {
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return -1;
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}
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len = R_MIN (len, priv->size - priv->cur);
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st64 r = r_buf_read_at (priv->parent, priv->base + priv->cur, buf, len);
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if (r < 0) {
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return r;
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}
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priv->cur += r;
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return r;
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}
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static ut64 buf_ref_get_size(RBuffer *b) {
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struct buf_ref_priv *priv = get_priv_ref (b);
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return priv->size;
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}
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static st64 buf_ref_seek(RBuffer *b, st64 addr, int whence) {
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struct buf_ref_priv *priv = get_priv_ref (b);
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switch (whence) {
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case R_BUF_CUR:
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priv->cur += addr;
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break;
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case R_BUF_SET:
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priv->cur = addr;
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break;
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case R_BUF_END:
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priv->cur = priv->size + addr;
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break;
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default:
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r_warn_if_reached ();
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return -1;
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}
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return priv->cur;
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}
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static const RBufferMethods buffer_ref_methods = {
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.init = buf_ref_init,
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.fini = buf_ref_fini,
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.read = buf_ref_read,
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.get_size = buf_ref_get_size,
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.resize = buf_ref_resize,
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.seek = buf_ref_seek,
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};
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