GhostPDF - revamp PDF information extraction

A customer requested that we make pdf_info.ps work with the new
PDF interpreter, and generate the same information.

This commit modifies the way we extract information on a
page-by-page basis to potentially include the names of spot inks
and information about fonts used on the page.

This is now returned to the PostScript environment using a PDF
dictionary instead of a C structure. The pdf_info.ps program has
been updated so that it use the new information in broadly the
same way as the information from the old PDF interpreter.

There are differences; pdf_info.ps extracts font information
itself, rather than having the interpreter do it. This is not
possible with the new interpreter which is why we have the
PDF interpreter do it for us. In addition the pdf_info.ps
program only descended to the page level whereas the new PDF
interpreter evaluates all objects on the page, potentially
meaning that more fonts (and technically spot inks) might be
detected.

We now have an additional PostScript operator '.PDFPageInfoExt'
which returns 'extended' information about a page. This is the
same as .PDFPageInfo but includes the font and spot ink
information.

Running with -dPDFINFO using either Ghostscript or GhostPDF will
print more information than before, including the spot inks and
considerably more information about fonts than the pdf_info.ps
program emits, including embedding status, descendant fonts
(and their membedding status) and the presence of ToUnicode
CMaps.

Updated documentation for all of the above.

1 files changed, 230 insertions, 125 deletions

diff --git a/psi/zpdfops.c b/psi/zpdfops.c
index 1b0e07140..c76ca556d 100644
--- a/psi/zpdfops.c
+++ b/psi/zpdfops.c
@@ -22,6 +22,9 @@
 #include "gzht.h"
 #include "gsrefct.h"
 #include "pdf_misc.h"
+#include "pdf_stack.h"
+#include "pdf_dict.h"
+#include "pdf_array.h"
 
 #include "iminst.h"
 #include "dstack.h"
@@ -624,6 +627,164 @@ static int zPDFclose(i_ctx_t *i_ctx_p)
     return code;
 }
 
+static int PDFobj_to_PSobj(i_ctx_t *i_ctx_p, pdfctx_t *pdfctx, pdf_obj *PDFobj, ref *PSobj);
+
+static int PDFdict_to_PSdict(i_ctx_t *i_ctx_p, pdfctx_t *pdfctx, pdf_dict *PDFdict, ref *PSdict)
+{
+    int code = 0;
+    uint64_t index = 0;
+    pdf_name *Key = NULL;
+    pdf_obj *Value = NULL;
+    ref nameref, valueref;
+    char *str = NULL;
+    int len = 0;
+
+    code = dict_create(pdfi_dict_entries(PDFdict), PSdict);
+    if (code < 0)
+        return code;
+
+    code = pdfi_dict_first(pdfctx->ctx, PDFdict, (pdf_obj **)&Key, &Value, &index);
+    if (code == gs_error_undefined)
+        return 0;
+
+    while (code >= 0) {
+        code = pdfi_string_from_name(pdfctx->ctx, Key, &str, &len);
+        if (code < 0)
+            goto exit;
+
+        code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)str, len, &nameref, 1);
+        if (code < 0)
+            goto exit;
+
+        code = PDFobj_to_PSobj(i_ctx_p, pdfctx, Value, &valueref);
+        if (code < 0)
+            goto exit;
+
+        code = dict_put(PSdict, &nameref, &valueref, &i_ctx_p->dict_stack);
+        if (code < 0)
+            goto exit;
+
+        pdfi_countdown(Key);
+        pdfi_countdown(Value);
+        Key = NULL;
+        Value = NULL;
+        (void)pdfi_free_string_from_name(pdfctx->ctx, str);
+        str = NULL;
+        code = pdfi_dict_next(pdfctx->ctx, PDFdict, (pdf_obj **)&Key, &Value, &index);
+        if (code == gs_error_undefined) {
+            code = 0;
+            break;
+        }
+    }
+exit:
+    (void)pdfi_free_string_from_name(pdfctx->ctx, str);
+    pdfi_countdown(Key);
+    pdfi_countdown(Value);
+    return code;
+}
+
+static int PDFarray_to_PSarray(i_ctx_t *i_ctx_p, pdfctx_t *pdfctx, pdf_array *PDFarray, ref *PSarray)
+{
+    int code = 0, i = 0;
+    ref PS_ref;
+    pdf_obj *array_obj = NULL;
+    ref *eltp = NULL;
+
+    code = ialloc_ref_array(PSarray, a_all, pdfi_array_size(PDFarray), "zPDFInfo");
+    if (code < 0)
+        return code;
+
+    for (i = 0;i < pdfi_array_size(PDFarray); i++) {
+        code = pdfi_array_get(pdfctx->ctx, PDFarray, i, &array_obj);
+        if (code < 0)
+            goto exit;
+        code = PDFobj_to_PSobj(i_ctx_p, pdfctx, array_obj, &PS_ref);
+        if (code < 0) {
+            pdfi_countdown(array_obj);
+            goto exit;
+        }
+
+        eltp = PSarray->value.refs + i;
+        ref_assign_old((const ref *)PSarray, eltp, &PS_ref, "zPDFInfo");
+
+        pdfi_countdown(array_obj);
+        array_obj = NULL;
+    }
+exit:
+    return code;
+}
+
+static int PDFobj_to_PSobj(i_ctx_t *i_ctx_p, pdfctx_t *pdfctx, pdf_obj *PDFobj, ref *PSobj)
+{
+    int code = 0;
+
+    switch(pdfi_type_of(PDFobj)) {
+        case PDF_NAME:
+            {
+                char *str = NULL;
+                int len;
+
+                code = pdfi_string_from_name(pdfctx->ctx, (pdf_name *)PDFobj, &str, &len);
+                if (code < 0)
+                    return code;
+                code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)str, len, PSobj, 1);
+                (void)pdfi_free_string_from_name(pdfctx->ctx, str);
+            }
+            break;
+        case PDF_STRING:
+            {
+                byte *sbody;
+                uint size = ((pdf_name *)PDFobj)->length;
+
+                sbody = ialloc_string(size, "string");
+                if (sbody == 0) {
+                    code = gs_note_error(gs_error_VMerror);
+                } else {
+                    make_string(PSobj, a_all | icurrent_space, size, sbody);
+                    memcpy(sbody, ((pdf_name *)PDFobj)->data, size);
+                }
+            }
+            break;
+        case PDF_INT:
+            {
+                int64_t i;
+
+                code = pdfi_obj_to_int(pdfctx->ctx, PDFobj, &i);
+                if (code < 0)
+                    return code;
+                make_int(PSobj, i);
+            }
+            break;
+        case PDF_BOOL:
+            if (PDFobj == PDF_TRUE_OBJ)
+                make_bool(PSobj, 1);
+            else
+                make_bool(PSobj, 0);
+            break;
+        case PDF_REAL:
+            {
+                double d;
+
+                code = pdfi_obj_to_real(pdfctx->ctx, PDFobj, &d);
+                if (code < 0)
+                    return code;
+                make_real(PSobj, d);
+            }
+            break;
+        case PDF_DICT:
+            code = PDFdict_to_PSdict(i_ctx_p, pdfctx, (pdf_dict *)PDFobj, PSobj);
+            break;
+        case PDF_ARRAY:
+            code = PDFarray_to_PSarray(i_ctx_p, pdfctx, (pdf_array *)PDFobj, PSobj);
+            break;
+        default:
+            gs_note_error(gs_error_typecheck);
+            break;
+    }
+
+    return code;
+}
+
 static int zPDFinfo(i_ctx_t *i_ctx_p)
 {
     os_ptr op = osp;
@@ -704,6 +865,36 @@ static int zPDFinfo(i_ctx_t *i_ctx_p)
             }
             gs_free_object(pdfctx->ctx->memory, names_array, "free collection temporary filenames");
             code = 0;
+        } else {
+            if (pdfctx->ctx->Info != NULL) {
+                code = PDFobj_to_PSobj(i_ctx_p, pdfctx, (pdf_obj *)pdfctx->ctx->Info, (ref *)op);
+                if (code < 0)
+                    return code;
+
+                code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"NumPages", 8, &nameref, 1);
+                if (code < 0)
+                    return code;
+
+                make_int(&intref, pdfctx->ctx->num_pages);
+
+                code = dict_put(op, &nameref, &intref, &i_ctx_p->dict_stack);
+                if (code < 0)
+                    return code;
+            } else {
+                code = dict_create(1, op);
+                if (code < 0)
+                    return code;
+
+                code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"NumPages", 8, &nameref, 1);
+                if (code < 0)
+                    return code;
+
+                make_int(&intref, pdfctx->ctx->num_pages);
+
+                code = dict_put(op, &nameref, &intref, &i_ctx_p->dict_stack);
+                if (code < 0)
+                    return code;
+            }
         }
     }
     else {
@@ -721,10 +912,9 @@ error:
 static int zPDFpageinfo(i_ctx_t *i_ctx_p)
 {
     os_ptr op = osp;
-    ref aref, boolref, nameref, numref, *eltp;
-    int page = 0, code = 0, i;
+    int page = 0, code = 0;
     pdfctx_t *pdfctx;
-    pdf_info_t info;
+    pdf_dict *InfoDict = NULL;
     pdfi_switch_t i_switch;
 
     check_op(2);
@@ -739,7 +929,7 @@ static int zPDFpageinfo(i_ctx_t *i_ctx_p)
         code = pdfi_gstate_from_PS(pdfctx->ctx, igs, &i_switch, pdfctx->profile_cache);
 
         if (code >= 0) {
-            code = pdfi_page_info(pdfctx->ctx, (uint64_t)page, &info);
+            code = pdfi_page_info(pdfctx->ctx, (uint64_t)page, &InfoDict, false);
 
             pdfi_gstate_to_PS(pdfctx->ctx, igs, &i_switch);
         }
@@ -750,141 +940,52 @@ static int zPDFpageinfo(i_ctx_t *i_ctx_p)
         pop(1);
         op = osp;
 
-        code = dict_create(4, op);
-        if (code < 0)
-            return code;
-
-        code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"HasAnnots", 9, &nameref, 1);
-        if (code < 0)
-            return code;
-        make_bool(&boolref, false);
-        code = dict_put(op, &nameref, &boolref, &i_ctx_p->dict_stack);
+        code = PDFobj_to_PSobj(i_ctx_p, pdfctx, (pdf_obj *)InfoDict, op);
+        pdfi_countdown(InfoDict);
         if (code < 0)
             return code;
+    }
+    else {
+        return_error(gs_error_ioerror);
+    }
+    return 0;
+}
 
-        code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"UsesTransparency", 16, &nameref, 1);
-        if (code < 0)
-            return code;
-        make_bool(&boolref, info.HasTransparency);
-        code = dict_put(op, &nameref, &boolref, &i_ctx_p->dict_stack);
-        if (code < 0)
-            return code;
+static int zPDFpageinfoExt(i_ctx_t *i_ctx_p)
+{
+    os_ptr op = osp;
+    int page = 0, code = 0;
+    pdfctx_t *pdfctx;
+    pdf_dict *InfoDict = NULL;
+    pdfi_switch_t i_switch;
 
-        code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"NumSpots", 8, &nameref, 1);
-        if (code < 0)
-            return code;
-        make_int(&numref, info.NumSpots);
-        code = dict_put(op, &nameref, &numref, &i_ctx_p->dict_stack);
-        if (code < 0)
-            return code;
+    check_op(2);
 
-        if (info.boxes & MEDIA_BOX) {
-            code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"MediaBox", 8, &nameref, 1);
-            if (code < 0)
-                return code;
-            code = ialloc_ref_array(&aref, a_all, 4, "array");
-            if (code < 0)
-                return code;
-            refset_null(aref.value.refs, 4);
-            for (i=0;i < 4;i++) {
-                make_real(&numref, info.MediaBox[i]);
-                eltp = aref.value.refs + i;
-                ref_assign_old(&aref, eltp, &numref, "put");
-            }
-            code = dict_put(op, &nameref, &aref, &i_ctx_p->dict_stack);
-            if (code < 0)
-                return code;
-        }
+    check_type(*op, t_integer);
+    page = op->value.intval;
 
-        if (info.boxes & CROP_BOX) {
-            code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"CropBox", 7, &nameref, 1);
-            if (code < 0)
-                return code;
-            code = ialloc_ref_array(&aref, a_all, 4, "array");
-            if (code < 0)
-                return code;
-            refset_null(aref.value.refs, 4);
-            for (i=0;i < 4;i++) {
-                make_real(&numref, info.CropBox[i]);
-                eltp = aref.value.refs + i;
-                ref_assign_old(&aref, eltp, &numref, "put");
-            }
-            code = dict_put(op, &nameref, &aref, &i_ctx_p->dict_stack);
-            if (code < 0)
-                return code;
-        }
+    check_type(*(op - 1), t_pdfctx);
+    pdfctx = r_ptr(op - 1, pdfctx_t);
 
-        if (info.boxes & TRIM_BOX) {
-            code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"TrimBox", 7, &nameref, 1);
-            if (code < 0)
-                return code;
-            code = ialloc_ref_array(&aref, a_all, 4, "array");
-            if (code < 0)
-                return code;
-            refset_null(aref.value.refs, 4);
-            for (i=0;i < 4;i++) {
-                make_real(&numref, info.TrimBox[i]);
-                eltp = aref.value.refs + i;
-                ref_assign_old(&aref, eltp, &numref, "put");
-            }
-            code = dict_put(op, &nameref, &aref, &i_ctx_p->dict_stack);
-            if (code < 0)
-                return code;
-        }
+    if (pdfctx->pdf_stream != NULL || pdfctx->UsingPDFFile) {
+        code = pdfi_gstate_from_PS(pdfctx->ctx, igs, &i_switch, pdfctx->profile_cache);
 
-        if (info.boxes & ART_BOX) {
-            code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"ArtBox", 6, &nameref, 1);
-            if (code < 0)
-                return code;
-            code = ialloc_ref_array(&aref, a_all, 4, "array");
-            if (code < 0)
-                return code;
-            refset_null(aref.value.refs, 4);
-            for (i=0;i < 4;i++) {
-                make_real(&numref, info.ArtBox[i]);
-                eltp = aref.value.refs + i;
-                ref_assign_old(&aref, eltp, &numref, "put");
-            }
-            code = dict_put(op, &nameref, &aref, &i_ctx_p->dict_stack);
-            if (code < 0)
-                return code;
-        }
+        if (code >= 0) {
+            code = pdfi_page_info(pdfctx->ctx, (uint64_t)page, &InfoDict, true);
 
-        if (info.boxes & BLEED_BOX) {
-            code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"BleedBox", 8, &nameref, 1);
-            if (code < 0)
-                return code;
-            code = ialloc_ref_array(&aref, a_all, 4, "array");
-            if (code < 0)
-                return code;
-            refset_null(aref.value.refs, 4);
-            for (i=0;i < 4;i++) {
-                make_real(&numref, info.BleedBox[i]);
-                eltp = aref.value.refs + i;
-                ref_assign_old(&aref, eltp, &numref, "put");
-            }
-            code = dict_put(op, &nameref, &aref, &i_ctx_p->dict_stack);
-            if (code < 0)
-                return code;
+            pdfi_gstate_to_PS(pdfctx->ctx, igs, &i_switch);
         }
 
-        code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"Rotate", 6, &nameref, 1);
         if (code < 0)
             return code;
-        make_real(&numref, info.Rotate);
-        code = dict_put(op, &nameref, &numref, &i_ctx_p->dict_stack);
+
+        pop(1);
+        op = osp;
+
+        code = PDFobj_to_PSobj(i_ctx_p, pdfctx, (pdf_obj *)InfoDict, op);
+        pdfi_countdown(InfoDict);
         if (code < 0)
             return code;
-
-        if (info.UserUnit != 1) {
-            code = names_ref(imemory->gs_lib_ctx->gs_name_table, (const byte *)"UserUnit", 8, &nameref, 1);
-            if (code < 0)
-                return code;
-            make_real(&numref, info.UserUnit);
-            code = dict_put(op, &nameref, &numref, &i_ctx_p->dict_stack);
-            if (code < 0)
-                return code;
-        }
     }
     else {
         return_error(gs_error_ioerror);
@@ -929,7 +1030,10 @@ static int zPDFdrawpage(i_ctx_t *i_ctx_p)
         code = pdfi_gstate_from_PS(pdfctx->ctx, igs, &i_switch, pdfctx->profile_cache);
 
         if (code >= 0) {
-            code = pdfi_page_render(pdfctx->ctx, page, false);
+            if (pdfctx->ctx->args.pdfinfo)
+                code = pdfi_output_page_info(pdfctx->ctx, page);
+            else
+                code = pdfi_page_render(pdfctx->ctx, page, false);
             if (code >= 0)
                 pop(2);
 
@@ -1336,6 +1440,7 @@ const op_def zpdfops_op_defs[] =
     {"1.PDFClose", zPDFclose},
     {"1.PDFInfo", zPDFinfo},
     {"1.PDFPageInfo", zPDFpageinfo},
+    {"1.PDFPageInfoExt", zPDFpageinfoExt},
     {"1.PDFMetadata", zPDFmetadata},
     {"1.PDFDrawPage", zPDFdrawpage},
     {"1.PDFDrawAnnots", zPDFdrawannots},