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#include "mupdf/pdf.h"
static void
res_table_free(fz_context *ctx, pdf_res_table *table)
{
int i, n;
pdf_obj *res;
if (table == NULL)
return;
if (table->hash != NULL)
{
n = fz_hash_len(ctx, table->hash);
for (i = 0; i < n; i++)
{
res = fz_hash_get_val(ctx, table->hash, i);
if (res)
pdf_drop_obj(ctx, res);
}
fz_drop_hash(ctx, table->hash);
}
fz_free(ctx, table);
}
static void
res_image_get_md5(fz_context *ctx, fz_image *image, unsigned char *digest)
{
fz_pixmap *pixmap;
fz_md5 state;
int h;
unsigned char *d;
pixmap = fz_get_pixmap_from_image(ctx, image, NULL, NULL, 0, 0);
fz_md5_init(&state);
d = pixmap->samples;
h = pixmap->h;
while (h--)
{
fz_md5_update(&state, d, pixmap->w * pixmap->n);
d += pixmap->stride;
}
fz_md5_final(&state, digest);
fz_drop_pixmap(ctx, pixmap);
}
/* Image specific methods */
static void
res_image_init(fz_context *ctx, pdf_document *doc, pdf_res_table *table)
{
int len, k;
pdf_obj *obj;
pdf_obj *type;
pdf_obj *res = NULL;
fz_image *image = NULL;
unsigned char digest[16];
fz_var(obj);
fz_var(image);
fz_var(res);
fz_try(ctx)
{
table->hash = fz_new_hash_table(ctx, 4096, 16, -1);
len = pdf_count_objects(ctx, doc);
for (k = 1; k < len; k++)
{
obj = pdf_load_object(ctx, doc, k);
type = pdf_dict_get(ctx, obj, PDF_NAME_Subtype);
if (pdf_name_eq(ctx, type, PDF_NAME_Image))
{
image = pdf_load_image(ctx, doc, obj);
res_image_get_md5(ctx, image, digest);
fz_drop_image(ctx, image);
image = NULL;
/* Don't allow overwrites. */
if (fz_hash_find(ctx, table->hash, digest) == NULL)
fz_hash_insert(ctx, table->hash, digest, obj);
}
else
{
pdf_drop_obj(ctx, obj);
}
obj = NULL;
}
}
fz_always(ctx)
{
fz_drop_image(ctx, image);
pdf_drop_obj(ctx, obj);
}
fz_catch(ctx)
{
res_table_free(ctx, table);
fz_rethrow(ctx);
}
}
static pdf_obj *
res_image_search(fz_context *ctx, pdf_document *doc, pdf_res_table *table, void *item, unsigned char *digest)
{
fz_image *image = item;
fz_hash_table *hash = table->hash;
pdf_obj *res;
if (hash == NULL)
res_image_init(ctx, doc, doc->resources->image);
hash = doc->resources->image->hash;
/* Create md5 and see if we have the item in our table */
res_image_get_md5(ctx, image, digest);
res = fz_hash_find(ctx, hash, digest);
if (res)
pdf_keep_obj(ctx, res);
return res;
}
/* Font specific methods */
/* We do need to come up with an effective way to see what is already in the
* file to avoid adding to what is already there. This is avoided for pdfwrite
* as we check as we add each font. For adding text to an existing file though
* it may be more problematic */
static void
res_font_init(fz_context *ctx, pdf_document *doc, pdf_res_table *table)
{
table->hash = fz_new_hash_table(ctx, 4096, 16, -1);
}
static void
res_font_get_md5(fz_context *ctx, fz_buffer *buffer, unsigned char *digest)
{
fz_md5 state;
fz_md5_init(&state);
fz_md5_update(&state, buffer->data, buffer->len);
fz_md5_final(&state, digest);
}
static pdf_obj *
res_font_search(fz_context *ctx, pdf_document *doc, pdf_res_table *table, void *item, unsigned char digest[16])
{
fz_buffer *buffer = item;
fz_hash_table *hash = table->hash;
pdf_obj *res;
if (hash == NULL)
res_font_init(ctx, doc, doc->resources->font);
hash = doc->resources->font->hash;
/* Create md5 and see if we have the item in our table */
res_font_get_md5(ctx, buffer, digest);
res = fz_hash_find(ctx, hash, digest);
if (res)
pdf_keep_obj(ctx, res);
return res;
}
/* Accessible methods */
pdf_obj *
pdf_find_resource(fz_context *ctx, pdf_document *doc, pdf_res_table *table, void *item, unsigned char md5[16])
{
return table->search(ctx, doc, table, item, md5);
}
pdf_obj *
pdf_insert_resource(fz_context *ctx, pdf_res_table *table, void *key, pdf_obj *obj)
{
pdf_obj *res;
fz_try(ctx)
{
res = fz_hash_insert(ctx, table->hash, key, obj);
if (res != NULL)
fz_warn(ctx, "warning: resource already present");
else
res = pdf_keep_obj(ctx, obj);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
return res;
}
void
pdf_drop_resource_tables(fz_context *ctx, pdf_document *doc)
{
if (doc->resources == NULL)
return;
res_table_free(ctx, doc->resources->color);
res_table_free(ctx, doc->resources->font);
res_table_free(ctx, doc->resources->image);
res_table_free(ctx, doc->resources->pattern);
res_table_free(ctx, doc->resources->shading);
fz_free(ctx, doc->resources);
doc->resources = NULL;
}
void
pdf_init_resource_tables(fz_context *ctx, pdf_document *doc)
{
fz_try(ctx)
{
doc->resources = fz_calloc(ctx, 1, sizeof(pdf_resource_tables));
doc->resources->image = fz_calloc(ctx, 1, sizeof(pdf_res_table));
doc->resources->image->search = res_image_search;
doc->resources->font = fz_calloc(ctx, 1, sizeof(pdf_res_table));
doc->resources->font->search = res_font_search;
}
fz_catch(ctx)
{
pdf_drop_resource_tables(ctx, doc);
fz_rethrow(ctx);
}
}
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